B5973D_0808 Datasheet, PDF (1/12 Pages) STMicroelectronics – 2 A step down switching regulator for automotive applications

B5973D
2 A step down switching regulator
for automotive applications
Features
■ Qualified following the AEC-Q100
requirements (temperature Grade 1), see
PPAP for more details.
■ 2 A DC output current
■ 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
■ 250 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
■ Dedicated to automotive applications
Figure 1. Typical application
HSOP8 exposed pad
Description
The B5973D is a step down monolithic power
switching regulator with a minimum switch current
limit of 2.25 A so it is able to deliver up to 2 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_th(JA) down to
approximately 40 °C/W. The device uses an
internal P-channel DMOS transistor (with a typical
R_DSon of 250 mΩ) as switching element to
minimize the size of the external components. An
internal oscillator fixes the switching frequency at
250 kHz. Having a minimum input voltage of 4V
only, it is particularly suitable for 5 V bus. Pulse by
pulse current limit with the internal frequency
modulation offers an effective constant current
short circuit protection. Pulse by pulse current
limit with the internal frequency modulation offers
an effective constant current short circuit
protection.
VIN=4V to 35V
C1
10uF
35V
C E R AM IC
C4
22nF
C3
220pF
VCC
8
COMP
4
6
R3 ^VREF
3.3V
4k7
OUT
1
BA5973D
7
SYNCH
2
FB
5
3
GND INH
L1 15uH
D1
STPS340U
Vout=3.3V
R1
5k6
C2
330uF
6.3V
R2
3k3
August 2008
Rev 3
1/11
www.st.com
1