LTC3388-1/LTC3388-3
9
338813fa
For more information www.linear.com/LTC3388
PIN FUNCTIONS
EN (Pin 1): Enable Input. Logic level input referenced to
V
IN2
. A logic high on EN will enable the buck converter.
Driving EN to V
IN2
will result in no additional quiescent
current on V
IN
. However, if EN is driven near V
IH
or V
IL
40nA of additional quiescent current can appear on V
IN
.
STBY (Pin 2): Standby Input. Logic level input referenced
to V
IN2
. A logic high on STBY will place the part in standby
mode. Driving STBY to V
IN2
will result in no additional
quiescent current on V
IN
. However, if STBY is driven
near V
IH
or V
IL
40nA of additional quiescent current can
appear on V
IN
.
CAP (Pin 3): Internal rail referenced to V
IN
to serve as gate
drive for buck PMOS switch. A 1µF capacitor should be
connected between CAP and V
IN
. This pin is not intended
for use as an external system rail.
V
IN
(Pin 4): Input Voltage. A 2.2µF or larger capacitor
should be connected from V
IN
to GND.
SW (Pin 5): Switch Pin for the Buck Switching Regulator.
A 22µH or larger inductor should be connected from SW
to V
OUT
.
V
OUT
(Pin 6): Sense pin used to monitor the output volt-
age and adjust it through internal feedback.
V
IN2
(Pin 7): Internal low voltage rail to serve as gate drive
for buck NMOS switch. Also serves as a logic high rail for
output voltage select bits D0 and D1. A 4.7µF capacitor
should be connected from V
IN2
to GND. This pin is not
intended for use as an external system rail.
D1 (Pin 8): Output Voltage Select Bit. D1 should be tied
high to V
IN2
or low to GND to select desired V
OUT
(see
Table 1).
D0 (Pin 9): Output Voltage Select Bit. D0 should be tied
high to V
IN2
or low to GND to select desired V
OUT
(see
Table 1).
PGOOD (Pin 10): Power Good Open-Drain NMOS Output.
The PGOOD pin is Hi-Z when V
OUT
is above 92% of the
target value.
GND (Exposed Pad Pin 11): Ground. The exposed pad
should be connected to a continuous ground plane on the
second layer of the printed circuit board by several vias
directly under the LTC3388-1/LTC3388-3.
