L5973AD_07 Datasheet, PDF (1/21 Pages) STMicroelectronics – 2A switch step down switching regulator

L5973AD
2A switch step down switching regulator
General features
■ 2A Internal switch
■ Operating input voltage from 4V to 36V
■ 3.3V / (±2%) reference voltage
■ Output voltage adjustable from 1.235V to 35V
■ Low dropout operation: 100% duty cycle
■ 500KHz Internally fixed frequency
■ Voltage feedforward
■ Zero load current operation
■ Internal current limiting
■ Inhibit for zero current consumption
■ Synchronization
■ Protection against feedback disconnection
■ Thermal shutdown
Applications
■ Consumer: STB, DVD, TV, VCR, car radio,
LCD monitors
■ Networking: XDSL, modems, DC-DC modules
■ Computer: printers, audio/graphic cards,
optical storage, hard disk drive
■ Industrial: chargers, car battery, DC-DC
converters
Test application circuit
HSOP8 Exposed Pad
Description
The L5973AD is a step down monolithic power
switching regulator with a switch current limit of
2A so it is able to deliver more than 1.5A DC
current to the load depending on the application
conditions.
The output voltage can be set from 1.235V to 35V.
The high current level is also achieved thanks to
an SO8 package with exposed frame, that allows
to reduce the R_thJA down to approximately
40°C/W.
The device uses an internal P-Channel D-MOS
transistor (with a typical of 200mΩ) as switching
element to avoid the use of bootstrap capacitor
and guarantee high efficiency.
An internal oscillator fixes the switching frequency
at 500KHz to minimize the size of external
components.
Having a minimum input voltage of 4V only, it is
particularly suitable for 5V bus, available in all
computer related applications.
Pulse by pulse current limit with the internal
frequency modulation offers an effective constant
current short circuit protection.
VIN = 4V to 35V
C1
10µF
35V
CERAMIC
VREF
3.3V
VCC
SYNC.
COMP
C4
22nF
6
1
8 _L5973AD
2
4
3
5
7
INH
GND
C3
220pF
R3
4.7K
OUT
FB
L1 15µH
D1
STPS340U
VOUT=3.3V
R1
5.6K
R2
3.3K
C2
330µF
10V
January 2007
Rev 6
D03IN1453
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