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Switch-Mode 1-Cell Li+ Chargers

Smallest, Simplest Switch-Mode Li+ Charger in 4mm x 4mm QFN Package

Product Details

Key Features

Applications/Uses

Parametric specs for Battery Chargers
Charging VIN (V) (max) 12
Max. ICHG (A) 2
Cell Chemistry Li-Ion
Li-Polymer
# Lithium Ion Cells 1
Protected VIN (V) (max) 12
Charger (V) 4.2
Oper. Temp. (°C) -40 to +85
Package/Pins TQFN/12
Budgetary
Price (See Notes)
1.8
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Simplified Block Diagram

Technical Docs

Data Sheet Switch-Mode 1-Cell Li+ Chargers Nov 15, 2002

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Parameters

Parametric specs for Battery Chargers
Charging VIN (V) (max) 12
Max. ICHG (A) 2
Cell Chemistry Li-Ion
Li-Polymer
# Lithium Ion Cells 1
Protected VIN (V) (max) 12
Charger (V) 4.2
Oper. Temp. (°C) -40 to +85
Package/Pins TQFN/12
Budgetary
Price (See Notes)
1.8

Key Features

  • 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
  • Programmable Safety Timer
  • Autorestart at Cell = 4V
  • Thermistor Monitor Input
  • Applications/Uses

    • Cradle Chargers
    • Digital Still Cameras
    • PDAs
    • Self-Charging Battery Packs

    Description

    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.

    Simplified Block Diagram

    MAX1925, MAX1926: Typical Operating Circuit MAX1925, MAX1926: Typical Operating Circuit Zoom icon

    Technical Docs

    Data Sheet Switch-Mode 1-Cell Li+ Chargers Nov 15, 2002

    Support & Training

    Search our knowledge base for answers to your technical questions.

    Filtered Search

    Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .