Datasheet

LM3671
LM3671Q
SNVS294Q –NOVEMBER 2004–REVISED NOVEMBER 2013 www.ti.com
LDO - Low Dropout Operation
The LM3671-ADJ can operate at 100% duty cycle (no switching; PMOS switch completely on) for low dropout
support of the output voltage. In this way the output voltage will be controlled down to the lowest possible input
voltage. When the device operates near 100% duty cycle, output voltage ripple is approximately 25 mV.
The minimum input voltage needed to support the output voltage is
V
IN, MIN
= I
LOAD
* (R
DSON, PFET
+ R
INDUCTOR
) + V
OUT
where
• I
LOAD: Load current
• R
DSON, PFET: Drain to source resistance of PFET switch in the triode region
• R
INDUCTOR: Inductor resistance
(1)
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