AP61300Q/AP61302Q

Document number: DS44605 Rev. 1 - 2

3 of 21

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January 2022

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AP61300Q/AP61302Q

Pin Descriptions

Pin Name

Pin Number

Function

FB

1

Feedback sensing terminal for the output voltage. Connect this pin to the resistive divider of the output.

See Setting the Output Voltage section for more details.

GND

2

Power Ground.

VIN

3

Power Input. VIN supplies the power to the IC as well as the step-down converter power MOSFETs. Drive VIN with a

2.4V to 5.5V power source. Bypass VIN to GND with a suitably large capacitor to eliminate noise due to the switching

of the IC. See Input Capacitor section for more details.

SW

4

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.

EN

5

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

turn it off. EN is used to program the Operation Mode (PFM or PWM). See Enable section for more details.

OUT

(AP61300Q)

6

Output Voltage Power Rail. Connect OUT to the output load as shown in Figure 1. OUT cannot be tied to GND but

can be treated as a No Connect pin and left floating. If left floating, then a feed-forward capacitor, C3, must be used

as shown in Figure 2.

PG

(AP61302Q)

Power-Good. Open drain power-good output that is pulled to GND when the output voltage is out of its regulation

limits or during soft-start.

Functional Block Diagram

EN

SW

VIN

3

0.6V

4

2

GND

+

+

-

+

Control

Logic

SE

OCP

S

VIN

Q

R

Q

SW

On-Time

Compute

One-Shot

Minimum

Off-Time

VIN OVP

UVLO

Internal

Reference

Internal

Soft-Start

0.6V

Q1

Q2

ON

5

MODE

Control

Shutdown

Comparator

DISCHARGE

MODE

FB

OUT

AP61300Q

1

6

Thermal

Shutdown

5MΩ

VIN

6

PG

AP61302Q

DISCHARGE

MODE

Figure 5. Functional Block Diagram