PM8903 demonstration board

PM8903

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Doc ID 022748 Rev 1

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PM8903 demonstration board

The PM8903 demonstration board realizes, in a four-layer PCB, a high efficiency

synchronous step-down monolithic switching converter capable of delivering up to 3 A

continuous output current.

The demonstration board shows the operation of the device in a general purpose

application. Two devices are present on the demonstration board and connected through the

SYNCH pin, also allowing testing of the synchronization capability of the PM8903. The two

devices are synchronized to each other with 180 ° phase shift switching interleaving,

reducing RMS current absorption from the input filter and preventing beating frequency

noise, therefore allowing a reduction in the size and cost of input filter.

Figure 13.

PM8903 demonstration board

The input voltage (VIN) can range from 2.8 V to 6 V and the supply voltage (VCC) can range

from 2.9 V to 5.5 V.

The output voltage is programmed to be 1.5 V but can be easily programmed, changing a

and temperature.

A simple resistor connected from the PSKIP / MS pin to ground enables / disables pulse-

skipping technology and assigns to the IC master or slave status.

The dedicated dip switch SW1 allows the enabling / disabling of each device and offers easy

control on the power sequencing or to reset latched protection. Forcing EN low, the device

enters a shutdown state and absorbs a total quiescent current from VCC and VIN less than

15

μA.