PM6680A Datasheet, PDF (1/48 Pages) STMicroelectronics – Dual synchronous step-down controller with adjustable output voltages plus LDO

PM6680A
Dual synchronous step-down controller
with adjustable output voltages plus LDO
Features
■ 6 V to 36 V input voltage range
■ Adjustable output voltages
■ 5V LDO delivers 100 mA peak current
■ 1.237 V ± 1 % reference voltage available
externally
■ Current sensing using low side MOSFETs
R_DS(on)
■ Valley current sensing
■ Soft-start internally fixed at 2ms
■ Soft output discharge
■ Latched OVP and UVP
■ Selectable pulse skipping at light loads
■ Selectable minimum frequency (33 kHz) in
pulse skip mode
■ 5mW maximum quiescent power
■ Independent power good signals
■ Output voltage ripple compensation
■ Thermal shutdown
Applications
■ Embedded computer system
■ FPGA system power
■ Industrial applications on 24 V
■ High performance and high density DC/DC
modules
VFQFPN-32 5X5
Description
PM6680A is a dual step-down controller
specifically designed to provide extremely high
efficiency conversion, with loss less 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 PM6680A 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.
Table 1. Device summary
Order codes
PM6680A
PM6680ATR
Package
VFQFPN-32 5X5 (exposed pad)
December 2007
Rev 2
Packaging
Tube
Tape and reel
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www.st.com
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