L5970D
UP TO 1A STEP DOWN SWITCHING REGULATOR
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UP TO 1A OUTPUT CURRENT
OPERATING INPUT VOLTAGE FROM 4.4V
TO 36V
3.3V / (±2%) / REFERENCE VOLTAGE
OUTPUT VOLTAGE ADJUSTABLE FROM
1.2V TO 35V
LOW DROPOUT OPERATION: 100% DUTY
CYCLE
250KHz INTERNALLY FIXED FREQUENCY
VOLTAGE FEEDFORWARD
ZERO LOAD CURRENT OPERATION
INTERNAL CURRENT LIMITING
INHIBIT FOR ZERO CURRENT
CONSUMPTION
SINCHRONIZATION
PROTECTION AGAINST FEEDBACK
DISCONNECTION
THERMAL SHUTDOWN
SO8
ORDERING NUMBERS: L5970D (SO8)
L5970D013TR (T&R)
DESCRIPTION
The L5970D is a step down monolithic power
switching regulator capable to deliver up to 1A at
output voltages from 1.2V to 35V.
The device uses an internal P-Channel D-MOS
transistor (with a typical Rdson of 250mΩ) as
switching element to minimize the size of the ex-
ternal components.
An internal oscillator fixes the switching frequency
at 250KHz.
Having a minimum input voltage of 4.4V only, it is
particularly suitable for 5V bus, available in all
computer related applications.
Pulse by pulse current limit with the internal fre-
quency modulation offers an effective constant
current short circuit protection.
APPLICATIONS:
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CONSUMER: STB, DVD, TV, VCR,CAR
RADIO, LCD MONITORS
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NETWORKING: XDSL, MODEMS,DC-DC
MODULES
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COMPUTER: PRINTERS, AUDIO/GRAPHIC
CARDS, OPTICAL STORAGE, HARD DISK
DRIVE
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INDUSTRIAL: CHARGERS, CAR BATTERY
DC-DC CONVERTERS
TEST APPLICATION CIRCUIT
3.3V
VIN = 4.4V to 35V
VREF
VCC
SYNC.
6
8
2
4
INH.
1
OUT
L1 33µH
D1
STPS2L40U
VOUT=3.3V
L5970D
3
7
5
GND
FB
R1
5.6K
C1
10µF
35V
CERAMIC
COMP
C4
22nF
C3
220pF
C2
100µF
10V
R3
4.7K
R2
3.3K
D98IN954C
May 2003
1/10
STMICROELECTRONICS [ STMICROELECTRONICS ]
