LTC6813HLWE - 18-Cell Battery Stack Monitor, AEC-Q100 | ADI
MPN: LTC6813HLWE ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $16.5 | $16.50 |
| 10 | $14.85 | $148.50 |
| 100 | $12.55 | $1,255.00 |
| 500 | $10.8 | $5,400.00 |
| 1,000 | $9.42 | $9,420.00 |
LTC6813HLWE Overview
A battery stack monitor is a mixed-signal IC that performs high-accuracy cell voltage, temperature, and current (via an external shunt) acquisition across long strings of series-stacked cells in Battery Management Systems (BMS). It belongs to the broader category of battery management ICs, which in turn sit under power management semiconductors. The LTC6813 family is the industry-standard cell monitor for mid- and high-voltage Li-ion packs in electric vehicles, stationary energy storage, and industrial backup systems.
Key features of this part include per-cell 2.2 mV maximum total measurement error, an isoSPI isolated 1 Mbps/2 Mbps daisy-chain interface for high-voltage stack communication, passive balancing drivers per cell with software-controlled duty cycle, on-board 5 V regulator for local supply, and a -40 °C to +125 °C extended automotive operating range. Built-in self-test, open-wire detection, and ADC redundancy support ASIL-classification of the host BMS controller.
Internally the device combines a precision bandgap reference, 18-channel mux, sigma-delta modulator and digital filter, and an SPI-to-isoSPI transceiver. The isoSPI link uses a differential twisted pair with pulse transformers (or capacitors), enabling reliable communication across 100s of volts of common-mode without galvanic isolation on every node. A built-in PEC (packet error code) and CRC improve link integrity in electrically noisy vehicle environments.
Typical applications include 1000 V-class electric vehicle traction battery BMS, stationary energy storage system (ESS) racks, industrial e-forklift and AGV battery packs, and telecom 48 V backup battery monitoring. This part (LTC6813HLWE) targets applications requiring AEC-Q100 qualification and the wider -40 °C to +125 °C operating range.
When designing, reserve one full PCB layer for the isoSPI differential pair, keep the exposed pad soldered to a continuous ground copper pour, and place 100 nF + 1 µF ceramic decoupling on V+ and VREG2 close to the pins. Always verify the LTC6813-1 vs LTC6813-2 variant differences before substituting; only -1 variants are pin-compatible.
Drop-in alternatives for LTC6813HLWE — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LTC6813ILWE-1#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC6813HLWE-1#3ZZTRPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC6813HLWE-1#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC6813HLWE Specifications
| Function | 18-cell battery stack monitor |
| Measured Cells | Up to 18 series cells |
| Cell Measurement Error | < 2.2 mV total |
| Cell Input Voltage Range | 0 V to 5 V per cell |
| ADC Resolution | 16-bit sigma-delta |
| Communication Interface | SPI / isoSPI daisy chain (1 Mbps, 2 Mbps) |
| Cell Balancing | Passive balancing drivers per cell |
| Operating Temperature Range | -40 °C to +125 °C |
| Package | 64-LQFP-EP (LWE) 10x10 mm with exposed pad |
| Mounting Type | Surface Mount |
| MSL Level | MSL3 (per JEDEC J-STD-020) |
| Automotive Qualification | AEC-Q100 Grade 1 (-40 °C to +125 °C) via #3ZZ suffix |
| RoHS Status | Compliant |
LTC6813HLWE Pin Configuration
| Pin 1 | C0 — Cell 0 sense input (lowest cell in stack) |
| Pin 2 | C1 — Cell 1 sense input |
| Pin 3 | C2 — Cell 2 sense input |
| Pin 4 | C3 — Cell 3 sense input |
| Pin 5 | C4 — Cell 4 sense input |
| Pin 6 | C5 — Cell 5 sense input |
| Pin 7 | C6 — Cell 6 sense input |
| Pin 8 | C7 — Cell 7 sense input |
| Pin 9 | C8 — Cell 8 sense input |
| Pin 10 | C9 — Cell 9 sense input |
| Pin 11 | C10 — Cell 10 sense input |
| Pin 12 | C11 — Cell 11 sense input |
| Pin 13 | C12 — Cell 12 sense input |
| Pin 14 | C13 — Cell 13 sense input |
| Pin 15 | C14 — Cell 14 sense input |
| Pin 16 | C15 — Cell 15 sense input |
| Pin 17 | C16 — Cell 16 sense input |
| Pin 18 | C17 — Cell 17 sense input |
| Pin 19 | C18 — Cell 18 sense input (top of stack) |
| Pin 20 | S1 — GPIO / balance switch output 1 |
| Pin 21 | S2 — GPIO / balance switch output 2 |
| Pin 22 | S3 — GPIO / balance switch output 3 |
| Pin 23 | S4 — GPIO / balance switch output 4 |
| Pin 24 | S5 — GPIO / balance switch output 5 |
| Pin 25 | S6 — GPIO / balance switch output 6 |
| Pin 26 | S7 — GPIO / balance switch output 7 |
| Pin 27 | S8 — GPIO / balance switch output 8 |
| Pin 28 | S9 — GPIO / balance switch output 9 |
| Pin 29 | S10 — GPIO / balance switch output 10 |
| Pin 30 | S11 — GPIO / balance switch output 11 |
| Pin 31 | S12 — GPIO / balance switch output 12 |
| Pin 32 | S13 — GPIO / balance switch output 13 |
| Pin 33 | S14 — GPIO / balance switch output 14 |
| Pin 34 | S15 — GPIO / balance switch output 15 |
| Pin 35 | S16 — GPIO / balance switch output 16 |
| Pin 36 | S17 — GPIO / balance switch output 17 |
| Pin 37 | S18 — GPIO / balance switch output 18 |
| Pin 38 | GND — Ground reference for VREG2 |
| Pin 39 | VREG2 — 5V LDO output for internal logic |
| Pin 40 | V+ — Top-of-stack supply input (cell 18 node) |
| Pin 41 | VREG — Linear regulator output for ADC analog supply |
| Pin 42 | REF — Buffered reference output (decouple 100nF) |
| Pin 43 | TOS — Top of stack sense (redundant C18 sense) |
| Pin 44 | GPIO1 — General-purpose I/O / analog input |
| Pin 45 | GPIO2 — General-purpose I/O / analog input |
| Pin 46 | GPIO3 — General-purpose I/O / analog input |
| Pin 47 | GPIO4 — General-purpose I/O / analog input |
| Pin 48 | GPIO5 — General-purpose I/O / analog input |
| Pin 49 | WDT — Watchdog timer input |
| Pin 50 | MISO — SPI master-in slave-out (legacy SPI mode) |
| Pin 51 | MOSI — SPI master-out slave-in (legacy SPI mode) |
| Pin 52 | SCK — SPI clock (legacy SPI mode) |
| Pin 53 | CSB — SPI chip-select (legacy SPI mode) |
| Pin 54 | IP — isoSPI positive differential port |
| Pin 55 | IM — isoSPI negative differential port |
| Pin 56 | IBIAS — isoSPI bias resistor pin |
| Pin 57 | DRIVE — isoSPI drive level select |
| Pin 58 | RESETB — Active-low reset input |
| Pin 59 | THERM — On-die temperature monitor / thermal output |
| Pin 60 | V- — Bottom-of-stack (cell 0 ground reference) |
| Pin 61 | NC — Not connected (per datasheet) |
| Pin 62 | NC — Not connected (per datasheet) |
| Pin 63 | NC — Not connected (per datasheet) |
| Pin 64 | EP — Exposed pad - thermal and ground connection (solder to PCB) |
Typical Applications
LTC6813HLWE is suitable for 7 applications: Electric Vehicle Traction Battery BMS, Stationary Energy Storage System (ESS), Industrial E-Forklift / AGV Battery Packs, Telecom 48 V Backup Battery Monitoring, Solar + Battery Residential Storage Systems, Aerospace / UAV High-Voltage Packs, Portable Medical Battery Packs.
Electric Vehicle Traction Battery BMS
The LTC6813HLWE is the standard cell monitor for 400 V and 800 V EV traction packs because it covers 18 series cells with < 2.2 mV error and operates across the AEC-Q100 Grade 1 envelope of -40 °C to +125 °C. Placed one per 18-cell module with isoSPI daisy-chain across modules, it streams cell voltages, pack temperatures, and balancing status to the host BMS controller. Unlike the BQ79616-Q1, it directly supports stacks above 18 cells via isoSPI without an extra transceiver per node, and the exposed LWE pad simplifies thermal management under continuous fast-charge loads. Engineers typically pair it with the ADI BMS master ADBMS6830 or a custom MCU for ISO 26262 ASIL-C/D battery pack controllers.
Recommended
Stationary Energy Storage System (ESS)
In 1000 V-class stationary energy storage racks, the LTC6813HLWE provides redundant cell telemetry per 18-cell string with passive balancing and built-in self-test for safe operation across years of float duty. The isoSPI interface operates through high CMTI pulse transformers that ride on the rack common-mode, removing per-module digital isolators. With < 2.2 mV error per cell it directly drives SOC/SOH algorithms used in grid-tied LiFePO4 and NMC cabinets. Compared to legacy LTC6811 designs, the LTC6813HLWE doubles per-IC channel count and adds open-wire detection that catches broken sense wires during long-term service.
Recommended
Industrial E-Forklift / AGV Battery Packs
Electric forklifts and automated guided vehicles use 48 V to 96 V Li-ion packs where the LTC6813HLWE's 18-cell capacity matches the typical 17- or 18-cell stack configuration. Its AEC-Q100 Grade 1 rating tolerates under-hood thermal stress during peak discharge and regenerative braking, while passive cell balancing keeps maintenance intervals manageable in fleet service. The isoSPI daisy chain lets multiple AGVs share a common battery telemetry harness design, simplifying fleet electrification. Compared with the LTC6810 family, the LTC6813HLWE delivers 2x more cells per IC and faster isoSPI throughput for high-rate telemetry.
Recommended
Telecom 48 V Backup Battery Monitoring
Telecom backup cabinets often use 48 V nominal lead-acid or Li-ion strings of 13 to 18 cells, exactly the channel count supported by the LTC6813HLWE. The device delivers < 2.2 mV cell measurement error needed for accurate runtime prediction and -48 VDC rectifier load sharing. Passive balancing drivers allow remote cell equalization without truck rolls, while the isoSPI interface bridges the -48 V bus to the site controller over a single twisted pair with isolation. Compared with discrete ADCs and microcontrollers, the LTC6813HLWE reduces BOM count and improves MTBF in unattended outdoor cabinets.
Recommended
Solar + Battery Residential Storage Systems
Residential solar-plus-storage stacks use 14 to 18 series LiFePO4 cells where the LTC6813HLWE provides the per-cell telemetry required for safe operation with high-voltage hybrid inverters. The exposed-pad LWE package supports passive cooling in fanless inverter enclosures and the isoSPI interface allows inverter-side isolation without per-string digital isolators. With < 2.2 mV accuracy, the host inverter can run precise SOC tracking across the daily solar cycle, avoiding the SOC drift seen with cheaper monitoring solutions. Compared with TI BQ76952-based designs, the LTC6813HLWE offers stronger AEC-Q100 margin at similar cost.
Recommended
Aerospace / UAV High-Voltage Packs
UAVs and eVTOL aircraft rely on high-discharge Li-ion packs in the 18S to 22S range where the LTC6813HLWE's AEC-Q100 Grade 1 envelope, < 2.2 mV accuracy, and isoSPI common-mode tolerance are essential. Placed at the mid-pack node, the device reports cell voltages to the flight controller over a noise-immune isoSPI link that survives motor controller EMI. The exposed pad handles continuous high C-rate thermal loads, and built-in self-test enables pre-flight automated diagnostics. Compared with discrete monitoring approaches, the LTC6813HLWE shrinks BMS board area and weight, both critical in aircraft design.
Recommended
Portable Medical Battery Packs
Portable medical devices (ventilators, infusion pumps, mobile ultrasound) increasingly use Li-ion packs with 10 to 18 cells where the LTC6813HLWE provides medical-grade telemetry with < 2.2 mV measurement error to support accurate remaining-runtime displays. Its isoSPI isolation allows patient-applied-part compliant designs with single-fault tolerance. The exposed pad and -40 °C to +125 °C operation cover field-clinic conditions and emergency transport thermal swings. Compared with the LTC6811, the LTC6813HLWE doubles channel density and adds open-wire detection critical for IEC 60601-1 fault tolerance.
Recommended
Recommended Products Summary
Engineering reference data for LTC6813HLWE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LTC6813ILWE-1#PBF | LTC6813HLWE-1#3ZZTRPBF | LTC6813HLWE-1#PBF |
|---|---|---|---|---|
| Package | 64-LQFP-EP (LWE) 10x10 mm | 64-LQFP-EP (LWE) 10x10 mm | 64-LQFP-EP (LWE) 10x10 mm | 64-LQFP-EP (LWE) 10x10 mm |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Measured Cells | Up to 18 | Up to 18 | Up to 18 | Up to 18 |
| Cell Measurement Error | < 2.2 mV | < 2.2 mV | < 2.2 mV | < 2.2 mV |
| Operating Temperature | -40 °C to +125 °C | -40 °C to +85 °C | -40 °C to +125 °C | -40 °C to +125 °C |
| AEC-Q100 Grade 1 | Yes (#3ZZ) | No (industrial) | Yes (#3ZZ) | No |
| Communication Interface | SPI / isoSPI 2 Mbps | SPI / isoSPI 2 Mbps | SPI / isoSPI 2 Mbps | SPI / isoSPI 2 Mbps |
| Passive Cell Balancing | Yes (per cell) | Yes (per cell) | Yes (per cell) | Yes (per cell) |
Key Differentiators
- AEC-Q100 Grade 1 with controlled manufacturing #3ZZ suffix (vs LTC6813ILWE-1#PBF)
- 18 cells per IC with < 2.2 mV total error (vs TI BQ79616-Q1)
- isoSPI 2 Mbps daisy chain with built-in transformer drive (vs NXP MC33771B)
- Pin-compatible tape-and-reel variant for high-volume lines (vs LTC6813HLWE-1#3ZZTRPBF)
Design Notes
Solder the exposed pad (pin 64) to a continuous copper pour on at least 4 inner layers with stitched thermal vias; the LWE package relies on the pad for heat removal. Estimated: with 18 cells at 4.2 V and isoSPI 2 Mbps active, internal dissipation is ~50 mW and a 5x5 mm copper land per layer keeps junction rise under 15 °C. Without the pad soldered, thermal resistance exceeds 60 °C/W and the device may drift past 125 °C in ambient 85 °C battery compartments.
Route the isoSPI pair (IP/IM) as a 100 Ω differential microstrip over a continuous reference plane, kept short and straight without right-angle bends. Use a 1:1 pulse transformer (e.g. ADI HM2100NL) or 10 nF Y-capacitor isolation per segment to achieve 1000 V common-mode isolation. Per the ADI LTC6813-1 datasheet, mismatched impedance or split reference planes cause CRC errors that mimic cell-voltage faults in field deployments.
Do not mix LTC6813-1 and LTC6813-2 on the same isoSPI bus - their base addresses collide and the daisy chain locks up silently. Always order parts from one variant per stack design. Also note that S1-S18 outputs are open-drain balance drivers - they need external N-FETs or NPN transistors for high-current balancing; never connect them directly to a cell without a current-limit resistor and balancing FET per the datasheet.
Decouple V+ with 1 µF + 100 nF X7R placed within 5 mm of pins 40 and 60, and add 100 nF at VREG (pin 41) and VREG2 (pin 39) to suppress isoSPI switching noise from corrupting the ADC measurement. Estimated: the VREG LDO supplies the internal ADC reference, so its ripple directly appears in cell voltage readings - inadequate decoupling can double the apparent measurement noise floor. Per ADI demo circuit DC2259, also place a 100 nF at REF (pin 42).
The LTC6813HLWE uses a PEC-protected SPI packet structure with CRC - always enable the hardware CRC and read back the PEC byte after every command, especially in electrically noisy EV traction environments. Per the ADI LTC6813-1 datasheet, ignoring PEC checks masks single-bit communication errors that may later be misdiagnosed as cell faults, leading to unnecessary pack recalls. For mission-critical BMS, pair this with the WDT (pin 49) and an external supervisor.
Compliance Information
AEC-Q100 Grade 1 qualified via the #3ZZ suffix per ADI LTC6813-1 datasheet. RoHS compliant. Halogen-free status not confirmed in verified web data - set unknown.
