PM8903

Device description

Doc ID 022748 Rev 1

13/34

5

Device description

The PM8903 is a high efficiency synchronous step-down monolithic switching regulator

capable of delivering up to 3 A continuous output current.

range from 2.9 V to 5.5 V.

Thanks to 0.6 V internal reference and 0-100% duty cycle capability, the PM8903 can

LS (low-side) and implements the proprietary pulse-skipping technology, therefore, the

PM8903 guarantees high efficiency over all the load range.

The voltage mode control loop with high bandwidth error amplifier and external

compensation enables a wide range of output filter configurations (including all MLCC

solutions) and fast response to load transient. The high-switching frequency (typically 1.1

MHz) and the small VFQFPN16 3x3 mm package allow very compact VR solutions.

The PM8903 features a full set of protections and output voltage monitoring:

●

Precise and accurate dual level overcurrent protection (internally compensated against

temperature variations)

●

Over and undervoltage protection

●

Overtemperature protection

●

Undervoltage lockout on both signal and power supply

●

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

voltage

By simply connecting two PM8903s through the SYNCH pin, they can synchronize each

other with 180 ° phase shift switching interleaving, reducing RMS current absorption from

the input filter and preventing beating frequency noise, therefore allowing the size and cost

of the input filter to be reduced.

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

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

The dedicated enable pin (EN) offers easy control on the power sequencing or to reset the

latched protection. Forcing the EN low, the device enters shutdown state and absorbs a total

quiescent current from VCC and VIN less than 15

μA.

5.1

Power section

high-side switches, optimized for fast switching transition and high efficiency over all the load

range. The power stage is designed to deliver a continuous output current up to 3 A.

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

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

are connected together and to the PHASE pins (see

Figure 2 on page 4). The driving

assures the proper driving voltage over all the VIN range.