Pin No.

Pin Name

I/O

Description

12

PGOOD

O

PGOOD is an open collector output used to indicate the status of

the converter output voltage. This pin is pulled low when the

converter output is not within ±10% of the DACOUT reference

voltage. Exception to this behavivor is the ¢11111¢ VID pin com-

bination which disables the converter; in this case, PGOOD as-

serts a high level.

13

PHASE

O

Connect the PHASE pin to the upper MOSFET source. This pin

is used to monitor the voltage drop across the MOSFET for

over-current protection. This pin also provides the return path

for the upper gate drive.

14

UGATE

O

Connect UGATE to the upper MOSFET gate. This pin provides

the gate drive for the upper MOSFET.

15

BOOT

I

This pin provides bias voltage to the upper MOSFET driver. A

bootstrap circuit may be used to create a BOOT voltage suitable

to drive a standard N-Channel MOSFET.

16

PGND

P

This is the power ground connection. Tie the lower MOSFET

source to this pin.

17

LGATE

O

Connect LGATE to the lower MOSFET gate. This pin provides

the gate drive for the lower MOSFET.

18

VCC

P

Provide a 12V bias supply for the chip to this pin.

19

OVP

O

The OVP pin can be used to drive an external SCR in the event

of an overvoltage condition.

20

RT

I

This pin provides oscillator switching frequency adjustment. By

200kHz switching frequency is increased.

510

R(k )

6

T

´

W

VCC reduces the switching frequency.

410

R(k )

7

T

´

W

Absolute Maximum Ratings

Supply Voltage ......................................... +15V

Storage Temperature ............... -50°Cto125°C

Operating Temperature ............ -20°Cto75°C

Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maxi-

mum Ratings² may cause substantial damage to the device. Functional operation of this device

at other conditions beyond those listed in the specification is not implied and prolonged expo-

sure to extreme conditions may affect device reliability.

HT82P604B

3

March 23, 2000

Preliminary