Top

Multichemistry Battery Chargers with Automatic System Power Selector

0.5% Accurate Multichemistry Battery Chargers for Single- and Dual-Battery Systems

Product Details

Key Features

Parametric specs for Battery Chargers
Charging VIN (V) (max) 28
Max. ICHG (A) 5
Cell Chemistry Lead Acid
Li-Ion
Li-Polymer
NiCd
NiMH
Universal
# NiMH/ NiCd Cells 4
5
6
7
8
9
10
# Lithium Ion Cells 3
4
Protected VIN (V) (max) 28
Charger (V) 0 to 17.6
Oper. Temp. (°C) -40 to +85
Package/Pins TQFN/28
Budgetary
Price (See Notes)
3.6
View Less

Simplified Block Diagram

Technical Docs

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 .

Sampling:
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.

Parameters

Parametric specs for Battery Chargers
Charging VIN (V) (max) 28
Max. ICHG (A) 5
Cell Chemistry Lead Acid
Li-Ion
Li-Polymer
NiCd
NiMH
Universal
# NiMH/ NiCd Cells 4
5
6
7
8
9
10
# Lithium Ion Cells 3
4
Protected VIN (V) (max) 28
Charger (V) 0 to 17.6
Oper. Temp. (°C) -40 to +85
Package/Pins TQFN/28
Budgetary
Price (See Notes)
3.6

Key Features

  • Precise Measurement Improves Safety and Performance
    • ±0.5% Accurate Charge Voltage (0°C to +85°C)
    • ±3% Accurate Input Current Limiting
    • ±5% Accurate Charge Current
    • Analog Inputs Control Charge Current and Charge Voltage
  • Charge Any Battery Chemistry: Li+, NiCd, NiMH, Lead Acid, etc.
    • Up to 17.65V (max) Battery Voltage
    • Maximum 28V Input Voltage
    • Programmable Charge Current > 4A
  • Intelligent AC Adapter Interface Makes Design Easier
    • Automatic System Power/Source Selection
    • Analog Monitoring of Current Drawn from AC Input Source
    • Digital Output Indicates AC Adapter Presence
  • Greater than 95% Efficiency Extends Battery Life

Applications/Uses

  • Handheld Data Terminals
  • Notebook and Subnotebook Computers

Description

The MAX1909/MAX8725 highly integrated control ICs simplify construction of accurate and efficient multichemistry battery chargers. The MAX1909/MAX8725 use analog inputs to control charge current and voltage, and can be programmed by a host microcontroller (µC) or hardwired. High efficiency is achieved through use of buck topology with synchronous rectification.

The maximum current drawn from the AC adapter is programmable to avoid overloading the AC adapter when supplying the load and the battery charger simultaneously. The MAX1909/MAX8725 provide a digital output that indicates the presence of an AC adapter, and an analog output that monitors the current drawn from the AC adapter. Based on the presence or absence of the AC adapter, the MAX1909/MAX8725 automatically select the appropriate source for supplying power to the system by controlling two external p-channel MOSFETs. Under system control, the MAX1909/MAX8725 allow the battery to undergo a relearning or conditioning cycle in which the battery is completely discharged through the system load and then recharged.

The MAX1909 includes a conditioning charge feature while the MAX8725 does not. The MAX1909/MAX8725 are available in space-saving 28-pin, 5mm x 5mm thin QFN packages and operate over the extended -40°C to +85°C temperature range. The MAX1909/MAX8725 are now available in lead-free packages.

Simplified Block Diagram

MAX1909, MAX8725: Pin Configuration MAX1909, MAX8725: Pin Configuration Zoom icon

Technical Docs

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 .

Sampling:
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.