AP65111A

Document number: DS39760 Rev. 1 - 2

2 of 13

www.diodes.com

June 2017

© Diodes Incorporated

AP65111A

Pin Descriptions

Pin Number

Pin Name

Function

1

IN

Power Input. IN supplies the power to the IC, as well as the step-down converter switches. Drive IN with a 4.5V

to 18V power source. Bypass IN to GND with a suitably large capacitor to eliminate noise on the input to the IC.

See Input Capacitor.

2

GND

Ground

3

SW

Power Switching Output. SW is the switching node that supplies power to the output. Connect the output LC

filter from SW to the output load. Note that a capacitor is required from SW to BST to power the high-side

switch.

4

BST

High-Side Gate Drive Boost Input. BST supplies the drive for the high-side N-Channel MOSFET a 0.01µF or

greater capacitor from SW to BST to power the high side switch.

5

EN

Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the regulator; low to

turn it off. Attach to IN with a 100kΩ pull up resistor for automatic startup.

6

FB

Feedback Input. FB senses the output voltage and regulates it. Drive FB with a resistive voltage divider

connected to it from the output voltage. The feedback threshold is 0.8V. See Setting the Output Voltage.

Functional Block Diagram

Internal

Reference

0.4V

0.8V

1.1V

Regulator

+

-

+

-

+

-

-

+

1.1V

0.4V

+

0.8V

Internal SS

Error

Amplifier

OVP

PWM

Comparator

Oscillator

500kHz

+

Logic

Ref

62pF

650k

1pF

OCP

UVP

HS

LS

5

EN

6

FB

2

GND

3

SW

4

BST

1

IN

Figure 2. Functional Block Diagram