IR3535 datasheet(12/17 Pages) IRF

12 / 17 page

March 13, 2013 | FINAL DATASHEET

IR3535

Synchronous Buck Converter Driver

DESIGN PROCEDURES

INDUCTOR CURRENT SENSING CAPACITOR

CCS AND RESISTOR RCS

The DC resistance of the inductor is utilized to sense the

inductor current. Usually the resistor RCS and capacitor CCS

in parallel with the inductor are chosen to match the time

constant of the inductor, and therefore the voltage across

the capacitor CCS represents the inductor current.

Determine the inductance L and the inductor DC resistance

RL based on measurement or the datasheet specifications.

Pre‐select the capacitor CCS and calculate RCS as follows:

BOOTSTRAP CAPACITOR CBOOST

A minimum of 0.22uF 0402 16Vdc capacitor is required for

the bootstrap circuit. A high temperature 0.22uF or greater

value 0603 capacitor is recommended.

VCC AND PVCC DECOUPLING CAPACITOR CVCC

A 1uF ceramic decoupling capacitor is required at the VCC

and PVCC pins.

BODY‐BRAKING® FEATURE

The BBR# pin should be pulled up to VCC if the feature is

not used by the PWM controller. Use of a small value

resistor or a direct connection to VCC is recommended.

IR3535 Datasheet(PDF) 12 Page - International Rectifier