ISL95874, ISL95875, ISL95876

9

FN7933.0

October 21, 2011

ISL95876 Functional Pin Descriptions

PIN NUMBER

SYMBOL

DESCRIPTION

1

RTN

2

VID1

Logic input for setpoint voltage selector. Use in conjunction with the VID0 pin to select among four setpoint reference

voltages.

3

VID0

Logic input for setpoint voltage selector. Use in conjunction with the VID1 pin to select among four setpoint reference

voltages.

4

SREF

Soft-start and voltage slew-rate programming capacitor input and setpoint reference voltage programming resistor

5, 6, 7

SET0, SET1,

SET2

Voltage set-point programming resistor input.

8

FB

Voltage feedback sense input. Connects internally to the inverting input of the control-loop error transconductance

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

9

OCSET

pin to the sense node.

10

VO

detection circuit.

11

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.

12

PGOOD

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

regulated voltage.

13

EN

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

14

PHASE

current polarity detector input.

15

UGATE

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

16

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.

17

VCC

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

18

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.

19

LGATE

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

20

PGND

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

Bottom Pad

GND

IC ground for bias supply and signal reference.