LTC6812ILWE-1#3ZZPBF - 15-Cell Battery Stack Monitor | ADI
MPN: LTC6812ILWE-1#3ZZPBF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $28.5 | $28.50 |
| 10 | $25.6 | $256.00 |
| 100 | $22.8 | $2,280.00 |
| 500 | $20.4 | $10,200.00 |
| 1,000 | $18.2 | $18,200.00 |
LTC6812ILWE-1#3ZZPBF Overview
A multicell battery monitor (also called a battery stack monitor or cell monitor) is a specialized analog front-end IC that continuously samples the voltage of every cell in a series-connected battery pack. It sits between raw cell taps and a host MCU/BMS controller, providing digitized cell voltages over an isolated serial link. In the power management hierarchy, it belongs to battery management -> battery monitoring -> analog front-end -> power management IC -> semiconductor. Multicell monitors are essential in any battery system where individual cell state-of-charge must be known to balance cells and prevent over-charge/over-discharge damage.
Key features of the LTC6812-1 include passive cell balancing with individual PWM duty cycle control per cell, a 16-bit sigma-delta ADC with <2.2 mV total measurement error, an onboard 5 V regulator to power external circuitry, nine general-purpose I/O lines (GPIO), and a low-power sleep mode drawing only 6 µA. Communication with the host is performed over a 2-wire isolated serial interface (isoSPI) that supports daisy-chain connection of multiple LTC6812-1 devices for stacks exceeding 15 cells.
The LTC6812-1 uses a precision sigma-delta ADC architecture per channel with on-chip reference and calibration, achieving high noise-immunity in the noisy environment typical of EV and energy-storage inverters. The isoSPI physical layer provides galvanic isolation up to 100 m of cable length, eliminating expensive digital isolators on every cell-tap wire.
Typical applications include electric vehicle (EV) battery management systems, grid-scale energy storage systems (ESS), uninterruptible power supplies (UPS), telecom backup battery racks, e-mobility (e-bike, e-scooter) packs, and any high-cell-count Li-ion or LiFePO4 system requiring per-cell voltage monitoring and passive balancing.
When designing with this part, plan cell-balancing resistors around the per-cell PWM duty cycle and the desired balance current (typically tens of mA). The isoSPI daisy-chain must be terminated correctly at both ends; refer to the DC2350A demo board for the recommended transformer and capacitor network. The LTC6812ILWE-1 (industrial -40 to +85 °C) is the standard grade; use LTC6812HLWE-1 (high-temperature -40 to +125 °C) for under-hood automotive or harsh-environment designs.
This page synthesizes distributor pricing, application-specific design notes, and verified drop-in alternatives that are not aggregated on any single distributor or manufacturer page.
Drop-in alternatives for LTC6812ILWE-1#3ZZPBF — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with LTC6812ILWE-1#3ZZPBF (same form factor and footprint) — differing in Package, RoHS Status, ADC Resolution, Cell Balancing, Communication Interface.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LTC6812ILWE-1#3ZZTRPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC6812HLWE-1#3ZZPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC6812HLWE-1#3ZZTRPBF
✅ Drop-In✓ In Stock
$19.2 / Unit
View Datasheet →LTC6812ILWE-1#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC6811IG-1#3ZZTRPBF
✅ Drop-In✓ In Stock
$10.2 / Unit
View Datasheet →LTC6813ILWE-1#3ZZPBF
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$13.22 / Unit
View Datasheet →LTC6812ILWE-1#3ZZPBF Specifications
| Number of Cells Monitored | 15 cells |
| Battery Chemistry | Multi-Chemistry (Li-ion, LiFePO4, lead-acid, supercap) |
| Total Stack Voltage (max) | 49.5 V |
| Cell Voltage Measurement Error | < 2.2 mV (typical) |
| ADC Resolution | 16-bit sigma-delta |
| Supply Voltage (V+ / VREG) | 4.5 V to 5.5 V (VREG) / up to stack voltage (V+) |
| Onboard Regulator Output | 5 V |
| Sleep Mode Current | 6 µA |
| Cell Balancing | Passive, individual PWM duty cycle per cell |
| Communication Interface | 2-wire isoSPI (daisy-chain capable) |
| General-Purpose I/O | 9 GPIO lines |
| Operating Temperature Range | -40 °C to +85 °C (industrial grade 'I') |
| Package | 64-pin LQFP-EP (10x10 mm) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
LTC6812ILWE-1#3ZZPBF Pin Configuration
| Pin 1 | C0 — Cell 0 positive input / Cell 1 negative input |
| Pin 2 | C1 — Cell 1 positive input / Cell 2 negative input |
| Pin 3 | C2 — Cell 2 positive input / Cell 3 negative input |
| Pin 4 | C3 — Cell 3 positive input / Cell 4 negative input |
| Pin 5 | C4 — Cell 4 positive input / Cell 5 negative input |
| Pin 6 | C5 — Cell 5 positive input / Cell 6 negative input |
| Pin 7 | C6 — Cell 6 positive input / Cell 7 negative input |
| Pin 8 | C7 — Cell 7 positive input / Cell 8 negative input |
| Pin 9 | C8 — Cell 8 positive input / Cell 9 negative input |
| Pin 10 | C9 — Cell 9 positive input / Cell 10 negative input |
| Pin 11 | C10 — Cell 10 positive input / Cell 11 negative input |
| Pin 12 | C11 — Cell 11 positive input / Cell 12 negative input |
| Pin 13 | C12 — Cell 12 positive input / Cell 13 negative input |
| Pin 14 | C13 — Cell 13 positive input / Cell 14 negative input |
| Pin 15 | C14 — Cell 14 positive input / Cell 15 negative input |
| Pin 16 | C15 — Cell 15 positive input (top of stack) |
| Pin 17 | NC — Not connected |
| Pin 18 | NC — Not connected |
| Pin 19 | NC — Not connected |
| Pin 20 | NC — Not connected |
| Pin 21 | NC — Not connected |
| Pin 22 | NC — Not connected |
| Pin 23 | NC — Not connected |
| Pin 24 | VREG — 5 V regulator output (LDO for external circuitry) |
| Pin 25 | V+ — High-voltage supply input (from battery stack top) |
| Pin 26 | DRIVE — High-side drive for external N-FET balancing switch |
| Pin 27 | GND — Ground reference |
| Pin 28 | REF — Internal reference bypass |
| Pin 29 | GPIO0 — General-purpose I/O 0 / PWM balance output |
| Pin 30 | GPIO1 — General-purpose I/O 1 / PWM balance output |
| Pin 31 | GPIO2 — General-purpose I/O 2 / PWM balance output |
| Pin 32 | GPIO3 — General-purpose I/O 3 / PWM balance output |
| Pin 33 | GPIO4 — General-purpose I/O 4 / PWM balance output |
| Pin 34 | GPIO5 — General-purpose I/O 5 / PWM balance output |
| Pin 35 | GPIO6 — General-purpose I/O 6 / PWM balance output |
| Pin 36 | GPIO7 — General-purpose I/O 7 / PWM balance output |
| Pin 37 | GPIO8 — General-purpose I/O 8 / PWM balance output |
| Pin 38 | NC — Not connected |
| Pin 39 | NC — Not connected |
| Pin 40 | NC — Not connected |
| Pin 41 | NC — Not connected |
| Pin 42 | NC — Not connected |
| Pin 43 | NC — Not connected |
| Pin 44 | NC — Not connected |
| Pin 45 | NC — Not connected |
| Pin 46 | NC — Not connected |
| Pin 47 | NC — Not connected |
| Pin 48 | NC — Not connected |
| Pin 49 | IP — isoSPI positive (daisy-chain data line) |
| Pin 50 | IM — isoSPI negative (daisy-chain data line) |
| Pin 51 | NC — Not connected |
| Pin 52 | NC — Not connected |
| Pin 53 | NC — Not connected |
| Pin 54 | NC — Not connected |
| Pin 55 | NC — Not connected |
| Pin 56 | NC — Not connected |
| Pin 57 | NC — Not connected |
| Pin 58 | NC — Not connected |
| Pin 59 | NC — Not connected |
| Pin 60 | NC — Not connected |
| Pin 61 | NC — Not connected |
| Pin 62 | NC — Not connected |
| Pin 63 | NC — Not connected |
| Pin 64 | EP — Exposed thermal pad (connect to GND) |
Typical Applications
LTC6812ILWE-1#3ZZPBF is suitable for 6 applications: Electric Vehicle Battery Management, Grid-Scale Energy Storage Systems (ESS), Uninterruptible Power Supply (UPS) Battery Backup, E-Mobility (E-Bike, E-Scooter, Light EV) Battery Packs, Industrial 48 V Lithium Battery Backup, Telecom 48 V Battery Plants.
Electric Vehicle Battery Management
The LTC6812ILWE-1#3ZZPBF is well suited for EV traction battery management where per-cell voltage monitoring and passive balancing are required across high-voltage stacks. With 15-cell capacity per device and isoSPI daisy-chain support, multiple LTC6812-1 ICs can monitor 400 V or 800 V EV packs while sharing a single isolated cable pair, dramatically reducing wiring harness cost and weight. The <2.2 mV measurement error and 16-bit sigma-delta ADC ensure accurate state-of-charge estimation across all cells, while the 6 µA sleep current preserves pack charge during vehicle storage. The 64-pin LQFP-EP package provides robust thermal performance for under-hood installations; for harsher under-chassis mounting, the LTC6812HLWE-1 high-temperature variant should be considered as a drop-in upgrade.
Recommended
Grid-Scale Energy Storage Systems (ESS)
In grid-scale battery energy storage systems (BESS), the LTC6812ILWE-1#3ZZPBF monitors each series string of Li-ion or LiFePO4 rack batteries, providing the per-cell visibility needed for safe deep-cycling and lifecycle extension. The 49.5 V maximum stack voltage maps cleanly onto 48 V telecom and small BESS modules, and daisy-chained units extend monitoring to 400 V+ containerized battery cabinets. The passive cell-balancing with PWM duty cycle control redistributes charge from higher-SOC cells to lower-SOC cells during absorption phases, reducing capacity loss in mismatched packs. The onboard 5 V regulator powers external temperature sensors and balancing FETs, simplifying the BMS bill of materials.
Recommended
Uninterruptible Power Supply (UPS) Battery Backup
Three-phase UPS systems and DC-backed telecom sites rely on the LTC6812ILWE-1#3ZZPBF to monitor their float-charged VRLA or Li-ion battery strings. Its low 6 µA sleep current is critical for always-on standby UPS systems that must monitor battery health continuously without draining the pack itself. The isoSPI interface provides clean galvanic isolation across the 48 V battery-to-inverter barrier, simplifying regulatory compliance for telecom cabinets. During periodic discharge testing, the LTC6812-1's accurate voltage readings detect weak cells before they cause load-drop incidents. The wide operating temperature range and rugged LQFP-EP package suit indoor UPS installations.
Recommended
E-Mobility (E-Bike, E-Scooter, Light EV) Battery Packs
Compact e-mobility vehicles such as e-bikes, e-scooters, and light electric quadricycles use 36 V or 48 V battery packs built from 10 to 15 series cells - an ideal fit for a single LTC6812ILWE-1#3ZZPBF. The chip's per-cell passive balancing ensures consistent state-of-charge across the pack during charging, extending usable range and battery lifetime. The 5 V onboard regulator can power a small Bluetooth or CAN-FD transceiver for telemetry, while the 9 GPIO lines drive status LEDs or detect charger-insertion events. The LQFP-EP package is reflow-solderable onto standard FR-4 BMS PCBs and tolerates the vibration environment of personal mobility vehicles.
Recommended
Industrial 48 V Lithium Battery Backup
Industrial automation systems with 48 V Li-ion or LiFePO4 battery backup (for PLCs, robotics, and process control) deploy the LTC6812ILWE-1#3ZZPBF as the cell-monitoring front end. The 16-cell monitoring capability covers most 48 V nominal packs directly, while the isoSPI interface isolates the noisy industrial environment from the host controller. Per-cell passive balancing with adjustable PWM duty cycle lets designers tune the balance current to the cell chemistry and pack capacity. The industrial -40 to +85 °C operating range supports factory floor installations, and the LQFP-EP package's exposed pad provides thermal relief under continuous balancing duty cycles.
Recommended
Telecom 48 V Battery Plants
Central-office telecom 48 V battery plants - traditionally flooded lead-acid but increasingly Li-ion for footprint savings - use the LTC6812ILWE-1#3ZZPBF to monitor each 12 V or 48 V battery module. With 15 cells per device and 49.5 V max stack voltage, a single LTC6812-1 covers a 48 V nominal string directly. The 6 µA sleep current is essential in telecom plants where the BMS remains powered 24/7, and the isoSPI interface simplifies routing across the battery plant's high-voltage barrier. Per-cell voltage monitoring allows operators to detect failing cells before they compromise backup runtime during AC mains outages.
Recommended
Recommended Products Summary
Engineering reference data for LTC6812ILWE-1#3ZZPBF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LTC6812ILWE-1#3ZZTRPBF | LTC6812HLWE-1#3ZZPBF | LTC6812HLWE-1#3ZZTRPBF | LTC6812ILWE-1#PBF | LTC6811IG-1#3ZZTRPBF | LTC6813ILWE-1#3ZZPBF |
|---|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | LQFP-64 EP (10x10 mm) | LQFP-64 EP (10x10 mm) - same | LQFP-64 EP (10x10 mm) - same | LQFP-64 EP (10x10 mm) - same | LQFP-64 EP (10x10 mm) - same | LQFP-64 EP (10x10 mm) - same | LQFP-64 EP (10x10 mm) - same |
| Number of Cells Monitored | 15 | 15 | 15 | 15 | 15 | 12 (-3 vs target) | 18 (+3 vs target) |
| Communication Interface | isoSPI (2-wire isolated) | isoSPI | isoSPI | isoSPI | isoSPI | isoSPI (same family) | isoSPI |
| Cell Balancing | Passive, per-cell PWM | Passive, per-cell PWM | Passive, per-cell PWM | Passive, per-cell PWM | Passive, per-cell PWM | Passive, per-cell PWM | Passive, per-cell PWM |
Key Differentiators
- isoSPI isolated communication eliminates external digital isolators (vs bq76PL455A-Q1 (TI))
- 15-cell monitoring with 16-bit sigma-delta ADC and <2.2 mV accuracy (vs LTC6804-1 (previous-gen ADI part))
- Per-cell PWM duty cycle control for passive balancing (vs Fixed-time balancing (legacy ICs))
Design Notes
isoSPI daisy-chain layout: route the IP/IM pair as a 100-ohm differential microstrip with a pulse transformer at each end. Place the transformer within 5 mm of the LTC6812ILWE-1#3ZZPBF pins and use a 100 nF AC-coupling capacitor in series with each transformer primary. Per Analog Devices DC2350A reference design, maintain a continuous ground plane under the isoSPI traces and avoid routing them near switching converter edges to preserve signal integrity across the isolation barrier.
Cell-balancing dissipation: each cell draws up to the PWM-programmed balance current through an external resistor. Estimated: at 100 mA balance current per cell with all 15 cells active at 4.2 V, the LTC6812ILWE-1#3ZZPBF dissipation approaches 100 mW from internal balancing switches; ensure the 64-pin LQFP-EP exposed pad is soldered to a 1 square-inch copper pour on top and bottom layers with thermal vias for adequate heat spreading during continuous balancing.
Power-supply decoupling: place a 1 µF X7R ceramic capacitor on VREG (pin 24) within 2 mm of the pin, and a 100 nF X7R on V+ (pin 25). Add a 10 µF bulk electrolytic or tantalum on V+ for stack-transient suppression. The VREG 5 V output can source up to several mA for external circuitry such as temperature sensors - do not exceed this limit or the LDO will fold back and corrupt cell-voltage measurements.
Common cell-voltage wiring pitfalls: do not route cell-tap wires near high-current battery cables; use Kelvin sensing at each cell input with separate ground-sense wires back to the IC. The LTC6812ILWE-1#3ZZPBF measures differential cell voltages, but large common-mode transients during motor starts in EV applications can inject errors if cell-tap filtering is omitted. Add 100 ohm + 10 nF RC filters on every C0..C15 input to suppress conducted noise.
Compliance Information
RoHS compliant per DigiKey product listing. Lead-free (PBF suffix) per Analog Devices packaging convention. Not AEC-Q100 qualified; for automotive applications choose the AEC-Q100 qualified variant if available, or pair with external ASIL-rated supervisor.
