ISL78227

FN8808 Rev.6.02

Page 3 of 43

Feb 28, 2025

Pin Configuration

32 LD 5x5 WFQFN

TOP VIEW

VCC

SLOPE

FB

COMP

SS

IMON

TRACK

PGOOD

UG1

PH1

LG1

PVCC

PGND

LG2

PH2

UG2

1

2

3

4

5

6

7

8

24

23

22

21

20

19

18

17

32 31 30

29 28

27 26

25

9

10 11

12 13

14 15

16

SGND

Functional Pin Description

PIN NAME

PIN #

DESCRIPTION

VCC

1

IC bias power input pin for the internal analog circuitry. Use aminimum1µF ceramic capacitor between VCC and ground for noise

decoupling purposes. VCC is typically biased by PVCC or an external bias supply with voltage ranging from 4.75V to 5.5V.

Because PVCC provides pulsing drive current, a small resistor (10Ω or smaller) between PVCC and VCC can help filter out the

noises from PVCC to VCC.

SLOPE

2

Programs the slope of the internal slope compensation. A resistor should be connected from the SLOPE pin to GND. Refer to

“Adjustable Slope Compensation” on page 32 for information about how to select this resistor value.

FB

3

The inverting input of the error amplifier for the voltage regulation loop. A resistor network must be placed between the FB

pin and the output rail to set the boost converter’s output voltage. Refer to “Output Voltage Setting” on page 37 for more details.

Output overvoltage and undervoltage comparators also monitor this pin. Refer to “Output Overvoltage Fault Protection” and

“Output Undervoltage Indication” on page 34 for more details.

COMP

4

The output of the transconductance error amplifier (Gm1) for the output voltage regulation loop. Place the compensation

network between the COMP pin and ground. Refer to “Output Voltage Regulation Loop” on page 25 for more details.

The COMP pin voltage can also be controlled by the constant current control loop error amplifier (Gm2) output through a diode

(DCC) when the constant current control loop is used to control the input average current. Refer to “Constant Current Control

(CC)” on page 35 for more details.

SS

5

A capacitor placed from SS to ground sets up the soft-start ramp rate and in turn, determines the soft-start time. Refer to

“Soft-Start” on page 30 for more details.