FAN5361 pdf,datasheet (6MHz, 6

The FAN5361 is a 600mA, step-down, switching voltage
regulator that delivers a fixed output from an input voltage
supply of 2.3V to 5.5V. Using a proprietary architecture with
synchronous rectification, the FAN5361 is capable of
delivering a peak efficiency of 92%, while maintaining
efficiency over 80% at load currents as low as 1mA.
The regulator operates at a nominal fixed frequency of
6MHz, which reduces the value of the external components
to 470nH for the output inductor and 4.7µF for the output
capacitor. The PWM modulator can be synchronized to an
external frequency source.
At moderate and light loads, pulse frequency modulation is
used to operate the device in power-save mode with a
typical quiescent current of 35µA. Even with such a low
quiescent current, the part exhibits excellent transient
response during large load swings. At higher loads, the
system automatically switches to fixed-frequency control,
operating at 6MHz. In shutdown mode, the supply current
drops below 1µA, reducing power consumption. For
applications that require minimum ripple or fixed frequency,
PFM mode can be disabled using the MODE pin.
The FAN5361 is available in 6-bump, 0.4mm pitch, Wafer-
Level Chip-Scale Package (WLCSP).