LTC4052-4.2

5

405242f

BLOCK DIAGRA

4052 BD

–

+

–

+

–

+

–

+

–

+

–

+

CHARGE

PUMP

TRIPLER

LOGIC

+

TIMERS

8

2

5

4

3

7

1

+

–

+

–

SENSE

GATE

BAT

105mV

45mV

TRICKLE

FAST

1.23V

1.23V

THERMAL

SHUTDOWN

REFERENCE

OSCILLATOR

100ms

FILTER

6

40

µA

GND

TIMER

CHRG

SLEEP

ACPR

CLK

STOP

C/10

TEMP

BAT

24mA

10m

Ω

PI FU CTIO S

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.