LP38855 Datasheet, PDF (1/14 Pages) National Semiconductor (TI) – 1.5A Fast-Response High-Accuracy LDO Linear Regulator with Enable

December 2006
LP38855
1.5A Fast-Response High-Accuracy LDO Linear Regulator
with Enable
General Description
The LP38855 is a high-current, fast-response regulator which
can maintain output voltage regulation with an extremely 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 circuits, 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 reg-
ulators, the CMOS architecture consumes extremely low qui-
escent current at any output 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 LP38855 is
available in TO-220 and TO-263 5-Lead packages.
Dropout Voltage: 130 mV (typical) at 1.5A load current.
Low Ground Pin Current: 14 mA (typical) at 1.5A 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
■ ^{Standard V}_OUT ^{values of 0.8V and 1.2V}
■ ^{Wide V}_BIAS ^{Supply operating range of 3.0V to 5.5V}
■ ^{Stable with 10 µF ceramic capacitors}
■ ^{Dropout voltage of 130 mV (typical) at 1.5A load current}
■ ^{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
■ ^{Over-Temperature and Over-Current protection}
■ ^{Available in 5 lead TO-220 and TO-263 packages}
■ ^{Custom V}_OUT ^{values between 0.8V and 1.2V are available}
■ ^{-40°C to +125°C Operating Temperature Range}
Applications
■ ^{ASIC Power Supplies In:}
- Desktops, Notebooks, and Graphics Cards, Servers
- Gaming Set Top Boxes, Printers and Copiers
■ ^{Server Core and I/O Supplies}
■ ^{DSP and FPGA Power Supplies}
■ ^{SMPS Post-Regulator}
Typical Application Circuit
© 2007 National Semiconductor Corporation 202026
20202601
www.national.com