MAX17019 High-Input-Voltage Quad
EVALUATION KIT AVAILABLE
High-Input-Voltage Quad-Output Controller
●● Embedded Control Systems
●● Set-Top Boxes
●● 1x Internal 3AP-P Step-Down Regulator
●● 1x 2A Source/Sink Linear Regulator with Dynamic
REFIN
●● Internal BST Diodes
●● Internal 5V 50mA Linear Regulator
●● Fault Protection—Undervoltage, Overvoltage,
Thermal, Peak Current Limit
●● Independent Enable Inputs and Power-Good Outputs
●● Voltage-Controlled Soft-Start
●● High-Impedance Shutdown
●● 10μA (typ) Shutdown Current
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX17019ATM+
-40°C to +125°C
48 TQFN-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Pin Configuration
LXA
DHA
POKA
FBA
TOP VIEW
BSTA
Applications
●● 1x Internal 5AP-P Step-Down Regulator
DLA
The MAX17019 is available in a 48-pin, 6mm x 6mm thin
QFN package.
●● 1x Step-Down Controller
LXB
Separate enable inputs and independent open-drain
power-good outputs allow flexible power sequencing. A
soft-start function gradually ramps up the output voltage to
reduce the inrush current. Disabled regulators enter highimpedance states to avoid negative output voltage created
by rapidly discharging the output through the low-side
MOSFET. The MAX17019 also includes output undervoltage, output overvoltage, and thermal-fault protection.
●● 5.5V to 38V Input Range (Step-Down)
LXB
The step-down converters use a peak current-mode,
fixed-frequency control scheme—an easy to implement architecture that does not sacrifice fast-transient
response. This architecture also supports peak currentlimit protection and pulse-skipping operation to maintain
high efficiency under light-load conditions.
●● Fixed-Frequency, Current-Mode Controllers
LXB
The internal switching regulators include 5V synchronous
MOSFETs that can be powered directly from a single Li+
cell or from the main 3.3V/5V power stages. Finally, the
linear regulator is capable of sourcing and sinking 2A to
support DDR termination requirements or to generate a
fixed output voltage.
Features
BSTB
The MAX17019 is a high-input-voltage quad-output controller (up to 38V). The MAX17019 provides a compact,
low-cost controller capable of providing four independent
regulators—a main stage, a 3AP-P internal stepdown, a
5AP-P internal step-down, and a 2A source/sink linear
regulator. The input voltage is up to 38V.
POKB
General Description
FBB
MAX17019
36
35
34
33
32
31
30
29
28
27
26
25
ONB 37
24 CSPA
SYNC 38
23 CSNA
ONA 39
22 AGND
INBC 40
21 REF
INBC 41
20 FREQ
INBC 42
19 UP/DN
MAX17019
INBC 43
18 INA
VDD 44
17 VCC
POKD 45
16 BYP
OND 46
15 LDO5
ONC 47
14 INLDO
EXPOSED PAD = PGND
LXC
9
10
11
12
REFIND
LXC
8
VTTR
LXC
7
THIN QFN
19-4225; Rev 1; 10/14
13 SHDN
6
FBD
5
IND
4
OUTD
3
OUTD
2
LXC
1
BSTC
+
POKC
FBC 48
MAX17019
High-Input-Voltage Quad-Output Controller
Absolute Maximum Ratings
INLDO, SHDN to GND............................................-0.3V to +43V
LDO5, INA, VDD, VCC to GND.................................-0.3V to +6V
DHA to LXA.............................................-0.3V to (VBSTA + 0.3V)
ONA, ONB, ONC, OND to GND...............................-0.3V to +6V
POKA, POKB, POKC, POKD to GND.........-0.3V to (VCC + 0.3V)
REF, REFIND, FREQ, UP/DN,
SYNC to GND.......................................-0.3V to (VCC + 0.3V)
FBA, FBB, FBC, FBD to GND.....................-0.3V to (VCC + 0.3V)
BYP to GND...........................................-0.3V to (VLDO5 + 0.3V)
CSPA, CSNA to GND .................................-0.3V to (VCC + 0.3V)
DLA to GND................................................-0.3V to (VDD + 0.3V)
INBC, IND to GND....................................................-0.3V to +6V
OUTD to GND...........................................-0.3V to (VIND + 0.3V)
VTTR to GND...........................................-0.3V to (VBYP + 0.3V)
LXB, LXC to GND....................................-1.0V to (VINBC + 0.3V)
BSTB to GND...................................(VDD - 0.3V) to (VLXB + 6V)
BSTC to GND..................................(VDD - 0.3V) to (VLXC + 6V)
BSTA to GND...................................(VDD - 0.3V) to (VLXA + 6V)
REF Short-Circuit Current......................................................1mA
Continuous Power Dissipation (TA = +70°C)
TQFN (derate 37mW/°C above +70°C)............................2.9W
(Multilayer Board)
Operating Temperature Range ..........................-40°C to +105°C
Junction Temperature.......................................................+150°C
Storage Temperature Range ..............................-65°C to +150°C
Lead Temperature (soldering, 10s)...................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these
or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.
Electrical Characteristics
(Circuit of Figure 1, VINLDO = 12V, VINA = VINBC = VDD = VCC = VBYP = VCSPA = VCSNA = 5V, VIND = 1.8V, VSHDN = VONA = VONB
= VONC = VOND = 5V, IREF = ILDO5 = IOUTD = no load, FREQ = GND, UP/DN = VCC, TA = 0°C to +85°C, unless otherwise noted.
Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
Input Voltage Range
INA Undervoltage Threshold
VINA(UVLO)
CONDITIONS
MIN
UP/DN = LDO5, INLDO, INA = LDO5
5.5
UP/DN = LDO5, INA = VCC, rising edge,
hysteresis = 160mV
4.0
INBC Input Voltage Range
TYP
4.2
2.3
MAX
UNITS
38
V
4.4
V
5.5
V
SUPPLY CURRENTS
VINLDO Shutdown Supply Current
IIN(SHDN)
VINLDO = 5.5V to 38V, SHDN = GND
10
15
µA
IIN(SUS)
VINLDO = 5.5V to 38V, ON_ = GND,
SHDN = INLDO
50
80
µA
VCC Shutdown Supply Current
SHDN = ONA = ONB = ONC = OND =
GND, TA = +25°C
0.1
1
µA
VDD Shutdown Supply Current
SHDN = ONA = ONB = ONC = OND =
GND, TA = +25°C
0.1
1
µA
SHDN = ONA = ONB = ONC = OND =
GND, UP/DN = VCC
7
10
µA
VINLDO Suspend Supply Current
INA Shutdown Current
IINA
VCC Supply Current
Main Step-Down Only
ONA = VCC, ONB = ONC = OND =
GND; does not include switching losses,
measured from VCC
210
300
µA
VCC Supply Current
Main Step-Down and Regulator B
ONA = ONB = VCC, ONC = OND =
GND; does not include switching losses,
measured from VCC
280
350
µA
VCC Supply Current
Main Step-Down and Regulator C
ONA = ONC = VCC, ONB = OND =
GND; does not include switching losses,
measured from VCC
280
350
µA
VCC Supply Current
Main Step-Down and Regulator D
ONA = OND = VCC, ONB = ONC =
GND; does not include switching losses,
measured from VCC
2.2
3
mA
ONA = VCC, UP/DN = VCC
40
60
µA
INA Supply Current
www.maximintegrated.com
IINA
Maxim Integrated │ 2
MAX17019
High-Input-Voltage Quad-Output Controller
Electrical Characteristics (continued)
(Circuit of Figure 1, VINLDO = 12V, VINA = VINBC = VDD = VCC = VBYP = VCSPA = VCSNA = 5V, VIND = 1.8V, VSHDN = VONA = VONB
= VONC = VOND = 5V, IREF = ILDO5 = IOUTD = no load, FREQ = GND, UP/DN = VCC, TA = 0°C to +85°C, unless otherwise noted.
Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
4.75
5.0
5.2
V
70
160
250
mA
Ω
5V LINEAR REGULATOR (LDO5)
LDO5 Output Voltage
VLDO5
LDO5 Short-Circuit Current Limit
VINLDO = 5.5V to 38V, ILDO5 = 0 to 50mA,
BYP = GND
LDO5 = BYP = GND, VINLDO = 5.5V
BYP Switchover Threshold
VBYP
Rising edge
4.65
LDO5-to-BYP Switch Resistance
RBYP
LDO5 to BYP, VBYP = 5V, ILDO5 = 50mA
1.5
4
V
VREF
No load
1.25
1.263
V
3
10
mV
1.25V REFERENCE
Reference Output Voltage
Reference Load Regulation
Reference Undervoltage Lockout
ΔVREF
1.237
IREF = -1µA to +50µA
VREF(UVLO)
1.0
V
OSCILLATOR
Oscillator Frequency
fOSC
FREQ = VCC
500
FREQ = REF
750
FREQ = GND
Switching Frequency
0.9
kHz
1.0
1.1
fSWA
Regulator A
1/2 fOSC
fSWB
Regulator B
fOSC
fSWC
Regulator C
1/2 fOSC
Maximum Duty Cycle
(All Switching Regulators)
DMAX
Minimum On-Time
(All Switching Regulators)
tON(MIN)
90
MHz
93.5
FREQ = VCC or GND
90
FREQ = REF
75
MHz
%
ns
REGULATOR A (Main Step-Down)
Output Voltage-Adjust Range
Step-down configuration (UP/DN = VCC)
1.0
FBA Regulation Voltage
VFBA
Step-down configuration (UP/DN = VCC),
VCSPA - VCSNA = 0 to 20mV, 90% duty cycle
0.968
FBA Regulation Voltage
(Overload)
VFBA
Step-down configuration (UP/DN = VCC),
VCSPA - VCSNA = 0 to 20mV, 90% duty cycle
0.930
FBA Load Regulation
∆VFBA
UP/DN = VCC,
0 to 100% duty cycle
FBA Line Regulation
FBA Input Current
IFBA
Current-Sense Input CommonMode Range
VCSA
Current-Sense Input Bias Current
Step-down configuration (UP/DN = VCC),
VCSPA - VCSNA = 0 to 20mV
ICSA
Idle Mode™ Threshold
VIDLEA
Current-Limit Threshold (Positive)
VILIMA
Step-down
(UP/DN = VCC)
UP/DN = GND or VCC, TA = +25°C
0.97
VCC +
0.3
V
1.003
V
1.003
V
16
mV
10
16
22
mV
-100
-5
+100
nA
VCC +
0.3V
V
0
TA = +25°C
40
60
4
18
20
µA
mV
22
mV
Idle Mode is a trademark of Maxim Integrated Products, Inc.
www.maximintegrated.com
Maxim Integrated │ 3
MAX17019
High-Input-Voltage Quad-Output Controller
Electrical Characteristics (continued)
(Circuit of Figure 1, VINLDO = 12V, VINA = VINBC = VDD = VCC = VBYP = VCSPA = VCSNA = 5V, VIND = 1.8V, VSHDN = VONA = VONB
= VONC = VOND = 5V, IREF = ILDO5 = IOUTD = no load, FREQ = GND, UP/DN = VCC, TA = 0°C to +85°C, unless otherwise noted.
Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
Zero-Crossing Threshold
VIZX
DHA Gate Driver On-Resistance
RDH
DLA Gate Driver On-Resistance
RDL
DHA Gate Driver Source/Sink
Current
DLA Gate Driver Source/Sink
Current
CONDITIONS
MIN
TYP
MAX
1
UNITS
mV
DHA forced high and low
2.5
5
DLA forced high
2.5
5
DLA forced low
1.5
3
IDH
DHA forced to 2.5V
0.7
IDL(SRC)
DLA forced to 2.5V
0.7
IDL(SNK)
DLA forced to 2.5V
1.5
Ω
Ω
A
A
REGULATOR B (Internal 3A Step-Down Converter)
FBB Regulation Voltage
FBB Regulation Voltage (Overload)
FBB Load Regulation
VFBB
LXB Idle-Mode Trip Level
LXB Zero-Crossing Trip Level
ILXB = 0 to 2.5A, 0% duty cycle (Note 2)
0.720
0 to 100% duty cycle
IFBB
Internal MOSFET On-Resistance
LXB Peak Current Limit
0.747
∆VFBB/∆ILXB ILXB = 0 to 2.5A
FBB Line Regulation
FBB Input Current
ILXB = 0% duty cycle (Note 2)
TA = +25°C
0.755
0.762
V
0.762
V
-5
7
10
mV
nA
-5
+100
High-side n-channel
75
150
Low-side n-channel
40
80
3.45
4.0
IPKB
-100
mV/A
8
3.0
mΩ
A
IIDLEB
0.8
A
IZXB
100
mA
REGULATOR C (Internal 5A Step-Down Converter)
FBC Regulation Voltage
FBC Regulation Voltage (Overload)
FBC Load Regulation
VFBC
LXC Idle-Mode Trip Level
LXC Zero-Crossing Trip Level
ILXC = 0 to 4A, 0% duty cycle (Note 2)
0.710
0 to 100% duty cycle
IFBC
Internal MOSFET On-Resistance
LXC Peak Current Limit
0.747
∆VFBC/∆ILXC ILXC = 0 to 4A
FBC Line Regulation
FBC Input Current
ILXC = 0A, 0% duty cycle (Note 2)
0.755
0.762
0.762
-7
V
V
mV/A
12
14
16
mV
-100
-5
+100
nA
High-side n-channel
50
100
Low-side n-channel
25
40
5.75
6.5
TA = +25°C
IPKC
5.0
mΩ
A
IIDLEC
1.2
A
IZXC
100
mA
REGULATOR D (Source/Sink Linear Regulator and VTTR Buffer)
IND Input Voltage Range
VIND
1
IND Supply Current
OND = VCC
IND Shutdown Current
OND = GND, TA = +25°C
REFIND Input Range
REFIND Input Bias Current
OUTD Output Voltage Range
www.maximintegrated.com
VREFIND = 0 to 1.5V, TA = +25°C
VOUTD
10
2.8
V
50
µA
10
µA
0.5
1.5
V
-100
+100
nA
0.5
1.5
V
Maxim Integrated │ 4
MAX17019
High-Input-Voltage Quad-Output Controller
Electrical Characteristics (continued)
(Circuit of Figure 1, VINLDO = 12V, VINA = VINBC = VDD = VCC = VBYP = VCSPA = VCSNA = 5V, VIND = 1.8V, VSHDN = VONA = VONB
= VONC = VOND = 5V, IREF = ILDO5 = IOUTD = no load, FREQ = GND, UP/DN = VCC, TA = 0°C to +85°C, unless otherwise noted.
Typical values are at TA = +25°C.) (Note 1)
PARAMETER
FBD Output Accuracy
SYMBOL
VFBD
CONDITIONS
MIN
VFBD with respect to VREFIND, OUTD =
FBD, IOUTD = +50µA (source load)
-10
VFBD with respect to VREFIND,
OUTD = FBD, IOUTD = -50µA (sink load)
0
TYP
MAX
0
mV
IOUTD = ±1A
FBD Line Regulation
VIND = 1.0V to 2.8V, IOUTD = ±200mA
FBD Input Current
VFBD = 0 to 1.5V, TA = +25°C
OUTD Linear-Regulator Current
Limit
Source load
+2
+4
Sink load
-2
-4
Current-Limit Soft-Start Time
With respect to internal OND signal
160
High-side on-resistance
120
250
Low-side on-resistance
180
450
VTTR Output Accuracy
REFIND to VTTR
-17
+10
FBD Load Regulation
Internal MOSFET On-Resistance
UNITS
-13
mV/A
1
mV
0.1
0.5
A
µs
IVTTR = ±0.5mA
-10
+10
IVTTR = ±3mA
-20
+20
VTTR Maximum Current Rating
µA
±5
mΩ
mV
mA
FAULT PROTECTION
SMPS POK and Fault Thresholds
VTT LDO POKD and Fault
Threshold
Upper threshold rising edge,
hysteresis = 50mV
9
12
14
Lower threshold falling edge,
hysteresis = 50mV
-14
-12
-9
Upper threshold rising edge,
hysteresis = 50mV
6
12
16
Lower threshold falling edge,
hysteresis = 50mV
-16
-12
-6
%
%
POK Propagation Delay
tPOK
FB_ forced 50mV beyond POK_ trip
threshold
5
µs
Overvoltage Fault Latch Delay
tOVP
FB_ forced 50mV above POK_ upper
trip threshold
5
µs
SMPS Undervoltage Fault
Latch Delay
tUVP
FBA, FBB, or FBC forced 50mV below
POK_ lower trip threshold
5
µs
VTT LDO Undervoltage Fault
Latch Delay
tUVP
FBD forced 50mV below POKD lower
trip threshold
5000
µs
POK Output Low Voltage
VPOK
ISINK = 3mA
POK Leakage Currents
IPOK
VFBA = 1.05V, VFBB = VFBC = 0.8V, VFBD =
VREFIND + 50mV (POK high impedance);
POK_ forced to 5V, TA = +25°C
Thermal-Shutdown Threshold
www.maximintegrated.com
TSHDN
Hysteresis = 15°C
+160
0.4
V
1
µA
°C
Maxim Integrated │ 5
MAX17019
High-Input-Voltage Quad-Output Controller
Electrical Characteristics (continued)
(Circuit of Figure 1, VINLDO = 12V, VINA = VINBC = VDD = VCC = VBYP = VCSPA = VCSNA = 5V, VIND = 1.8V, VSHDN = VONA = VONB
= VONC = VOND = 5V, IREF = ILDO5 = IOUTD = no load, FREQ = GND, UP/DN = VCC, TA = 0°C to +85°C, unless otherwise noted.
Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
0.5
1.6
V
SHDN = 0~16V
-2
+2
SHDN = 17V~38V
-2
+150
0.5
1.6
V
GENERAL LOGIC LEVELS
SHDN Input Logic Threshold
Hysteresis = 20mV
SHDN Input Bias Current
TA = +25°C
ON_ Input Logic Threshold
Hysteresis = 170mV
ON_ Input Bias Current
TA = +25°C
UP/DN Input Logic Threshold
TA = +25°C
UP/DN Input Bias Current
High (VCC)
FREQ Input Voltage Levels
-1
+1
µA
0.5
1.6
V
-1
+1
µA
3.8
V
VCC - 0.4V
Unconnected/REF
1.65
Low (GND)
FREQ Input Bias Current
0.5
TA = +25°C
SYNC Input Logic Threshold
SYNC Input Bias Current
µA
TA = +25°C
-2
+2
µA
1.5
3.5
V
-1
+1
µA
Electrical Characteristics
(Circuit of Figure 1, VINLDO = 12V, VINA = VINBC = VDD = VCC = VBYP = VCSPA = VCSNA = 5V, VIND = 1.8V, VSHDN = VONA = VONB
= VONC = VOND = 5V, IREF = ILDO5 = IOUTD = no load, FREQ = GND, UP/DN = VCC, TA = -40°C to +125°C.) (Note 1)
PARAMETER
SYMBOL
Input Voltage Range
INA Undervoltage Threshold
CONDITIONS
UP/DN = LDO5, INLDO, INA = LDO5
UP/DN = LDO5, INA = VCC, rising edge,
VINA(UVLO)
hysteresis = 160mV
INBC Input Voltage Range
MIN
TYP
MAX
UNITS
5.5
24
V
3.9
4.5
V
2.3
5.5
V
SUPPLY CURRENTS
VINLDO Shutdown Supply Current
IIN(SHDN)
VINLDO = 5.5V to 38V, SHDN = GND
15
µA
VINLDO Suspend Supply Current
IIN(SUS)
VINLDO = 5.5V to 38V, ON_ = GND,
SHDN = INLDO
80
µA
SHDN = ONA = ONB = ONC = OND = GND,
UP/DN = VCC
10
µA
VCC Supply Current
Main Step-Down Only
ONA = VCC, ONB = ONC = OND =
GND; does not include switching losses,
measured from VCC
350
µA
VCC Supply Current
Main Step-Down and Regulator B
ONA = ONB = VCC, ONC = OND =
GND; does not include switching losses,
measured from VCC
400
µA
VCC Supply Current
Main Step-Down and Regulator C
ONA = ONC = VCC, ONB = OND =
GND, does not include switching losses,
measured from VCC
400
µA
INA Shutdown Current
www.maximintegrated.com
IINA
Maxim Integrated │ 6
MAX17019
High-Input-Voltage Quad-Output Controller
Electrical Characteristics (continued)
(Circuit of Figure 1, VINLDO = 12V, VINA = VINBC = VDD = VCC = VBYP = VCSPA = VCSNA = 5V, VIND = 1.8V, VSHDN = VONA = VONB
= VONC = VOND = 5V, IREF = ILDO5 = IOUTD = no load, FREQ = GND, UP/DN = VCC, TA = -40°C to +125°C.) (Note 1)
PARAMETER
SYMBOL
VCC Supply Current
Main Step-Down and Regulator D
INA Supply Current (Step-Down)
IINA
CONDITIONS
MIN
TYP
MAX
UNITS
ONA = OND = VCC, ONB = ONC =
GND, does not include switching losses,
measured from VCC
3.5
mA
ONA = VCC, UP/DN = VCC (step-down)
75
µA
5.25
V
5V LINEAR REGULATOR
LDO5 Output Voltage
VLDO5
LDO5 Short-Circuit Current Limit
VINLDO = 5.5V to 38V, ILDO5 = 0 to 50mA,
BYP = GND
LDO5 = BYP = GND, VINLDO = 5.5V
4.75
55
mA
1.25V REFERENCE
Reference Output Voltage
Reference Load Regulation
VREF
∆VREF
No load
1.237
IREF = -1µA to +50µA
1.263
V
12
mV
1.1
MHz
OSCILLATOR
Oscillator Frequency
fOSC
Maximum Duty Cycle
(All Switching Regulators)
DMAX
FREQ = GND
0.9
89
%
REGULATOR A (Main Step-Down)
Output Voltage Adjust Range
Step-down configuration (UP/DN = VCC)
1.0
VCC +
0.3V
V
FBA Regulation Voltage
Step-down configuration,
VCSPA - VCSNA = 0mV, 90% duty cycle
0.963
1.008
V
Step-down configuration (UP/DN = VCC),
VCSPA - VCSNA = 0 to 20mV, 90% duty cycle
0.925
1.008
V
10
33
mV
V
FBA Regulation Voltage
(Overload)
VFBA
FBA Line Regulation
Step-down (UP/DN = VCC)
Current-Sense Input CommonMode Range
VCSA
0
VCC +
0.3V
Current-Limit Threshold (Positive)
VILIMA
17
23
mV
ILXB = 0A, 0% duty cycle (Note 2)
0.742
0.766
V
ILXB = 0 to 2.5A , 0% duty cycle (Note 2)
0.715
0.766
V
6
12
mV
2.7
4.2
A
ILXC = 0A, 0% duty cycle (Note 2)
0.742
0.766
V
ILXC = 0 to 4A, 0% duty cycle (Note 2)
0.705
0.766
V
11
20
mV
5.0
6.5
A
REGULATOR B (Internal 3A Step-Down Converter)
FBB Regulation Voltage
FBB Regulation Voltage (Overload)
VFBB
FBB Line Regulation
LXB Peak Current Limit
IPKB
REGULATOR C (Internal 5A Step-Down Converter)
FBC Regulation Voltage
FBC Regulation Voltage (Overload)
VFBC
FBC Line Regulation
LXC Peak Current Limit
www.maximintegrated.com
IPKC
Maxim Integrated │ 7
MAX17019
High-Input-Voltage Quad-Output Controller
Electrical Characteristics (continued)
(Circuit of Figure 1, VINLDO = 12V, VINA = VINBC = VDD = VCC = VBYP = VCSPA = VCSNA = 5V, VIND = 1.8V, VSHDN = VONA = VONB
= VONC = VOND = 5V, IREF = ILDO5 = IOUTD = no load, FREQ = GND, UP/DN = VCC, TA = -40°C to +125°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
REGULATOR D (Source/Sink Linear Regulator and VTTR Buffer)
IND Input Voltage Range
VIND
IND Supply Current
1
REFIND Input Range
OUTD Output Voltage Range
FBD Output Accuracy
2.8
V
70
µA
0.5
1.5
V
0.5
1.5
V
-12
0
0
+12
OND = VCC
VOUTD
VFBD
VFBD with respect to VREFIND,
OUTD = FBD, IOUTD = +50µA (source load)
VFBD with respect to VREFIND,
OUTD = FBD, IOUTD = -50µA (sink load)
mV
FBD Load Regulation
IOUTD = ±1A
-20
OUTD Linear-Regulator Current
Limit
Source load
+2
+4
Sink load
-2
-4
Internal MOSFET On-Resistance
VTTR Output Accuracy
mV/A
High-side on-resistance
300
Low-side on-resistance
475
REFIND to VTTR, IVTTR = ±3mA
-20
+20
Upper threshold rising edge,
hysteresis = 50mV
8
16
Lower threshold falling edge,
hysteresis = 50mV
-16
-8
Upper threshold rising edge,
hysteresis = 50mV
6
16
Lower threshold falling edge,
hysteresis = 50mV
-16
-6
A
mΩ
mV
FAULT PROTECTION
SMPS POK and Fault Thresholds
VTT LDO POKD and Fault
Threshold
POK Output Low Voltage
VPOK
%
%
ISINK = 3mA
0.4
V
GENERAL LOGIC LEVELS
SHDN Input Logic Threshold
Hysteresis = 20mV
0.5
1.6
V
ON_ Input Logic Threshold
Hysteresis = 170mV
0.5
1.6
V
0.5
1.6
V
3.8
V
UP/DN Input Logic Threshold
High (VCC)
FREQ Input Voltage Levels
Unconnected/REF
VCC - 0.4V
1.65
Low (GND)
SYNC Input Logic Threshold
0.5
1.5
3.5
V
Note 1: Limits are 100% production tested at TA = +25°C. Maximum and minimum limits are guaranteed by design and
characterization.
Note 2: Regulation voltage tested with slope compensation. Typical value is equivalent to 0% duty cycle. In real applications, the
regulation voltage is higher due to the line regulation times the duty cycle.
www.maximintegrated.com
Maxim Integrated │ 8
MAX17019
High-Input-Voltage Quad-Output Controller
Typical Operating Characteristics
(TA = +25°C, Circuit of Figure 1, unless otherwise noted.)
85
VIN = 20V
75
VIN = 12V
70
65
60
4.95
95
4.90
4.85
VIN = 8V
50
0.001
0.01
0.1
1
4.75
10
0
VIN = 5V
70
65
0.01
LOAD CURRENT (A)
90
MAX17019 toc04
VIN = 5V
VIN = 2.5V
VIN = 3.3V
0.1
1
10
LOAD CURRENT (A)
SMPS REGULATOR C EFFICIENCY
vs. LOAD CURRENT
VIN = 2.5V
85
80
EFFICIENCY (%)
OUTPUT VOLTAGE (V)
75
50
0.001
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
SMPS REGULATOR B OUTPUT VOLTAGE
vs. LOAD CURRENT
1.77
VIN = 3.3V
80
55
LOAD CURRENT (A)
1.82
85
60
4.80
55
VIN = 2.5V
90
VIN = 12V
MAX17019 toc03
VIN = 20V
SMPS REGULATOR B EFFICIENCY
vs. LOAD CURRENT
MAX17019 toc05
80
5.00
100
EFFICIENCY (%)
EFFICIENCY (%)
90
SMPS REGULATOR A OUTPUT VOLTAGE
vs. LOAD CURRENT
MAX17019 toc02
VIN = 8V
OUTPUT VOLTAGE (V)
95
5.05
MAX17019 toc01
100
SMPS REGULATOR A EFFICIENCY
vs. LOAD CURRENT
VIN = 3.3V
75
70
VIN = 5V
65
60
55
0.5
1.0
1.5
2.0
2.5
OUTPUT VOLTAGE (V)
0.01
0.1
1
10
LOAD CURRENT (A)
SMPS REGULATOR C OUTPUT VOLTAGE
vs. LOAD CURRENT
REGULATOR D VOLTAGE
vs. SOURCE/SINK LOAD CURRENT
0.930
1.03
VIN = 5V
1.02
1.01
VIN = 2.5V
1.00
VIN = 3.3V
0.99
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
LOAD CURRENT (A)
www.maximintegrated.com
MAX17019 toc07
LOAD CURRENT (A)
1.04
0.98
50
0.001
3.0
0.925
0.920
VTT VOLTAGE (V)
1.05
0
MAX17019 toc06
1.72
0.915
0.910
0.905
0.900
0.895
0.890
0.885
0.880
-2.0 -1.5 -1.0 -0.5
0
0.5
1.0
1.5
2.0
LOAD CURRENT (A)
Maxim Integrated │ 9
MAX17019
High-Input-Voltage Quad-Output Controller
Typical Operating Characteristics (continued)
(TA = +25°C, Circuit of Figure 1, unless otherwise noted.)
REG A STARTUP WAVEFORM
(HEAVY LOAD)
REG B STARTUP WAVEFORM
(HEAVY LOAD)
REG A SHUTDOWN WAVEFORM
MAX17019 toc08
MAX17019 toc10
MAX17019 toc09
ONA
ONA
OUTA
ONB
OUTA
POKA
OUTB
POKB
POKA
ILA
ILA
ILB
LXA
LXA
LXB
400µs/div
400µs/div
400µs/div
RLOAD = 1.6Ω
ONA: 5V/div
OUTA: 5V/div
POKA: 5V/div
ILA: 5A/div
LXA: 10V/div
RLOAD = 2.5Ω
ONA: 5V/div
OUTA: 5V/div
POKA: 5V/div
ILA: 5A/div
LXA: 10V/div
REG C STARTUP WAVEFORM
(HEAVY LOAD)
REG B SHUTDOWN WAVEFORM
MAX17019 toc11
RLOAD = 1.01Ω
ONB: 5V/div
OUTB: 2V/div
POKB: 5V/div
ILB: 2A/div
LXB: 5V/div
REG C SHUTDOWN
MAX17019 toc12
MAX17019 toc13
ONC
ONB
OUTB
ONC
OUTC
POKB
OUTC
POKC
POKC
ILB
ILC
ILC
LXB
LXC
LXC
400µs/div
ONB: 5V/div
OUTB: 2V/div
POKB: 5V/div
ILB: 2A/div
LXB: 5V/div
www.maximintegrated.com
100µs/div
400µs/div
RLOAD = 0.8Ω
ONC: 5V/div
OUTC: 1V/div
POKC: 5V/div
ILC: 5A/div
LXC: 5V/div
RLOAD = 0.25Ω
ONC: 5V/div
OUTC: 1V/div
POKC: 5V/div
ILC: 5A/div
LXC: 5V/div
RLOAD = 0.25Ω
Maxim Integrated │ 10
MAX17019
High-Input-Voltage Quad-Output Controller
Typical Operating Characteristics (continued)
(TA = +25°C, Circuit of Figure 1, unless otherwise noted.)
REG A LOAD TRANSIENT (1A TO 3.2A)
REG B LOAD TRANSIENT (0.4A TO 2A)
MAX17019 toc14
OUTA
LXA
OUTC
LXB
LXC
ILC
ILB
IOUTC
IOUTB
20µs/div
OUTA: 100mV/div
LXA: 10V/div
ILA: 2A/div
IOUTA: 2A/div
MAX17019 toc16
OUTB
ILA
IOUTA
REG C LOAD TRANSIENT (0.8A TO 3A)
MAX17019 toc15
20µs/div
20µs/div
VINA = 12V, LOAD TRANSIENT
IS FROM 1A TO 3.2A
OUTB: 50mV/div
LXB: 5V/div
ILB: 1A/div
IOUTB: 2A/div
VINBC = 5V, 0.4A TO 2.0A
LOAD TRANSIENT
OUTC: 50mV/div
LXC: 5V/div
ILC: 2A/div
IOUTC: 2A/div
REG D LOAD TRANSIENT (SINK)
REG D LOAD TRANSIENT (SOURCE/SINK)
REG D LOAD TRANSIENT (SOURCE)
MAX17019 toc18
MAX17019 toc17
VINBC = 5V, 0.8A TO 3.0A
LOAD TRANSIENT
MAX17019 toc19
OUTD
OUTD
OUTD
IOUTD
IOUTD
IOUTD
20µs/div
20µs/div
OUTD: 20mV/div VIND = 1.8V, VREFIND = 0.9V,
IOUTD: 1A/div
COUT = 2 x 10µF, LOAD TRANSIENT
IS FROM 1A SOURCING TO 1A SINKING
www.maximintegrated.com
OUTD: 10mV/div
IOUTD: 1A/div
VIND = 1.8V, VREFIND = 0.9V,
COUT = 2 x 10µF, LOAD TRANSIENT
IS FROM 0 TO 1A SINKING
20µs/div
OUTD: 10mV/div
IOUTD: 1A/div
VIND = 1.8V, VREFIND = 0.9V,
COUT = 2 x 10µF, LOAD TRANSIENT
IS FROM 0 TO 1A SOURCING
Maxim Integrated │ 11
MAX17019
High-Input-Voltage Quad-Output Controller
Pin Description
PIN
NAME
1
POKC
Open-Drain Power-Good Output for the Internal 5A Step-Down Converter. POKC is low if FBC is more than
12% (typ) above or below the nominal 0.75V feedback regulation threshold. POKC is held low during startup
and in shutdown. POKC becomes high impedance when FBC is in regulation.
2
BSTC
Boost Flying Capacitor Connection for the Internal 5A Step-Down Converter. The MAX17019 includes an
internal boost switch/diode connected between VDD and BSTC. Connect to an external capacitor as shown in
Figure 1.
3–6
LXC
7, 8
OUTD
9
IND
Source/Sink Linear-Regulator Input. Bypass IND with a 10µF or greater ceramic capacitor to ground.
10
FBD
Feedback Input for the Internal Source/Sink Linear Regulator. FBD tracks and regulates to the REFIND
voltage.
11
VTTR
12
REFIND
13
SHDN
Shutdown Control Input. The device enters its 5µA supply current shutdown mode if VSHDN is less than
the SHDN input falling-edge trip level and does not restart until VSHDN is greater than the SHDN input
rising-edge trip level. Connect SHDN to VINLDO for automatic startup of LDO5.
14
INLDO
Input of the Startup Circuitry and the LDO5 Internal 5V Linear Regulator. Bypass to GND with a 0.1µF or
greater ceramic capacitor close to the controller.
In the single-cell step-up applications, the 5V linear regulator is no longer necessary for the 5V bias supply.
Connect BYP and INLDO to the system’s 5V supply to effectively disable the linear regulator.
LDO5
5V Internal Linear-Regulator Output. Bypass with 4.7µF or greater ceramic capacitor. The 5V linear regulator
provides the bias power for the gate drivers (VDD) and analog control circuitry (VCC). The linear regulator
sources up to 50mA (max guaranteed). When BYP exceeds 4.65V (typ), the MAX17019 bypasses the linear
regulator through a 1.5Ω bypass switch. When the linear regulator is bypassed, LDO5 supports loads up to
100mA.
In the single-cell step-up applications, the 5V linear regulator is no longer necessary for the 5V bias supply.
Bypass SHDN to ground and leave LDO5 unconnected. Connect BYP and INLDO to effectively disable the
linear regulator.
BYP
Linear-Regulator Bypass Input. When BYP exceeds 4.65V, the controller shorts LDO5 to BYP through a 1.5Ω
bypass switch and disables the linear regulator. When BYP is low, the linear regulator remains active.
The BYP input also serves as the VTTR buffer supply, allowing VTTR to remain active even when the source/
sink linear regulator (OUTD) has been disabled under system standby/suspend conditions.
In the single-cell step-up applications, the 5V linear regulator is no longer necessary for the 5V bias supply.
Bypass LDO5 to ground with a 1µF capacitor and leave this output unconnected. Connect BYP and INLDO to
the system’s 5V supply to effectively disable the linear regulator.
15
16
FUNCTION
Inductor Connection for the Internal 5A Step-Down Converter. Connect LXC to the switched side of the
inductor.
Source/Sink Linear-Regulator Output. Bypass OUTD with 2x 10µF or greater ceramic capacitors to ground.
Dropout needs additional output capacitance (see the VTT LDO Output Capacitor Selection (COUTD) section).
Ouput of Reference Buffer. Bypass with 0.22µF for ±3mA of output current.
Dynamic Reference Input Voltage for the Source/Sink Linear Regulator and the Reference Buffer. The
linear-regulator feedback threshold (FBD) tracks the REFIND voltage.
www.maximintegrated.com
Maxim Integrated │ 12
MAX17019
High-Input-Voltage Quad-Output Controller
Pin Description (continued)
PIN
NAME
FUNCTION
17
VCC
5V Analog Bias Supply. VCC powers all the analog control blocks (error amplifiers, current-sense amplifiers,
fault comparators, etc.) and control logic. Connect VCC to the 5V system supply with a series 10Ω resistor, and
bypass to analog ground using a 1µF or greater ceramic capacitor.
18
INA
Input to the Circuit in Reg A in Boost Mode. Connect INA to LDO5 in step-down mode (UP/DN = VCC).
19
UP/DN
Converter Configuration Selection Input for Regulator A. When UP/DN is pulled high (UP/DN = VCC), regulator
A operates as a step-down converter (Figure 1). When UP/DN is pulled low (UP/DN = GND), regulator A
operates as a low-voltage step-up converter. (Refer to the MAX17017 data sheet for step-up configuration.)
FREQ
Trilevel Oscillator Frequency Selection Input:
FREQ = VCC: RegA = 250kHz, RegB = 500kHz, RegC = 250kHz
FREQ = REF: RegA = 375kHz, RegB = 750kHz, RegC = 375kHz
FREQ = GND: RegA = 500kHz, RegB = 1MHz, RegC = 500kHz
20
1.25V Reference-Voltage Output. Bypass REF to analog ground with a 0.1µF ceramic capacitor. The
reference sources up to 50µA for external loads. Loading REF degrades output voltage accuracy according to
the REF load-regulation error. The reference shuts down when the system pulls SHDN low in buck mode
(UP/DN = GND).
21
REF
22
AGND
Analog Ground
23
CSNA
Negative Current-Sense Input for the Main Switching Regulator. Connect to the negative terminal of the currentsense resistor. Due to the CSNA bias current requirements, limit the series impedance to less than 10Ω.
24
CSPA
Positive Current-Sense Input for the Main Switching Regulator. Connect to the positive terminal of the currentsense resistor. Due to the CSPA bias current requirements, limit the series impedance to less than 10Ω.
25
FBA
26
POKA
27
DHA
High-Side Gate-Driver Output for the Main Switching Regulator. DHA swings from LXA to BSTA.
28
LXA
Inductor Connection of Converter A. Connect LXA to the switched side of the inductor.
29
BSTA
Boost Flying Capacitor Connection of Converter A. The MAX17019 needs an external boost switch/diode
connected between VDD and BSTA. Connect to an external capacitor as shown in Figure 1.
30
DLA
Low-Side Gate-Driver Output for the Main Switching Regulator. DLA swings from GND to VDD.
31, 32,
33
LXB
Inductor Connection for the Internal 3A Step-Down Converter. Connect LXB to the switched side of the
inductor.
34
BSTB
Boost Flying Capacitor Connection for the Internal 3A Step-Down Converter. The MAX17019 includes an
internal boost switch/diode connected between VDD and BSTB. Connect to an external capacitor as shown in
Figure 1.
35
POKB
Open-Drain Power-Good Output for the Internal 3A Step-Down Converter. POKB is low if FBB is more than
12% (typ) above or below the nominal 0.75V feedback-regulation threshold. POKB is held low during soft-start
and in shutdown. POKB becomes high impedance when FBB is in regulation.
Feedback Input for the Main Switching Regulator. FBA regulates to 1.0V.
Open-Drain Power-Good Output for the Main Switching Regulator. POKA is low if FBA is more than 12%
(typ) above or below the nominal 1.0V feedback regulation point. POKA is held low during soft-start and in
shutdown. POKA becomes high impedance when FBA is in regulation.
www.maximintegrated.com
Maxim Integrated │ 13
MAX17019
High-Input-Voltage Quad-Output Controller
Pin Description (continued)
PIN
NAME
36
FBB
Feedback Input for the Internal 3A Step-Down Converter. FBB regulates to 0.75V.
FUNCTION
37
ONB
Switching Regulator B Enable Input. When ONB is pulled low, LXB is high impedance. When ONB is driven
high, the controller enables the 3A internal switching regulator.
38
SYNC
39
ONA
Switching Regulator A Enable Input. When ONA is pulled low, DLA and DHA are pulled low. When ONA is
driven high, the controller enables the step-up/step-down converter.
40–43
INBC
Input for Regulators B and C. Power INBC from a 2.5V to 5.5V supply. Internally connected to the drain
of the high-side MOSFETs for both regulator B and regulator C. Bypass to PGND with 2x 10µF or greater
ceramic capacitors to support the RMS current.
44
VDD
5V Bias Supply Input for the Internal Switching Regulator Drivers. Bypass with a 1µF or greater ceramic
capacitor. Provides power for the BSTB and BSTC driver supplies.
45
POKD
Open-Drain Power-Good Output for the Internal Source/Sink Linear Regulator. POKD is low if FBD is more
than 10% (typ) above or below the REFIND regulation threshold. POKD is held low during soft-start and in
shutdown. POKD becomes high impedance when FBD is in regulation.
46
OND
Source/Sink Linear Regulator (Regulator D) and Reference Buffer Enable Input. When OND is pulled low,
OUTD is high impedance. When OND is driven high, the controller enables the source/sink linear regulator.
47
ONC
Switching Regulator C Enable Input. When ONC is pulled low, LXC is high impedance. When ONC is driven
high, the controller enables the 5A internal switching regulator.
48
FBC
Feedback Input for the Internal 5A Step-Down Converter. FBC regulates to 0.75V.
EP
PGND
External Synchronization Input. Used to override the internal switching frequency.
Power Ground. The source of the low-side MOSFETs (REG B and REG C), the drivers for all switching
regulators, and the sink MOSFET of the VTT LDO are all internally connected to the exposed pad.
Connect the exposed backside pad to system power ground planes through multiple vias.
Detailed Description
The MAX17019 standard application circuit (Figure 1)
provides a 5V/5AP-P main stage, a 1.8V/3AP-P VDDQ
and 0.9A/2A VTT outputs for DDR, and a 1.05V/5AP-P
chipset supply.
The MAX17019 supports four power outputs—one highvoltage step-down controller, two internal MOSFET stepdown switching regulators, and one high-current source/
sink linear regulator. The step-down switching regulators
use a current-mode fixed-frequency architecture compensated by the output capacitance. An internal 50mA
5V linear regulator provides the bias supply and driver
supplies, allowing the controller to power up from input
supplies greater than 5.5V.
Fixed 5V Linear Regulator (LDO5)
An internal linear regulator produces a preset 5V lowcurrent output from INLDO. LDO5 powers the gate drivers
www.maximintegrated.com
for the external MOSFETs, and provides the bias supply
required for the SMPS analog controller, reference, and
logic blocks. LDO5 supplies at least 50mA for external
and internal loads, including the MOSFET gate drive,
which typically varies from 5mA to 15mA per switching
regulator, depending on the switching frequency. Bypass
LDO5 with a 4.7μF or greater ceramic capacitor to guarantee stability under the fullload conditions.
The MAX17019 switch-mode step-down switching regulators require a 5V bias supply in addition to the mainpower
input supply. This 5V bias supply is generated by the
controller’s internal 5V linear regulator (LDO5). This bootstrappable LDO allows the controller to power up independently. The gate driver VDD input supply is typically
connected to the fixed 5V linear regulator output (LDO5).
Therefore, the 5V LDO supply must provide LDO5 (PWM
controller) and the gatedrive power during power-up.
Maxim Integrated │ 14
MAX17019
High-Input-Voltage Quad-Output Controller
C1
4.7µF, 6V
0603
INLDO
SHDN
LDO5
INA
PWR
VDD
C2
R1
1.0µF, 6V
10Ω
0402 5%, 0402
BSTA
UP/DN
DHA
VCC
ONA
ON OFF
ONB
ON OFF
ONC
ON OFF
OND
5V SMPS
OUTPUT
C3
0.1µF, 6V
0402
NH1
NL1
DLA
CSPA
C8
0.1µF
PWR
CSNA
FBA
INBC
BSTB
POKA
POKB
POKC
AGND
C16
0.1µF, 6V
0402
C5
0.1µF, 6V
0402
LXB
POKD
L2
1µH, 7A, 14mΩ
R5
14.0kΩ
1%, 0402
FREQ
FBB
SYNC
AGND
BSTC
C6
0.1µF, 6V
0402
LXC
REF
C14
1000pF, 50V
0402
AGND
R7
4.02kΩ
1%, 0402
VTTR
FBC
IND
REFIND
R14
15.0kΩ
1%, 0402
C15
2200pF, 50V
0402
AGND
C8
1µF, 6V
0402
PWR
OUTD
AGND
FBD
GND
PWR
R3
40.2kΩ
1%, 0402
R15
0Ω
5%, 0402
C10
10µF, 6V
0805
PWR
C11, C12
(2x) 10µF, 6V
0805
PWR
5V
2.0A
C22
150µF
35mΩ, 6V, B2 CASE
PWR
R4
10.0kΩ
1%, 0402
AGND
C7
1µF, 16V
0402
C9
10µF, 6V
0805
PWR
PWR
2A
1.8V
2.5A
C23
330µF
15mΩ, 2.5V, B2 CASE
R6
10.0kΩ
1%, 0402
PWR
AGND
L3
1H, 7A, 14mΩ
AGND
C4
0.22µF, 4V
0402
R13 AGND
15kΩ
1%, 0402
R4 4mΩ
5%, 1206
C13
680pF, 50V
0402
AGND
BYP
R9–R12
(4x) 100kΩ
5%, 0402
1.8V SMPS
OUTPUT
R16
1Ω
5%
5.5V TO 38V
PWR
L1
3.3µH, 6A, 30mΩ
MAX17019
R2
0Ω
1%, 0402
C21
22µF, 50V
LXA
AGND
ON OFF
C19, C20
(2x) 4.7µF, 50V
1206
PWR
C17, C18
(2x) 1µF, 50V
0603
PWR LDO5
R8
10.0kΩ
1%, 0402
1.05V
4.0A
C24
330µF
15mΩ, 2.5V, B2 CASE
PWR
AGND
0.9V
1A
AGND
Figure 1. Standard Application Circuit
www.maximintegrated.com
Maxim Integrated │ 15
MAX17019
High-Input-Voltage Quad-Output Controller
BYP
UP/DN
VCC
LDO5
INLDO
TSDN
UP/DN = VCC [BUCK],
LOW BUCK MODE
TSDN
MAX17019
VDD
INA
SHDN
BYP_OK
VCC_OK
REF_OK
ONLDO
SW EN
DRV
FB
VCC
CSPA
CSNA
ONA
BSTA
LDO5
VCC
BIAS
EN
VCCOK
*ONA (SHDN)
REG A
ANALOG
UVLO
LXA
VDD
EN
VCC
REF
DHA
REF
DLA
VCC
EN
REFOK
EN
FBA
SSDA+
SYNC
OSC
BSTB
OND
INBC
IND
VCC
OUTD
PGND
FBD
REG B
ANALOG
ONB
INBC_OK
REG D PWR
LXB
VDD
EN
FBB
BSTC
+
REFIND
CSB
REG D
ANALOG
BYP
VTTR
VCC
EN
INBC_OK
INBC
REFIND
VCC
ONA
ONB
ONC
OND
ON_VTTR
POKX
PGOOD AND
FAULT
PROTECTION
INBC
UVLO
FAULTX
ONX
CSC
REG C
ANALOG
ONC
INBC_OK
LXC
VDD
EN
FBC
*BUCK REF ENABLED BY SHDN;
BOOST REF ENABLED BY ONA.
+SSDA ONLY USED IN STEP-UP MODE. SSDA = HIGH IN STEP-DOWN MODE.
Figure 2. Block Diagram
www.maximintegrated.com
Maxim Integrated │ 16
MAX17019
High-Input-Voltage Quad-Output Controller
SMPS Detailed Description
LDO5 Bootstrap Switchover
When the bypass input (BYP) exceeds the LDO5 bootstrap-switchover threshold for more than 500μs, an internal
1.5Ω (typ) p-channel MOSFET shorts BYP to LDO5, while
simultaneously disabling the LDO5 linear regulator. This
bootstraps the controller, allowing power for the internal
circuitry and external LDO5 loading to be generated by the
output of a 5V switching regulator. Bootstrapping reduces
power dissipation due to driver and quiescent losses by
providing power from a switch-mode source, rather than
from a much-less-efficient linear regulator. The current
capability increases from 50mA to 100mA when the LDO5
output is switched over to BYP. When BYP drops below the
bootstrap threshold, the controller immediately disables the
bootstrap switch and reenables the 5V LDO.
Fixed-Frequency, Current-Mode
PWM Controller
The heart of each current-mode PWM controller is a
multi-input, open-loop comparator that sums multiple
signals: the output voltage-error signal with respect to the
reference voltage, the current-sense signal, and the slope
compensation ramp (Figure 3). The MAX17019 uses a
direct-summing configuration, approaching ideal cycle-tocycle control over the output voltage without a traditional
error amplifier and the phase shift associated with it.
Frequency Selection (FREQ)
The FREQ input selects the PWM mode switching frequency. Table 1 shows the switching frequency based
on the FREQ connection. High-frequency (FREQ =GND)
operation optimizes the application for the smallest component size, trading off efficiency due to higher switching
losses. This might be acceptable in ultraportable devices
where the load currents are lower. Low-frequency (FREQ
= 5V) operation offers the best overall efficiency at the
expense of component size and board space.
Reference (REF)
The 1.25V reference is accurate to ±1% over temperature and load, making REF useful as a precision system
reference. Bypass REF to GND with a 0.1μF or greater
ceramic capacitor. The reference sources up to 50μA and
sinks 5μA to support external loads. If highly accurate
specifications are required for the main SMPS output
voltages, the reference should not be loaded. Loading
the reference slightly reduces the output voltage accuracy
because of the reference load-regulation error.
VL
R1
R2
TO PWM
LOGIC
UNCOMPENSATED
HIGH-SPEED
LEVEL TRANSLATOR
AND BUFFER
OUTPUT DRIVER
FB_
I1
I2
I3
VBIAS
REF
CSH_
CSL_
SLOPE COMPENSATION
Figure 3. PWM Comparator Functional Diagram
www.maximintegrated.com
Maxim Integrated │ 17
MAX17019
High-Input-Voltage Quad-Output Controller
Table 1. FREQ Table
REG A AND REG C
REG B
SWITCHING
FREQUENCY
SOFT-START TIME
STARTUP
BLANKING
TIME
SWITCHING
FREQUENCY
SOFT-START
TIME
STARTUP
BLANKING
TIME
fSWA AND fSWC
REG A: 1200/fSWA
REG C: 900/fSWC
1500/fSWA
fSWB
1800/fSWB
3000/fSWB
LDO5
250kHz
REG A: 4.8ms
REG C: 3.6ms
6ms
500kHz
3.6ms
6ms
REF
375kHz
REG A: 3.2ms
REG C: 2.4ms
4ms
750kHz
2.4ms
4ms
GND
500kHz
REG A: 2.4ms
REG C: 1.8ms
3ms
1MHz
1.8ms
3ms
SYNC
0.5 x fSYNC
—
—
fSYNC
—
—
PIN
SELECT
Light-Load Operation Control
The MAX17019 uses a light-load pulse-skipping operating
mode for all switching regulators. The switching regulators turn off the low-side MOSFETs when the current
sense detects zero inductor current. This keeps the inductor from discharging the output capacitors and forces the
switching regulator to skip pulses under light-load conditions to avoid overcharging the output.
Idle-Mode Current-Sense Threshold
When pulse-skipping mode is enabled, the on-time of
the step-down controller terminates when the output
voltage exceeds the feedback threshold and when the
current-sense voltage exceeds the idle-mode currentsense threshold. Under light-load conditions, the ontime
duration depends solely on the idle-mode current-sense
threshold. This forces the controller to source a minimum
amount of power with each cycle. To avoid overcharging
the output, another on-time cannot begin until the output
voltage drops below the feedback threshold. Since the
zero-crossing comparator prevents the switching regulator from sinking current, the MAX17019 switching regulators must skip pulses. Therefore, the controller regulates
the valley of the output ripple under light-load conditions.
Automatic Pulse-Skipping Crossover
In skip mode, an inherent automatic switchover to PFM
takes place at light loads. This switchover is affected by
a comparator that truncates the low-side switch on-time
www.maximintegrated.com
at the inductor current’s zero crossing. The zero-crossing
comparator senses the inductor current during the offtime.
For regulator A, once VCSPA - VCSNA drops below the
1mV zero-crossing current-sense threshold, the comparator turns off the low-side MOSFET (DLA pulled low). For
regulators B and C, once the current through the lowside
MOSFET drops below 100mA, the zero-crossing comparator turns off the low-side MOSFET.
The minimum idle-mode current requirement causes the
threshold between pulse-skipping PFM operation and
constant PWM operation to coincide with the boundary
between continuous and discontinuous inductor-current
operation (also known as the critical conduction point).
The load-current level at which PFM/PWM crossover
occurs (ILOAD(SKIP)) is equivalent to half the idle-mode
current threshold (see the Electrical Characteristics table
for the idle-mode thresholds of each regulator). The
switching waveforms can appear noisy and asynchronous
when light loading causes pulse-skipping operation, but
this is a normal operating condition that results in high
light-load efficiency. Trade-offs in PFM noise vs. lightload efficiency are made by varying the inductor value.
Generally, low inductor values produce a broader efficiency vs. load curve, while higher values result in higher
full-load efficiency (assuming that the coil resistance
remains fixed) and less output voltage ripple. Penalties for
using higher inductor values include larger physical size
and degraded load-transient response (especially at low
input-voltage levels).
Maxim Integrated │ 18
MAX17019
High-Input-Voltage Quad-Output Controller
SMPS POR, UVLO, and Soft-Start
soft-start sequence terminates, POK_ becomes high
impedance as long as the output remains within ±8%
(min) of the nominal regulation voltage set by FB_. POK_
goes low once its corresponding output drops 12% (typ)
below its nominal regulation point, an output overvoltage
fault occurs, or the output is shut down. For a logic-level
POK_ output voltage, connect an external pullup resistor
between POK_ and LDO5. A 100kΩ pullup resistor works
well in most applications.
Regulator A Startup
SMPS Fault Protection
Once the 5V bias supply rises above this input UVLO
threshold and ONA is pulled high, the main step-down
controller (regulator A) is enabled and begins switching.
The internal voltage soft-start gradually increments the
feedback voltage by 10mV every 12 switching cycles.
Therefore, OUTA reaches its nominal regulation voltage
1200/fSWA after regulator A is enabled (see the REG
A Startup Waveform (Heavy Load) graph in the Typical
Operating Characteristics).
Output Overvoltage Protection (OVP)
Power-on reset (POR) occurs when VCC rises above
approximately 1.9V, resetting the undervoltage, overvoltage, and thermal-shutdown fault latches. The POR circuit
also ensures that the low-side drivers are pulled low until
the SMPS controllers are activated. The VCC input undervoltage lockout (UVLO) circuitry prevents the switching
regulators from operating if the 5V bias supply (VCC and
VDD) is below its 4.2V UVLO threshold.
Regulator B and C Startup
The internal step-down controllers start switching and the
output voltages ramp up using soft-start. If the bias supply
voltage drops below the UVLO threshold, the controller
stops switching and disables the drivers (LX_becomes
high impedance) until the bias supply voltage recovers.
Once the 5V bias supply and INBC rise above their
respective input UVLO thresholds (SHDN must be pulled
high to enable the reference), and ONB or ONC is pulled
high, the respective internal step-down controller (regulator B or C) becomes enabled and begins switching.
The internal voltage soft-start gradually increments the
feedback voltage by 10mV every 24 switching cycles
for regulator B or every 12 switching cycles for regulator
C. Therefore, OUTB reaches its nominal regulation voltage 1800/fSWB after regulator B is enabled, and OUTC
reaches its nominal regulation voltage 900/fSWC after
regulator C is enabled (see the REG B Startup Waveform
(Heavy Load) and REG C Startup Waveform (Heavy
Load) graphs in the Typical Operating Characteristics).
SMPS Power-Good Outputs (POK)
POKA, POKB, and POKC are the open-drain outputs of
window comparators that continuously monitor each output for undervoltage and overvoltage conditions. POK_
is actively held low in shutdown (SHDN = GND), standby
(ONA = ONB = ONC = GND), and soft-start. Once the
www.maximintegrated.com
If the output voltage rises above 112% (typ) of its nominal regulation voltage, the controller sets the fault latch,
pulls POK_ low, shuts down the respective regulator, and
immediately pulls the output to ground through its lowside MOSFET. Turning on the low-side MOSFET with
100% duty cycle rapidly discharges the output capacitors and clamps the output to ground. However, this
commonly undamped response causes negative output
voltages due to the energy stored in the output LC at
the instant the OVP occurs. If the load cannot tolerate a
negative voltage, place a power Schottky diode across
the output to act as a reverse-polarity clamp. If the condition that caused the overvoltage persists (such as a
shorted high-side MOSFET), the input source also fails
(short-circuit fault). Cycle VCC below 1V or toggle the
respective enable input to clear the fault latch and restart
the regulator.
Output Undervoltage Protection (UVP)
Each MAX17019 includes an output UVP circuit that
begins to monitor the output once the startup blanking
period has ended. If any output voltage drops below 88%
(typ) of its nominal regulation voltage, the UVP protection
immediately sets the fault latch, pulls the respective POK
output low, forces the high-side and low-side MOSFETs
into high-impedance states (DH = DL = low), and shuts
down the respective regulator. Cycle VCC below 1V or
toggle the respective enable input to clear the fault latch
and restart the regulator.
Thermal-Fault Protection
The MAX17019 features a thermal fault-protection circuit.
When the junction temperature rises above +160°C, a
thermal sensor activates the fault latch, pulls all POK
outputs low, and shuts down all regulators. Toggle SHDN
to clear the fault latch and restart the controllers after the
junction temperature cools by 15°C.
Maxim Integrated │ 19
MAX17019
High-Input-Voltage Quad-Output Controller
VTT LDO Detailed Description
VTT LDO Power-Good Output (POKD)
POKD is the open-drain output of a window comparator
that continuously monitors the VTT LDO output for undervoltage and overvoltage conditions. POKD is actively held
low when the VTT LDO is disabled (OND = GND) and in
soft-start. Once the startup blanking time expires, POKD
becomes high impedance as long as the output remains
within ±6% (min) of the nominal regulation voltage set
by REFIND. POKD goes low once its corresponding
output drops or rises 12% (typ) beyond its nominal regulation point or the output is shut down. For a logic-level
POKD output voltage, connect an external pullup resistor
between POKD and LDO5. A 100kΩ pullup resistor works
well in most applications.
VTT LDO Fault Protection
LDO Output OVP
If the output voltage rises above 112% (typ) of its nominal
regulation voltage, the controller sets the fault latch, pulls
POKD low, shuts down the source/sink linear regulator,
and immediately pulls the output to ground through its
low-side MOSFET. Turning on the low-side MOSFET with
100% duty cycle rapidly discharges the output capacitors
and clamps the output to ground. Cycle VCC below 1V or
toggle OND to clear the fault latch and restart the linear
regulator.
LDO Output UVP
Each MAX17019 includes an output UVP circuit that
begins to monitor the output once the startup blanking
period has ended. If the source/sink LDO output voltage
drops below 88% (typ) of its nominal REFIND regulation
voltage for 5ms, the UVP sets the fault latch, pulls the
POKD output low, forces the output into a highimpedance
state, and shuts down the linear regulator. Cycle VCC
below 1V or toggle OND to clear the fault latch and restart
the regulator.
SMPS Design Procedure
(Step-Down Regulators)
Firmly establish the input voltage range and maximum
load current before choosing a switching frequency and
inductor operating point (ripple-current ratio). The primary design trade-off lies in choosing a good switching
frequency and inductor operating point, and the following
four factors dictate the rest of the design:
www.maximintegrated.com
• Input voltage range. The maximum value (VIN(MAX))
must accommodate the worst-case, high ACadapter
voltage. The minimum value (VIN(MIN)) must account
for the lowest battery voltage after drops due to connectors, fuses, and battery selector switches. If there
is a choice at all, lower input voltages result in better
efficiency.
• Maximum load current. There are two values to
consider. The peak load current (ILOAD(MAX)) determines the instantaneous component stresses and
filtering requirements and thus drives output capacitor
selection, inductor saturation rating, and the design of
the current-limit circuit. The continuous load current
(ILOAD) determines the thermal stresses and thus
drives the selection of input capacitors, MOSFETs,
and other critical heat-contributing components.
• Switching frequency. This choice determines the
basic trade-off between size and efficiency. The optimal frequency is largely a function of maximum input
voltage, due to MOSFET switching losses that are
proportional to frequency and VIN2.
• Inductor operating point. This choice provides tradeoffs between size vs. efficiency and transient response
vs. output ripple. Low inductor values provide better
transient response and smaller physical size, but also
result in lower efficiency, higher output ripple, and
lower maximum load current due to increased ripple
currents. The minimum practical inductor value is one
that causes the circuit to operate at the edge of critical
conduction (where the inductor current just touches
zero with every cycle at maximum load). Inductor
values lower than this grant no further size-reduction
benefit. The optimum operating point is usually found
between 20% and 50% ripple current. When pulse
skipping (light loads), the inductor value also determines the loadcurrent value at which PFM/PWM switchover occurs.
Step-Down Inductor Selection
The switching frequency and inductor operating point
determine the inductor value as follows:
L=
VOUT (VIN - VOUT )
VINf SWILOAD(MAX)LIR
Find a low-loss inductor having the lowest possible DC
resistance that fits in the allotted dimensions. Most inductor manufacturers provide inductors in standard values,
Maxim Integrated │ 20
MAX17019
High-Input-Voltage Quad-Output Controller
such as 1.0μH, 1.5μH, 2.2μH, 3.3μH, etc. Also look for
nonstandard values, which can provide a better compromise in LIR across the input voltage range. If using a
swinging inductor (where the no-load inductance decreases linearly with increasing current), evaluate the LIR
with properly scaled inductance values. For the selected
inductance value, the actual peak-to-peak inductor ripple
current (ΔIINDUCTOR) is defined by:
VOUT (VIN - VOUT )
∆IINDUCTOR =
VINf SW L
Ferrite cores are often the best choice, although soft
saturating molded core inductors are inexpensive and can
work well at 500kHz. The core must be large enough not
to saturate at the peak inductor current (IPEAK):
 ∆I

=
IPEAK ILOAD(MAX) +  INDUCTOR 
2


SMPS Output Capacitor Selection
The output filter capacitor selection requires careful
evaluation of several different design requirements—stability, transient response, and output ripple voltage—that
place limits on the output capacitance and ESR. Based
on these requirements, the typical application requires a
low-ESR polymer capacitor (lower cost but higher outputripple voltage) or bulk ceramic capacitors (higher cost but
low output-ripple voltage).
SMPS Loop Compensation
Voltage positioning dynamically lowers the output voltage
in response to the load current, reducing the loop gain.
This reduces the output capacitance requirement (stability
and transient) and output power dissipation requirements
as well. The load-line is generated by sensing the inductor current through the high-side MOSFET on-resistance,
and is internally preset to -5mV/A (typ) for regulator B and
-7mV/A (typ) for regulator C. The loadline ensures that the
output voltage remains within the regulation window over
the full-load conditions.
The load line of the internal SMPS regulators also provides the AC ripple voltage required for stability. To maintain stability, the output capacitive ripple must be kept
smaller than the internal AC ripple voltage, and crossover
must occur before the Nyquist pole—(1 + duty)/(2fSW)—
occurs. Based on these loop requirements, a minimum
output capacitance can be determined from the following:
www.maximintegrated.com

 VREF  VOUT 
1
C OUT > 

1 +

2f
R
VIN 
 SW DROOP  VOUT 
where RDROOP is 2RSENSE for regulator A, 5mV/A for
regulator B, or 7mV/A for regulator C as defined in the
Electrical Characteristics table, and fSW is the switching
frequency selected by the FREQ setting (see Table 1).
Additionally, an additional feedback pole—capacitor from
FB to analog ground (CFB)—might be necessary to cancel the unwanted ESR zero of the output capacitor. In
general, if the ESR zero occurs before the Nyquist pole,
then canceling the ESR zero is recommended:
If:


1+ D
ESR > 

 4πf SW C OUT 
Then:
C
ESR 
C FB >  OUT

R
FB


where RFB is the parallel impedance of the FB resistive
divider.
SMPS Output Ripple Voltage
With polymer capacitors, the effective series resistance
(ESR) dominates and determines the output ripple
voltage. The step-down regulator’s output ripple voltage (VRIPPLE) equals the total inductor ripple current
(ΔIINDUCTOR) multiplied by the output capacitor’s ESR.
Therefore, the maximum ESR to meet the output ripple
voltage requirement is:


VINf SW L
R ESR ≤ 
 VRIPPLE
(VIN - VOUT )VOUT 
where fSW is the switching frequency. The actual capacitance value required relates to the physical case size
needed to achieve the ESR requirement, as well as to the
capacitor chemistry. Thus, polymer capacitor selection is
usually limited by ESR and voltage rating rather than by
capacitance value. Alternatively, combining ceramics (for
the low ESR) and polymers (for the bulk capacitance)
helps balance the output capacitance vs. output ripplevoltage requirements.
Maxim Integrated │ 21
MAX17019
High-Input-Voltage Quad-Output Controller
Internal SMPS Transient Response
The load-transient response depends on the overall output impedance over frequency, and the overall amplitude
and slew rate of the load step. In applications with large,
fast load transients (load step > 80% of full load and slew
rate > 10A/μs), the output capacitor’s high-frequency
response—ESL and ESR—needs to be considered. To
prevent the output voltage from spiking too low under a
load-transient event, the ESR is limited by the following
equation (ignoring the sag due to finite capacitance):


VSTEP
R ESR ≤ 
- R PCB 
 ∆ILOAD(MAX)



where VSTEP is the allowed voltage drop, ΔILOAD(MAX) is
the maximum load step, and RPCB is the parasitic board
resistance between the load and output capacitor.
The capacitance value dominates the midfrequency
output impedance and dominates the load-transient
response as long as the load transient’s slew rate is less
than two switching cycles. Under these conditions, the
sag and soar voltages depend on the output capacitance,
inductance value, and delays in the transient response.
Low inductor values allow the inductor current to slew
faster, replenishing charge removed from or added to the
output filter capacitors by a sudden load step, especially
with low differential voltages across the inductor. The sag
voltage (VSAG) that occurs after applying the load current
can be estimated by the following:
VSAG
(
L ∆ILOAD(MAX)
)
2
2C OUT (VIN × D MAX - VOUT )
+
∆ILOAD(MAX) (T - ∆T)
C OUT
where DMAX is the maximum duty factor (see the
Electrical Characteristics table), T is the switching period
(1/fOSC), and ΔT equals VOUT/VIN x T when in PWM
mode, or L x IIDLE/(VIN - VOUT) when in pulse-skipping
mode. The amount of overshoot voltage (VSOAR) that
occurs after load removal (due to stored inductor energy)
can be calculated as:
VSOAR
(∆ILOAD(MAX))
≈
2
L
2C OUT VOUT
When using low-capacity ceramic filter capacitors, capacitor size is usually determined by the capacity needed to
prevent VSOAR from causing problems during load transients. Generally, once enough capacitance is added to
meet the overshoot requirement, undershoot at the rising
load edge is no longer a problem.
www.maximintegrated.com
Input Capacitor Selection
The input capacitor must meet the ripple current requirement (IRMS) imposed by the switching currents. The IRMS
requirements of an individual regulator can be determined
by the following equation:
I

IRMS =  LOAD  VOUT (VIN - VOUT )
V
 IN 
The worst-case RMS current requirement occurs when
operating with VIN = 2VOUT. At this point, the above
equation simplifies to IRMS = 0.5 x ILOAD. However, the
MAX17019 uses an interleaved fixed-frequency architecture, which helps reduce the overall input RMS current on
the INBC input supply.
For the MAX17019 system (INA) supply, nontantalum
chemistries (ceramic, aluminum, or OS-CON) are preferred due to their resistance to inrush surge currents
typical of systems with a mechanical switch or connector
in series with the input. For the MAX17019 INBC input
supply, ceramic capacitors are preferred on input due
to their low parasitic inductance, which helps reduce the
high-frequency ringing on the INBC supply when the internal MOSFETs are turned off. Choose an input capacitor
that exhibits less than +10°C temperature rise at the RMS
input current for optimal circuit longevity.
BST Capacitors
The boost capacitors (CBST) must be selected large
enough to handle the gate charging requirements of the
high-side MOSFETs. For these low-power applications,
0.1μF ceramic capacitors work well.
Regulator A Power-MOSFET Selection
Most of the following MOSFET guidelines focus on the
challenge of obtaining high load-current capability when
using high-voltage (> 20V) AC adapters. Low current
applications usually require less attention.
The high-side MOSFET (NH) must be able to dissipate
the resistive losses plus the switching losses at both
VIN(MIN) and VIN(MAX). Ideally, the losses at VIN(MIN)
should be roughly equal to the losses at VIN(MAX), with
lower losses in between. If the losses at VIN(MIN) are
significantly higher, consider increasing the size of NH.
Conversely, if the losses at VIN(MAX) are significantly
higher, consider reducing the size of NH. If VIN does not
vary over a wide range, maximum efficiency is achieved
by selecting a high-side MOSFET (NH) that has conduction losses equal to the switching losses.
Choose a low-side MOSFET (NL) that has the lowest
possible on-resistance (RDS(ON)), comes in a moderatesized package (i.e., 8-pin SO, DPAK, or D2PAK), and
Maxim Integrated │ 22
MAX17019
High-Input-Voltage Quad-Output Controller
is reasonably priced. Ensure that the MAX17019 DLA
gate driver can supply sufficient current to support the
gate charge and the current injected into the parasitic
drain-to-gate capacitor caused by the high-side MOSFET
turning on; otherwise, cross-conduction problems might
occur. Switching losses are not an issue for the low-side
MOSFET since it is a zero-voltage switched device when
used in the step-down topology.
Power-MOSFET Dissipation
Worst-case conduction losses occur at the duty factor
extremes. For the high-side MOSFET (NH), the worstcase
power dissipation due to resistance occurs at minimum
input voltage:
V

2
PD(NH Resistive) =  OUT (ILOAD ) R DS(ON)
 VIN 
Generally, use a small high-side MOSFET to reduce switching losses at high input voltages. However, the RDS(ON)
required to stay within package power-dissipation limits often
limits how small the MOSFET can be. The optimum occurs
when the switching losses equal the conduction (RDS(ON))
losses. High-side switching losses do not become an issue
until the input is greater than approximately 15V.
Calculating the power dissipation in high-side MOSFETs
(NH) due to switching losses is difficult, since it must allow
for difficult-to-quantify factors that influence the turn-on
and turn-off times. These factors include the internal
gate resistance, gate charge, threshold voltage, source
inductance, and PCB layout characteristics. The following switching loss calculation provides only a very rough
estimate and is no substitute for breadboard evaluation,
preferably including verification using a thermocouple
mounted on NH:
PD(NH Switching) =
 ILOADQ G(SW ) C OSS VIN(MAX) 
+

 VIN(MAX)f SW
I GATE
2


where COSS is the output capacitance of NH, QG(SW) is
the charge needed to turn on the NH MOSFET, and IGATE
is the peak gate-drive source/sink current (1A typ).
Switching losses in the high-side MOSFET can become
a heat problem when maximum AC adapter voltages are
applied, due to the squared term in the switchingloss equation (C x VIN2 x fSW). If the high-side MOSFET chosen for
adequate RDS(ON) at low battery voltages becomes extraordinarily hot when subjected to VIN(MAX), consider choosing
another MOSFET with lower parasitic capacitance.
www.maximintegrated.com
For the low-side MOSFET (NL) the worst-case power dissipation always occurs at maximum battery voltage:
  V

OUT  I
PD(NL Resistive) = 1 − 
( LOAD ) 2R DS(ON)

  VIN(MAX) 
The absolute worst case for MOSFET power dissipation
occurs under heavy overload conditions that are greater
than ILOAD(MAX), but are not high enough to exceed the
current limit and cause the fault latch to trip. To protect
against this possibility, “overdesign” the circuit to tolerate:
 ∆I

ILOAD = ILIMIT -  INDUCTOR 
2


where ILIMIT is the peak current allowed by the currentlimit circuit, including threshold tolerance and senseresistance variation. The MOSFETs must have a relatively
large heatsink to handle the overload power dissipation.
Choose a Schottky diode (DL) with a forward voltage
drop low enough to prevent the low-side MOSFET’s body
diode from turning on during the dead time. As a general rule, select a diode with a DC current rating equal
to 1/3 the load current. This diode is optional and can be
removed if efficiency is not critical.
VTT LDO Design Procedure
IND Input Capacitor Selection (CIND)
The value of the IND bypass capacitor is chosen to limit
the amount of ripple and noise at IND, and the amount
of voltage sag during a load transient. Typically, IND
connects to the output of a step-down switching regulator, which already has a large bulk output capacitor.
Nevertheless, a ceramic capacitor equivalent to half the
VTT output capacitance should be added and placed as
close as possible to IND. The necessary capacitance
value must be increased with larger load current, or if the
trace from IND to the power source is long and results in
relatively high input impedance.
VTT LDO Output Voltage (FBD)
The VTT output stage is powered from the IND input. The
VTT output voltage is set by the REFIND input. REFIND
sets the VTT LDO feedback regulation voltage (VFBD =
VREFIND) and the VTTR output voltage. The VTT LDO
(FBD voltage) and VTTR track the REFIND voltage over
a 0.5V to 1.5V range. This reference input feature makes
the MAX17019 ideal for memory applications in which the
termination supply must track the supply voltage.
Maxim Integrated │ 23
MAX17019
High-Input-Voltage Quad-Output Controller
VTT LDO Output Capacitor
Selection (COUTD)
VTT LDO Power Dissipation
A minimum value of 20μF or greater ceramic is needed
to stabilize the VTT output (OUTD). This value of capacitance limits the switching regulator’s unity-gain bandwidth frequency to approximately 1.2MHz (typ) to allow
adequate phase margin for stability. To keep the capacitor acting as a capacitor within the switching regulator’s
bandwidth, it is important that ceramic capacitors with low
ESR and ESL be used.
Since the gain bandwidth is also determined by the transconductance of the output MOSFETs, which increases
with load current, the output capacitor might need to be
greater than 20μF if the load current exceeds 1.5A, but
can be smaller than 20μF if the maximum load current
is less than 1.5A. As a guideline, choose the minimum
capacitance and maximum ESR for the output capacitor
using the following:
= 20µF ×
C OUT_MIN
ILOAD
1.5A
Power loss in the MAX17019 VTT LDO is significant
and can become a limiting design factor in the overall
MAX17019 design:
PDVTT = 2A x 0.9V = 1.8W
The 1.8W total power dissipation is within the 40-pin
TQFN multilayer board power-dissipation specification
of 2.9W. The typical DDR termination application does
not actually continuously source or sink high currents.
The actual VTT current typically remains around 100mA
to 200mA under steady-state conditions. VTTR is down
in the microampere range, though the Intel specification
requires 3mA for DDR1 and 1mA for DDR2. True worstcase power dissipation occurs on an output short-circuit
condition with worst-case current limit. The MAX17019
does not employ any foldback current limiting, and relies
on the internal thermal shutdown for protection. Both the
VTT and VTTR output voltages are referenced to the
same REFIND input.
Applications Information
Minimum Input Voltage
and:
R ESR_MAX
= 5mΩ ×
ILOAD
1.5A
RESR value is measured at the unity-gain-bandwidth frequency given by approximately:
f=
GBW
36
C OUT
×
ILOAD
1.5A
Once these conditions for stability are met, additional
capacitors, including those of electrolytic and tantalum
types, can be connected in parallel to the ceramic capacitor (if desired) to further suppress noise or voltage ripple
at the output.
VTTR Output Capacitor Selection
The VTTR buffer is a scaled-down version of the VTT
regulator, with much smaller output transconductance.
Therefore, the VTTR compensation requirements also
scale. For typical applications requiring load currents up
to ±3mA, a 0.22μF or greater ceramic capacitor is recommended (RESR < 0.3Ω).
www.maximintegrated.com
The minimum input operating voltage (dropout voltage) is
restricted by the maximum duty-cycle specification (see
the Electrical Characteristics table). For the best dropout
performance, use the slowest switching frequency setting
(FREQ = GND). However, keep in mind that the transient
performance gets worse as the stepdown regulators
approach the dropout voltage, so bulk output capacitance
must be added (see the voltage sag and soar equations
in the SMPS Design Procedure (Step-Down Regulators)
section). The absolute point of dropout occurs when the
inductor current ramps down during the off-time (ΔIDOWN)
as much as it ramps up during the on-time (ΔIUP). This
results in a minimum operating voltage defined by the following equation:
 1

VIN(MIN) = VOUT + VCHG + h
- 1(VOUT + VDIS )
 D MAX 
where VCHG and VDIS are the parasitic voltage drops in
the charge and discharge paths, respectively. A reasonable minimum value for h is 1.5, while the absolute minimum input voltage is calculated with h = 1.
Maxim Integrated │ 24
MAX17019
High-Input-Voltage Quad-Output Controller
Maximum Input Voltage
The MAX17019 controller includes a minimum on-time
specification, which determines the maximum input
operating voltage that maintains the selected switching frequency (see the Electrical Characteristics table).
Operation above this maximum input voltage results in
pulse skipping to avoid overcharging the output. At the
beginning of each cycle, if the output voltage is still above
the feedback threshold voltage, the controller does not
trigger an on-time pulse, effectively skipping a cycle.
This allows the controller to maintain regulation above
the maximum input voltage, but forces the controller to
effectively operate with a lower switching frequency. This
results in an input threshold voltage at which the controller
begins to skip pulses (VIN(SKIP)):


1

VIN(SKIP) = VOUT 
 f OSCt ON(MIN) 


where fOSC is the switching frequency selected by FREQ.
PCB Layout Guidelines
Careful PCB layout is critical to achieving low switching
losses and clean, stable operation. The switching power
stage requires particular attention. If possible, mount all
the power components on the top side of the board, with
their ground terminals flush against one another.
• Keep the high-current paths short, especially at the
ground terminals. This practice is essential for stable,
jitter-free operation.
• Keep the power traces and load connections short.
This practice is essential for high efficiency. Using
thick copper PCBs (2oz vs. 1oz) can enhance fullload
efficiency by 1% or more. Correctly routing PCB traces
is a difficult task that must be approached in terms of
fractions of centimeters, where a single milliohm of
excess trace resistance causes a measurable efficiency penalty.
• Minimize current-sensing errors by connecting CSPA
and CSNA directly across the current-sense resistor
(RSENSE_).
• When trade-offs in trace lengths must be made, it is
preferable to allow the inductor charging path to be
made longer than the discharge path. For example,
it is better to allow some extra distance between the
input capacitors and the high-side MOSFET than to
allow distance between the inductor and the lowside
MOSFET or between the inductor and the output filter
capacitor.
• Route high-speed switching nodes (BST_, LX_, DHA,
and DLA) away from sensitive analog areas (REF,
REFIND, FB_, CSPA, CSNA).
Follow the MAX17019 evaluation kit layout and use the
following guidelines for good PCB layout:
Chip Information
PROCESS: BiCMOS
www.maximintegrated.com
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.com/packages. Note
that a “+”, “#”, or “-” in the package code indicates RoHS status
only. Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE NO.
LAND
PATTERN
NO.
48 TQFN-EP
T4866+2
21-0141
90-0007
Maxim Integrated │ 25
MAX17019
High-Input-Voltage Quad-Output Controller
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
DESCRIPTION
0
8/08
Initial release
—
1
10/14
Removed automotive references from the General Description and Applications
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2014 Maxim Integrated Products, Inc. │ 26
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement