A5970AD Datasheet, PDF (1/17 Pages) STMicroelectronics – Up to 1 A switch step down switching regulator for automotive applications

A5970AD
Up to 1 A switch step down switching regulator
for automotive applications
Features
■ Qualified following the AEC-Q100
requirements (temperature grade 3), see
PPAP for more details.
■ Temperature range -40 °C to 85 °C
■ 1 A DC output current
■ Operating input voltage from 4.4 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
■ Dedicated to automotive applications
Figure 1. Application schematic
SO-8
Description
The A5970AD is a step down monolithic power
switching regulator with a switch current limit of
1.35 A so it is able to deliver more than 1 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 device uses an internal P-channel
D-MOS transistor (with a typical R_DS(on) of
250 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
4.4 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=4.4V to 35V
C1
10uF
35V
CERAMIC
C4
22nF
C3
220pF
VCC
8
COMP
4
6
R3 ^VREF
3.3V
4k7
OUT
1
A5970AD
7
3
SYNCH
2
FB
5
GND INH
L1 15uH
D1
STPS340U
Vout=3.3V
R1
5k6
C2
100uF
10V
R2
3k3
May 2008
Rev 1
1/16
www.st.com
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