MAX1925, MAX1926

Switch-Mode 1-Cell Li+ Chargers

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

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Status Explanations for product status codes

Active: In Production.

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.
 

Data Sheet

Download this datasheet in PDF formatDownload Rev 1 (PDF, 448kB)
Send this datasheet to any email addressE-Mail
An evaluation kit is available: MAX1926EVKIT

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
   

Key Specifications:

Battery Chargers
Part Number Cell Chemistry Lithium Ion Cells Protected VIN
(V)
Charging VIN
(V)
Charge Rate Set by Max. ICHG
(A)
Charge Termination Charge Regulation EV Kit Oper. Temp.
(°C)
Package/Pins Smallest Available Pckg.
(mm2)
Budgetary Price
max max max w/pins See Notes
MAX1925 
Li-Ion
Li-Polymer
1 12 12 Resistor 2 Timer Switchmode Yes -40 to +85
TQFN/12
16.8 $1.71 @1k
MAX1926  6.1
TQFN/12
$1.71 @1k
See All Battery Chargers (68)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.


Diagram

MAX1925, MAX1926: Typical Operating Circuit
Typical Operating Circuit

Notes and Comments

The MAX1925/MAX1926 are low-cost and simple charging solutions for 1-cell Li+ batteries.

More Information

Topmark Coding MAX1925
Topmark Coding MAX1926
New Product Press Release 2002-09-16 ]

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Information Index

Document Ref.: 19-2556 Rev 1; 2002-11-15
This page last modified: 2007-07-13




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