July 16, 2014 | DATASHEET V3.3

4

IR3553

40A Integrated PowIRstage®

PIN DESCRIPTIONS

PIN #

PIN NAME

PIN DESCRIPTION

1

CSIN-

Inverting input to the current sense amplifier. Connect to LGND if the current sense

amplifier is not used.

2

CSIN+

Non-Inverting input to the current sense amplifier. Connect to LGND if the current sense

amplifier is not used.

3

VCC

Bias voltage for control logic. Connect a minimum 1uF cap between VCC and PGND (pin

4) if current sense amplifier is used. Connect a minimum 0.22uF capacitor between VCC

and PGND (pin 4) if current sense amplifier is not used.

4, 12, 13

PGND

Power ground of MOSFET driver and the synchronous MOSFET. MOSFET driver signal is

referenced to this pin.

5, 25

GATEL

Low-side MOSFET driver pins that can be connected to a test point in order to observe

the waveform.

6 – 11

SW

Switch node of synchronous buck converter.

14 – 16

VIN

High current input voltage connection. Recommended operating range is 4.5V to 15V.

Connect at least two 10uF 1206 ceramic capacitors and a 0.22uF 0402 ceramic

capacitor. Place the capacitors as close as possible to VIN pins and PGND pins (12-13).

The 0.22uF 0402 capacitor should be on the same side of the PCB as the IR3553.

17

BOOST

Bootstrap capacitor connection. The bootstrap capacitor provides the charge to turn on

the control MOSFET. Connect a minimum 0.22µF capacitor from BOOST to SW pin. Place

the capacitor as close to BOOST pin as possible and minimize parasitic inductance of

PCB routing from the capacitor to SW pin.

18

PHSFLT#

Open drain output of the phase fault circuits. Connect to an external pull-up resistor.

Output is low when a MOSFET fault or over temperature condition is detected.

19

PWM

3.3V logic level tri-state PWM input and 7V tolerant. “High” turns the control MOSFET

on, and “Low” turns the synchronous MOSFET on. “Tri-state” turns both MOSFETs off in

Body-Braking® mode. In diode emulation mode, “Tri-state” activates internal diode

emulation control. See “PWM Tri-state Input” Section for further details about the PWM

Tri-State functions.

20

BBRK#

3.3V logic level input and 7V tolerant with internal weak pull-up to 3.3V. Logic low

disables both MOSFETs. Pull up to VCC directly or by a 4.7kΩ resistor if Body-Braking® is

not used. The second function of the BBRK# pin is to select diode emulatiom mode.

Pulling BBRK# low at least 20ns after VCC passes its UVLO threshold selects internal

diode emulation control. See “Body-Braking

21

LGND

Signal ground. Driver control logic, analog circuits and IC substrate are referenced to

this pin.

22

REFIN

Reference voltage input from the PWM controller. IOUT signal is referenced to the

voltage on this pin. Connect to LGND if the current sense amplifier is not used.

23

IOUT

Current output signal. Voltage on this pin is equal to V(REFIN) + 32.5 * [V(CSIN+) –

V(CSIN-)]. Float this pin if the current sense amplifier is not used.

24

TGND

This pin is connected to internal power and signal ground of the driver. For best

performance of the current sense amplifier, TGND must be electrically isolated from

Power Ground (PGND) and Signal Ground (LGND) in the PCB layout. Connect to PGND if

the current sense amplifier is not used.