ISL9443

FN7663 Rev 1.00

Page 2 of 23

February 24, 2012

Pin Configuration

ISL9443

(32 LD 5x5 QFN)

TOP VIEW

Ordering Information

PART NUMBER

(Notes 1, 2, 3)

PART

MARKING

TEMP. RANGE

(°C)

PACKAGE

(Pb-Free)

PKG.

DWG. #

ISL9443IRZ

ISL9443 IRZ

-40 to +85

32 Ld 5x5 QFN

L32.5X5B

NOTES:

1. Add “-T*” for tape and reel. Please refer to TB347 for details on reel specifications.

2. These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte

tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Intersil

Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.

3. For Moisture Sensitivity Level (MSL), please see device information page for ISL9443. For more information on MSL please see techbrief TB363.

EN/SS1

RT

VCC_5V

VIN

PGOOD

OCSET1

FB1

ISEN2

PGND

LGATE3

UGATE3

BOOT3

PHASE3

ISEN3

1

ISEN1

32

31

30

29

28

27

26

25

9

10

11

12

13

14

15

16

2

3

4

5

6

7

8

24

23

22

21

20

19

18

17 MODE/SYNC

Pin Descriptions

PIN

NAME

FUNCTION

1

ISEN1

Current signal input for PWM1. This pin is used to monitor the voltage drop across the lower MOSFET for current loop

feedback and overcurrent protection.

2

VCC_5V

Output of the internal 5V linear regulator. This output supplies bias for the IC, the low side gate drivers, and the external

boot circuitry for the high-side gate drivers. The VCC_5V pin must be always decoupled to power ground with a minimum

of 4.7µF ceramic capacitor, placed very close to the pin. Do not allow the voltage at VCC_5V to exceed VIN at any time.

3

VIN

This pin should be tied to the input rail. It provides power to the internal linear drive circuitry and is also used by the feed-

forward controller to adjust the amplitude of each PWM sawtooth. Decouple this pin with a small ceramic capacitor

(0.1µF to 1µF) to ground.

4

EN/SS1

This pin provides an enable/disable function and soft-starting for PWM1 output. The output is disabled when the pin is

pulled to GND. During start-up, a regulated 1.55µA soft-start current charges an external capacitor connected at this pin.

When the voltage on the EN/SS1 pin reaches 1.3V, the PWM1 output becomes active. From 1.3V to 2.0V, the reference

voltage of the PWM1 is clamped to the voltage at EN/SS1 minus 1.3V. The capacitance of the soft-start capacitors sets

the soft-starting time and enable delay time. Setting the soft-starting time too short might create undesirable overshoot

at the output during start-up. VCC_5V UVLO discharges the EN/SS1 via an internal MOSFET.