Le blog de l'entreprise Mingjiada Supply ADI LTC6813 18-Cell Battery Stack Monitor With Daisy Chain Interface

Mingjiada Supply ADI LTC6813 18-Cell Battery Stack Monitor With Daisy Chain Interface

Introduction at a Glance: The ADI LTC6813 is an 18-channel battery monitor designed for multi-cell battery packs in series, with a typical total measurement error of approximately ±2.2 mV. It can complete measurements for all 18 cells within approximately 290 µs and features built-in isoSPI isolated communication and passive balancing control. Mingjiada Electronics supplies relevant models in this series and supports both sample procurement and bulk orders.

Product Positioning Overview
The LTC6813 forms part of ADI’s multi-cell battery monitor product line and is primarily used in the battery sampling front-end of battery management systems (BMS): it is connected directly across multiple cells in series to measure the voltage of each cell, monitor temperature, control passive balancing, and transmit data to the main controller via an isoSPI isolated interface. It does not perform vehicle-level control or algorithms directly, but is responsible for ‘accurately and rapidly acquiring battery status data’.
Its core features can be summarised in four points: 18-cell channels, measurement accuracy of ±2.2 mV, full-channel scan time of 290 µs, and isoSPI isolated cascading.

LTC6813 Core Specifications at a Glance
Number of monitoring channels: 18 cells in series
Single-cell measurement range: 0 V to 5 V
Total measurement error: approximately ±2.2 mV (typical)
ADC type: 16-bit dual ADC
Full-channel measurement time: approximately 290 µs (18 cells, typical)
Communication interface: isoSPI, approximately 1 Mbps, isolated
Balancing method: built-in passive balancing switches, programmable PWM
GPIC: 9 general-purpose I/O pins
Internal Temperature Monitoring: Built-in temperature sensor
Package: 64-pin LQFP
Operating Temperature: –40°C to 125°C

Interpretation of the LTC6813 Performance Specifications
1. Measurement Accuracy: What does ±2.2 mV mean?
For a BMS, single-cell voltage accuracy directly affects SOC estimation, balancing decisions and overcharge/over-discharge protection. A total measurement error of ±2.2 mV is particularly valuable in chemical systems with flat voltage platforms, such as lithium iron phosphate (LiFePO₄), as voltage variations within the plateau region are minimal; even a slight error can easily lead to misjudgement. Actual system accuracy is also influenced by voltage-divider resistors, PCB layout, temperature drift and calibration strategies; the device specifications are merely a starting point.
2. Scan Speed: 290 µs for all channels
Measuring all 18 cells takes approximately 290 µs, meaning a high sampling refresh rate can still be maintained in battery packs comprising multiple cascaded cells. Scan speed is a critical metric for scenarios requiring rapid capture of dynamic operating conditions, particularly in conjunction with balancing and protection functions. Actual throughput is also influenced by the isoSPI rate, the number of cascades, and command overhead.
3. isoSPI Isolated Communication
isoSPI is ADI’s isolated SPI solution, which utilises transformer or capacitive isolation for data transmission. It supports speeds of approximately 1 Mbps, long cable runs, and daisy-chain or loopback topologies. Its value lies in providing electrical isolation between high-voltage battery packs and low-voltage controllers, whilst reducing the number of wiring harnesses and isolation components. The loopback topology also offers a degree of diagnostic capability in the event of a single-point cable break; specific redundancy behaviour must be designed in accordance with the manual.
4. Passive Equalisation and GPIO
The LTC6813 features a built-in discharge switch per channel; the equalisation time and duty cycle can be configured via registers, whilst external resistors or transistors can be added to support higher currents. The nine GPIOs can be connected to NTC temperature sensors or other diagnostic signals; when used in conjunction with the internal temperature sensor, this facilitates temperature compensation and thermal management.
5. Diagnostics and Functional Safety
The LTC6813 supports diagnostic features such as open-circuit detection, self-test, watchdog and CRC checks; ADI provides documentation relating to functional safety. For automotive and energy storage customers, these serve as the foundation for ASIL-level certification; however, system-level functional safety still requires compliance across the entire board, software and processes.

Suitable Products and Application Scenarios
Typical applications for the LTC6813 centre on scenarios involving ‘multiple batteries connected in series, requiring isolated sampling and balancing’:
Electric vehicle/hybrid vehicle BMS: Battery pack sampling front-end, working in conjunction with the main controller to perform SOC/SOH, balancing and protection;
Energy Storage Systems (ESS): Battery cluster monitoring for grid-scale, commercial and industrial, and residential energy storage;
UPS and Standby Battery Systems: Backup power for data centres and telecommunications base stations;
Electric Two-Wheelers/Low-Speed Vehicles/AGVs: Monitoring of medium- and high-voltage battery packs;
Industrial Battery Packs and Portable Energy Storage: Sampling and balancing of multi-cell lithium-ion battery packs;
Test Equipment and Battery Simulation Front-Ends: Multi-channel battery voltage acquisition.

Mingjiada Electronics Supply and Procurement Notes
Mingjiada Electronics supplies relevant models from the ADI LTC6813 series. When requesting a quotation, please provide: the full part number/suffix, package type, quantity and target batch. Different suffixes for the LTC6813 may vary in terms of temperature rating, package type or delivery documentation. Please check the ADI data sheet and part number against each item before placing an order. Specific stock availability, prices and lead times are subject to Mingjiada Electronics’ real-time quotations.

Conclusion: The value of the LTC6813 lies not merely in the number of channels, but in the combination of 18 channels, ±2.2 mV accuracy, fast scanning and isoSPI isolation, making it suitable for the sampling front-end of multi-cell battery packs. When selecting a device, it is more reliable to evaluate accuracy, scanning speed, isolation topology, balancing capability and functional safety documentation together, rather than focusing on a single parameter.

Mingjiada Electronics is a long-term supplier of the [ADI] LTC6813 | 18-cell battery monitor. For further product details or to enquire about sample prices, please visit the Mingjiada Electronics website (https://www.integrated-ic.com/) for more supply information.
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