2 Channel 5.5V 1.5A 1.5MHz DC-DC Step down PMU

•

Efficiency

•

Output ripple voltage

•

Over current ruggedness

The device has been optimized for use with nominal LC values as shown in the Application Diagram.

BUCK Power Supply Recommendations

HM5213 are designed to operate from input voltage supply range between 2.5V and 5.5V. This input supply must

be well regulated. If the input supply is located more than a few inches, additional bulk capacitance may be required

in addition to the ceramic bypass capacitors. A ceramic capacitor with a value of 10uF is a typical choice.

VIN must be connected to input capacitors as close as possible.

BUCK Inductor Selection

The recommended inductor values are shown in the Application Diagram. It is important to guarantee the inductor

core does not saturate during any foreseeable operational situation. The inductor should be rated to handle the peak

load current plus the ripple current: Care should be taken when reviewing the different saturation current ratings

that are specified by different manufacturers. Saturation current ratings are typically specified at 25°C, so ratings at

maximum ambient temperature of the application should be requested from the manufacturer.

���� =

where

•

: Max inductor Current

•

: Max load current

•

Peak-to-Peak inductor current

•

D

: Estimated duty factor

•

: Input voltage

•

: Output voltage

•

: Switching frequency, Hertz

Recommended Method for BUCK Inductor Selection

The best way to guarantee the inductor does not saturate is to choose an inductor that has saturation current rating

greater than the maximum device current limit, as specified in the Electrical Characteristics. In this case the device

will prevent inductor saturation by going into current limit before the saturation level is reached.

Alternate Method for BUCK Inductor Selection

If the recommended approach cannot be used care must be taken to guarantee that the saturation current is greater

than the peak inductor current:

2

HM5213