LP38856 Datasheet, PDF (1/14 Pages) National Semiconductor (TI) – 3A Fast-Response High-Accuracy LDO Linear Regulator with Enable

June 2006
LP38856
3A Fast-Response High-Accuracy LDO Linear Regulator
with Enable
General Description
The LP38856 is a high-current, fast-response regulator
which can maintain output voltage regulation with an ex-
tremely low input to output voltage drop. Fabricated on a
CMOS process, the device operates from two input voltages:
V_BIAS provides power for the internal bias and control cir-
cuits, as well as drive for the gate of the N-MOS power
transistor, while V_IN supplies power to the load. The use of
an external bias rail allows the part to operate from ultra low
V_IN voltages. Unlike bipolar regulators, the CMOS architec-
ture consumes extremely low quiescent current at any out-
put load current. The use of an N-MOS power transistor
results in wide bandwidth, yet minimum external capacitance
is required to maintain loop stability.
The fast transient response of this device makes it suitable
for use in powering DSP, Microcontroller Core voltages and
Switch Mode Power Supply post regulators. The LP38856 is
available in TO-220 and TO-263 5-Lead packages.
Dropout Voltage: 240 mV (typical) at 3A load current.
Low Ground Pin Current: 14 mA (typical) at 3A load cur-
rent.
Shutdown Current: 1 µA (typical) I_IN(GND) when EN pin is
low.
Precision Output Voltage: ±1.0% for T_J = 25˚C and ±2.0%
for 0˚C ≤ T_J ≤ +125˚C, across all line and load conditions
Features
n Standard V_OUT values of 0.8V and 1.2V
n Stable with 10 µF ceramic capacitors
n Dropout voltage of 240 mV (typical) at 3A load current
n Precision Output Voltage across all line and load
conditions:
— ±1.0% for T_J = 25˚C
— ±2.0% for 0˚C ≤ T_J ≤ +125˚C
— ±3.0% for -40˚C ≤ T_J ≤ +125˚C
n Over-Temperature and Over-Current protection
n Available in 5 lead TO-220 and TO-263 packages
n Custom V_OUT values between 0.8V and 1.2V are
available
n -40˚C to +125˚C Operating Temperature Range
Applications
n ASIC Power Supplies In:
- Desktops, Notebooks, and Graphics Cards, Servers
- Gaming Set Top Boxes, Printers and Copiers
n Server Core and I/O Supplies
n DSP and FPGA Power Supplies
n SMPS Post-Regulator
Typical Application Circuit
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