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High-Accuracy 12-/16-Cell Measurement AFEs

Industry's Most Accurate and Flexible Battery Management System Building Block

Product Details

The MAX14920/MAX14921 battery measurement analog front-end devices accurately sample cell voltages and provide level shifting for primary/secondary battery packs up to 16 cells/+65V (max). The MAX14920 monitors up to 12 cells, while the MAX14921 monitors up to 16 cells. Both devices simultaneously sample all cell voltages, allowing accurate state-of-charge and source-resistance determination. All cell voltages are level shifted to ground reference with unity gain, simplifying external ADC data conversion.

The devices have a low-noise, low-offset amplifier that buffers differential voltages of up to +5V, allowing monitoring of all common lithium-ion (Li+) cell technologies. The resulting cell voltage error is ±0.5mV.

The devices’ high accuracy make them ideal for monitoring cell chemistries with very flat discharge curves, such as lithium-metal phosphate.

Passive-cell balancing is supported by external FET drivers. Integrated diagnostics in the devices allow open-wire detection and undervoltage/overvoltage alarms. The devices are controlled by a daisy-chainable SPI interface.

The MAX14920 is available in a 64-pin (10mm x 10mm) TQFP package with an exposed pad. The MAX14921 is available in an 80-pin (12mm x 12mm) TQFP package. Both devices are specified over the -40°C to +85°C extended temperature range.

Key Features

  • High Accuracy
    • ±0.5mV (max) Cell Voltage Error
    • Simultaneous Cell Voltage Sampling
    • Self-Calibration
  • Integrated Diagnostics
    • Open-Wire and Short Fault Detection
    • Undervoltage/Overvoltage Warning
    • Thermal Shutdown
  • High Flexibility
    • SPI Interface
    • 12-Cell and 16-Cell Versions
    • +6V Minimum (3 Cells) Operation
    • +0.5V to +4.5V Cell Voltage Range
    • Integrated Cell-Balancing FET Drivers
    • Integrated 5V LDO
  • Low Power
    • 1µA Shutdown Mode
    • 1µA/10µA Cell Current Draw

Applications/Uses

  • e-Transportation Energy Packs
  • Energy Storage Packs
  • Industrial Battery Backup Systems
  • Telecom Battery Backup Systems
Parametric specs for Battery Fuel Gauges, Protectors, and Monitors
Functions Status Monitor
Battery Type 3-12 Cell Li-Ion
Interface SPI
Parameters Measured Temperature
Voltage
Applications Pack
Battery Protection Features Over-Temperature
Over/Under Voltage
VSUPPLY (V) (min) 6
VSUPPLY (V) (max) 65
Package/Pins TQFP/64
Oper. Temp. (°C) -40 to +85
Budgetary
Price (See Notes)
$5.24 @1k
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Simplified Block Diagram

MAX14920, MAX14921: Functional Diagram MAX14920, MAX14921: Functional Diagram Zoom icon

Design & Development

Click any title below to view the detail page where available.

Description

The MAX14921 evaluation kit (EV kit) demonstrates a high-accuracy 16-cell battery-management reference design. The MAX14921 is a high-accuracy 16-cell measurement analog front-end (AFE) in an 80-pin TQFP surface-mount package. The EV kit features an ADC and reference, and an isolated interface to a PC through a USB port to easily measure all cell voltages. Cell stacks up to 16 cells or 65V can be monitored, whichever is lower.
The EV kit circuit demonstrates all the features of the device through a GUI application on a Windows®-based PC.

View Details

Features

  • 16-Cell/65V (max) Stack Operating Voltage Range
  • Built-In Isolated USB Interface to a Windows-Based PC
  • Plugh-and-Play GUI Demonstrates All the Major Features of the MAX14921
  • µC Firmware in C Available Upon Request
  • Screw Terminal Battery Connector
  • Proven PCB Layout
  • Fully Assembled and Tested

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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.

Parameters

Parametric specs for Battery Fuel Gauges, Protectors, and Monitors
Functions Status Monitor
Battery Type 3-12 Cell Li-Ion
Interface SPI
Parameters Measured Temperature
Voltage
Applications Pack
Battery Protection Features Over-Temperature
Over/Under Voltage
VSUPPLY (V) (min) 6
VSUPPLY (V) (max) 65
Package/Pins TQFP/64
Oper. Temp. (°C) -40 to +85
Budgetary
Price (See Notes)
$5.24 @1k

Key Features

  • High Accuracy
    • ±0.5mV (max) Cell Voltage Error
    • Simultaneous Cell Voltage Sampling
    • Self-Calibration
  • Integrated Diagnostics
    • Open-Wire and Short Fault Detection
    • Undervoltage/Overvoltage Warning
    • Thermal Shutdown
  • High Flexibility
    • SPI Interface
    • 12-Cell and 16-Cell Versions
    • +6V Minimum (3 Cells) Operation
    • +0.5V to +4.5V Cell Voltage Range
    • Integrated Cell-Balancing FET Drivers
    • Integrated 5V LDO
  • Low Power
    • 1µA Shutdown Mode
    • 1µA/10µA Cell Current Draw

Applications/Uses

  • e-Transportation Energy Packs
  • Energy Storage Packs
  • Industrial Battery Backup Systems
  • Telecom Battery Backup Systems

Description

The MAX14920/MAX14921 battery measurement analog front-end devices accurately sample cell voltages and provide level shifting for primary/secondary battery packs up to 16 cells/+65V (max). The MAX14920 monitors up to 12 cells, while the MAX14921 monitors up to 16 cells. Both devices simultaneously sample all cell voltages, allowing accurate state-of-charge and source-resistance determination. All cell voltages are level shifted to ground reference with unity gain, simplifying external ADC data conversion.

The devices have a low-noise, low-offset amplifier that buffers differential voltages of up to +5V, allowing monitoring of all common lithium-ion (Li+) cell technologies. The resulting cell voltage error is ±0.5mV.

The devices’ high accuracy make them ideal for monitoring cell chemistries with very flat discharge curves, such as lithium-metal phosphate.

Passive-cell balancing is supported by external FET drivers. Integrated diagnostics in the devices allow open-wire detection and undervoltage/overvoltage alarms. The devices are controlled by a daisy-chainable SPI interface.

The MAX14920 is available in a 64-pin (10mm x 10mm) TQFP package with an exposed pad. The MAX14921 is available in an 80-pin (12mm x 12mm) TQFP package. Both devices are specified over the -40°C to +85°C extended temperature range.

Simplified Block Diagram

MAX14920, MAX14921: Functional Diagram MAX14920, MAX14921: Functional Diagram Zoom icon

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.