Datasheet

5
LTC4068-4.2/LTC4068X-4.2
406842fa
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Charge Current vs Supply Voltage
Charge Current
vs Ambient Temperature
Recharge Threshold Voltage
vs Temperature
Power FET “ON” Resistance
vs Temperature
V
CC
(V)
4
0
I
BAT
(mA)
100
200
300
400
600
4.5
5 5.5 6
405842 G13
6.5 7
500
V
BAT
= 4V
T
A
= 25°C
θ
JA
= 40°C/W
R
PROG
= 2k
R
PROG
= 10k
TEMPERATURE (°C)
–50
I
BAT
(mA)
400
500
600
25 75
405842 G14
300
200
–25 0
50 100 125
100
0
V
CC
= 5V
V
BAT
= 4V
θ
JA
= 40°C/W
R
PROG
= 2k
ONSET OF THERMAL REGULATION
R
PROG
= 10k
TEMPERATURE (°C)
–50
4.04
V
RECHRG
(V)
4.06
4.08
4.10
4.12
4.16
–25
02550
405842 G15
75 100
4.14
V
CC
= 5V
R
PROG
= 10k
TEMPERATURE (°C)
–50
R
DS(ON)
(mΩ)
700
650
600
550
500
450
400
350
–25
02550
405842 G17
75 125100
V
CC
= 4.2V
I
BAT
= 100mA
R
PROG
= 2k
UU
U
PI FU CTIO S
ITERM (Pin 1): Charge Termination Program. The charge
termination current threshold current is programmed by
connecting a 1% resistor, R
TERM
, to ground. The current
threshold I
TERM
, is set by the following formula:
I
V
R
R
V
I
TERM
TERM
TERM
TERM
==
100 100
,
BAT (Pin 2): Charge Current Output. Provides charge
current to the battery from the internal P-channel MOSFET,
and regulates the final float voltage to 4.2V. An internal
precision resistor divider from this pin sets the float
voltage. This divider is disconnected in shutdown mode to
minimize current drain from the battery.
CHRG (Pin 3): Charge Status Open-Drain Output. When
the battery is charging, the CHRG pin is pulled low by an
internal N-channel MOSFET. When the charge cycle is
completed, CHRG becomes high impedance.
GND (Pins 4, 9): Ground/Exposed Pad. The exposed
backside package pad (Pin 9) is electrical ground and
must be soldered to the PC board for maximum heat
transfer.