Datasheet

LTC3529
6
3529fb
The LTC3529 is a 1.5MHz synchronous boost converter in
an 8-lead 2mm × 3mm DFN package. The device operates
with an input voltage as low as 1.8V and features fi xed-
frequency current-mode PWM control for exceptional line
and load regulation. Internal MOSFET switches with low
R
DS(ON)
and low gate charge enable the device to maintain
high effi ciency over a wide range of load current.
PWM Operation
The LTC3529 operates in a fi xed-frequency PWM mode
using current-mode control at all load currents. At very
BLOCK DIAGRAM
light loads, the LTC3529 will exhibit pulse-skipping
operation.
Soft-Start
The LTC3529 provides soft-start by ramping the inductor
current limit from zero to its peak value in approximately
2ms. The internal soft-start capacitor is discharged in
the event of a fault, thermal shutdown or when the IC is
disabled via the SHDN pin.
3529 BD
SW
C
IN
3.3μF
1.8V
TO
5.25V
V
OUT
, 5V
L1
4.7μH
FAULT
V
OUT
SHDN
C
OUT
10μF
2
PGND
4
GND (BP)
9
RST
7
V
IN
V
IN
V
IN
8 3
5
SNSGND
6
1
22ms
FAULT TIMER
ANTI-RING
PWM LOGIC
AND
DRIVERS
CLOCK
FAULT OR
THERMAL
SHUTDOWN
BULK CONTROL
SIGNALS
CURRENT
SENSE
–
+
–
+
+
–
+
–
SOFT-START
1.25V
2A
SD
C
C
C2
1.25V
R2
625k
THERMAL SD
REFERENCE
GM ERROR
AMPLIFIER
OSCILLATOR
3
+
+
+
–
IZERO
COMP
PWM
COMP
I
LIM
COMP
R1
1.875M
R
C
OPERATION