LTC3541-1 Datasheet, PDF (7/20 Pages) Linear Technology – High Efficiency Buck + VLDO Regulator

LTC3541-1
PI FU CTIO S
V_IN (Pin 1): Main Supply Pin. This pin must be closely
decoupled to GND with a 10µF or greater capacitor.
ENBUCK (Pin 2): Buck Enable Pin. This pin enables the
buck regulator when driven to a logic high.
BUCKFB (Pin 3): Buck Regulator Feedback Pin. This pin
receives the buck regulator’s feedback voltage from an
external resistive divider.
LFB (Pin 4): VLDO/Linear Regulator Feedback Pin. This
pin receives either the VLDO or linear regulator’s feedback
voltage from an external resistive divider.
LV_OUT (Pin 5): VLDO/Linear Regulator Output Pin. This
pin provides the regulated output voltage from the VLDO
or linear regulator.
LV_IN (Pin 6): VLDO/Linear Regulator Input Supply Pin.
This pin provides the input supply voltage for the VLDO
power FET.
GND (Pin 7): Analog Ground Pin.
MODE (Pin 8): Buck Mode Selection Pin. This pin enables
buck Pulse-Skip operation when driven to a logic high
and enables buck Burst Mode operation when driven to
a logic low.
ENVLDO (Pin 9): VLDO/Linear Regulator Enable Pin.
When driven to a logic high, this pin enables the linear
regulator when the ENBUCK pin is driven to a logic low,
and enables the VLDO when the ENBUCK pin is driven to
a logic high.
SW (Pin 10): Switch Node Pin. This pin connects the
internal main and synchronous power MOSFET switches
to the external inductor for the buck regulator.
Exposed Pad (Pin 11): Ground Pin. This pin must be
soldered to the PCB to provide both electrical contact to
ground and good thermal contact to the PCB.
Note: Table 1 details the truth table for the control pins
of the LTC3541-1.
Table 1. LTC3541-1 Control Pin Truth Table
PIN NAME
OPERATIONAL DESCRIPTION
ENBUCK ENVLDO MODE
0
0
X LTC3541-1 Powered Down
0
1
X Buck Powered Down, VLDO Regulator
Powered Down, Linear Regulator
Enabled
1
0
0 Buck Enabled, VLDO Regulator Powered
Down, Linear Regulator Powered Down,
Burst Mode Operation
1
0
1 Buck Enabled, VLDO Regulator Powered
Down, Linear Regulator Powered Down,
Pulse-Skip Mode Operation
1
1
0 Buck Enabled, VLDO Regulator Enabled,
Linear Regulator Powered Down, Burst
Mode Operation
1
1
1 Buck Enabled, VLDO Regulator Enabled,
Linear Regulator Powered Down, Pulse-
Skip Mode Operation
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