L7981ATR Datasheet, PDF (1/44 Pages) STMicroelectronics – 3 A step-down switching regulator

L7981
3 A step-down switching regulator
Features
■ 3 A DC output current
■ 4.5 V to 28 V input voltage
■ Output voltage adjustable from 0.6 V
■ 250 kHz switching frequency, programmable
up to 1 MHz
■ Internal soft-start and enable
■ Low dropout operation: 100% duty cycle
■ Voltage feed-forward
■ Zero load current operation
■ Overcurrent and thermal protection
■ VFQFPN3x3-8L and HSOP8 package
Applications
■ Consumer:
STB, DVD, DVD recorder, car audio, LCD TV
and monitors
■ Industrial:
PLD, PLA, FPGA, chargers
■ Networking: XDSL, modems, DC-DC modules
■ Computer:
Optical storage, hard disk drive, printers,
audio/graphic cards
■ Suitable for LED driving
Figure 1. Application circuit
VFQFPN8 3x3
HSOP8 exposed pad
Description
The L7981 is a step down switching regulator with
3.7 A (minimum) current limited embedded power
MOSFET, so it si able to deliver up to 3 A current
to the load depending on the application
conditions.
The input voltage can range from 4.5 V to 28 V,
while the output voltage can be set starting from
0.6 V to V_IN.
Requiring a minimum set of external components,
the device includes an internal 250 kHz switching
frequency oscillator that can be externally
adjusted up to 1 MHz.
The QFN and the HSOP packages with exposed
pad allow reducing the R_thJA down to 60°C/W and
40°C/W respectively.
July 2010
Doc ID 15182 Rev 3
1/44
www.st.com
44