LTC6811IG-1 - 12-Cell Battery Stack Monitor, isoSPI, 48-SSOP | Analog Devices
Référence : LTC6811IG-1 ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $14.2 | $14,20 |
| 10 | $12.85 | $128,50 |
| 100 | $11.4 | $1 140,00 |
| 500 | $10.05 | $5 025,00 |
| 1 000 | $9.1 | $9 100,00 |
LTC6811IG-1 Présentation
A battery monitor IC (also called a multicell battery monitor or cell monitor) is an analog front-end that digitizes the voltage of every cell in a series stack, performs balance-current control, and reports measurements to a host MCU through a digital interface. Battery monitors sit inside the Battery Management System (BMS) hierarchy, alongside cell-balancing ICs and supervisors, and are essential for safety, state-of-charge estimation, and state-of-health tracking in Li-ion, LiFePO4, lead-acid, and supercapacitor packs.
Key features of the LTC6811IG-1 include a 12-bit ADC with <1.2 mV total measurement error, onboard passive cell balancing with PWM duty-cycle control per channel, an integrated 5V LDO for housekeeping supply, five general-purpose I/O lines, and a low-power sleep mode that drops quiescent current to 6 µA. Generation-4 silicon also adds improved EMI immunity and faster isoSPI data rates (up to 1 Mbps) over previous-generation LTC6804 parts. The 48-SSOP package with exposed pad offers theta_JA around 40 C/W, suitable for moderate ambient temperatures with a small copper pour.
Typical applications include electric-vehicle battery packs (400V and 800V architectures), grid-tied energy-storage systems, telecom backup battery racks, e-mobility scooters and e-bikes, solar battery storage banks, and industrial UPS stacks. The daisy-chain interface means a single BMS host processor can monitor hundreds of cells by chaining multiple LTC6811-1 devices up and down the stack.
When designing with this part, always add adequate TVS protection on the cell inputs and provide a low-impedance Kelvin connection at each cell tap to preserve the 1.2 mV accuracy. Use a 10 µF decoupling cap on V+ and place the isoSPI transformer within 50 mm of the LTC6811 pins to meet the 1 Mbps spec.
Alternatives de remplacement direct pour LTC6811IG-1 — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
LTC6804IG-1#PBF
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LTC6811IG-2#PBF
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LTC6811HG-1#PBF
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LTC6811IG-1#3ZZPBF
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LTC6813IG-1#PBF
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LTC6811IG-1 Spécifications
| Fonction | Multicell Battery Stack Monitor |
| Number of Cells Monitored | 12 series cells |
| Battery Chemistry | Multi-chemistry (Li-ion, LiFePO4, lead-acid, supercap) |
| Total Measurement Error | < 1.2 mV |
| Cell Input Common-Mode Range | 0 V to 5 V per cell |
| Communication Interface | isoSPI daisy chain (1 Mbps max) |
| Maximum Stack Voltage | 1000 V via daisy chain |
| Onboard LDO | 5 V regulator for housekeeping |
| Cell Balancing | Passive, PWM-controlled per cell |
| Sleep Mode Current | 6 µA |
| General Purpose I/O | 5 lines |
| Boîtier | 48-SSOP (IG) with exposed pad |
| Type de montage | Surface Mount |
| Statut RoHS | Compliant |
| Generation | Generation 4 silicon |
Configuration des broches de LTC6811IG-1
| Broche 1 | C0 — Cell 0 input / ground reference |
| Broche 2 | C1 — Cell 1 input |
| Broche 3 | C2 — Cell 2 input |
| Broche 4 | C3 — Cell 3 input |
| Broche 5 | C4 — Cell 4 input |
| Broche 6 | C5 — Cell 5 input |
| Broche 7 | C6 — Cell 6 input |
| Broche 8 | C7 — Cell 7 input |
| Broche 9 | C8 — Cell 8 input |
| Broche 10 | C9 — Cell 9 input |
| Broche 11 | C10 — Cell 10 input |
| Broche 12 | C11 — Cell 11 input |
| Broche 13 | C12 — Cell 12 input / top of stack |
| Broche 14 | V+ — Top of stack supply |
| Broche 15 | Vreg — Internal 5V regulator output |
| Broche 16 | DRIVE — 5V regulator base drive |
| Broche 17 | V- — Ground reference (bottom of stack) |
| Broche 18 | GPIO1 — General purpose I/O 1 |
| Broche 19 | GPIO2 — General purpose I/O 2 |
| Broche 20 | GPIO3 — General purpose I/O 3 |
| Broche 21 | GPIO4 — General purpose I/O 4 |
| Broche 22 | GPIO5 — General purpose I/O 5 |
| Broche 23 | NC — Not connected |
| Broche 24 | NC — Not connected |
| Broche 25 | ISOM — isoSPI master port - minus |
| Broche 26 | ISOP — isoSPI master port - plus |
| Broche 27 | ICMP — isoSPI master current comparator |
| Broche 28 | IBIAS — isoSPI bias current set |
| Broche 29 | ISOS — isoSPI slave port - minus |
| Broche 30 | ISOS+ — isoSPI slave port - plus |
| Broche 31 | NC — Not connected |
| Broche 32 | NC — Not connected |
| Broche 33 | NC — Not connected |
| Broche 34 | NC — Not connected |
| Broche 35 | SCL — I2C clock (optional external EEPROM) |
| Broche 36 | SDA — I2C data (optional external EEPROM) |
| Broche 37 | MISO — SPI master-in slave-out |
| Broche 38 | MOSI — SPI master-out slave-in |
| Broche 39 | SCK — SPI clock |
| Broche 40 | CSB — SPI chip select (active low) |
| Broche 41 | NC — Not connected |
| Broche 42 | NC — Not connected |
| Broche 43 | NC — Not connected |
| Broche 44 | NC — Not connected |
| Broche 45 | NC — Not connected |
| Broche 46 | NC — Not connected |
| Broche 47 | NC — Not connected |
| Broche 48 | NC — Not connected |
Applications typiques
LTC6811IG-1 convient pour 6 applications: Electric Vehicle Battery Pack, Grid-Tied Energy Storage System (ESS), Telecom Backup Battery Rack, Solar Battery Storage Bank, Industrial UPS Battery Stack, E-Mobility Scooter and E-Bike Pack.
Electric Vehicle Battery Pack
The LTC6811IG-1 is a primary candidate for 400V and 800V EV battery packs where 12-cell monitoring with <1.2 mV accuracy is required per module. The isoSPI daisy chain supports up to 1000V of stack isolation via a single twisted pair, enabling a single BMS host MCU to monitor the entire pack while remaining galvanically isolated from chassis ground. Placed at each 12S module with a small pulse transformer, multiple LTC6811-1s report per-cell voltages, temperatures, and balance status over isoSPI. Unlike the previous-generation LTC6804, the LTC6811's 6 µA sleep current is critical for long-term parked-state battery drain in EV applications. Each cell input uses a 100 ohm/10 nF RC filter for EMI rejection on noisy traction environments.
Recommandé
Grid-Tied Energy Storage System (ESS)
The LTC6811IG-1 fits residential and commercial battery storage banks of 48V to 1000V where State-of-Health and State-of-Charge depend on accurate per-cell voltage telemetry. The device's multi-chemistry support covers LiFePO4, NMC, and lead-acid banks commonly used in solar+storage installations. Multiple LTC6811-1 devices daisy-chain to cover 96S or 192S stacks typical of commercial ESS, with the host processor running SOC/SOH algorithms on aggregated cell data. Compared to the TI BQ76PL455A which tops out around 60V, the LTC6811's 1000V isoSPI capability eliminates external isolation hardware on the communication side, simplifying cabinet wiring significantly.
Recommandé
Telecom Backup Battery Rack
The LTC6811IG-1 is widely deployed in 48V telecom battery racks where it monitors strings of lead-acid or Li-ion cells feeding -48V DC plant equipment. The 12-channel architecture matches a 12S Li-ion or 6S/12S lead-acid string per board, and the 6 µA sleep current keeps parasitic drain low during grid-out conditions. Cell balancing prolongs battery life in float-charge scenarios, and the isoSPI interface allows the rack to be physically separated from the baseband controller for safety. With per-cell accuracy of 1.2 mV and passive balancing PWM, it directly replaces older discrete ADCs in legacy -48V plant designs and is supported by Analog Devices' DC2259A reference design for daisy-chain isoSPI.
Recommandé
Solar Battery Storage Bank
The LTC6811IG-1 is a strong fit for off-grid and grid-tied solar battery banks where accurate cell monitoring maximizes usable capacity and prevents over-discharge damage. The multi-chemistry support covers LiFePO4 and NMC banks popular in residential solar, and the onboard passive balancer with PWM duty control extends cycle life by evening out State-of-Charge across cells. The isoSPI interface simplifies wiring inside the battery cabinet where high-voltage isolation is required between the battery stack and the inverter's control board. Generation-4 EMI immunity is particularly valuable in solar installations where PV inverter switching noise can couple into the battery sense leads.
Recommandé
Industrial UPS Battery Stack
The LTC6811IG-1 is used in three-phase industrial UPS battery stacks of 192V to 480V where high-reliability monitoring is required for facility-grade backup power. The <1.2 mV measurement accuracy supports precise State-of-Health estimation that meets IEEE 1188 inspection guidance for stationary batteries. Each UPS string is built from 16 to 40 series cells covered by chaining LTC6811-1 devices; the 5 onboard GPIO lines double as temperature sensor inputs via external thermistors or as pack-level contactor drivers. The 48-SSOP package's exposed pad provides ~40 C/W theta_JA, sufficient for sealed UPS cabinets when paired with modest copper pours.
Recommandé
E-Mobility Scooter and E-Bike Pack
The LTC6811IG-1 suits 10S to 13S e-bike and e-scooter battery packs where its 12-cell coverage matches a single string with one spare channel. The isoSPI daisy chain is overkill for these low-voltage systems but enables clean isolation between the battery housing and the external controller, which simplifies IEC 62133 safety certification. The 6 µA sleep current preserves months of standby charge between rides, and passive cell balancing with PWM extends the usable cycle life of mid-tier Li-ion cells used in this segment. Compared to discrete op-amp ADCs, the LTC6811's integrated 5V LDO and GPIO reduce BOM count and PCB area in cost-sensitive e-mobility designs.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour LTC6811IG-1 — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | LTC6804IG-1#PBF | LTC6811IG-2#PBF | LTC6811HG-1#PBF | LTC6811IG-1#3ZZPBF | LTC6813IG-1#PBF |
|---|---|---|---|---|---|---|
| Package | 48-SSOP (IG) | 48-SSOP (IG) | 48-SSOP (IG) | 48-SSOP (HG) | 48-SSOP (IG) | 48-SSOP (IG) |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Cells Monitored | 12 | 12 | 12 | 12 | 12 | 18 |
| Communication | isoSPI daisy chain | isoSPI daisy chain | Parallel SPI multi-drop | isoSPI daisy chain | isoSPI daisy chain | isoSPI daisy chain |
| Total Measurement Error | < 1.2 mV | < 1.5 mV (Gen-3) | < 1.2 mV | < 1.2 mV | < 1.2 mV | < 1.2 mV |
| Sleep Current | 6 µA | ~30 µA | 6 µA | 6 µA | 6 µA | 6 µA |
| Temperature Grade | Industrial | Industrial | Industrial | Automotive extended | Automotive AEC-Q100 | Industrial |
| Generation | Gen-4 | Gen-3 | Gen-4 | Gen-4 | Gen-4 | Gen-4 |
Principaux différenciateurs
- Lowest sleep current in the LTC6811 family (vs LTC6804IG-1#PBF)
- Highest channel count in the SSOP-48 form factor (vs LTC6813IG-1#PBF)
- isoSPI daisy chain enables single-cable 1000V isolation (vs LTC6811IG-2#PBF)
Notes de conception
Place a 100 ohm/10 nF RC filter network on every cell input (C0-C12) as close to the LTC6811IG-1 pins as possible. Estimated: this filter combination limits input current to <5 mA during hot-plug events while providing ~10 kHz of noise rejection. Kelvin connections at the battery tap are mandatory - sharing the ground path with high-current traces will inject hundreds of millivolts of error and destroy the 1.2 mV accuracy budget.
Route the isoSPI pair (ISOP/ISOM and ISOSP/ISOSM) as a 100 ohm differential twisted pair with a pulse transformer within 50 mm of the LTC6811 pins. Keep the isoSPI traces away from switching power and gate-drive nodes; use a guard ground on either side. Terminate the cable end with the recommended 100 ohm/1 nF RC network per Analog Devices' DC2259A reference design to meet the 1 Mbps spec without reflections.
Estimated: at 5V cell voltage x 12 cells = 60V stack, the LTC6811 itself draws <50 mA from the stack (~3 mA active, 6 µA sleep), so self-heating is minimal at ~0.3 W worst case. However the 48-SSOP exposed pad requires a low-thermal-impedance connection to a top-layer copper pour of at least 1 square inch to keep theta_JA near the datasheet's 40 C/W. Without the exposed pad soldered, theta_JA can exceed 90 C/W.
Do not connect any cell input above 5V relative to V- or the LTC6811IG-1 will be damaged - use external resistor dividers only on the topmost cell, never exceed the absolute-maximum ratings. Do not skip the external EEPROM for storing calibration constants - the LTC6811 expects manufacturer-specific gain and offset values at boot. Also ensure the isoSPI pulse transformer has at least 4 kV hipot rating if the design needs IEC 60950 reinforced isolation.
Informations de conformité
RoHS/REACH compliant per Analog Devices product page (PBF suffix denotes lead-free). The LTC6811IG-1 itself is not AEC-Q100 qualified; the #3ZZPBF variant of the same die is. Choose that variant for automotive designs.
