LM2696 3A, Constant On Time Buck Regulator
October 2005
LM2696
3A, Constant On Time Buck Regulator
General Description
The LM2696 is a pulse width modulation (PWM) buck regu-
lator capable of delivering up to 3A into a load. The control
loop utilizes a constant on-time control scheme with input
voltage feed forward. This provides a topology that has
excellent transient response without the need for compen-
sation. The input voltage feed forward ensures that a con-
stant switching frequency is maintained across the entire V
IN
range.
The LM2696 is capable of switching frequencies in the range
of 100 kHz to 500 kHz. Combined with an integrated 130 m鈩?/div>
high side NMOS switch the LM2696 can utilize small sized
external components and provide high efficiency. An internal
soft-start and power-good flag are also provided to allow for
simple sequencing between multiple regulators.
The LM2696 is available with an adjustable output in an
exposed pad TSSOP-16 package.
Features
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Input voltage range of 4.5V鈥?4V
Constant On-Time
No compensation needed
Maximum Load Current of 3A
Switching frequency of 100 kHz鈥?00 kHz
Constant frequency across input range
TTL compatible shutdown thresholds
Low standby current of 12 碌A
130 m鈩?internal MOSFET switch
Applications
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High efficiency step-down switching regulators
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LCD Monitors
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Set-Top Boxes
Typical Application Circuit
20153401
漏 2005 National Semiconductor Corporation
DS201534
www.national.com
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