LT3650-8.2_15 Datasheet, PDF (1/22 Pages) Linear Technology – High Voltage 2 Amp Monolithic 2-Cell Li-Ion Battery Charger

Features
n _{Wide Input Voltage Range: 9V 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 _{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}
Applications
n _{Industrial Handheld Instruments}
n _{12V to 24V Automotive and Heavy Equipment}
n _{Desktop Cradle Chargers}
n _{Notebook Computers}
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LT3650-8.2/LT3650-8.4
High Voltage 2 Amp
Monolithic 2-Cell
Li-Ion Battery Charger
Description
The LT^®3650 is a complete monolithic 2-cell Li-Ion/Polymer
battery charger that operates over a 9V to 32V input volt-
age range (11.5V 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 LT3650 is available in a low profile (0.75mm) 3mm ×
3mm 12-pin DFN and 12-pin MSOP packages.
Typical Application
11.5V to 32V 2-Cell 2A Charger
CMSH3-40MA
V_IN
11.5V TO 32V
10µF
0.68µF
V_IN
SW
CLP
SHDN
CHRG
LT3650-8.2
BOOST
SENSE
FAULT
TIMER
BAT
NTC
RNG/SS
CMSH3-40MA
1µF
10µH
CMPSH1-4
0.05Ω
+
10µF
BATTERY
365082 TA01a
Charge Current, Efficiency and Power Loss vs Time
3.0
V_IN = 20V
2.5
95
EFFICIENCY
85
POWER
2.0
LOSS
75
CHARGE
CURRENT
1.5
65
1.0
55
0.5
45
0
35
0 20 40 60 80 100 120 140 160 180 200
TIME (MINUTES)
365082 TA01b
36508284fd
1