AP7330

Document number: DS40022 Rev. 2 - 2

9 of 13

www.diodes.com

February 2018

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AP7330

Application Information

Output Capacitor

An output capacitor (COUT) is needed to improve transient response and maintain stability. The AP7330 is stable with very small ceramic output

capacitors. The ESR (equivalent series resistance) and capacitance drives the selection. If the application has large load variations, it is

recommended to utilize low-ESR bulk capacitors. It is recommended to place ceramic capacitors as close as possible to the load and the ground

pin and care should be taken to reduce the impedance in the layout.

Input Capacitor

To prevent the input voltage from dropping during load steps, it is recommended to utilize an input capacitor (CIN). A minimum 0.47μF ceramic

capacitor is recommended between VIN and GND pins to decouple input power supply glitch. This input capacitor must be located as close as

possible to the device to assure input stability and reduce noise. For PCB layout, a wide copper trace is required for both VIN and GND pins.

Enable Control

The AP7330 is turned on by setting the EN pin high, and is turned off by pulling it low. If this feature is not used, the EN pin should be tied to VIN pin

to keep the regulator output on at all times. To ensure proper operation, the signal source used to drive the EN pin must be able to swing above

and below the specified turn-on/off voltage thresholds listed in the Electrical Characteristics section.

Short Circuit Protection

When VOUT pin is short-circuit to GND, short circuit protection will be triggered and clamp the output current to approximately 60mA. This feature

protects the regulator from overcurrent and damage due to overheating.

Layout Considerations

For good ground loop and stability, the input and output capacitors should be located close to the input, output, and ground pins of the device. The

regulator ground pin should be connected to the external circuit ground to reduce voltage drop caused by trace impedance. Ground plane is

generally used to reduce trace impedance. Wide trace should be used for large current paths from VIN to VOUT, and load circuit.

Adjustable Operation

The AP7330 provides output voltage from 1V to 4.5V through external resistor divider as shown below.

1

μF

VIN

GND

EN

VOUT

Enable

ADJ

R2

R1

1

μF

VIN

VOUT

AP7330

The output voltage is calculated by:

T =

F

Where VREF = 0.8V (the internal reference voltage)

Rearranging the equation will give the following that is used for adjusting the output to a particular voltage:

1

T

F

To maintain the stability of the internal reference voltage, R2 need to be kept smaller than 10k.