SC4216 Very Low Input /Very Low Dropout 3 Amp Regulator With Enable

SC4216 Very Low Input /Very Low Dropout 3 Amp Regulator With Enable
SC4216
Very Low Input /Very Low Dropout
3 Amp Regulator With Enable
POWER MANAGEMENT
Features
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Input Voltage as low as 1.45V
500mV dropout @ 3A
Adjustable output from 0.5V to 3.8V
Over current and over temperature protection
Enable pin
10µA quiescent current in shutdown
Full industrial temperature range
Available in SOIC-8-EDP Lead-free package, fully WEEE
and RoHS compliant
Applications
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Description
Telecom/Networking cards
Motherboards/Peripheral cards
Industrial applications
Wireless infrastructure
Set top boxes
Medical equipment
Notebook computers
Battery powered systems
The SC4216 is a high performance positive voltage regulator designed for use in applications requiring very low
input voltage and very low dropout voltage at up to 3
amperes. It operates with a Vin as low as 1.45V, with output
voltage programmable as low as 0.5V. The SC4216 features
ultra low dropout, ideal for applications where Vout is very
close to Vin. Additionally, the SC4216 has an enable pin to
further reduce power dissipation while shut- down. The
SC4216 provides excellent regulation over variations in
line, load and temperature.
The SC4216 is available in the SOIC-8-EDP (Exposed Die
Pad) package. The output voltage can be set via an external divider or to fixed settings of 0.5V and 1.2V depending
on how the FB pin is configured.
Typical Application Circuit
January 28, 2009
© 2009 Semtech Corporation
1
SC4216
Pin Configuration
Ordering Information
Device
Package
SC4216STRT(1)(2)
SOIC-8-EDP
SC4216EVB
Evaluation Board
Notes:
(1) Available in tape and reel only. A reel contains 2,500 devices.
(2) Available in lead-free package only. Device is WEEE and RoHS
compliant.
Marking Information
2
SC4216
Absolute Maximum Ratings
Recommended Operating Conditions
VIN, EN, VO, FB to GND (V) . . . . . . . . . . . . . . . . . . -0.3 to +7.0
VIN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.45 <VIN < 5.5
Power Dissipation . . . . . . . . . . . . . . . . . . . . . Internally Limited
Ambient Temperature Range (°C) . . . . . . . . . -40 < TA < +105
(1)
ESD Protection Level (kV) . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Junction Temperature Range (°C) . . . . . . . . . -40 < TJ < +125
Maximum Output Current (A) . . . . . . . . . . . . . . . . . . . . . . . . .3
Thermal Information
Thermal Resistance, Junction to Ambient(2) (°C/W) . . . . 36
Thermal Resistance, Junction to Case(2) (°C/W). . . . . . . . 5.5
Maximum Junction Temperature (°C) . . . . . . . . . . . . . .+150
Storage Temperature Range (°C) . . . . . . . . . . . . -65 to +150
Peak IR Reflow Temperature (10s to 30s) (°C) . . . . . . +260
Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters
specified in the Electrical Characteristics section is not recommended.
NOTES:
(1) Tested according to JEDEC standard JESD22-A114-B.
(2) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.
Electrical Characteristics
Unless specified: VEN = VIN, VFB = VO, VIN = 1.45V to 5.5V, IO = 10µA to 3A, TA = 25° C.
Values in bold apply over the full operating temperature range.
Parameter
Symbol
Conditions
Min
Typ
Max
Units
3
mA
50
µA
VIN
Quiescent Current
IQ
VIN = 3.3V, IO = 0A
VIN = 5.5V, VEN =0V
10
VO
Output Voltage(1)
(Fixed Voltage, VFB = 0)
VO
VIN= VO + 0.5V, IO = 10mA
-2%
1.45V ≤ VIN ≤ 5.5V, IO = 10mA
-3%
+2%
VO
V
+3%
Line Regulation(1)
REG (LINE)
IO =10mA
0.2
0.4
%/V
Load Regulation(1)
REG(LOAD)
10mA ≤ IO ≤ 3A, 1.6V ≤ VIN ≤ 5.5V
0.25
1.0
%
75
150
IO =500mA
Dropout Voltage(1)(2)
VDO
200
mV
150
IO =1A
250
300
3
SC4216
Electrical Characteristics (continued)
Parameter
Symbol
Conditions
Min
Typ
Max
250
350
IO =1.5A
400
300
IO = 2A
VDO
IO = 2.5A
mV
450
400
IO
Current Limit(4)
ICL
550
700
IO = 3A, 1.6V ≤ VIN ≤ 5.5V
Minimum Load Current
450
600
IO =3A
(3)(4)
400
500
350
Dropout Voltage(1)(2)
Units
500
650
10
µA
A
3.5
4.5
5.0
0.495
0.5
0.505
Feedback
Reference Voltage(1)
VREF
Feedback Pin Current(4)
IADJ
(5)
Feedback Pin Threshold
VIN = 3.3V, VFB = VOUT , IO =10mA
V
0.490
VFB = VREF
V TH(FB)
0.05
0.510
80
200
nA
0.10
0.15
V
1.5
10
µA
EN
Enable Pin Current
Enable Pin Threshold
IEN
VIH
VIL
VEN = 0V, VIN =3.3V
1.6
VIN=3.3V
V
0.4
Over Temperature Protection
High Trip Level
Hysteresis
THI
160
O
THYST
10
O
C
C
Notes:
(1) Low duty cycle pulse testing with Kelvin connections required.
(2) VDO = VIN -VO when VO decreases by 1.5% of its nominal output voltage with VIN = VO +0.8V.
(3) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet this requirement.
(4) Guaranteed by design.
(5) When VFB exceeds this threshold, the “Sense Select” switch disconnects the internal feedback chain from the error amplifier and connects VFB
instead.
4
SC4216
Typical Characteristics
5
SC4216
Pin Descriptions
Pin #
Pin Name
2
EN
Enable Input. Pulling this pin below 0.4V turns the regulator off, reducing the quiescent current to
a fraction of its operating value. The device will be enabled if this pin is left open. Connect to VIN if
not being used.
3
VIN
Input voltage. For regulation at full load, the input to this pin must be between (VO+ 0.5V) and
5.5V. Minimum VIN = 1.45V. A large bulk capacitance should be placed closely to this pin to ensure
that the input supply does not sag below 1.4V. Also a minimum of 4.7uF ceramic capacitor should
be placed directly at this pin.
6
VO
The pin is the power output of the device. A minimum of 10uF capacitor should be placed directly
at this pin.
7
FB
When this pin is grounded, an internal resistor divider sets the output voltage to 1.2V. If connected
to the Vo pin, the output voltage will be set at 0.5V. If external feedback resistors are used, the
output voltage will be determined by the resistor ratio (See Application Circuits on page 1):
8
GND
1, 4, 5
NC
THERMAL PAD
Pin Function
Reference ground. The GND pin and the exposed die pad must be connected together at the IC
pin.
No Connection.
Pad for heatsinking purposes. Connect to ground plane using multiple vias.
Block Diagram
6
SC4216
Applications Information (continued)
Introduction
The SC4216 is intended for applications where high
current capability and very low dropout voltage are
required. It provides a very simple, low cost solution that
uses very little PCB real estate. Additional features include
an enable pin to allow for a very low power consumption
standby mode, and a fully adjustable output.
Component Selection
Input capacitor: A large bulk capacitance ≥ 10µF/A
(output load) should be closely placed to the input supply
pin of the SC4216 to ensure that Vin does not sag below
1.45V. Also a minimum of 4.7µF ceramic capacitor is recommended to be placed directly next to the Vin pin. This
allows for the device being some distance from any bulk
capacitance on the rail. Additionally, input droop due to
load transients is reduced, improving load transient
response. Additional capacitance may be added if required
by the application.
Output capacitor: A minimum bulk capacitance of ≥
10µF/A (output load), along with a 0.1µF ceramic decoupling capacitor is recommended. Increasing the bulk
capacitance will improve the overall transient response.
The use of multiple lower value ceramic capacitors in parallel to achieve the desired bulk capacitance will not cause
stability issues. Although designed for use with ceramic
output capacitors, the SC4216 is extremely tolerant of
output capacitor ESR values and thus will also work comfortably with tantalum output capacitors.
≤50kΩ). A suitable value for R2 can be chosen in the range
of 1kΩ to 50kΩ. R1 can then be calculated from.
R1 = R 2 ⋅
(VO − VREF )
VREF
The highest output voltage achievable with external resistors is 4V. An attempt to set a higher voltage may result in
VFB(TH) not being exceeded which will force the device into
the 1.2V output mode.
The SC4216H does not have this limitation and is recommended for applications requiring VO above 3.8V.
Enable: Pulling this pin below 0.4V turns the regulator off,
reducing the quiescent current to a fraction of its operating value. A pull up resistor up to 400kOhms should be
connected from this pin to the VIN pin in applications
where supply voltages of Vin < 1.9V are required. For
applications with higher voltages than 1.9V, EN pin could
be left open or connected to VIN.
Thermal Considerations
The power dissipation in the SC4216 is given by:
PD ≈ IO ⋅ (VIN − VO )
The allowable power dissipation will be dependant on the
thermal impedance achieved in the application. The derating curve below is valid for the thermal impedance specified in the Thermal Information section on page 3.
Noise immunity: In very electrically noisy environments,
it is recommended that 0.1µF ceramic capacitors be placed
from IN to GND and OUT to GND as close to the device
pins as possible.
Internal voltage selection: By connecting the FB pin to
GND, an internal resistor divider will regulate the output
voltage to 1.2V.
If the FB pin is connected directly to the VO pin, the output
voltage will be regulated to the 0.5V internal reference.
External voltage selection resistors: The use of 1%
resistors, and designing for a current flow ≥ 10µA is recommended to ensure a well regulated output (thus R2
7
SC4216
Outline Drawing — SOIC-8-EDP-2
8
SC4216
Land Pattern — SOIC-8-EDP-2
Contact Information
Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805) 498-2111 Fax: (805) 498-3804
www.semtech.com
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