LP38842 Datasheet, PDF (1/11 Pages) National Semiconductor (TI) – 1.5A Ultra Low Dropout Linear Regulators Stable with Ceramic Output Capacitors

December 2004
LP38842
1.5A Ultra Low Dropout Linear Regulators
Stable with Ceramic Output Capacitors
General Description
The LP38842 is a high current, fast response regulator
which can maintain output voltage regulation with minimum
input to output voltage drop. Fabricated on a CMOS process,
the device operates from two input voltages: Vbias provides
voltage to drive the gate of the N-MOS power transistor,
while Vin is the input voltage which supplies power to the
load. The use of an external bias rail allows the part to
operate from ultra low Vin voltages. Unlike bipolar regula-
tors, the CMOS architecture consumes extremely low quies-
cent current at any output load current. The use of an
N-MOS power transistor results in wide bandwidth, yet mini-
mum external capacitance is required to maintain loop sta-
bility.
The fast transient response of these devices makes them
suitable for use in powering DSP, Microcontroller Core volt-
ages and Switch Mode Power Supply post regulators. The
parts are available in TO-220 and TO-263 packages.
Dropout Voltage: 115 mV (typ) @ 1.5A load current.
Quiescent Current: 30 mA (typ) at full load.
Shutdown Current: 30 nA (typ) when S/D pin is low.
Precision Output Voltage: 1.5% room temperature accu-
racy.
Features
n Ideal for conversion from 1.8V or 1.5V inputs
n Designed for use with low ESR ceramic capacitors
n 0.8V, 1.2V and 1.5V standard voltages available
n Ultra low dropout voltage (115mV @ 1.5A typ)
n 1.5% initial output accuracy
n Load regulation of 0.1%/A (typical)
n 30nA quiescent current in shutdown (typical)
n Low ground pin current at all loads
n Over temperature/over current protection
n Available in 5 lead TO220 and TO263 packages
n −40˚C to +125˚C junction 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
* Minimum value required if Tantalum capacitor is used (see Application Hints).
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