Datasheet

LTC3129-1
10
31291fa
For more information www.linear.com/LTC3129-1
pin FuncTions
(QFN/MSOP)
PGND (Pin 15/Pin 13, Exposed Pad Pin 17/Pin 17): Power
Ground. Provide a short direct PCB path between PGND
and the ground plane. The exposed pad must also be
soldered to the PCB ground plane. It serves as a power
ground connection, and as a means of conducting heat
away from the die.
SW1 (Pin 16/Pin 14): Switch Pin. Connect to one side of
the inductor. Keep PCB trace lengths as short and wide
as possible to reduce EMI.
Table 1. V
OUT
Program Settings
VS3 PIN VS2 PIN VS1 PIN V
OUT
0 0 0 2.5V
0 0 V
CC
3.3V
0 V
CC
0 4.1V
0 V
CC
V
CC
5V
V
CC
0 0 6.9V
V
CC
0 V
CC
8.2V
V
CC
V
CC
0 12V
V
CC
V
CC
V
CC
15V
block DiagraM
31291 BD
LDO
V
REF
START
V
REF
V
CC
V
CC
V
CC_GD
START
START
4.1V
1.175V
V
REF
+
–
SD
UVLO
+
–
–
+
+
–
–
+
THERMAL
SHUTDOWN
+
–
–
+
PWM
600mV
–7.5%
OSC
GND
SLEEP
100mV
RESET
ENABLE
I
LIM
I
ZERO
I
SENSE
20mA
I
SENSE
V
REF_GD
500mA
PGND
CLAMP
+
–
1.175V
FB
–
+
–
+
–
+
–
+
DRIVER
DRIVER
DRIVER
DRIVER
I
SENSE
I
SENSE
DRV_C
1.1V
UV
VS1
V
OUT
V
CC
V
OUT
VS2
VS3DRV_D
DRV_B
DRV_A
I
SENSE
LOGIC
PGOOD
SOFT-START
+
–
MPPC
RUN
V
CC
V
IN
V
IN
BST1 SW1 SW2
D
C
A
B
BST2
PWM
SLEEP
V
IN
0.9V
1.22V
1.175V
5M
1.175V
V
C
V
OUT
SELECT
INPUTS