LT3650EMSE-8.4#TRPBF
Features
Wide Input Voltage Range: 9V to 32V (40V Absolute Maximum)
Programmable Charge Current: Up to 2A
User-Selectable Termination: C/10 or Onboard Termination Timer
Dynamic Charge Rate Programming/Soft-Start Pin
Programmable Input Current Limit
1MHz Fixed Frequency
Average Current Mode Control
0.5% Float Voltage Accuracy
5% Charge Current Accuracy
2.5% C/10 Detection Accuracy
NTC Resistor Temperature Monitor
Auto-Recharge at 97.5% Float Voltage
Auto-Precondition at <70% Float Voltage
Bad-Battery Detection with Auto-Reset
Binary Coded Open-Collector Status Pins
3mm × 3mm DFN-12 or MSOP-12 Package
Applications
Industrial Handheld Instruments
12V to 24V Automotive and Heavy Equipment
Desktop Cradle Chargers
Notebook Computers
Description
TheLT®3650 is a completemonolithic 2-cellLi-Ion/Polymer battery charger that operates over a 9V to 32V input voltage 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 andsuspends chargingif a batterydoesnotrespond to preconditioning.
The LT3650 can be configured to terminate charging when charge current falls to C/10, or one-tenth the programmed maximumcurrent. Oncechargingisterminated, theLT3650 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 continue 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.
Overview
LT3650is a completemonolithic, mid-power, Li-Ionbattery charger, addressing high input voltage applications with solutions that use a minimum of external components. The IC uses a 1MHz constant-frequency, average current mode step-down architecture.
The LT3650 incorporates a 2A switch that is driven by a bootstrappedsupplytomaximizeefficiencyduringcharging cycles. A wide input range allows the operation to fullcharge from 9V to 32V. A precision threshold shutdown pin allows incorporation of UVLO functionality using a simple resistor divider. The IC can also be put into a low current shutdown mode, in which the input supply bias is reduced to only 15µA.
The LT3650incorporates severaldegreesof charge current control freedom. The overall maximum charge current is set using an external inductor current sense resistor. A maximum charge current programming pin allows dynamic manipulation of the battery charge current. The LT3650 also incorporates a system input supply current limit control feature that servos the battery charge current to accommodate overall system load requirements.
