MAX17503 4.5V-60V, 2.5A, High-Efficiency, Synchronous Step-Down DC-DC Converter With Internal Compensation

MAX17503 4.5V-60V, 2.5A, High-Efficiency, Synchronous Step-Down DC-DC Converter With Internal Compensation
EVALUATION KIT AVAILABLE
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
General Description
The MAX17503 high-efficiency, high-voltage, synchro­
nously rectified step-down converter with dual integrated
MOSFETs operates over a 4.5V to 60V input. It delivers
up to 2.5A and 0.9V to 90%VIN output voltage. Built-in
compensation across the output voltage range eliminates
the need for external components. The feedback (FB)
regulation accuracy over -40NC to +125NC is ±1.1%. The
device is available in a compact (4mm x 4mm) TQFN
lead(Pb)-free package with an exposed pad. Simulation
models are available.
The device features a peak-current-mode control
architecture with a MODE feature that can be used to
operate the device in pulse-width modulation (PWM),
pulse-frequency modulation (PFM), or discontinuousconduction mode (DCM) control schemes. PWM operation
provides constant frequency operation at all loads, and is
useful in applications sensitive to switching frequency.
PFM operation disables negative inductor current and
additionally skips pulses at light loads for high efficiency.
DCM features constant frequency operation down to
lighter loads than PFM mode, by not skipping pulses but
only disabling negative inductor current at light loads.
DCM operation offers efficiency performance that lies
between PWM and PFM modes. The low-resistance,
on-chip MOSFETs ensure high efficiency at full load and
simplify the layout.
A programmable soft-start feature allows users to reduce
input inrush current. The device also incorporates an
output enable/undervoltage lockout pin (EN/UVLO) that
allows the user to turn on the part at the desired inputvoltage level. An open-drain RESET pin provides a
delayed power-good signal to the sys­tem upon achieving
successful regulation of the output voltage.
Benefits and Features
● Eliminates External Components and Reduces Total
Cost
• No Schottky-Synchronous Operation for High
Efficiency and Reduced Cost
• Internal Compensation for Stable Operation at Any
Output Voltage
• All-Ceramic Capacitor Solution: Ultra-Compact
Layout with as Few as Eight External Components
●
Reduces Number of DC-DC Regulators to Stock
• Wide 4.5V to 60V Input Voltage Range
• 0.9V to 90%VIN Output Voltage
• Delivers Up to 2.5A Over Temperature
• 100kHz to 2.2MHz Adjustable Frequency with
External Synchronization
• Available in a 20-Pin, 4mm x 4mm TQFN Package
● Reduces Power Dissipation
• Peak Efficiency > 90%
• PFM and DCM Modes for High Light-Load
Efficiency
• Shutdown Current = 2.8FA (typ)
● Operates Reliably
• Hiccup-Mode Current Limit and Autoretry Startup
• Built-In Output-Voltage Monitoring (Open-Drain
RESET Pin)
• Resistor-Programmable EN/UVLO Threshold
• Adjustable Soft-Start and Prebiased Power-Up
• -40NC to +125NC Operation
Applications
●
●
●
●
●
●
Industrial Power Supplies
Distributed Supply Regulation
Base Station Power Supplies
Wall Transformer Regulation
High-Voltage Single-Board Systems
General-Purpose Point-of-Load
19-6669; Rev 1; 4/14
Ordering Information appears at end of data sheet.
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Absolute Maximum Ratings
VIN to PGND..........................................................-0.3V to +65V
EN/UVLO to SGND................................................-0.3V to +65V
LX to PGND................................................-0.3V to (VIN + 0.3V)
BST to PGND.........................................................-0.3V to +70V
BST to LX..............................................................-0.3V to +6.5V
BST to VCC............................................................-0.3V to +65V
CF, RESET, SS, MODE, SYNC,
RT to SGND......................................................-0.3V to +6.5V
FB to SGND..........................................................-0.3V to +1.5V
VCC to SGND........................................................-0.3V to +6.5V
SGND to PGND.....................................................-0.3V to +0.3V
LX Total RMS Current............................................................±4A
Output Short-Circuit Duration.....................................Continuous
Continuous Power Dissipation (TA = +70ºC) (multilayer board)
TQFN (derate 30.3mW/ºC above TA = +70ºC).......2424.2mW
Operating Temperature Range...........................-40NC to +125ºC
Junction Temperature....................................................... +150ºC
Storage Temperature Range..............................-65NC to +160ºC
Lead Temperature (soldering, 10s).................................. +300ºC
Soldering Temperature (reflow)........................................ +260ºC
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.
Package Thermal Characteristics (Note 1)
TQFN
Junction-to-Ambient Thermal Resistance (θJA)...........33ºC/W
Junction-to-Case Thermal Resistance (θJC)..................2ºC/W
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
Electrical Characteristics
(VIN = VEN/UVLO = 24V, RRT = 40.2kI (500kHz), CVCC = 2.2μF, VPGND = VSGND = VMODE = VSYNC = 0V, LX = SS = RESET = open,
VBST to VLX = 5V, VFB = 1V, TA = TJ = -40ºC to +125ºC, unless otherwise noted. Typical values are at TA = +25ºC. All voltages are
referenced to SGND, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
60
V
VEN/UVLO = 0V (shutdown mode)
2.8
4.5
VFB = 1V, MODE = RT = open
118
INPUT SUPPLY (VIN)
Input Voltage Range
Input Shutdown Current
VIN
IIN-SH
IQ_PFM
Input Quiescent Current
4.5
VFB = 1V, MODE = open
162
IQ-DCM
DCM mode, VLX = 0.1V
1.16
IQ_PWM
Normal switching mode, fSW = 500kHz, VFB
= 0.8V
9.5
µA
1.8
mA
ENABLE/UVLO (EN/UVLO)
EN/UVLO Threshold
EN/UVLO Input Leakage Current
VENR
VEN/UVLO rising
1.19
1.215
1.26
VENF
VEN/UVLO falling
1.068
1.09
1.131
-50
0
+50
nA
4.75
5
5.25
V
VCC = 4.3V, VIN = 6V
26.5
54
100
mA
VIN = 4.5V, IVCC = 20mA
4.2
VCC_UVR
VCC rising
4.05
4.2
4.3
VCC_UVF
VCC falling
3.65
3.8
3.9
IEN
VEN/UVLO = 0V, TA = +25ºC
V
LDO
VCC Output Voltage Range
VCC Current Limit
VCC Dropout
VCC UVLO
www.maximintegrated.com
VCC
IVCC-MAX
VCC-DO
6V < VIN < 60V, IVCC = 1mA
1mA ≤ IVCC ≤ 25mA
V
V
Maxim Integrated │ 2
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Electrical Characteristics (continued)
(VIN = VEN/UVLO = 24V, RRT = 40.2kI (500kHz), CVCC = 2.2μF, VPGND = VSGND = VMODE = VSYNC = 0V, LX = SS = RESET = open,
VBST to VLX = 5V, VFB = 1V, TA = TJ = -40ºC to +125ºC, unless otherwise noted. Typical values are at TA = +25ºC. All voltages are
referenced to SGND, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
POWER MOSFET AND BST DRIVER
High-Side nMOS On-Resistance
RDS-ONH
ILX = 0.3A
165
325
mI
Low-Side nMOS On-Resistance
RDS-ONL
ILX = 0.3A
80
150
mI
LX Leakage Current
ILX_LKG
VLX = VIN - 1V, VLX = VPGND + 1V, TA = +25ºC
-2
+2
µA
VSS = 0.5V
4.7
5
5.3
µA
-40ºC ≤ TA ≤ +125ºC
0.89
0.9
0.91
V
0 < VFB < 1V, TA = +25ºC
-50
+50
nA
SOFT-START (SS)
Charging Current
ISS
FEEDBACK (FB)
FB Regulation Voltage
VFB_REG
FB Input Bias Current
IFB
MODE
VCC 1.6
VM-DCM
MODE = VCC (DCM mode)
VM-PFM
MODE = open (PFM mode)
VM-PWM
MODE = GND (PWM mode)
FB Threshold for Entering
Hibernate Mode
VFB_HBR
VFB rising
100.8
102.3
103.5
%
FB Threshold for Exiting Hibernate
Mode
VFB_HBF
VFB falling
100
101.1
102.3
%
IPEAK-LIMIT
3.2
3.7
4.3
A
IRUNAWAY-LIMIT
3.7
4.3
5
A
0
+0.16
MODE Threshold
V
VCC / 2
1.4
PFM/HIBERNATE MODE
CURRENT LIMIT
Peak Current-Limit Threshold
Runaway Current-Limit Threshold
Valley Current-Limit Threshold
ISINK-LIMIT
PFM Current-Limit Threshold
IPFM
MODE = open/VCC
-0.16
MODE = GND
-1.8
MODE = open
0.6
0.75
0.9
RRT = 210kΩ
90
100
110
RRT = 102kΩ
180
200
220
RRT = 40.2kΩ
475
500
525
RRT = 8.06kΩ
1950
2200
2450
RRT = open
460
500
fSW set by RRT
1.1 x
fSW
A
A
RT AND SYNC
Switching Frequency
SYNC Frequency Capture Range
www.maximintegrated.com
fSW
kHz
540
1.4 x
fSW
kHz
Maxim Integrated │ 3
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Electrical Characteristics (continued)
(VIN = VEN/UVLO = 24V, RRT = 40.2kI (500kHz), CVCC = 2.2μF, VPGND = VSGND = VMODE = VSYNC = 0V, LX = SS = RESET = open,
VBST to VLX = 5V, VFB = 1V, TA = TJ = -40ºC to +125ºC, unless otherwise noted. Typical values are at TA = +25ºC. All voltages are
referenced to SGND, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
SYNC Pulse Width
SYNC Threshold
FB Undervoltage Trip Level to
Cause Hiccup
MIN
TYP
MAX
50
VIH
ns
2.1
VIL
0.8
VFB-HICF
Hiccup Timeout
0.56
(Note 3)
Minimum On-Time
tON-MIN
Minimum Off-Time
tOFF-MIN
0.58
0.65
32,768
140
LX Dead Time
RESET Output Level Low
IRESET = 10mA
RESET Output Leakage Current
TA = TJ = +25ºC, VRESET = 5.5V
-0.1
V
V
Cycles
135
ns
160
ns
5
RESET
UNITS
ns
0.4
V
+0.1
µA
FB Threshold for RESET Assertion
VFB-OKF
VFB falling
90.5
92
94.6
%VFB-
FB Threshold for RESET
Deassertion
VFB-OKR
VFB rising
93.8
95
97.8
%VFB-
RESET Deassertion Delay After FB
Reaches 95% Regulation
REG
REG
1024
Cycles
165
ºC
10
ºC
THERMAL SHUTDOWN
Thermal-Shutdown Threshold
Temperature rising
Thermal-Shutdown Hysteresis
Note 2: All limits are 100% tested at +25ºC. Limits over temperature are guaranteed by design.
Note 3: See the Overcurrent Protection/Hiccup Mode Section for more details.
www.maximintegrated.com
Maxim Integrated │ 4
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Typical Operating Characteristics
(VIN = VEN/UVLO = 24V, VPGND = VSGND = 0V, CVIN = CVCC = 2.2µF, CBST = 0.1µF, CSS = 5600pF, RT = MODE = open, TA = TJ = -40ºC
to +125ºC, unless otherwise noted. Typical values are at TA = +25ºC. All voltages are referenced to GND, unless otherwise noted.)
70
VIN = 48V
VIN = 12V
60
80
VIN = 24V
70
VIN = 36V
VIN = 48V
VIN = 12V
60
5V OUTPUT, PFM MODE, FIGURE 4a
CIRCUIT EFFICIENCY vs. LOAD CURRENT
VIN = 12V
95
VIN = 24V
90
85
80
75
VIN = 48V
70
50
50
1500
2000
2500
2000
2500
1
10
100
1000 2500
5V OUTPUT, DCM MODE, FIGURE 4a
CIRCUIT EFFICIENCY vs. LOAD CURRENT
3.3V OUTPUT, DCM MODE, FIGURE 4b
CIRCUIT EFFICIENCY vs. LOAD CURRENT
90
75
70
65
VIN = 48V
1
100
20
1000 2500
60
VIN = 24V
50
VIN = 36V
40
VIN = 36V
30
MODE = VCC
1
10
100
20
1000 2500
MODE = VCC
1
10
100
1000 2500
5V OUTPUT, PWM MODE, FIGURE 4a
CIRCUIT LOAD AND LINE REGULATION
3.3V OUTPUT, PWM MODE, FIGURE 4b
CIRCUIT LOAD AND LINE REGULATION
5V OUTPUT, PFM MODE, FIGURE 4a
CIRCUIT LOAD AND LINE REGULATION
3.35
5.00
VIN = 12V VIN = 24V VIN = 36V
VIN = 48V
4.96
MODE = SGND
500
1000
1500
2000
LOAD CURRENT (mA)
www.maximintegrated.com
2500
3.33
3.32
3.31
3.30
3.29
VIN = 12V VIN = 24V VIN = 36V
3.28
3.27
VIN = 48V
3.26
3.25
5.5
MODE = SGND
0
500
5.4
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
5.01
4.97
3.34
1000
1500
2000
LOAD CURRENT (mA)
2500
MAX17503 toc09
LOAD CURRENT (mA)
5.02
0
VIN = 48V
LOAD CURRENT (mA)
5.03
4.98
70
LOAD CURRENT (mA)
5.04
4.99
50
30
MAX17503 toc07
5.05
10
VIN = 48V
VIN = 24V
VIN = 12V
80
40
VIN = 36V
MODE = OPEN
55
70
60
90
EFFICIENCY (%)
EFFICIENCY (%)
80
VIN = 12V
80
100
MAX17503 toc05
VIN = 24V
VIN = 12V
100
MAX17503 toc06
3.3V OUTPUT, PFM MODE, FIGURE 4b
CIRCUIT EFFICIENCY vs. LOAD CURRENT
60
OUTPUT VOLTAGE (V)
1500
LOAD CURRENT (mA)
85
4.95
1000
MODE = OPEN
LOAD CURRENT (mA)
90
50
500
0
VIN = 36V
LOAD CURRENT (mA)
95
EFFICIENCY (%)
1000
60
MAX17503 toc08
100
500
0
40
MAX17503 toc04
40
65
MODE = SGND
MODE = SGND
MAX17503 toc03
100
EFFICIENCY (%)
VIN = 36V
VIN = 24V
90
EFFICIENCY (%)
80
3.3V OUTPUT, PWM MODE, FIGURE 4b
CIRCUIT EFFICIENCY vs. LOAD CURRENT
MAX17503 toc02
90
EFFICIENCY (%)
100
MAX17503 toc01
100
5V OUTPUT, PWM MODE, FIGURE 4a
CIRCUIT EFFICIENCY vs. LOAD CURRENT
5.3
VIN = 24V
5.2
5.1
5.0
4.9
VIN = 36V
4.8
4.7
VIN = 48V
4.6
4.5
VIN = 12V
MODE = OPEN
0
500
1000
1500
2000
LOAD CURRENT (mA)
2500
Maxim Integrated │ 5
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Typical Operating Characteristics (continued)
(VIN = VEN/UVLO = 24V, VPGND = VSGND = 0V, CVIN = CVCC = 2.2µF, CBST = 0.1µF, CSS = 5600pF, RT = MODE = open, TA = TJ = -40ºC
to +125ºC, unless otherwise noted. Typical values are at TA = +25ºC. All voltages are referenced to GND, unless otherwise noted.)
3.4
VIN = 48V
3.3
3.2
VIN = 24V
VIN = 36V
3.1
3.0
MODE = OPEN
0
500
1000
1500
2000
2500
LOAD CURRENT (mA)
SOFT-START/SHUTDOWN FROM EN/UVLO
5V OUTPUT, 2.5A LOAD CURRENT,
FIGURE 4a CIRCUIT
2400
2200
2000
1800
1600
1400
1200
1000
800
600
400
200
0
SWITCHING FREQUENCY vs.
RT RESISTANCE
MAX17503 toc11
SWITCHING FREQUENCY (kHz)
VIN = 12V
3.5
OUTPUT VOLTAGE (V)
MAX17503 toc10
3.6
3.3V OUTPUT, PFM MODE, FIGURE 4b
CIRCUIT LOAD AND LINE REGULATION
0
10 20 30 40 50 60 70 80 90 100
RRT (kΩ)
SOFT-START/SHUTDOWN FROM EN/UVLO
3.3V OUTPUT, 2.5A LOAD CURRENT,
FIGURE 4b CIRCUIT
MAX17503 toc12
MAX17503 toc13
SOFT-START/SHUTDOWN FROM EN/UVLO
5V OUTPUT, PFM MODE, 5mA LOAD CURRENT,
FIGURE 4a CIRCUIT
MAX17503 toc14
MODE = OPEN
VEN/UVLO
2V/div
VEN/UVLO
2V/div
VEN/UVLO
2V/div
VOUT
2V/div
VOUT
2V/div
IOUT
1A/div
IOUT
1A/div
VRESET
5V/div
VRESET
5V/div
VOUT
1V/div
VRESET
5V/div
2ms/div
1ms/div
1ms/div
SOFT-START/SHUTDOWN FROM EN/UVLO,
3.3V OUTPUT, PFM MODE, 5mA LOAD
CURRENT, FIGURE 4b CIRCUIT
5V OUTPUT, PWM MODE
SOFT-START WITH 2.5V PREBIAS,
FIGURE 4a CIRCUIT
3.3V OUTPUT, PFM MODE
SOFT-START WITH 2.5V PREBIAS,
FIGURE 4b CIRCUIT
MODE = OPEN
MODE = SGND
MODE = OPEN
MAX17503 toc16
MAX17503 toc15
VEN/UVLO
2V/div
VEN/UVLO
2V/div
VEN/UVLO
2V/div
VOUT
1V/div
VOUT
2V/div
VOUT
1V/div
VRESET
5V/div
VRESET
5V/div
2ms/div
www.maximintegrated.com
MAX17503 toc17
VRESET
5V/div
1ms/div
1ms/div
Maxim Integrated │ 6
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Typical Operating Characteristics (continued)
(VIN = VEN/UVLO = 24V, VPGND = VSGND = 0V, CVIN = CVCC = 2.2µF, CBST = 0.1µF, CSS = 5600pF, RT = MODE = open, TA = TJ = -40ºC
to +125ºC, unless otherwise noted. Typical values are at TA = +25ºC. All voltages are referenced to GND, unless otherwise noted.)
5V OUTPUT, 2.5A LOAD CURRENT
STEADY-STATE SWITCHING WAVEFORMS,
FIGURE 4a CIRCUIT
5V OUTPUT, PWM MODE, NO LOAD
STEADY-STATE SWITCHING WAVEFORMS,
FIGURE 4a CIRCUIT
MAX17503 toc19
MAX17503 toc18
VOUT (AC)
50mV/div
VOUT (AC)
50mV/div
VLX
10V/div
VLX
10V/div
MODE = SGND
ILX
500mA/div
ILX
1A/div
1µs/div
1µs/div
5V OUTPUT, PFM MODE, 25mA LOAD
STEADY-STATE SWITCHING WAVEFORMS,
FIGURE 4a CIRCUIT
5V OUTPUT, DCM MODE, 25mA LOAD
STEADY-STATE SWITCHING WAVEFORMS,
FIGURE 4a CIRCUIT
MAX17503 toc20
MAX17503 toc21
VOUT (AC)
100mV/div
VOUT (AC)
20mV/div
VLX
10V/div
VLX
10V/div
ILX
500mA/div
ILX
200mA/div
MODE = OPEN
MODE = VCC
10µs/div
1µs/div
5V OUTPUT, PWM MODE
(LOAD CURRENT STEPPED FROM 1A TO 2A),
FIGURE 4a CIRCUIT
3.3V OUTPUT, PWM MODE
(LOAD CURRENT STEPPED FROM 1A TO 2A),
FIGURE 4b CIRCUIT
MODE = SGND
MODE = SGND
MAX17503 toc22
VOUT (AC)
50mV/div
VOUT (AC)
100mV/div
IOUT
1A/div
IOUT
1A/div
40µs/div
www.maximintegrated.com
MAX17503 toc23
40µs/div
Maxim Integrated │ 7
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Typical Operating Characteristics (continued)
(VIN = VEN/UVLO = 24V, VPGND = VSGND = 0V, CVIN = CVCC = 2.2µF, CBST = 0.1µF, CSS = 5600pF, RT = MODE = open.,TA = TJ = -40ºC
to +125ºC, unless otherwise noted. Typical values are at TA = +25ºC. All voltages are referenced to GND, unless otherwise noted.)
5V OUTPUT, PWM MODE (LOAD CURRENT
STEPPED FROM NO-LOAD TO 1A),
FIGURE 4a CIRCUIT
3.3V OUTPUT, PWM MODE (LOAD CURRENT
STEPPED FROM NO-LOAD TO 1A),
FIGURE 4b CIRCUIT
MODE = SGND
MODE = SGND
MAX17503 toc24
MAX17503 toc25
VOUT (AC)
100mV/div
VOUT (AC)
50mV/div
IOUT
1A/div
IOUT
1A/div
40µs/div
40µs/div
5V OUTPUT, PFM MODE (LOAD CURRENT
STEPPED FROM 5mA TO 1A),
FIGURE 4a CIRCUIT
3.3V OUTPUT, PFM MODE (LOAD CURRENT
STEPPED FROM 5mA TO 1A),
FIGURE 4b CIRCUIT
MODE = OPEN
MODE = OPEN
MAX17503 toc26
MAX17503 toc27
VOUT (AC)
100mV/div
VOUT (AC)
50mV/div
IOUT
500mA/div
IOUT
500mA/div
2ms/div
2ms/div
5V OUTPUT, DCM MODE (LOAD CURRENT
STEPPED FROM 50mA TO 1A),
FIGURE 4a CIRCUIT
3.3V OUTPUT, DCM MODE (LOAD CURRENT
STEPPED FROM 50mA TO 1A),
FIGURE 4b CIRCUIT
MODE = VCC
MODE = VCC
MAX17503 toc28
MAX17503 toc29
VOUT (AC)
100mV/div
VOUT (AC)
100mV/div
IOUT
500mA/div
IOUT
500mA/div
200µs/div
www.maximintegrated.com
200µs/div
Maxim Integrated │ 8
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Typical Operating Characteristics (continued)
(VIN = VEN/UVLO = 24V, VPGND = VSGND = 0V, CVIN = CVCC = 2.2µF, CBST = 0.1µF, CSS = 5600pF, RT = MODE = open, TA = TJ = -40ºC
to +125ºC, unless otherwise noted. Typical values are at TA = +25ºC. All voltages are referenced to GND, unless otherwise noted.)
5V OUTPUT, APPLICATION OF
EXTERNAL CLOCK AT 700kHz,
FIGURE 4a CIRCUIT
5V OUTPUT, OVERLOAD PROTECTION,
FIGURE 4a CIRCUIT
MAX17503 toc30
MAX17503 toc31
VLX
10V/div
IOUT
1A/div
VSYNC
2V/div
2µs/div
5V OUTPUT, 2.5A LOAD CURRENT
BODE PLOT, FIGURE 4a CIRCUIT
5V OUTPUT, 2.5A LOAD CURRENT
BODE PLOT, FIGURE 4b CIRCUIT
MAX17503 toc32
MAX17503 toc33
80
50
30
60
40
80
20
40
30
60
20
20
40
GAIN
10
0
0
-10
-20
CROSSOVER
FREQUENCY = 58.2kHz
-30
PHASE MARGIN = 63.4°
-40
-50
2
1k
4 6 81
2
-20
4 6 81
10k
FREQUENCY (Hz)
www.maximintegrated.com
100k
2
GAIN (dB)
60
PHASE
PHASE (°)
100
50
GAIN (dB)
MODE = SGND
20ms/div
120
100
PHASE
40
GAIN
10
20
0
-40
-10
CROSSOVER
FREQUENCY = 62.5kHz
-60
-20
PHASE MARGIN = 61.2°
-80
-30
-100
-40
2
1k
4 6 81
2
0
PHASE (°)
VOUT
500mV/div
-20
-40
4 6 81
10k
100k
2
-60
-80
FREQUENCY (Hz)
Maxim Integrated │ 9
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
PGND
SGND
VCC
MODE
TOP VIEW
PGND
Pin Configuration
15
14
13
12
11
PGND 16
10
RT
LX 17
9
FB
8
CF
7
SS
6
SYNC
MAX17503
LX 18
LX 19
2
3
4
5
EN/UVLO
RESET
VIN
1
VIN
+
VIN
BST 20
TQFN
4mm × 4mm
* EXPOSED PAD (CONNECT TO GROUND).
Pin Description
PIN
NAME
1–3
VIN
Power-Supply Input. 4.5V to 60V input supply range. Connect the VIN pins together. Decouple to PGND
with a 2.2µF capacitor; place the capacitor close to the VIN and PGND pins. Refer to the MAX17503 EV
kit data sheet for a layout example.
4
EN/UVLO
Enable/Undervoltage Lockout. Drive EN/UVLO high to enable the output voltage. Connect to the center
of the resistor-divider between VIN and SGND to set the input voltage at which the device turns on. Pull
up to VIN for always-on operation.
5
RESET
6
SYNC
7
SS
Soft-Start Input. Connect a capacitor from SS to SGND to set the soft-start time.
8
CF
At switching frequencies lower than 500kHz, connect a capacitor from CF to FB. Leave CF open if
switching frequency is equal or more than 500kHz. See the Loop Compensation section for more details.
9
FB
Feedback Input. Connect FB to the center tap of an external resistor-divider from the output to GND to
set the output voltage. See the Adjusting Output Voltage section for more details.
10
RT
Connect a resistor from RT to SGND to set the regulator’s switching frequency. Leave RT open for the
default 500kHz frequency. See the Setting the Switching Frequency (RT) section for more details.
MODE
MODE pin configures the device to operate either in PWM, PFM, or DCM modes of operation. Leave
MODE unconnected for PFM operation (pulse skipping at light loads). Connect MODE to SGND for
constant-frequency PWM operation at all loads. Connect MODE to VCC for DCM operation. See the
MODE Setting section for more details.
11
www.maximintegrated.com
FUNCTION
Open-Drain RESET Output. The RESET output is driven low if FB drops below 92% of its set value.
RESET goes high 1024 clock cycles after FB rises above 95% of its set value.
The device can be synchronized to an external clock using this pin. See the External Frequency
Synchronization section for more details.
Maxim Integrated │ 10
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Pin Description (continued)
PIN
NAME
FUNCTION
12
VCC
13
SGND
5V LDO Output. Bypass VCC with 2.2µF ceramic capacitance to SGND.
Analog Ground
14–16
PGND
Power Ground. Connect the PGND pins externally to the power ground plane. Connect the SGND and
PGND pins together at the ground return path of the VCC bypass capacitor. Refer to the MAX17503 EV
kit data sheet for a layout example.
17–19
LX
20
BST
—
EP
Switching Node. Connect LX pins to the switching side of the inductor. Refer to the MAX17503 EV kit
data sheet for a layout example.
Boost Flying Capacitor. Connect a 0.1µF ceramic capacitor between BST and LX.
Exposed pad. Connect to the SGND pin. Connect to a large copper plane below the IC to improve heat
dissipation capability. Add thermal vias below the exposed pad. Refer to the MAX17503 EV kit data sheet
for a layout example.
Block Diagram
VCC
5V
BST
MAX17503
LDO
VIN
SGND
CURRENT-SENSE
LOGIC
EN/UVLO
HICCUP
1.215V
PWM/
PFM/
HICCUP
LOGIC
AND
DRIVERS
LX
RT
PGND
OSCILLATOR
SYNC
CF
FB
VCC
SS
SWITCHOVER
LOGIC
VBG = 0.9V
SLOPE
COMPENSATION
5µA
FB
HICCUP
www.maximintegrated.com
MODE
SELECTION
LOGIC
ERROR AMPLIFIER/
LOOP COMPENSATION
EN/UVLO
MODE
RESET
RESET
LOGIC
Maxim Integrated │ 11
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Detailed Description
PFM Mode Operation
The device features a peak-current-mode control
architecture. An internal transconductance error amplifier
produces an integrated error voltage at an internal node,
which sets the duty cycle using a PWM comparator, a highside current-sense amplifier, and a slope-compensation
generator. At each rising edge of the clock, the highside MOSFET turns on and remains on until either
the appropriate or maximum duty cycle is reached, or
the peak current limit is detected. During the high-side
MOSFET’s on-time, the inductor current ramps up. During
the second half of the switching cycle, the high-side
MOSFET turns off and the low-side MOSFET turns on.
The inductor releases the stored energy as its current
ramps down and provides current to the output.
DCM Mode Operation
The MAX17503 high-efficiency, high-voltage, synchro­
nously rectified step-down converter with dual integrated
MOSFETs operates over a 4.5V to 60V input. It delivers
up to 2.5A and 0.9V to 90%VIN output voltage. Built-in
compensation across the output voltage range eliminates
the need for external components. The feedback (FB)
regulation accuracy over -40NC to +125NC is ±1.1%.
PFM mode of operation disables negative inductor current
and additionally skips pulses at light loads for high
efficiency. In PFM mode, the inductor current is forced to
a fixed peak of 750mA every clock cycle until the output
rises to 102.3% of the nominal voltage. Once the output
reaches 102.3% of the nominal voltage, both the high-side
and low-side FETs are turned off and the device enters
hibernate operation until the load discharges the output to
101.1% of the nominal voltage. Most of the internal blocks
are turned off in hibernate operation to save quiescent
current. After the output falls below 101.1% of the nominal
voltage, the device comes out of hibernate operation,
turns on all internal blocks, and again commences the
process of delivering pulses of energy to the output until it
reaches 102.3% of the nominal output voltage.
The advantage of the PFM mode is higher efficiency at
light loads because of lower quiescent current drawn from
supply. The disadvantage is that the output-voltage ripple
is higher compared to PWM or DCM modes of operation
and switching frequency is not constant at light loads.
The device features a MODE pin that can be used
to operate the device in PWM, PFM, or DCN control
schemes. The device integrates adjustable-input
undervoltage lockout, adjustable soft-start, open RESET,
and external frequency synchronization features.
DCM mode of operation features constant frequency
operation down to lighter loads than PFM mode, by not
skipping pulses but only disabling negative inductor current at light loads. DCM operation offers efficiency performance that lies between PWM and PFM modes.
Mode Selection (MODE)
Linear Regulator (VCC)
The logic state of the MODE pin is latched when VCC
and EN/UVLO voltages exceed the respective UVLO
rising thresholds and all internal voltages are ready to
allow LX switching. If the MODE pin is open at power-up,
the device operates in PFM mode at light loads. If the
MODE pin is grounded at power-up, the device operates
in constant-frequency PWM mode at all loads. Finally,
if the MODE pin is connected to VCC at power-up, the
device operates in constant-frequency DCM mode at light
loads. State changes on the MODE pin are ignored during
normal operation.
PWM Mode Operation
In PWM mode, the inductor current is allowed to go
negative. PWM operation provides constant frequency
operation at all loads, and is useful in applications
sensitive to switching frequency. However, the PWM
mode of operation gives lower efficiency at light loads
compared to PFM and DCM modes of operation.
www.maximintegrated.com
An internal linear regulator (VCC) provides a 5V nominal
supply to power the internal blocks and the low-side
MOSFET driver. The output of the linear regulator (VCC)
should be bypassed with a 2.2µF ceramic capacitor to
SGND. The device employs an undervoltage lockout
circuit that disables the internal linear regulator when VCC
falls below 3.8V (typ).
Setting the Switching Frequency (RT)
The switching frequency of the device can be programmed
from 100kHz to 2.2MHz by using a resistor connected
from the RT pin to SGND. The switching frequency (fSW)
is related to the resistor connected at the RT pin (RRT) by
the following equation:
R RT ≅
21× 10 3
− 1.7
f SW
where RRT is in kΩ and fSW is in kHz. Leaving the RT pin
open causes the device to operate at the default switching
frequency of 500kHz. See Table 1 for RT resistor values
for a few common switching frequencies. To operate the
MAX17503 at switching frequencies lower than 200kHz,
Maxim Integrated │ 12
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Table 1. Switching Frequency vs. RT
Resistor
SWITCHING FREQUENCY (kHz)
RT RESISTOR (kΩ)
500
Open
100
210
200
102
400
49.9
1000
19.1
2200
8.06
an R-C network has to be connected in parallel to the
resistor connected from RT to SGND, as shown in Figure
1. The values of the components R8 and C13 are 90.9kW
and 220pF, respectively.
R5
R8
C13
Figure 1. Setting the Switching Frequency
Operating Input Voltage Range
The minimum and maximum operating input voltages for
a given output voltage should be calculated as follows:
VIN(MIN) =
VOUT + (I OUT(MAX) × (R DCR + 0.15))
1- (f SW(MAX) × t OFF(MAX) )
+ (I OUT(MAX) × 0.175)
VIN(MAX) =
VOUT
f SW(MAX) × t ON(MIN) )
where VOUT is the steady-state output voltage, IOUT (MAX)
is the maximum load current, RDCR is the DC resistance
of the inductor, fSW(MAX) is the maximum switching
frequency, tOFF-MAX is the worst-case minimum switch
off-time (160ns), and tON-MIN is the worst-case minimum
switch on-time (135ns).
External Frequency Synchronization (SYNC)
The internal oscillator of the device can be synchronized
to an external clock signal on the SYNC pin. The external
synchronization clock frequency must be between 1.1
www.maximintegrated.com
x fSW and 1.4 x fSW, where fSW is the frequency
programmed by the RT resistor. The minimum external
clock pulse-width high should be greater than 50ns. See
the RT AND SYNC section in the Electrical Characteristics
table for details.
Overcurrent Protection/Hiccup Mode
The device is provided with a robust overcurrent protection
scheme that protects the device under overload and
output short-circuit conditions. A cycle-by-cycle peak
current limit turns off the high-side MOSFET whenever
the high-side switch current exceeds an internal limit
of 3.7A (typ). A runaway current limit on the high-side
switch current at 4.3A (typ) protects the device under
high input voltage, short-circuit conditions when there is
insufficient output voltage available to restore the inductor
current that was built up during the ON period of the
step-down converter. One occurrence of the runaway
current limit triggers a hiccup mode. In addition, if due to
a fault condition, feedback voltage drops to 0.58V (typ)
any time after soft-start is complete, and hiccup mode
is triggered. In hiccup mode, the converter is protected
by suspending switching for a hiccup timeout period of
32,768 clock cycles. Once the hiccup timeout period
expires, soft-start is attempted again. Note that when softstart is attempted under overload condition, if feedback
voltage does not exceed 0.58V, the device switches at
half the programmed switching frequency. Hiccup mode
of operation ensures low power dissipation under output
short-circuit conditions.
RESET Output
The device includes a RESET comparator to monitor the
output voltage. The open-drain RESET output requires
an external pullup resistor. RESET goes high (high
impedance) 1024 switching cycles after the regulator
output increases above 95% of the designed nominal
regulated voltage. RESET goes low when the regulator
output voltage drops to below 92% of the nominal
regulated voltage. RESET also goes low during thermal
shutdown.
Prebiased Output
When the device starts into a prebiased output, both the
high-side and the low-side switches are turned off so that
the converter does not sink current from the output. Highside and low-side switches do not start switching until
the PWM comparator commands the first PWM pulse, at
which point switching commences. The output voltage is
then smoothly ramped up to the target value in alignment
with the internal reference.
Maxim Integrated │ 13
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Thermal-Shutdown Protection
Thermal-shutdown protection limits total power dissipation
in the device. When the junction temperature of the device
exceeds +165ºC, an on-chip thermal sensor shuts down
the device, allowing the device to cool. The thermal sensor
turns the device on again after the junction temperature
cools by 10ºC. Soft-start resets during thermal shutdown.
Carefully evaluate the total power dissipation (see the
Power Dissipation section) to avoid unwanted triggering of
the thermal shutdown in normal operation.
Applications Information
Input Capacitor Selection
The input filter capacitor reduces peak currents drawn
from the power source and reduces noise and voltage
ripple on the input caused by the circuit’s switching.
The input capacitor RMS current requirement (IRMS) is
defined by the following equation:
=
IRMS I OUT(MAX) ×
VOUT × (VIN - VOUT )
VIN
where, IOUT(MAX) is the maximum load current. IRMS has
a maximum value when the input voltage equals twice
the output voltage (VIN = 2 x VOUT), so IRMS(MAX) =
IOUT(MAX)/2.
Choose an input capacitor that exhibits less than +10ºC
temperature rise at the RMS input current for optimal
long-term reliability. Use low-ESR ceramic capacitors with
high-ripple-current capability at the input. X7R capacitors
are recommended in industrial applications for their
temperature stability. Calculate the input capacitance
using the following equation:
C IN =
I OUT(MAX) × D × (1- D)
η × f SW × ∆VIN
where D = VOUT/VIN is the duty ratio of the controller,
fSW is the switching frequency, ΔVIN is the allowable input
voltage ripple, and E is the efficiency.
In applications where the source is located distant from
the device input, an electrolytic capacitor should be
added in parallel to the ceramic capacitor to provide
necessary damping for potential oscillations caused by
the inductance of the longer input power path and input
ceramic capacitor.
Inductor Selection
Three key inductor parameters must be specified for
operation with the device: inductance value (L), inductor
www.maximintegrated.com
saturation current (ISAT), and DC resistance (RDCR). The
switching frequency and output voltage determine the
inductor value as follows:
L=
VOUT
f SW
where VOUT, and fSW are nominal values.
Select a low-loss inductor closest to the calculated
value with acceptable dimensions and having the lowest
possible DC resistance. The saturation current rating
(ISAT) of the inductor must be high enough to ensure that
saturation can occur only above the peak current-limit
value of 3.7A.
Output Capacitor Selection
X7R ceramic output capacitors are preferred due to their
stability over temperature in industrial applications. The
output capacitors are usually sized to support a step load
of 50% of the maximum output current in the application,
so the output voltage deviation is contained to 3% of the
output voltage change. The minimum required output
capacitance can be calculated as follows:
C OUT=
1 I STEP × t RESPONSE
×
2
∆VOUT
t RESPONSE ≅ (
0.33
1
+
)
fC
f sw
where ISTEP is the load current step, tRESPONSE is the
response time of the controller, DVOUT is the allowable
output-voltage deviation, fC is the target closed-loop
crossover frequency, and fSW is the switching frequency.
Select fC to be 1/9th of fSW if the switching frequency is
less than or equal to 500kHz. If the switching frequency is
more than 500kHz, select fC to be 55kHz.
Soft-Start Capacitor Selection
The device implements adjustable soft-start operation to
reduce inrush current. A capacitor connected from the SS pin
to SGND programs the soft-start time. The selected output
capacitance (CSEL) and the output voltage (VOUT) determine
the minimum required soft-start capacitor as follows:
C SS ≥ 28 × 10 -6 × C SEL × VOUT
The soft-start time (tSS) is related to the capacitor
connected at SS (CSS) by the following equation:
C SS
t SS =
5.55 × 10 -6
For example, to program a 1ms soft-start time, a 5.6nF
capacitor should be connected from the SS pin to SGND.
Maxim Integrated │ 14
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
VIN
VOUT
R1
R3
EN/UVLO
FB
R2
R4
SGND
SGND
Figure 2. Setting the Input Undervoltage Lockout
Figure 3. Setting the Output Voltage
Table 2. C6 Capacitor Value at Various
Switching Frequencies
Calculate resistor R3 from the output to the FB pin as
follows:
SWITCHING FREQUENCY RANGE (kHz)
C6 (pF)
200 to 300
2.2
300 to 400
1.2
400 to 500
0.75
Setting the Input Undervoltage-Lockout Level
The device offers an adjustable input undervoltage-lockout
level. Set the voltage at which the device turns on with
a resistive voltage-divider connected from VIN to SGND.
Connect the center node of the divider to EN/UVLO.
Choose R1 to be 3.3MI and then calculate R2 as follows:
R2 =
R1× 1.215
(VINU - 1.215)
where VINU is the voltage at which the device is required
to turn on. Ensure that VINU is higher than 0.8 x VOUT.
Loop Compensation
The device is internally loop compensated. However, if
the switching frequency is less than 500kHz, connect a
0402 capacitor C6 between the CF pin and the FB pin.
Use Table 2 to select the value of C6.
R3 =
216 × 10 3
f C × C OUT
where R3 is in kΩ, crossover frequency fC is in kHz, and
the output capacitor COUT is in µF. Choose fC to be 1/9th
of the switching frequency, fSW, if the switching frequency
is less than or equal to 500kHz. If the switching frequency
is more than 500kHz, select fC to be 55kHz.
Calculate resistor R4 from the FB pin to SGND as follows:
R4 =
R3 × 0.9
(VOUT - 0.9)
Power Dissipation
Ensure that the junction temperature of the device
does not exceed 125ºC under the operating conditions
specified for the power supply.
At a particular operating condition, the power losses that
lead to temperature rise of the part are estimated as
follows:
(
1
PLOSS =
(POUT × ( - 1)) - I OUT 2 × R DCR
η
)
P=
OUT VOUT × I OUT
If the switching frequency is less than 200kHz, connect
an additional R-C network in parallel to the top resistor of
the feedback divider (R3). See Figure 5 to calculate the
values of the components R7, C12, and C6.
where POUT is the total output power, η is the efficiency
of the converter, and RDCR is the DC resistances of the
inductor. (See the Typical Operating Characteristics for more
information on efficiency at typical operating conditions.)
Adjusting Output Voltage
For a multilayer board, the thermal performance metrics
for the package are given below:
Set the output voltage with a resistive voltage-divider
connected from the positive terminal of the output
capacitor (VOUT) to SGND (see Figure 3). Connect the
center node of the divider to the FB pin. Use the following
procedure to choose the resistive voltage-divider values:
www.maximintegrated.com
θ JA = 33°C W
θ JC =2°C W
Maxim Integrated │ 15
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
The junction temperature of the device can be estimated
at any given maximum ambient temperature (TA_MAX)
from the equation below:
TJ_MAX
= T A _MAX + (θ JA × PLOSS )
If the application has a thermal management system that
ensures that the exposed pad of the device is maintained
at a given temperature (TEP_MAX) by using proper heat
sinks, then the junction temperature of the device can be
estimated at any given maximum ambient temperature
from the equation below:
T=
J_MAX TEP_MAX + (θ JC × PLOSS )
PCB Layout Guidelines
All connections carrying pulsed currents must be very
short and as wide as possible. The inductance of these
connections must be kept to an absolute minimum due to
the high di/dt of the currents. Since inductance of a current
carrying loop is proportional to the area enclosed by the
loop, if the loop area is made very small, inductance is
reduced. Additionally, small-current loop areas reduce
radiated EMI.
A ceramic input filter capacitor should be placed close
to the VIN pins of the IC. This eliminates as much trace
inductance effects as possible and gives the IC a cleaner
voltage supply. A bypass capacitor for the VCC pin also
should be placed close to the pin to reduce effects of trace
impedance.
When routing the circuitry around the IC, the analog
small-signal ground and the power ground for switching
currents must be kept separate. They should be connected
together at a point where switching activity is at a
minimum, typically the return terminal of the VCC bypass
capacitor. This helps keep the analog ground quiet.
The ground plane should be kept continuous/unbroken
as far as possible. No trace carrying high switching
current should be placed directly over any ground plane
discontinuity.
PCB layout also affects the thermal performance of the
design. A number of thermal vias that connect to a large
ground plane should be provided under the exposed pad
of the part, for efficient heat dissipation.
For a sample layout that ensures first pass success,
refer to the MAX17503 evaluation kit layout available at
www.maximintegrated.com.
www.maximintegrated.com
Maxim Integrated │ 16
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Typical Application Circuits
VIN
(6.5V TO 60V)
C1
2.2µF
VIN
EN/UVLO
RT
VIN
VIN
BST
SYNC
MAX17503
MODE
C2
2.2µF
C5
0.1µF
LX
L1
10µH
VOUT
5V, 2.5A
C4
22µF
LX
LX
VCC
R3
178kΩ
FB
SGND
R4
39kΩ
RESET
CF
SS
PGND
PGND
PGND
C3
5.6nF
fSW = 500kHz
Figure 4a - 5V Output, 500kHz Switching Frequency
VIN (6.5V TO 60V)
C1
2.2uF
VIN
VIN
EN/UVLO
RT
VIN
VIN
BST
SYNC
LX
MODE
C2
2.2µF
C5
0.1µF
L1
6.8µH
C4
47µF
LX
MAX17503
LX
VCC
VOUT
3.3V, 2.5A
R3
127kΩ
FB
SGND
R4
47.5kΩ
RESET
CF
SS
C3
5600pF
PGND
PGND
PGND
fSW = 500kHz
Figure 4b - 3.3V Output, 500kHz Switching Frequency
www.maximintegrated.com
Maxim Integrated │ 17
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Typical Application Circuits (continued)
VIN
C1
C13
220pF
2.2μF
C8
2.2μF
R8
EN/UVLO
90.9k
R5
VIN
VIN
VIN
RT
BST
C5
0.1μF
210k
SYNC
MODE
MAX17503
LX
L1
LX
33μH
VOUT
3.3V, 2.5A
C4
100μF C9
LX
C12
100μF
97.6k
R3
VCC
C2
R7
2.2μF
47pF
1k
FB
SGND
CF
RESETB
SS
C3
PGND
PGND
33000pF
C6
15pF
R4
36.5k
PGND
Fsw = 100kHz
C12 = 0.8/ (R5 X Fsw)
R7 = R5/100
C6 = 14/Fsw
Figure 5 - 3.3V Output, 100kHz Switching Frequency
Ordering Information
Package Information
PART
PIN-PACKAGE
MAX17503ATP+
20 TQFN-EP*
Note: All devices operate over the -40ºC to +125ºC temperature range, unless otherwise noted.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Chip 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.
20 TQFN-EP
T2044+4
21-0139
90-0409
PROCESS: BiCMOS
www.maximintegrated.com
Maxim Integrated │ 18
MAX17503
4.5V-60V, 2.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
0
8/13
Initial release
1
4/14
Added description and schematic for operation at 100kHz frequency
DESCRIPTION
—
1-9, 12-13, 15, 18
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim
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. │ 19
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