LT3650-4.1_15 Datasheet, PDF (1/22 Pages) Linear Technology – High Voltage 2 Amp Monolithic Li-Ion Battery Charger

LT3650-4.1/LT3650-4.2
High Voltage 2 Amp
Monolithic Li-Ion Battery Charger
Features
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 VIN 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}
Applications
n _{Industrial Handheld Instruments}
n _{12V to 24V Automotive and Heavy Equipment}
n _{Desktop Cradle Chargers}
n _{Notebook Computers}
Description
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 LT3650 is available in a low profile (0.75mm) 3mm ×
3mm 12-pin DFN and 12-pin MSOP packages.
L, LT, LTC, LTM, Linear Technology, PowerPath and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
Typical Application
7.5V to 32V Single-Cell Li-Ion 2A Charger
CMSH3-40MA
V_IN
7.5V to 32V
V_IN
SW
10µF
1µF
CLP
BOOST
6.8µH
LT3650-4.2
CMPSH1-4
SHDN
SENSE
CHRG
0.05Ω
FAULT
TIMER
BAT
NTC
RNG/SS
+
10µF
Li-ION
BATTERY
3650 TA01a
V_BAT and Efficiency vs I_BAT
100
V_BAT
4.20
90
V_IN = 12V
4.15
80
V_IN = 20V
4.10
70
4.05
60
0
0.5
1
1.5
2
I_BAT (A)
365042 TA01b
36504142fc
1