AP6502A

Document number: DS35812 Rev. 4 - 2

2 of 14

www.diodes.com

August 2015

© Diodes Incorporated

AP6502A

Pin Descriptions

Pin

Number

Pin

Name

Function

1

BS

High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-Channel MOSFET switch.

Connect a 0.01µF or greater capacitor from SW to BS to power the high side switch.

2

IN

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

4.75V to 23V power source. Bypass IN to GND with a suitably large capacitor to eliminate noise on the input

to the IC. See Input Capacitor.

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 BS to power the high-side

switch.

4

GND

Ground (Connect the exposed pad to Pin 4).

5

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 0.925V. See Setting the Output Voltage.

6

COMP

Compensation Node. COMP is used to compensate the regulation control loop. Connect a series RC network

from COMP to GND. In some cases, an additional capacitor from COMP to GND is required. See

Compensation Components.

7

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.

8

SS

Soft-Start Control Input. SS controls the soft-start period. Connect a capacitor from SS to GND to set the soft-

start period. A 0.1µF capacitor sets the soft-start period to 15ms. To disable the soft-start feature, leave SS

floating.

EP

EP

EP exposed thermal pad connect to Pin 4 GND.

Functional Block Diagram

E

+

-

+

-

+

-

+

-

+

-

+

1.1V

0.3 V

INTERNAL

REGULATORS

Logic

5V

SHUTDOWN

COMPARATOR

0.9V

+

-

ERROR

AMPLIFIER

LOCKOUT

COMPARATOR

8

7

5

80/240 KHz

OSCILLATOR

CURRENT

SENSE

AMPLIFIER

OVP

RAMP

CLK

CURRENT

COMPARATOR

EN OK

disable

IN < 4.10V

2

1

3

4

6

FB

6uA

EN

COMP

2.5V

SS

0.925 V

GND

SW

BS

IN

130m

Ω

130m

Ω

IN

Figure 3. Functional Block Diagram