The MAX1925/MAX1926 single-cell lithium-ion (Li+) switch-mode battery chargers use an external PMOS pass element step-down configuration. Charge current is programmable, and an external capacitor sets the maximum charge time.
Additional features include automatic input power detection (active-low ACON output), logic-controlled enable, and temperature monitoring with an external thermistor. The MAX1925 disables charging for inputs greater than 6.1V, while the MAX1926 charges for inputs between 4.25V and 12V.
The MAX1925/MAX1926 feature two precondition levels to restore near-dead cells. The devices source 4mA to a cell that is below 2V while sourcing C/10 to a cell between 2V and 3V. Full charge current is then applied above 3V. A active-low CHG output drives an LED to indicate charging (LED on) and fault conditions (LED blinking).
The MAX1925/MAX1926 are available in a 12-pin
4mm x 4mm thin QFN package and are specified over the extended temperature range (-40°C to +85°C). An evaluation kit is available to speed design.
Key Features
Applications/Uses
Small (4mm x 4mm) Package
4.25V to 12V Input Range (MAX1926)
Overvoltage Lockout at 6.1V (MAX1925)
±0.75% Battery Regulation Voltage
Set Charge Current with One Resistor
Automatic Input Power Sense
LED (or Logic-Out) Charge Status and Fault Indicator
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