LT3650-4.1/LT3650-4.2
1
36504142fc
Typical applicaTion
The LT
®
3650 is a complete monolithic single-cell Li-Ion/
Polymer battery charger that operates over a 4.75V to
32V input voltage range (7.5V minimum start-up voltage).
The LT3650 provides a constant-current/constant-voltage
charge characteristic, with maximum charge current
externally programmable up to 2A, set using an external
current sense resistor. A precondition feature trickle-
charges a low voltage battery, and bad-battery detection
provides a signal and suspends charging if a battery does
not respond to preconditioning.
The LT3650 can be configured to terminate charging when
charge current falls to C/10, or one-tenth the programmed
maximum current. Once charging is terminated, the LT3650
enters a low current (85µA) standby mode. An auto-restart
feature starts a new charging cycle if the battery voltage
drops 2.5% from the float voltage, or if a new battery is
inserted into a charging system.
The LT3650 contains a user-programmable internal safety
timer (typically set to a three hour full cycle time). The IC
can be configured to use this internal timer if a time-based
termination scheme is desired in which charging can con-
tinue below C/10 until a desired time is reached.
The LT
3650 is available in a low profile (0.75mm) 3mm ×
3mm 12-pin DFN and 12-pin MSOP packages.
FeaTures
applicaTions
DescripTion
High Voltage 2 Amp
Monolithic Li-Ion Battery Charger
7.5V to 32V Single-Cell Li-Ion 2A Charger
n
Wide Input Voltage Range: 4.75V to 32V
(40V Absolute Maximum)
n
Programmable Charge Current Up to 2A
n
User-Selectable Termination: C/10 or Onboard
Termination Timer
n
Dynamic Charge Rate Programming/Soft-Start Pin
n
Programmable Input Current Limit
n
No V
IN
Blocking Diode Required
n
1MHz Fixed Frequency
n
Average Current Mode Control
n
0.5% Float Voltage Accuracy
n
5% Charge Current Accuracy
n
2.5% C/10 Detection Accuracy
n
NTC Resistor Temperature Monitor
n
Auto-Recharge at 97.5% Float Voltage
n
Auto-Precondition at <70% Float Voltage
n
Bad-Battery Detection with Auto-Reset
n
Binary Coded Open-Collector Status Pins
n
3mm × 3mm DFN-12 or MSOP-12 Package
n
Industrial Handheld Instruments
n
12V to 24V Automotive and Heavy Equipment
n
Desktop Cradle Chargers
n
Notebook Computers
3650 TA01a
SW
V
IN
V
IN
7.5V to 32V
CLP
RNG/SS
BOOST
SENSE
BAT
NTC
TIMER
CMPSH1-4
CMSH3-40MA
1µF
10µF
6.8µH
0.05Ω
10µF
LT3650-4.2
Li-ION
BATTERY
+
SHDN
CHRG
FAULT
V
BAT
and Efficiency vs I
BAT
SPELL CHECK COMPLETED
I
BAT
(A)
V
BAT
(V)
0
EFFICIENCY (%)
80
90
100
365042 TA01b
70
60
4.15
4.20
4.10
4.05
0.5
1
1.5
2
V
BAT
V
IN
= 12V
V
IN
= 20V
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