Datasheet

PM8903A PM8903A demonstration board
Doc ID 024147 Rev 1 23/33
7 PM8903A demonstration board
The PM8903A 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 the testing of the synchronization capability of the PM8903A. 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 the input filter.
Figure 13. PM8903A 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
single resistor, from 0.6 V to almost V
IN
with a total accuracy better than ±1% over line, load
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.