Description
PM6681A is a dual step-down controller specifically designed to provide extremely high efficiency conversion, with lossless current sensing technique. The constant on-time architecture assures fast load transient response and the embedded voltage feed-forward provides nearly constant switching frequency operation. An embedded integrator control loop compensates the DC voltage error due to the output ripple. Pulse skipping technique increases efficiency at very light load. Moreover a minimum switching frequency of 33 kHz is selectable to avoid audio noise issues. The PM6681A provides a selectable switching frequency, allowing three different values of switching frequencies for the two switching sections. The output voltages OUT1 and OUT2 can be adjusted from 0.9 V to 5 V and from 0.9 V to 3.3 V respectively. The device provides also 2 LDOs, 5 V fixed and 0.9 V - 3.3 V adjustable.

Features
■ 6 V to 36 V input voltage range
■ Adjustable output voltages
■ 0.9 - 3.3 V LDO adjustable delivers 100 mA peak current
■ 5 V LDO delivers 100 mA peak current
■ 1.237 V ±1 % reference voltage available
■ No RSENSE current sensing using low side MOSFETs RDS(on)
■ Negative current limit
■ Soft-start internally fixed at 2 ms
■ Soft output discharge
■ Latched UVP
■ Not-latched OVP
■ Selectable pulse skipping at light loads
■ Selectable minimum frequency (33 kHz) in pulse skip mode
■ 5 mW maximum quiescent power
■ Independent Power Good signals
■ Output voltage ripple compensation

Applications
■ Embedded computer system
■ FPGA system power
■ Industrial applications on 24 V
■ High performance and high density DC-DC modules
■ Notebook computer