L6902D
UP TO 1A SWITCHING REGULATOR WITH
ADJUSTABLE CURRENT LIMIT
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UP TO 1A OUTPUT CURRENT
OPERATING INPUT VOLTAGE FROM 8V TO 36V
PRECISE 3.3V (卤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
SO8
ORDERING NUMBERS: L6902D
L6902D013TR (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 (卤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 250m鈩?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掳C with 20掳C hysteresis), the
power stage is turned off.
APPLICATIONS
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CHARGERS FOR NiCd, NiMH BATTERIES
AND PREREGULATOR FOR LITHIUM-ION
BATTERIES
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ADJUSTABLE CURRENT GENERATOR
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SIMPLE STEP-DOWN CONVERTERS WITH
ADJUSTABLE CURRENT LIMIT
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BATTERY EQUIPPED SYSTEMS
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DISTRIBUTED POWER SUPPLY
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MOBILE PC & SUBNOTEBOOK
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-
TEST AND APPLICATION CIRCUIT
V
IN
=8V to 36V
3.3V
C1
10碌F
25V
CERAMIC
V
CC
VREF
COMP
C2
22nF
R3
5.1K
8
6
4
1
OUT
L1 22碌H
D1
STPS340U
R
SENSE
100m鈩?/div>
R1
5.6K
V
OUT
=3.3V
2
3
7
GND
5
FB
C3
220pF
R2
3.3K
C4
100碌F
10V
POSCAP
D01IN1306A
June 2003
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