The LTC6811 is a multicell battery stack monitor that measures up to 12 series connected battery cells with a total measurement error of less than 1.2mV. The cell measurement range of 0V to 5V makes this device suitable for most battery chemistries. All 12 cells can be measured in 290µs, and lower data acquisition rates can be selected for high noise reduction. Multiple LTC6811 devices can be connected in series, permitting simultaneous cell monitoring of long, high voltage battery strings. Each LTC6811 has an isoSPI interface for high speed, RF-immune, long distance communications.

The LTC6811 from Linear Technology is a high voltage battery stack monitor, a drop-in replacement for the LTC6804 with higher performance, improved safety features and 25% lower price. It is a complete battery measuring IC for hybrid/electric vehicles that incorporates a deep buried Zener voltage reference, high voltage multiplexers, 16-bit delta-sigma ADCs and a 1Mbps isolated serial interface.

An LTC6811 can measure up to 12 series-connected battery cell voltages with better than 0.04% accuracy. With 8 programmable 3rd order low pass filter settings, this device provides outstanding noise reduction. In the fastest ADC mode, all cells can be measured within 290µsec.

For large battery packs, multiple LTC6811s can be interconnected and operated simultaneously, using Linear Technology’s proprietary 2-wire isoSPI™ interface. This built-in interface provides electrically isolated, high RF noise immune communication for data rates up to 1Mbps. Using twisted pair, many LTC6811s can be connected in a daisy chain to one host processor, enabling the measurement of hundreds of cells in high voltage battery stacks.

Using the LTC6811-1, multiple devices are connected in a daisy chain with one host processor connection for all devices. Using the LTC6811-2, multiple devices are connected in parallel to the host processor, with each device individually addressed.

The LTC6811 can be powered directly from the battery stack or from an isolated supply. It includes passive balancing for each cell, with individual PWM duty cycle control for each cell. Other features include an onboard 5V regulator, five general purpose I/O lines and a sleep mode, where current consumption is reduced to 6µA.

This latest device follows three generations of road-proven battery monitor ICs, designed to surpass the environmental, reliability and safety demands of automotive and industrial applications. It is fully specified for operation from 40°C to 125°C and has been engineered for ISO 26262 (ASIL) compliant systems with extensive fault coverage via its redundant voltage reference, logic test circuitry, cross-channel testing, open wire detection capability, a watchdog timer and packet error checking on the serial interface.

For existing designs using Linear Technology’s LTC6804 battery stack monitor, the LTC6811 is a drop-in replacement with additional filter cutoff frequencies, added passive and active balancing control features, new ADC commands and enhanced fault coverage for functional safety.

The LTC6811 is fully supported by Linear’s Linduino™ technology, an Arduino-based microcontroller board and software library. The microcontroller board includes an electrically isolated USB port and directly connects to the LTC6811 demonstration board, providing a simple platform for evaluating and developing the LTC6811.

The LTC6811 is offered in a small 8mm x 12mm surface mount SSOP package. Priced at $8.19 each in 1,000-piece quantities, samples and demonstration boards are now available at www.linear.com/product/LTC6811.

The USA list pricing shown is for budgetary use only. International prices may differ due to local duties, taxes, fees and exchange rates.

 

For more information, visit www.linear.com/product/LTC6811

 

Summary of Features of the LTC6811:

  • Pin-Compatible Upgrade to Linear Technology’s LTC6804
  • 25% Lower Cost than the LTC6804
  • Higher Performance
  • Software Compatible

    • Measures Up to 12 Battery Cells in Series
    • Stackable Architecture Supports 100s of Cells
    • Built-in isoSPI™ Interface
  • 1Mbps Isolated Serial Communications
  • Uses a Single Twisted Pair, up to 100 Meters
  • Low EMI Susceptibility & Emissions

    • 1.2mV Maximum Total Measurement Error
    • 290µs to Measure All Cells in a System
    • Synchronized Voltage & Current Measurement
    • 16-Bit Delta-Sigma ADC with Frequency Programmable 3rd Order Noise Filter
    • Engineered for ISO26262 Compliant Systems
    • Passive Cell Balancing with Programmable Timers
    • 5 General Purpose Digital I/O or Analog Inputs
  • Temperature or Other Sensor Inputs
  • Configurable as an I2C or SPI Master

    • 4µA Sleep Mode Supply Current
    • 48-Lead SSOP Package

 

Typical Application

 

 

 

 

 

 

Applications

  • Electric and Hybrid Electric Vehicles
  • Backup Battery Systems
  • Grid Energy Storage
  • High Power Portable Equipment

 

Linear Technology (UK) Limited
Tel: +44 (0)1628 477066
 

E-mail: uksales@linear.com

 
Web site: www.linear.com

 

Website for product information:  http://www.linear.com/product/LTC6811-1