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Step-Up/Step-Down Li+ Battery Charger

Step-Up/Step-Down Multichemistry Battery Charger Charges with Battery Voltages Above and Below the Adapter Voltage

Product Details

Key Features

Parametric specs for Battery Chargers
Charging VIN (V) (max) 28
Max. ICHG (A) 4
Cell Chemistry Li-Ion
Li-Polymer
NiCd
NiMH
# NiMH/ NiCd Cells 6
9
10
# Lithium Ion Cells 2
3
4
Protected VIN (V) (max) 28
Charger (V) 0 to 17.6
Oper. Temp. (°C) -40 to +85
Package/Pins TQFN/32
Budgetary
Price (See Notes)
7.11
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Simplified Block Diagram

Technical Docs

Data Sheet Step-Up/Step-Down Li+ Battery Charger Sep 01, 2015

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Parameters

Parametric specs for Battery Chargers
Charging VIN (V) (max) 28
Max. ICHG (A) 4
Cell Chemistry Li-Ion
Li-Polymer
NiCd
NiMH
# NiMH/ NiCd Cells 6
9
10
# Lithium Ion Cells 2
3
4
Protected VIN (V) (max) 28
Charger (V) 0 to 17.6
Oper. Temp. (°C) -40 to +85
Package/Pins TQFN/32
Budgetary
Price (See Notes)
7.11

Key Features

  • Highly Flexible Input Voltage Range Works with Affordable AC Adapters
    • Step-Up/Step-Down Control Scheme
    • Input Voltage from 8V to 28V
    • Analog Output Indicates Adapter Current
  • Accurately Charge Li+ or NiCd/NiMH Batteries
    • Battery Voltage from 0 to 17.6V
    • ±0.5% Charge-Voltage Accuracy
    • ±9% Charge-Current Accuracy
    • ±8% Input Current-Limit Accuracy
  • Tune Design to Increase Safety and Efficiency
    • Programmable Maximum Battery Charge Current
    • Analog Inputs Control Charge Current, Charge Voltage, and Input Current Limit
  • 32-Pin Thin QFN (5mm x 5mm) Package Saves Space While Supporting Step-Up and Step-Down Operation

Applications/Uses

  • Handheld Terminals
  • Notebook and Subnotebook Computers

Description

The MAX1870A step-up/step-down multichemistry battery charger charges with battery voltages above and below the adapter voltage. This highly integrated charger requires a minimum number of external components. The MAX1870A uses a proprietary step-up/stepdown control scheme that provides efficient charging. Analog inputs control charge current and voltage, and can be programmed by the host or hardwired.

The MAX1870A accurately charges two to four lithiumion (Li+) series cells at greater than 4A. A programmable input current limit is included, which avoids overloading the AC adapter when supplying the load and the battery charger simultaneously. This reduces the maximum adapter current, which reduces cost. The MAX1870A provides analog outputs to monitor the current drawn from the AC adapter and charge current. A digital output indicates the presence of an AC adapter. When the adapter is removed, the MAX1870A consumes less than 1µA from the battery.

The MAX1870A is available in a 32-pin thin QFN (5mm x 5mm) package and is specified over the -40°C to +85°C extended temperature range. The MAX1870A evaluation kit (MAX1870AEVKIT) is available to help reduce design time.

Simplified Block Diagram

MAX1870A: Functional Diagram MAX1870A: Functional Diagram Zoom icon

Technical Docs

Data Sheet Step-Up/Step-Down Li+ Battery Charger Sep 01, 2015

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 .