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Industry's Smallest 1.55A 1-Cell Li+ DC-DC Charger

Switching Charger Delivers High Efficiency (90%~92%)

Product Details

Key Features

Applications/Uses

Parametric specs for Battery Chargers
Charging VIN (V) (max) 7.5
Max. ICHG (A) 1.55
Cell Chemistry Li-Ion
Li-Polymer
# Lithium Ion Cells 1
Protected VIN (V) (max) 22
Charger (V) 4.1
4.15
4.2
4.35
Oper. Temp. (°C) -40 to +85
Package/Pins WLP/20
Budgetary
Price (See Notes)
1.25
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Simplified Block Diagram

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Parameters

Parametric specs for Battery Chargers
Charging VIN (V) (max) 7.5
Max. ICHG (A) 1.55
Cell Chemistry Li-Ion
Li-Polymer
# Lithium Ion Cells 1
Protected VIN (V) (max) 22
Charger (V) 4.1
4.15
4.2
4.35
Oper. Temp. (°C) -40 to +85
Package/Pins WLP/20
Budgetary
Price (See Notes)
1.25

Key Features

  • Switch-Mode Charger
    • High-Efficiency
    • Low Heat
    • Fast Charge Time
  • Small and Simple
  • Precise
    • Up to ±5% Current Regulation and 0.5% Voltage Regulation
  • Safe
    • JEITA Battery Temperature Monitor
    • Over/Undervoltage Protection, Safety Timers, Temperature Regulation
    • USB Friendly
  • Flexible
    • Programmable Voltage/Current
    • Status/Interrupts Through I2C
    • Automatic Input Current Limit
  • I2C Interface
    • Input Current Limit (100mA to 1500mA)
    • Fast-Charge/Termination Current (250mA to 1550mA)
    • Charge Voltage (4.1V, 4.15V, 4.2V, 4.35V)
    • Termination Enable
  • +22V Absolute Maximum Input Voltage Rating
  • Up to 7.5V Maximum Operating Input Voltage
  • 5V USB/Safeout LDO for USB PHY
  • 2.3A GSM RF Test Mode (Factory Testing)
  • Charge Current to Voltage Conversion (VICHG) for Baseband ADC
  • Reverse Battery Leakage Protection
  • Input/Output Overvoltage Protection
  • Interrupt Status Output

Applications/Uses

  • AR/VR Glasses
  • Bluetooth Headsets
  • Hearables
  • Portable Devices
  • Smartphones
  • USB Charging
  • Wearables

Description

The MAX8971 is a compact, high-frequency, high-efficiency switch-mode charger for a one-cell lithium-ion (Li+) battery. It delivers up to 1.55A of current to the battery from inputs up to 7.5V and withstands transient inputs up to 22V. The 4MHz switch-mode charger is ideally suited for small portable devices, such as Bluetooth® headsets, AR/VR glasses, and other lithium-ion powered accessories. It minimizes component size and heat.

Battery-protection features include: low-voltage prequalification, charge fault timer, die temperature monitoring, and battery temperature monitoring. The battery temperature monitoring adjusts the charge current and termination voltage for safe use of secondary lithium-ion batteries.

The IC accepts either a general DC input or USB. It has programmable automatic input-current limiting to protect upstream charging sources such as USB.

Charge parameters are easily adjustable through an I²C interface. Charge is terminated based on user-selectable minimum current level. Charge status is provided to the application processor through an interrupt pin.

The IC is available in a space-saving, 20-bump, 2.18mm x 1.62mm WLP package.

Simplified Block Diagram

MAX8971: Simplified Operating Circuit MAX8971: Simplified Operating Circuit 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 .