4

Pin Descriptions

PIN NO.

DESIGNATOR

FUNCTION

DESCRIPTION

15, 28

M12VIN

-12V Input

-12V Supply Input. Also provides power to the -12V overcurrent circuitry.

4, 11

FLTN

Fault Output

5V CMOS Fault Output; LOW = FAULT. An optional capacitor may be place from this pin to

ground to provide additional immunity from power supply glitches.

20, 23

3V5VG

3.3V/5V Gate Output

Drive the gates of the 3.3V and 5V MOSFETs. Connect a capacitor to ground to set the

start-up ramp. During turn on, this capacitor is charged with a 25

µA current source.

UV comparator disabled when this pin below 9.6V nominal.

21, 22

12VIN

12V Input

12V supply input for IC and 12VO. Both 12VIns to be connected to a single +12V supply.

16, 27

3VISEN

3.3V Current Sense

Connect to the load side of the current sense resistor in series with source of external 3.3V

MOSFET.

17, 26

3VS

3.3V Source

Connect to source of 3.3V MOSFET. This connection along with (3VISEN) senses the

voltage drop across the sense resistor.

19, 24

5VS

5V Source

Connect to source of 5V MOSFET switch. This connection along with (5VISEN) senses the

voltage drop across the sense resistor.

18, 25

5VISEN

5V Current Sense

Connect to the load side of the current sense resistor in series with source of external 5V

MOSFET.

3, 12

PWRON

Power On Control

Controls all four switches. High to turn switches ON, Low to turn them OFF.

6, 9

12VG

Gate of Internal PMOS Connect a capacitor between 12VG and 12VO to set the start-up ramp for the +12V supply.

This capacitor is charged with a 25

µA current source during start-up.

UV comparator disabled when this pin >1.4Vnominal.

7, 8

12VO

Switched 12V Output

Switched 12V output. Rated for 0.5A.

2, 13

M12VG

Gate of Internal NMOS Connect a capacitor between M12VG and M12VO to set the start-up ramp for the M12V

supply. This capacitor is charged with 25

µA during start-up.

1, 14

M12VO

Switched -12V

Output

Switched 12V Output. Rated for 100mA.

10

OCSET

Overcurrent Set

Connect a resistor from this pin to ground to set the overcurrent trip point of all eight

switches. All eight over current trips can be programmed by changing the value of this

resistor. The default (6.04k

Ω, 1%) is compatible with the maximum allowable currents as

outlined in the PCI specification.

5

VSS

Ground

Connect to common of power supplies.

HIP1011D