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PM8908

Device description

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5

Device description

The PM8908 is a high efficiency synchronous step-down monolithic switching regulator

capable to deliver or sink the current.

The power input voltage (VIN) can range from 1 V to 3.5 V, the signal input voltage (VCC)

can range from 4.5 V to 5.5 V.

The output voltage is regulated to the REFIN voltage which comes from an external

reference voltage. The output voltage accuracy is better than ±

temperature.

side).

The high-switching frequency selectable in two values - 600 kHz or 1 MHz and the small

package allows very compact VR solutions.

in Equation 1:

Equation 1

The PM8908 features a full set of protections and output voltage monitoring:



Precise and accurate overcurrent limit (internally compensated against temperature

variations)



Over and undervoltage protection



Overtemperature protection



Undervoltage lockout on analog supply (VCC)



Power Good open drain output easily provides real-time information about the output

voltage.

The dedicated ENABLE pin (EN) offers easy control on the power sequencing. Forcing the

EN low, the device enters the shutdown state and absorbs a total quiescent current from

VCC and VIN less than 15 µA.

5.1

Power section

switches, optimized for fast switching transition and high efficiency over the entire load

range.

The HS MOSFET drain is connected to the VIN pins (power input), the LS MOSFET source

is connected to the PGND pins (power ground), and the HS MOSFET source and LS

MOSFET drain are connected together and to the PHASE pins (see Figure 1 on page 4).

The driving section is supplied from the VCC pins that assure the proper driving voltage

over all the VIN range.

t

ON

V

OUT

V

IN

f

SW



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