© 2002 Fairchild Semiconductor Corporation

www.fairchildsemi.com

FAN5236 • Rev. 1.3.2

3

Pin Configuration

Figure 3. Pin Configuration

Pin Definitions

Pin #

Name

Description

1

AGND

Analog Ground

. This is the signal ground reference for the IC. All voltage levels are

measured with respect to this pin.

2

LDRV1

Low-Side Drive

. The low-side (lower) MOSFET driver output. Connect to gate of low-side

MOSFET.

27

LDRV2

3

PGND1

Power Ground

. The return for the low-side MOSFET driver. Connect to source of low-side

MOSFET.

26

PGND2

4

SW1

Switching Node

. Return for the high-side MOSFET driver and a current sense input.

Connect to source of high-side MOSFET and low-side MOSFET drain.

25

SW2

5

HDRV1

High-Side Drive

. High-side (upper) MOSFET driver output. Connect to gate of high-side

MOSFET.

24

HDRV2

6

BOOT1

BOOT

. Positive supply for the upper MOSFET driver. Connect as shown in Figure 4.

23

BOOT2

7

ISNS1

Current-Sense Input

. Monitors the voltage drop across the lower MOSFET or external

sense resistor for current feedback.

22

ISNS2

8

EN1

Enable

. Enables operation when pulled to logic HIGH. Toggling EN resets the regulator

after a latched fault condition. These are CMOS inputs whose state is indeterminate if left

open.

21

EN2

9

FPWM1

Forced PWM Mode

. When logic LOW, inhibits the regulator from entering Hysteretic Mode;

20

FPWM2

10

VSEN1

Output Voltage Sense

. The feedback from the outputs. Used for regulation as well as PG,

under-voltage, and over-voltage protection and monitoring.

19

VSEN2

11

ILIM1

Current Limit 1

. A resistor from this pin to GND sets the current limit.

12

SS1

Soft Start

. A capacitor from this pin to GND programs the slew rate of the converter during

initialization. During initialization, this pin is charged with a 5mA current source.

17

SS2

AGND

LDRV1

PGND1

SW1

HDRV1

BOOT1

ISNS1

EN1

FPWM1

VSEN1

ILIM1

SS1

DDR

VIN

FAN5236

1

2

3

4

5

6

7

8

9

10

11

12

13

14

28

27

26

25

24

23

22

21

20

19

18

17

16

15

VCC

LDRV2

PGND2

SW2

HDRV2

BOOT2

ISNS2

EN2

FPWM2

VSEN2

ILIM2/REF2

SS2

PG2/REF2OUT

PG1