[AP3603]

015000004-E-02

2015/07

- 5 -

■ Functions

No.

Pin Name

I/O

Function

1

FSYN

I

External Synchronous Pin

This pin switches boost N-channel MOSFET of CH1 ON, synchronizing the falling

edge of input clock. The pin is pulled-up by 10uA constant current internally.

2

RT

I

PWM Frequency Setting Pin

Connect the resistor to GND1 for setting the PWM frequency.

Refer 12.2 Operational Frequency Setting to calculate the resistance.

3

FB1

I

CH1 Output Voltage Feedback Pin

Output voltage is controlled so that FB1 pin voltage becomes 3.6V. Connect the

voltage divide node of feedback resistance should be connected to FB1 pin.

4

CC1

O

CH1 Error Amplifier Output Pin

Connect the resistance and capacitor in parallel between CC1 pin and SS pin to

compensate phase stability.

5

GND1

-

Signal Ground Pin

Connect GND2 at just below the AP3603 to prevent potential difference between

this pin and the GND2 pin.

6

SS

O

CH1 and CH2 Soft Start Pin

Connect a capacitor between SS pin and GND to set the soft start time. When the

capacitor value is 0.1uF, the soft start time becomes 12ms.

7

CC2

O

CH2 Error Amplifier Output Pin

Connect the resistance and capacitor in parallel between CC2 pin and SS pin to

compensate phase stability.

8

FB2

I

CH2 Output Voltage Feedback Pin

Connect the feedback resistance between the positive side of output capacitor and

GND1 during dual output application usage. Voltage divide node of feedback

resistance should be connected to FB2 pin.

Connect this pin to FB1 pin at the dual phase single output application usage.

9

PWON

I

Power On Signal Input Pin

After “H” signal input, the internal voltage source V5 is powered up and then the

start-up sequence is initiated.

10

MDC

O

Maximum On Duty Set Pin

Set the maximum on time by the external resistance connecting between MDC and

GND1.

11

RSP2

I

CH2 Current Detect Positive Pin

12

RSN2

I

CH2 Current Detect Negative Pin

13

DRV2

O

CH2 N-channel MOSFET Drive Pin

14

V4

O

V4 Linear Regulator Output Pin

Middle voltage node of boost driver. Connect MLCC 0.22μF or more between V4

pin and GND2 to stabilize the internal voltage.

15

V8

O

V8 Linear Regulator Output Pin

Power source of Boost driver. Connect MLCC 2.2μF or more between V8 and

GND2 to stabilize the internal voltage.

16

VDD

-

Main Power Source Pin

17

GND2

-

Power Ground Pin

Connect the GND1 at just below the AP3603 to prevent potential difference between

this pin and the GND1 pin.

18

DRV1

O

CH1 N-channel MOSFET Drive Pin

19

RSN1

I

CH1 Current Detect Negative Pin

20

RSP1

I

CH1 Current Detect Positive Pin