E-L5973AD Datasheet, PDF (1/22 Pages) STMicroelectronics – 2 A switch step down switching regulator

L5973AD
2 A switch step down switching regulator
Features
■ 2 A internal switch
■ Operating input voltage from 4 V to 36 V
■ 3.3 V / (±2%) reference voltage
■ Output voltage adjustable from 1.235 V to 35 V
■ Low dropout operation: 100% duty cycle
■ 500 kHz 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
Figure 1. Test application circuit
HSOP8 exposed pad
Description
The L5973AD is a step down monolithic power
switching regulator with a switch current limit of
2 A so it is able to deliver more than 1.5 A DC
current to the load depending on the application
conditions.
The output voltage can be set from 1.235 V
to 35 V. 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 200 mΩ) as switching
element to avoid the use of bootstrap capacitor
and guarantee high efficiency.
An internal oscillator fixes the switching frequency
at 500 kHz to minimize the size of external
components.
Having a minimum input voltage of 4 V only, it is
particularly suitable for 5 V 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
November 2009
D03IN1453
Doc ID 9552 Rev 9
1/22
www.st.com
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