Copyright

© ANPEC Electronics Corp.

Rev. A.5 - Mar., 2012

APW8720B

www.anpec.com.tw

8

Pin Description

PIN

NO.

SOP-8P

TDFN3x3-10

NAME

FUNCTION

1

1

BOOT

This pin provides the bootstrap voltage to the high-side gate driver for driving the

N-channel MOSFET. An external capacitor from PHASE to BOOT, an internal

diode, and the boot supply voltage (9V), generates the bootstrap voltage for the

high-side gate driver (UGATE).

2

2

UGATE

High-side Gate Driver Output. This pin is the gate driver for high-side MOSFET.

3

4

GND

Signal and Power ground. Connecting this pin to system ground.

4

5

LGATE

Low-side Gate Driver Output and Over-Current Setting Input. This pin is the gate

driver for low-side MOSFET. It also used to set the maximum inductor current.

Refer to the section in “Function Description” for detail.

5

6

VCC

Power Supply Input. Connect a nominal 5V to 12V power supply voltage to this

pin. A power-on-reset function monitors the input voltage at this pin. It is

recommended that a decoupling capacitor (1 to 10

µF) is connected to GND for

noise decoupling.

6

7

FB

Feedback Input of Converter. The converter senses feedback voltage via FB and

regulates the FB voltage at 0.8V. Connecting FB with a resistor-divider from the

output sets the output voltage of the converter.

7

8

COMP

This is a multiplexed pin. During soft-start and normal converter operation, this pin

represents the output of the error amplifier. It is used to compensate the regulation

control loop in combination with the FB pin.

pull-down device is released, the COMP pin will start to rise. When the COMP pin

and soft-start cycle.

8

3

PHASE

This pin is the return path for the high-side gate driver. Connecting this pin to the

high-side MOSFET source and connect a capacitor to BOOT for the bootstrap

voltage. This pin is also used to monitor the voltage drop across the low-side

MOSFET for over-current protection.

9

(Exposed Pad)

11

(Exposed Pad)

GND

Thermal Pad. Connect this pad to the system ground plan for good thermal

conductivity.

-

9

POK

POK is an open drain output used to indicate the status of the output voltage.

Connect the POK pin to 5 to 12V through a pull-high resistor.

-

10

NC

No Connect