ISL95874, ISL95875, ISL95876

7

FN7933.0

October 21, 2011

ISL95874 Functional Pin Descriptions

PIN NUMBER

SYMBOL

DESCRIPTION

1

GND

IC ground for bias supply and signal reference.

2

RTN

3

EN

Enable input for the IC. Pulling EN above the rising threshold voltage initializes the soft-start sequence.

4

SREF

setpoint amplifier.

5

FSEL

Input for programming the regulator switching frequency. Pull this pin to VCC for 1MHz switching. Pull this pin to GND

with a 100k

Ω resistor for 600kHz switching. Leave this pin floating for 500kHz switching. Pull this pin directly to GND

for 300kHz switching.

6

FB

Voltage feedback sense input. Connects internally to the inverting input of the control-loop error amplifier. The converter

is in regulation when the voltage at the FB pin equals the voltage on the SREF pin.

7

OCSET

pin to the sense node.

8

VO

detection circuit.

9

PGOOD

Power-good open-drain indicator output. This pin changes to high impedance when the converter is able to supply

regulated voltage.

10

PHASE

polarity detector input.

11

UGATE

High-side MOSFET gate driver output. Connect to the gate terminal of the high-side MOSFET of the converter.

12

BOOT

Positive input supply for the UGATE high-side MOSFET gate driver. The BOOT pin is internally connected to the cathode

of the Schottky boot-strap diode. Connect an MLCC between the BOOT pin and the PHASE pin.

13

VCC

Input for the IC bias voltage. Connect +5V to the VCC pin and decouple with at least a MLCC to the GND pin.

14

PVCC

Input for the LGATE and UGATE MOSFET driver circuits. The PVCC pin is internally connected to the anode of the Schottky

boot-strap diode. Connect +5V to the PVCC pin and decouple with a MLCC to the PGND pin.

15

LGATE

Low-side MOSFET gate driver output. Connect to the gate terminal of the low-side MOSFET of the converter.

16

PGND

Return current path for the LGATE MOSFET driver. Connect to the source of the low-side MOSFET.