LTC6813-1 18-Cell Battery Stack Monitor with Daisy Chain Interface FEATURES DESCRIPTION n Measures Up to 18 Battery Cells in Series The LTC 6813-1 is a multicell battery stack monitor that n 2.2mV Maximum Total Measurement Error measures up to 18 series connected battery cells with n Stackable Architecture for High Voltage Systems a total measurement error of less than 2.2mV. The cell n Built-In isoSPI Interface measurement range of 0V to 5V makes the LTC6813-1 n 1Mb Isolated Serial Communications suitable for most battery chemistries. All 18 cells can be n Uses a Single Twisted Pair, Up to 100 Meters measured in 290s, and lower data acquisition rates can n Low EMI Susceptibility and Emissions be selected for high noise reduction. n Bidirectional for Broken Wire Protection Multiple LTC6813-1 devices can be connected in series, n 290s to Measure All Cells in a System permitting simultaneous cell monitoring of long, high n Synchronized Voltage and Current Measurement voltage battery strings. Each LTC6813-1 has an isoSPI n 16-Bit Delta-Sigma ADC with Programmable interface for high speed, RF immune, long distance com- Noise Filter munications. Multiple devices are connected in a daisy n Engineered for ISO 26262-Compliant Systems chain with one host processor connection for all devices. n Passive Cell Balancing Up to 200mA (Max) with This daisy chain can be operated bidirectionally, ensuring Programmable Pulse-Width Modulation communication integrity, even in the event of a fault along n 9 General Purpose Digital I/O or Analog Inputs the communication path. n Temperature or Other Sensor Inputs 2 n Configurable as an I C or SPI Master The LTC6813-1 can be powered directly from the bat- n 6A Sleep Mode Supply Current tery stack or from an isolated supply. The LTC6813-1 n 64-Lead eLQFP Package includes passive balancing for each cell, with individual n AEC-Q100 Qualified for Automotive Applications PWM duty cycle control for each cell. Other features include an onboard 5V regulator, nine general purpose I/O lines and a sleep mode, where current consumption APPLICATIONS is reduced to 6A. n Electric and Hybrid Electric Vehicles All registered trademarks and trademarks are the property of their respective owners. Protected n Backup Battery Systems by U.S. patents, including 8908779, 9182428, 9270133. n Grid Energy Storage n High Power Portable Equipment TYPICAL APPLICATION Cell 18 Measurement Error vs Temperature 2.0 CELL VOLTAGE = 3.3V 18-Cell Monitor and Balance IC 5 TYPICAL UNITS 1.5 1.0 0.5 + CELL 18 0 + ISOLATED CELL 17 DATA WITH LTC6813-1 0.5 WIRE BREAK PROTECTION 1.0 + CELL 2 1.5 + CELL 1 68131 TA01a 2.0 50 25 0 25 50 75 100 125 TEMPERATURE (C) 68131 TA01b Rev. B 1 Document Feedback For more information www.analog.com MEASUREMENT ERROR (mV)LTC6813-1 TABLE OF CONTENTS Features ..................................................... 1 Discharge Timer Monitor ......................................36 2 Applications ................................................ 1 I C/SPI Master on LTC6813-1 Using GPIOs ..........37 Typical Application ........................................ 1 S Pin Pulsing Using the S Pin Control Settings ....42 Description.................................................. 1 S Pin Muting .........................................................43 Absolute Maximum Ratings .............................. 3 Serial Interface Overview ......................................43 Order Information .......................................... 3 4-Wire Serial Peripheral Interface (SPI) Pin Configuration .......................................... 3 PhysicalLayer ..................................................43 Electrical Characteristics ................................. 4 2-Wire Isolated Interface (isoSPI) PhysicalLayer .43 Typical Performance Characteristics ................... 9 Data Link Layer .....................................................54 Pin Functions .............................................. 15 Network Layer ......................................................54 Block Diagram ............................................. 16 Applications Information ................................ 70 Improvements from the LTC6811-1 .................... 17 Providing DC Power ..............................................70 Operation................................................... 18 Internal Protection and Filtering ...........................71 State Diagram ....................................................... 18 Cell Balancing ....................................................... 74 Core LTC6813-1 State Descriptions ...................... 18 Discharge Control During Cell Measurements ......75 isoSPI State Descriptions ..................................... 19 Digital Communications........................................78 Power Consumption ............................................. 19 Enhanced Applications .........................................85 ADC Operation ......................................................20 Reading External Temperature Probes ..................87 Data Acquisition System Diagnostics ...................26 Package Description ..................................... 88 Watchdog and Discharge Timer ............................33 Revision History .......................................... 89 Reset Behaviors ....................................................35 Typical Application ....................................... 90 S Pin Pulse-Width Modulation for Cell Balancing .36 Related Parts .............................................. 90 Rev. B 2 For more information www.analog.com