L5971 Datasheet, PDF (1/11 Pages) STMicroelectronics – 1.5A STEP DOWN SWITCHING REGULATOR

®
L5971
1.5A STEP DOWN SWITCHING REGULATOR
UP TO 1.5A STEP DOWN CONVERTER
OPERATING INPUT VOLTAGE FROM 6.5V
TO 28V
PRECISE 1.26V (±1%) INTERNAL REFER-
ENCE VOLTAGE
OUTPUT VOLTAGE ADJUSTABLE FROM
1.26V TO 20V
SWITCHING FREQUENCY ADJUSTABLE UP
TO 500KHz
VOLTAGE FEEDFORWARD
ZERO LOAD CURRENT OPERATION
INTERNAL CURRENT LIMITING (PULSE-BY-
PULSE AND HICCUP MODE)
INHIBIT FOR ZERO CURRENT CONSUMP-
TION
PROTECTION AGAINST FEEDBACK DIS-
CONNECTION
THERMAL SHUTDOWN
SOFT START FUNCTION
DESCRIPTION
The L5971 is a step down monolithic power
switching regulator delivering 1.5A at a voltage
between 1.26V and 20V (selected by a simple
external divider). Realized in BCD mixed technol-
ogy, the device uses an internal power D-MOS
transistor (with a typical Rdson of 0.25Ω) to ob-
tain very high efficency and high switching speed.
TYPICAL APPLICATION CIRCUIT
Minidip
SO16W
ORDERING NUMBERS: L5971 (Minidip)
L5971D (SO16)
A switching frequency up to 500KHz is achiev-
able (the maximum power dissipation of the pack-
ages must be observed).
Features of this new generations of DC-DC con-
verter include pulse-by-pulse current limit, hiccup
mode for short circuit protection, voltage feedfor-
ward regulation, soft-start, protection against
feedback loop disconnection, inhibit for zero cur-
rent consumption and thermal shutdown.
The device is available in plastic dual in line,
MINIDIP 8 for standard assembly, and SO16 for
SMD assembly.
Typical Applications:
- High efficiency step-down converter
- Portable computers
- Battery charger
- Distributed power
- PDAs and Mobile Comminicators
Vi=6V to 28V
C₁
47µF
30V
5(11)
8(14)
R₁
22K
L5971
3(4)
4(5,6)
2(3)
C₂
1.2nF
C₅
47nF
7(13) 1(2) 6(12)
R₂
9.1K
C₄
22nF
C₆
100nF
D1
STPS
3L40U
L1
30µH
C₈
330µF
V_O=2.5V/1.5A
R₃
R₄
May 2000
D98IN832C
1/11