PAM2401

Document number: DS37285 Rev. 1 - 2

5 of 10

www.diodes.com

May 2014

© Diodes Incorporated

PAM2401

A Product Line of

Diodes Incorporated

Application Information

Output Voltage Set Equation

connected to the FB pin and the typical value of the voltage at the FB pin is 0.6V. The following equation is used to set the

according to the equation, so a 750kΩ resistor should be chosen for R1.

Inductor Selection

To select an inductor for use in PAM2401 applications, it is worth noting that the inductor current saturation rating should be larger than the

possible peak inductor current to ensure proper operation, and should have low DCR (DC resistance). Using an inductor the saturation current of

which is lower than required can cause a dramatic drop in the inductance and can decay the maximum output current levels severely. For most

applications, the value of the inductor should be in the range ofs 1µH to 4.7µH. Its value is chosen based on the desired ripple current.

Larger value inductors result in lower ripple currents, and smaller value inductors result in higher ripple currents. A 1.5µH or 2.2µH inductor will be

the best choice for most PAM2401 applications. The following equation can also help give a good approximate value for the inductor.

Δ

=

ILxf

V INxD

L

(Ip).

Output and Input Capacitor Selection

Input Capacitor

At least a 10µF input capacitor is recommended to reduce the input ripple and switching noise for normal operating conditions, while a 10-22µF

capacitor may be required for higher power and dynamic loads. Larger values and lower ESR (Equivalent Series Resistance) may be needed if

the application require very low input ripple. It follows that ceramic capacitors are a good choice for applications. Note that the input capacitor

should be located as close as possible to the IC.

Output Capacitor

A minimum output capacitor value of 22µF is recommended and may be increase to a larger value. The ESR of the output capacitor is important

because it determines the peak to peak output voltage ripple by the following equation:

xRESR

IL

V OUT

Δ

>>

Δ

2

Multilayer ceramic capacitors are an excellent choice as they have extremely low ESR and are available in small footprints.