Datasheet

LTC4052-4.2
5
405242f
BLOCK DIAGRA
W
4052 BD
–
+
–
+
–
+
–
+
–
+
–
+
V
FLOAT
V
RECHRG
V
MIN
V
MAX
CHARGE
PUMP
TRIPLER
LOGIC
+
TIMERS
8
2
5
4
3
7
1
+
–
+
–
V
IN
SENSE
GATE
BAT
105mV
45mV
TRICKLE FAST
1.23V
1.23V
THERMAL
SHUTDOWN
REFERENCE
OSCILLATOR
100ms
FILTER
6
40µA
V
IN
GND
TIMER
CHRG
SLEEP
ACPR
CLK
STOP
C/10
TEMP
I
MAX
BAT
24mA
10mΩ
PI FU CTIO S
UUU
A series RC network from the GATE to the V
IN
pin is
required to control the slew rate at the V
IN
pin when the
switch is turned on or off. The slew rate control prevents
excessive current from the capacitor usually located in the
wall adapter from flowing into the battery when the pass
transistor turns on.
BAT (Pin 8): Battery Sense Input Pin. An internal resistor
divider presets the final float voltage to 4.2V. If the BAT pin
drops below 4.05V after the charge cycle has ended, the
timer resets and a new charge cycle begins. This pin is
clamped to 4.7V if the battery is disconnected while
charging.