AN1518 Datasheet, PDF (1/30 Pages) STMicroelectronics – The L5973D is a step-down monolithic power switching regulator capable

AN1518
Application note
Designing with the 2.5 A DC-DC converter L5973D
Introduction
The L5973D is a step-down monolithic power switching regulator capable of delivering up to
2.5 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 D-MOS 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. The device is housed in an HSOP8 package with exposed pad that helps
to reduce the thermal resistance junction-to-ambient (R_Thj-a) down to approximately
40 °C/W.
Figure 1. Evaluation board
L5973D (HSOP8) board dimensions: 23x20 mm
Figure 2. Package
HSOP8 - Exposed Pad
Figure 3. Pin connection
OUT
SYNC
INH
COMP
1
8
2
7
3
6
4
5
D98IN955
VCC
GND
VREF
FB
January 2008
Rev 4
1/30
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