Copyright

© ANPEC Electronics Corp.

Rev. A.4 - Feb., 2009

APW7088

www.anpec.com.tw

10

Pin Description

PIN

NAME

FUNCTION

1

UGATE1

High-side Gate Driver Output for channel 1. Connect this pin to the gate of high-side MOSFET.

This pin is monitored by the adaptive shoot-through protection circuitry to determine when the

high-side MOSFET has turned off.

2

BOOT1

Bootstrap Supply for the floating high-side gate driver of channel 1. Connect the Bootstrap

capacitor between the BOOT1 pin and the PHASE1 pin to form a bootstrap circuit. The bootstrap

from 0.1

µF to 1µF. Ensure that C

3

5VCC

Internal Regulator Output. This is the output pin of the linear regulator, which is converting power

from VCC and provides output current up to 20 mA minimums for internal bias and external usage.

4

AGND

Signal Ground for the IC. All voltage levels are measured with respect to this pin. Tie this pin to

ground island/plane through the lowest impedance connection available.

5

MODE

Operation Phase Selection Input. Pulling this pin lower than 0.64V sets two-phase operation with

both channels enabled. Pulling this pin higher than 0.8V sets single-phase operation with the

channel 2 disabled. Once operating in single-phase mode, the operation mode is latched. It is

required to toggle SS or 5VCC pin to reset the IC.

6

CSP1

Positive Input of current sensing Amplifier for channel 1. This pin combined with CSN1 senses the

inductor current through an RC network.

7

CSN1

Negative Input of current sensing amplifier for channel 1. This pin combined with CSP1 senses

the inductor current through an RC network.

8

CSN2

Negative Input of current sensing amplifier for channel 2. This pin combined with CSP2 senses

the inductor current through an RC network.

9

CSP2

Positive Input of current sensing Amplifier for Channel 2. This pin combined with CSN2 senses the

inductor current through an RC network.

10

DROOP

Load Line (droop) Setting. Connect a resistor between this pin and AGND to set the droop. A

sourcing current, proportional to output current is present on the DROOP pin. The droop scale

factor is set by the resistors (connected with CSP1, CSP2, and DROOP), resistance of the output

inductors and the internal voltage divider with the ratio of 5%.

11

VID0

This is one of the inputs for the internal DAC that provides the reference voltage for output

regulation. This pin responds to logic threshold. The APW7088 decodes the VID inputs to

establish the output voltage; see VID Tables for correspondence between DAC codes and output

voltage settings. This pin is internally pulled high at floating status.

12

COMP

2 or Type 3 feedback compensation.

13

FB

Feedback Voltage. This pin is the inverting input to the error comparator. A resistor divider from

the output to AGND is used to set the regulation voltage.

14

SS

Soft-start Current Output. Connect a capacitor from this pin to AGND to set the soft-start interval.

Pulling the voltage on this pin below 0.5V causes COMP to pull low and then shuts off the output.

15

VID1

One of DAC Inputs, same as VID0 and VID2.

16

POK

Power OK and 1.5V Reference Output. This pin is a reference output used to indicate the status of

17

BOOT2

Bootstrap Supply for the floating high-side gate driver of channel 2. Connect the Bootstrap

capacitor between the BOOT2 pin and the PHASE2 pin to form a bootstrap circuit. The bootstrap

from 0.1

µF to 1µF. Ensure that C

18

UGATE2

High-side Gate Driver Output for Channel 2. Connect this pin to the gate of high-side MOSFET.

This pin is monitored by the adaptive shoot-through protection circuitry to determine when the

high-side MOSFET has turned off.

19

PHASE2

Switch Node for Channel 2. Connect this pin to the source of high-side MOSFET and the drain of

the low-side MOSFET. This pin is used as sink for UGATE2 driver. This pin is also monitored by

the adaptive shoot-through protection circuitry to determine when the high-side MOSFET has

turned off. An Schottky diode between this pin and ground is recommended to reduce negative

transient voltage that is common in a power supply system.

20

LGATE2

Low-side Gate Driver Output for Channel 2. Connect this pin to the gate of low-side MOSFET.

This pin is monitored by the adaptive shoot-through protection circuitry to determine when the

low-side MOSFET has turned off.