3

Pin Descriptions

PIN #

SYMBOL

FUNCTION

DESCRIPTION

1

3V/12VS

3.3 V/12V Source

Connect to source of associated external N-Channel MOSFET switch to sense output

voltage.

2

3V/12VG

3.3V/12V Gate

Connect to the gate of associated N-Channel MOSFET switch. A capacitor from this node

to ground sets the turn-on ramp. At turn-on this capacitor will be charged to 17.4V by a 10

µA

current source when in 5v/12V mode of operation, otherwise capacitor will be charged to

11.4V. A small resistor (10 - 200

Ω) should be placed in series with the gate capacitor to

ground to prevent current oscillations.

Chip Supply

Connect to 12V supply. This can be either connected directly to the +12V rail supplying the

4

MODE/

PWRON1

Power ON/ Reset

Invokes 3.3V operation

PWRON1 and PWRON2 are used to turn-on and reset the chip. Both outputs turn-on when

either pin is driven low. After a current limit time out, the chip is reset by the rising edge of a

reset signal applied to either PWRON pin. Each input has 100

µA pull up capability which is

compatible with 3V and 5V open drain and standard logic. PWRON1 is also used to invoke

3.3V control operation in preference to +12V control. By tying pin 4 to pin 3 the charge pump

is disabled and the UV threshold also shifts to 2.8V.

5

PWRON2

Power ON/ Reset

6

5VG

5V Gate

Connect to the gate of the external 5V N-Channel MOSFET. A capacitor from this node to

ground sets the turn-on ramp. At turn-on this capacitor will be charged to 11.4V by a 10

µA

current source. A small resistor (10 - 200

Ω) should be placed in series with the gate

capacitor to ground to prevent current oscillations.

7

5VS

5V Source

Connect to the source side of 5V external N-Channel MOSFET switch to sense output

voltage.

8

5VISEN

5V Current Sense

Connect to the load side of the 5V sense resistor to measure the voltage drop across this

resistor between 5VS and 5VISEN pins.

9

PGOOD

Power Good indicator

Indicates that all output voltages are within specification. PGOOD is driven by an open drain

N-Channel MOSFET. It is pulled low when any output is not within specification.

10

Current Limit Timing

Capacitor

Connect a capacitor from this pin to ground. This capacitor controls the time between the

onset of current limit and chip shutdown (current limit time-out). The duration of current limit

time-out (in seconds) = 200k

11

Charge Pump

Capacitor

Connect a 0.1

when in 3.3V control mode.

12

GND

Chip Ground

13

Current Limit Set

Resistor

A resistor connected between this pin and ground determines the current level at which

the HIP1012A can accommodate a 5k

Ω resistor for a lower OC Vth (50mV).

14

3V/12VISEN

3.3V/12V Current Sense

Connect to the load side of sense resistor to measure the voltage drop across this resistor.

HIP1012, HIP1012A