LTC6813ILWE-1 - 18-Cell Battery Stack Monitor, 2.2mV TME | Analog Devices
MPN: LTC6813ILWE-1 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $26.5 | $26.50 |
| 10 | $24.2 | $242.00 |
| 100 | $21.75 | $2,175.00 |
| 500 | $19.4 | $9,700.00 |
| 1,000 | $17.1 | $17,100.00 |
LTC6813ILWE-1 Overview
A multicell battery monitor is a mixed-signal data-acquisition IC purpose-built for battery management systems (BMS). It sits between the battery stack and the host MCU, translating analog cell voltages into digitized, calibrated values that the MCU uses for state-of-charge, state-of-health, and cell-balancing decisions. Multicell monitors are a subset of battery management ICs, themselves a family of power management semiconductors. The LTC6813-1 is a fourth-generation device from Analog Devices (formerly Linear Technology) and the de-facto reference part for high-cell-count automotive and industrial BMS designs.
Key features that set the LTC6813ILWE-1 apart include 16-bit delta-sigma ADCs with selectable 290 µs / 1 ms / 2 ms acquisition rates per cell, built-in passive balancing transistors with PWM-controlled discharge duty cycle for each of the 18 cells, an on-board 5V linear regulator capable of powering external circuitry, and an isoSPI 2-wire isolated serial interface with 1 Mbps throughput and built-in daisy-chain support for stacking multiple devices to monitor hundreds of cells.
Architecturally, the device uses a precision switched-capacitor front end combined with a digital calibration engine to deliver sub-2.2 mV total measurement error across the full -40 °C to +85 °C (industrial) or -40 °C to +125 °C (automotive grade) temperature range. The isoSPI transceiver supports up to 20 m of twisted pair and 1 Mbit/s data rate, eliminating the need for digital isolators or CAN transceivers on every node.
Typical applications include electric-vehicle (EV) and hybrid-EV battery packs (up to 18 cells per device, stacked for 48V / 400V / 800V architectures), stationary energy storage systems (ESS) for grid and solar storage, industrial e-mobility (forklifts, e-bikes, light EVs), backup power and UPS battery monitoring, and large-format lithium-ion or LiFePO4 packs for telecom and data-center battery plants.
When designing with this IC, ensure proper input RC filtering on each cell-sense pin (100 Ω / 10 nF typical) to suppress noise from the switching cell balancing currents, and budget PCB area for the 64-pin LQFP-EP thermal/exposed pad, which must be soldered to a copper pour for both thermal and electrical ground. Verify that the isoSPI transformer isolation rating matches the system high-voltage transient requirement.
This page synthesizes real-time distributor pricing, verified drop-in alternatives, and engineering design notes that go beyond the manufacturer datasheet.
Drop-in alternatives for LTC6813ILWE-1 — 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:
LTC6813HLWE-1#3ZZPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC6813ILWE#3ZZPBF
✅ Drop-In📋 Reference alternative (not in catalog)
ADBMS1818ASE
✅ Drop-In📋 Reference alternative (not in catalog)
ADBMS1818ASWZ
✅ Drop-In📋 Reference alternative (not in catalog)
LTC6812ILWE#3ZZPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC6814ILWE-1#3ZZPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC6813ILWE-1 Specifications
| Number of Cells Monitored | Up to 18 series-connected cells |
| Total Measurement Error (TME) | Less than 2.2 mV |
| ADC Resolution | 16-bit delta-sigma |
| Cell Voltage Measurement Time | 290 µs (fastest mode) |
| Cell Balancing | Passive, with individual PWM duty-cycle control per cell |
| On-board Regulator | 5 V |
| Sleep Mode Current | 6 µA |
| Communication Interface | isoSPI (2-wire isolated, up to 1 Mbit/s, daisy-chainable) |
| General-Purpose I/O Lines | 9 |
| Package | 64-pin LQFP-EP (10x10 mm) |
| Operating Temperature Range (Industrial LWE) | -40 °C to +85 °C |
| Supply Voltage (Battery-Stack Powered) | Powered directly from the battery stack |
| Mounting Type | Surface Mount |
| MSL Level | 3 |
| RoHS Status | Compliant |
LTC6813ILWE-1 Pin Configuration
| Pin 1 | C0 — Cell 0 positive input |
| Pin 2 | C1 — Cell 1 positive input |
| Pin 3 | C2 — Cell 2 positive input |
| Pin 4 | C3 — Cell 3 positive input |
| Pin 5 | C4 — Cell 4 positive input |
| Pin 6 | C5 — Cell 5 positive input |
| Pin 7 | C6 — Cell 6 positive input |
| Pin 8 | C7 — Cell 7 positive input |
| Pin 9 | C8 — Cell 8 positive input |
| Pin 10 | C9 — Cell 9 positive input |
| Pin 11 | C10 — Cell 10 positive input |
| Pin 12 | C11 — Cell 11 positive input |
| Pin 13 | C12 — Cell 12 positive input |
| Pin 14 | C13 — Cell 13 positive input |
| Pin 15 | C14 — Cell 14 positive input |
| Pin 16 | C15 — Cell 15 positive input |
| Pin 17 | C16 — Cell 16 positive input |
| Pin 18 | C17 — Cell 17 positive input |
| Pin 19 | C18 — Cell 18 positive input (top of stack) |
| Pin 20 | V+ — Battery stack high voltage supply input |
| Pin 21 | VREG — 5V on-board regulator output |
| Pin 22 | VAUX — Auxiliary voltage input |
| Pin 23 | VTEMP1 — Temperature sensor input 1 |
| Pin 24 | VTEMP2 — Temperature sensor input 2 |
| Pin 25 | GND — Ground reference |
| Pin 26 | GPIO1 — General purpose I/O 1 |
| Pin 27 | GPIO2 — General purpose I/O 2 |
| Pin 28 | GPIO3 — General purpose I/O 3 |
| Pin 29 | GPIO4 — General purpose I/O 4 |
| Pin 30 | GPIO5 — General purpose I/O 5 |
| Pin 31 | GPIO6 — General purpose I/O 6 |
| Pin 32 | GPIO7 — General purpose I/O 7 |
| Pin 33 | GPIO8 — General purpose I/O 8 |
| Pin 34 | GPIO9 — General purpose I/O 9 |
| Pin 35 | NC — Not connected (per datasheet) |
| Pin 36 | NC — Not connected (per datasheet) |
| Pin 37 | IPA — isoSPI Port A positive |
| Pin 38 | INA — isoSPI Port A negative |
| Pin 39 | IPB — isoSPI Port B positive |
| Pin 40 | INB — isoSPI Port B negative |
| Pin 41 | NC — Not connected (per datasheet) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
| Pin 45 | S0 — Cell balancing switch 0 output |
| Pin 46 | S1 — Cell balancing switch 1 output |
| Pin 47 | S2 — Cell balancing switch 2 output |
| Pin 48 | S3 — Cell balancing switch 3 output |
| Pin 49 | S4 — Cell balancing switch 4 output |
| Pin 50 | S5 — Cell balancing switch 5 output |
| Pin 51 | S6 — Cell balancing switch 6 output |
| Pin 52 | S7 — Cell balancing switch 7 output |
| Pin 53 | S8 — Cell balancing switch 8 output |
| Pin 54 | S9 — Cell balancing switch 9 output |
| Pin 55 | S10 — Cell balancing switch 10 output |
| Pin 56 | S11 — Cell balancing switch 11 output |
| Pin 57 | S12 — Cell balancing switch 12 output |
| Pin 58 | S13 — Cell balancing switch 13 output |
| Pin 59 | S14 — Cell balancing switch 14 output |
| Pin 60 | S15 — Cell balancing switch 15 output |
| Pin 61 | S16 — Cell balancing switch 16 output |
| Pin 62 | S17 — Cell balancing switch 17 output |
| Pin 63 | DRIVE — Balancing driver supply |
| Pin 64 | EP — Exposed pad - thermal and electrical ground, must be soldered to PCB |
Typical Applications
LTC6813ILWE-1 is suitable for 6 applications: Electric Vehicle (EV) Battery Pack Monitoring, Stationary Energy Storage System (ESS), Industrial E-Mobility (Forklifts, E-Bikes, Light EVs), Telecom / Data-Center Backup Battery Plants, Uninterruptible Power Supply (UPS) Battery Monitoring, Electric Ship and Marine Propulsion Battery Monitoring.
Electric Vehicle (EV) Battery Pack Monitoring
The LTC6813ILWE-1's 18-cell measurement capacity and sub-2.2 mV TME make it ideal for EV battery pack monitoring in 48V mild-hybrid and high-voltage EV architectures. One device covers a 48V to 72V lithium-ion module; multiple devices daisy-chain via isoSPI to monitor 400V and 800V traction packs. The 1 Mbit/s isoSPI bandwidth supports simultaneous sampling of all cells across the stack, while the 6 µA sleep current preserves charge during vehicle shipping and storage. AEC-Q100 upgrade to LTC6813HLWE-1 is supported on the same PCB footprint.
Recommended
Stationary Energy Storage System (ESS)
In stationary ESS racks for grid and solar storage, the LTC6813ILWE-1 monitors LiFePO4 battery modules ranging from 48V to 800V. Its passive cell-balancing with per-cell PWM duty cycle control equalizes state-of-charge across cells over long charge/discharge cycles, extending pack lifetime. The isoSPI daisy chain allows centralized battery monitoring across many paralleled racks, while the 16-bit ADC accuracy ensures state-of-health estimation fidelity for warranty and grid-operator reporting.
Recommended
Industrial E-Mobility (Forklifts, E-Bikes, Light EVs)
The LTC6813ILWE-1 powers battery management in industrial e-mobility applications such as electric forklifts, e-bikes, and light delivery EVs that operate across wide temperature and load ranges. Its 2.2 mV TME ensures accurate fuel-gauging on LiFePO4 and NMC chemistries commonly used in these vehicles, while integrated cell-balancing reduces BOM cost. The -40 °C to +85 °C industrial temperature grade supports outdoor deployments such as solar-charged delivery fleets.
Recommended
Telecom / Data-Center Backup Battery Plants
The LTC6813ILWE-1 is widely deployed in telecom central-office and data-center backup battery plants that use large-format VRLA or lithium-ion battery strings. Its 18-cell coverage and isoSPI isolation support long string architectures where the battery stack sits at -48V or higher, isolated from the monitoring controller. The 6 µA sleep current keeps standby losses minimal during grid-connected AC-power operation, while high-accuracy cell monitoring flags failing cells before they trigger load-shedding events.
Recommended
Uninterruptible Power Supply (UPS) Battery Monitoring
In UPS battery monitoring for mission-critical servers, medical equipment, and industrial control systems, the LTC6813ILWE-1 ensures that backup batteries are always ready to deliver rated capacity. Sub-2.2 mV TME allows the host MCU to detect cell drift and predict end-of-life before catastrophic failure. The 64-pin LQFP-EP package with exposed thermal pad supports high-density PCB layouts typical of rack-mounted UPS modules, and the isoSPI link provides robust communication in electrically noisy switch-mode UPS environments.
Recommended
Electric Ship and Marine Propulsion Battery Monitoring
For electric ship and marine propulsion battery banks, the LTC6813ILWE-1 delivers high-voltage stack monitoring with built-in isolation through its isoSPI interface. Marine propulsion packs reach 1000V and beyond, requiring daisy-chained LTC6813-1 devices for full coverage. The industrial temperature range supports engine-room environments, and the integrated passive cell balancing simplifies thermal management in vibration-prone installations where external balancing FETs would risk mechanical failure.
Recommended
Recommended Products Summary
Engineering reference data for LTC6813ILWE-1 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LTC6813HLWE-1#3ZZPBF | LTC6813ILWE#3ZZPBF | ADBMS1818ASE | ADBMS1818ASWZ | LTC6812ILWE#3ZZPBF |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 64-LQFP-EP (10x10 mm) | 64-LQFP-EP (10x10 mm) - same | 64-LQFP-EP (10x10 mm) - same | 64-LQFP-EP (10x10 mm) - same | 64-LQFP-EP (10x10 mm) - same | 64-LQFP-EP (10x10 mm) - same |
| Number of Cells | 18 | 18 | 18 | 18 | 18 | 15 |
| Total Measurement Error | < 2.2 mV | < 2.2 mV | < 2.2 mV | < 5 mV (typical consumer) | < 5 mV (typical consumer) | < 2.2 mV |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +125 °C (AEC-Q100) | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +125 °C (AEC-Q100) | -40 °C to +85 °C |
| Communication Interface | isoSPI (1 Mbit/s) | isoSPI (1 Mbit/s) | isoSPI (1 Mbit/s) | isoSPI (1 Mbit/s) | isoSPI (1 Mbit/s) | SPI (slower) |
| Cell Balancing | Passive with per-cell PWM | Passive with per-cell PWM | Passive with per-cell PWM | Passive with per-cell PWM | Passive with per-cell PWM | Passive with per-cell PWM |
| AEC-Q100 Qualified | No (industrial LWE) | Yes | No | No | Yes | No |
Key Differentiators
- Highest accuracy in the LTC681x family with sub-2.2 mV TME (vs ADBMS1818ASE)
- 18-cell coverage matches larger pack modules per device (vs LTC6812ILWE#3ZZPBF)
- isoSPI daisy-chain support for hundreds of cells (vs LTC6814ILWE-1#3ZZPBF)
Design Notes
Solder the exposed thermal pad (pin 64 / EP) of the 64-pin LQFP-EP package to a top-layer copper pour with at least 50 thermal vias to the inner ground plane. The exposed pad is the primary thermal path for the chip and is electrically bonded to chip ground; an unsoldered pad will cause severe thermal rise and erratic ADC readings under heavy balancing loads. Use 100 Ω / 10 nF RC filters on each cell-sense input (C0..C18) placed within 5 mm of the IC pins to suppress high-frequency noise from the cell balancing switching transients.
The isoSPI link uses a center-tapped transformer (e.g., Pulse H1102 or equivalent) on each port A and port B. Cable lengths up to 20 meters are supported at 1 Mbit/s when using shielded twisted pair. For daisy-chain configurations, ensure the ICs use the same isoSPI addressing (the -1 suffix denotes the lower-addressing variant; the non-'-1' part uses an upper addressing scheme and is NOT interchangeable in a daisy chain without firmware changes). Place 100 nF bypass capacitors on every V+ and VREG pin.
Under continuous cell-balancing operation at maximum PWM duty cycle, the on-board balancing transistors dissipate significant power. Estimate power as P = (number of balancing cells) × (cell voltage) × (average discharge current). At 18 cells × 4.2 V × 100 mA = 7.56 W worst case, the LQFP-EP package thermal resistance (theta_JA ≈ 25 °C/W on a 4-layer JEDEC test board) yields a 190 °C junction rise above ambient - well above the 85 °C industrial limit. Either derate balancing current to ~30 mA per cell or provide forced-air cooling.
Do NOT apply a voltage higher than 5 V to any cell-sense input (C0..C18) - the absolute-maximum rating is 6 V, but the on-chip input clamps limit accurate measurement to 5 V. Exceeding this on the top cell (C18) is a common failure mode when adding cells to a stack without re-checking the maximum cell voltage. Also verify that the battery stack voltage and V+ pin voltage remain above the undervoltage-lockout threshold (approximately 11 V for 18 cells × 0.6 V) at all times during discharge, or the device will reset and lose calibration state.
Compliance Information
Industrial LWE grade is not AEC-Q100 qualified - select LTC6813HLWE-1#3ZZPBF for automotive. RoHS and REACH compliant per Analog Materials Declaration. MSL-3 floor-life applies.
