LTC3532_15 Datasheet, PDF (6/16 Pages) Linear Technology – Micropower Synchronous Buck-Boost DC/DC Converter

LTC3532
PI FU CTIO S
SHDN/SS (Pin 8): Combined Soft-Start and Shutdown.
Grounding this pin shuts down the IC. Tie to >1.5V to
enable the IC and >2.4V to ensure the error amp is not
clamped from soft-start. For Burst Mode operation, this pin
must be pulled up to within 0.5V of V_IN. An RC from the
shutdown command signal to this pin will provide a soft-
start function by limiting the rise time of the V_C pin.
FB (Pin 9): Feedback Pin. Connect resistor divider tap
here. The output voltage can be adjusted from 2.4V to
5.25V. The feedback reference is typically 1.22V. Set V_OUT
according to the formula:
V_OUT
=
1.22V
• (R1+
R2
R2)
V_C (Pin10): Error Amp Output: A frequency compensa-
tion network is connected from this pin to the FB pin to
compensate the loop. Refer to the Applications Information
section for component value selection.
Exposed Pad (Pin11): The exposed pad (DFN Package)
must be soldered to PCB ground for electrical contact and
rated thermal performance.
BLOCK DIAGRA
V_IN
7
SW A
3
SW1
SW B
GATE
DRIVERS
AND
ANTICROSS
CONDUCTION
4
SW2
SW D
SW C
REVERSE
AMP
V_OUT
6
6
R_T
1
PEAK CURRENT
+
LIMIT
1.1A
–
V_IN
+
2.3V
–
UVLO
PWM
LOGIC
PWM COMP
SLEEP
OSC
V_IN
SHDN/SS
8
SHUTDOWN
SOFT-START
V_CC
SHUTDOWN
GND
5
+
g_m = 1/60k
1A –
ERROR
AMP
1.22V
FB
9
V_C
10
AUTOMATIC
Burst Mode
CONTROL AND
V_C HOLD
V_REF
SS
1.22V
V_REF
THERMAL
SHUTDOWN
BURST
2
3532 BD
3532fc