L6902D_04 Datasheet, PDF (1/7 Pages) STMicroelectronics – UP TO 1A SWITCHING REGULATOR WITH ADJUSTABLE CURRENT LIMIT

L6902D
UP TO 1A SWITCHING REGULATOR WITH
ADJUSTABLE CURRENT LIMIT
1 FEATURES
■ UP TO 1A OUTPUT CURRENT
■ OPERATING INPUT VOLTAGE FROM 8V TO 36V
■ PRECISE 3.3V (±2%) REFERENCE VOLTAGE
■ 5% OUTPUT CURRENT ACCURACY
■ OUTPUT VOLTAGE ADJUSTABLE FROM
1.235V TO 34V
■ 250KHz INTERNALLY FIXED FREQUENCY
■ VOLTAGE FEEDFORWARD
■ ZERO LOAD CURRENT OPERATION
■ ADJUSTABLE CURRENT LIMIT
■ PROTECTION AGAINST FEEDBACK
DISCONNECTION
■ THERMAL SHUTDOWN
2 APPLICATIONS
■ CHARGERS FOR NiCd, NiMH BATTERIES
AND PREREGULATOR FOR LITHIUM-ION
BATTERIES
■ ADJUSTABLE CURRENT GENERATOR
■ SIMPLE STEP-DOWN CONVERTERS WITH
ADJUSTABLE CURRENT LIMIT
■ BATTERY EQUIPPED SYSTEMS
■ DISTRIBUTED POWER SUPPLY
■ MOBILE PC & SUBNOTEBOOK
3 DESCRIPTION
The L6902D is a complete and simple step down
switching regulator with adjustable current limit.
Based on a voltage mode structure it integrates a cur-
Figure 2. Test And Application Circuit
Figure 1. Package
SO-8
Table 1. Order Codes
Part Number
L6902D
L6902D013TR
Package
SO-8
SO-8 in Tape & Reel
rent error amplifier to have a constant voltage and con-
stant current control.
By means of an on board current sense resistor and
the availability of the current sense pins (both com-
patible to Vcc and for Cs- compatible with GND too)
a current limit programming is very simple and accu-
rate (±5%). Moreover constant current control can be
used to charge NiMH and NiCd batteries.
The device can be used as a standard DC/DC con-
verter with adjustable current limit (set by using the
external sense resistor).
The internal robust P-Channel DMOS transistor with a
typical of 250mΩ assures high efficiency and a mini-
mum dropout even at high output current level. The in-
ternal limiting current (latched function) of typical value
of 2.5A protects the device from accidental output short
circuit avoiding dangerous loads damage.
If the temperature of the chip goes higher than a fixed
internal threshold (150°C with 20°C hysteresis), the
power stage is turned off.
V_IN=8V to 36V
C1
10µF
25V
CERAMIC
C3
220pF
V_CC
VREF
3.3V
COMP
C2
22nF
R3
5.1K
8
6
4
7
GND
OUT
1
L1 22µH
R_SENSE
D1
100mΩ
STPS340U
2
R1
5.6K
3
FB
5
R2
3.3K
V_OUT=3.3V
C4
100µF
10V
POSCAP
D01IN1306A
October 2004
Rev. 8
1/7