PM6680
No Rsense dual step-down controller with adjustable voltages
for notebook system power
Features
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6 V to 28 V input voltage range
Adjustable output voltages
5V always voltage available deliver 100 mA
peak current
1.237 V
±
1% reference voltage available
Lossless current sensing using low side
MOSFETs R
DS(on)
Negative current limit
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
4mW maximum quiescent power
Independent power good signals
Output voltage ripple compensation
VFQFPN-32 5X5
Description
PM6680 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 33kHz is selectable to avoid audio
noise issues. The PM6680 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 5.5 V
and from 0.9 V to 3.3 V respectively.
Applications
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Notebook computers
Tablet PC or slates
Mobile system power supply
3-4 cells Li+ battery powered devices
Table 1.
Device summary
Order codes
PM6680
PM6680TR
Package
VFQFPN-32 5mm x 5mm (Exposed pad)
VFQFPN-32 5mm x 5mm (Exposed pad)
Packaging
Tube
Tape and reel
August 2007
Rev 6
1/49
49
STMICROELECTRONICS [ STMICROELECTRONICS ]
