AN1330 Datasheet, PDF (1/31 Pages) STMicroelectronics – Designing with the L5970D 1A high efficiency DC-DC converter

AN1330
Application note
Designing with the L5970D 1A high efficiency DC-DC converter
Introduction
The L5970D is a step-down monolithic power switching regulator capable of delivering up to
1 A at output voltages from 1.235 V to 35 V. The operating input voltage ranges from 4.4 V to
36 V. It has been designed using BCDV technology and the power switching element is
implemented through a P-channel DMOS transistor. It does not require a bootstrap
capacitor, and the duty cycle can range up to 100%. An internal oscillator fixes the switching
frequency at 250 kHz. This minimizes the LC output filter.
A synchronization pin is available for cases where a higher frequency (up to 500 kHz) is
required. Pulse-by-pulse and frequency foldback overcurrent protection offer effective short
circuit protection. Other features are voltage feed-forward, protection against feedback
disconnection, inhibit and thermal shutdown.
Figure 1. Demonstration board
L5970D (SO-8) board dimensions: 23 x 20 mm
Figure 2. Package
May 2008
SO-8
Figure 3. Pin connection
OUT
1
SYNC
2
INH
3
COMP
4
8
7
6
5
AM00004v1
VCC
GND
VREF
FB
Rev 3
1/31
www.st.com