MAX17031 pdf datasheet (Dual Q

The MAX17031 is a dual Quick-PWM? step-down
power-supply (SMPS) controller with synchronous rectification,
intended for main 5V/3.3V power generation in
battery-powered systems. Low-side MOSFET sensing
provides a simple low-cost, highly efficient current
sense for valley current-limit protection. Combined with
the output overvoltage and undervoltage protection features,
this current limit ensures robust output supplies.
The 5V/3.3V SMPS outputs can save power by operating
in pulse-skipping mode or in ultrasonic mode to
avoid audible noise. Ultrasonic mode forces the controller
to maintain switching frequencies greater than
20kHz at light loads. The SKIP input also has an accurate
logic threshold, allowing it to be used as a secondary
feedback input to refresh an external charge
pump or secondary winding without overcharging the
output voltages.
An internal 100mA linear regulator generates the 5V
bias needed for power-up or other low-power “alwayson”
suspend supplies. An internal bypass circuitry
allows automatic bypassing of the linear regulator when
the 5V SMPS is active.
The device includes independent shutdown controls
with well-defined logic thresholds to simplify power-up
and power-down sequencing. To prevent current
surges at startup, the internal voltage target is slowly
ramped up from zero to the final target over a 1ms period.
To prevent the output from ringing below ground in
shutdown, the internal voltage target is ramped down
from its previous value to zero over a 1ms period. A
combined power-good (PGOOD) output simplifies the
interface with external controllers. The MAX17031 is
available in a 24-pin thin QFN (4mm x 4mm) package.
Applications
Notebook Computers
Ultra-Mobile PC
Main System Supply (5V and 3.3V Supplies)
2 to 4 Li+ Cells Battery-Powered Devices
Telecommunication