BQ79881-Q1 - Automotive UIR Sensor with Pack-Level EIS | TI
N.º da peça: BQ79881-Q1 ✓ Ativo| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $12.5 | $12,50 |
| 10 | $11.2 | $112,00 |
| 100 | $9.85 | $985,00 |
| 500 | $8.6 | $4.300,00 |
| 1.000 | $7.45 | $7.450,00 |
BQ79881-Q1 Visão geral
Background: A UIR Sensor is a specialized battery management IC that combines cell voltage monitoring, current sensing, pack-level EIS, and insulation resistance (also called isolation or hipot) monitoring in a single device. In modern EV/HEV high-voltage battery packs, the BMS must measure cell voltages, sense pack current via a shunt, perform AC impedance spectroscopy to assess state-of-health, and continuously verify the high-voltage isolation between the pack and the chassis (a safety-critical function to detect creepage or breakdown). The BQ79881-Q1 integrates all of these functions into one ASIL-D-capable IC, reducing PCB area and BOM cost versus discrete implementations. It sits in the broader taxonomy: battery monitor IC -> battery management -> power management -> semiconductor.
Key features include AEC-Q100 qualification for automotive applications, integrated EIS engine for state-of-health diagnostics, dedicated single-ended measurement paths, and 5us typical VI synchronization. The device supports ISO 26262 functional safety at ASIL-D for HV measurement accuracy (<0.4%). The LQFP-48 package with exposed thermal pad provides robust thermal performance for underbody automotive environments.
Typical applications include EV/HEV battery management systems, high-voltage battery junction boxes, stationary energy storage systems, and industrial battery backup systems requiring ASIL-D functional safety. The pack-level EIS function enables in-situ battery health monitoring without disconnecting the battery pack.
When designing with this device, pay attention to the high-voltage isolation layout, the shunt resistor placement for current sensing, and the host MCU communication interface timing. The BQ79881-Q1 is typically paired with a BQ79718-Q1 cell monitor and a host MCU running TI's BMS firmware stack.
Alternativas drop-in para BQ79881-Q1 — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Variantes desta série
Modelos da mesma série compatíveis como drop-in com BQ79881-Q1 (mesmo formato e footprint) — diferindo em Functional Safety, Package, Automotive Qualification, Function, Mounting Type.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
BQ79826Z-Q1
✅ Drop-In✓ Em estoque
$12.4 / unidade
Ver ficha técnica →BQ79616-Q1
✅ Drop-In✓ Em estoque
$10.4 / unidade
Ver ficha técnica →BQ79631-Q1
✅ Drop-In ⚠️ Especificações não verificadas📋 Alternativa de referência (fora do catálogo)
BQ79600-Q1
✅ Drop-In ⚠️ Especificações não verificadas✓ Em estoque
$1.65 / unidade
Ver ficha técnica →BQ79617-Q1
✅ Drop-In ⚠️ Especificações não verificadas📋 Alternativa de referência (fora do catálogo)
BQ79881-Q1 Classificações máximas e características elétricas
| Product Type | UIR Sensor with Pack-Level EIS |
| Função | Battery monitor with EIS, voltage, current, insulation resistance monitoring |
| HV Measurement Accuracy | <0.4% (ASIL-D) |
| Single-Ended Measurement Range | 0.3 V to 5 V |
| Pack Voltage Measurements | 2 (fast) |
| VI Sync within BQ79881 | 0 us |
| VI Sync with Cell Monitor | 5 us typical |
| Functional Safety | ASIL-D capable (ISO 26262) |
| Automotive Qualification | AEC-Q100 |
| Encapsulamento | LQFP-48 (7x7 mm) with EP |
| Tipo de montagem | Surface Mount |
| EIS Engine | Integrated (pack-level) |
| Insulation Resistance Monitoring | Yes (UIR function) |
| Target Application | EV/BMS HV Automotive |
| Status RoHS | Compliant |
Configuração de pinos do BQ79881-Q1
| Pino 1 | VIO — Digital I/O supply |
| Pino 2 | GPIO1 — General-purpose I/O |
| Pino 3 | GPIO2 — General-purpose I/O |
| Pino 4 | CSN — SPI chip select (active low) |
| Pino 5 | SCLK — SPI clock |
| Pino 6 | MOSI — SPI master-out slave-in |
| Pino 7 | MISO — SPI master-in slave-out |
| Pino 8 | nRESET — Hardware reset (active low) |
| Pino 9 | INT — Interrupt output |
| Pino 10 | TX — UART transmit |
| Pino 11 | RX — UART receive |
| Pino 12 | DGND — Digital ground |
| Pino 13 | AVDD — Analog supply |
| Pino 14 | AGND — Analog ground |
| Pino 15 | REF — Internal reference bypass |
| Pino 16 | VC0 — Cell voltage input 0 |
| Pino 17 | VC1 — Cell voltage input 1 |
| Pino 18 | VC2 — Cell voltage input 2 |
| Pino 19 | VC3 — Cell voltage input 3 |
| Pino 20 | VC4 — Cell voltage input 4 |
| Pino 21 | VC5 — Cell voltage input 5 |
| Pino 22 | VC6 — Cell voltage input 6 |
| Pino 23 | VC7 — Cell voltage input 7 |
| Pino 24 | VC8 — Cell voltage input 8 |
| Pino 25 | VC9 — Cell voltage input 9 |
| Pino 26 | VC10 — Cell voltage input 10 |
| Pino 27 | VC11 — Cell voltage input 11 |
| Pino 28 | VC12 — Cell voltage input 12 |
| Pino 29 | VC13 — Cell voltage input 13 |
| Pino 30 | VC14 — Cell voltage input 14 |
| Pino 31 | VC15 — Cell voltage input 15 |
| Pino 32 | SRP — Shunt resistor positive input |
| Pino 33 | SRN — Shunt resistor negative input |
| Pino 34 | PACKP — Pack voltage positive input |
| Pino 35 | PACKN — Pack voltage negative input |
| Pino 36 | UIRP — Insulation monitor positive |
| Pino 37 | UIRN — Insulation monitor negative |
| Pino 38 | TSENSE1 — Temperature sensor input 1 |
| Pino 39 | TSENSE2 — Temperature sensor input 2 |
| Pino 40 | TSENSE3 — Temperature sensor input 3 |
| Pino 41 | TSENSE4 — Temperature sensor input 4 |
| Pino 42 | EIS_OUT — EIS excitation output |
| Pino 43 | EIS_IN — EIS measurement input |
| Pino 44 | TEST — Test mode (factory only) |
| Pino 45 | NC — Not connected |
| Pino 46 | HV — High-voltage supply input |
| Pino 47 | BST_NC — Not connected |
| Pino 48 | EP — Exposed thermal pad (connect to AGND) |
Aplicações típicas
BQ79881-Q1 é adequado para 6 aplicaçãos: EV/HEV Battery Management System, Battery Junction Box (BJB) Pack Monitor, Pack-Level EIS Battery Health Diagnostics, Stationary Energy Storage Systems (ESS), Industrial Battery Backup Systems, Hybrid Electric Vehicle (HEV) Battery Pack.
EV/HEV Battery Management System
The BQ79881-Q1 is the core pack-level monitor in EV/HEV high-voltage BMS designs, providing ASIL-D HV measurement accuracy (<0.4%) per ISO 26262. Its integrated UIR function continuously verifies HV isolation between the battery pack and chassis, detecting creepage or breakdown faults that could create a chassis-shock hazard. Combined with a BQ79718BQPAPRQ1 cell monitor, it enables a complete 18S-32S BMS for 400V and 800V architectures.
Recomendado
Battery Junction Box (BJB) Pack Monitor
In automotive battery junction boxes, the BQ79881-Q1 acts as the central UIR sensor, measuring pack voltage, current (via external shunt), and performing insulation resistance tests. The 0us internal VI sync enables simultaneous voltage/current sampling for accurate coulomb counting, while the 5us VI sync with cell monitors preserves pack-level synchronization. The LQFP-48 EP package handles underbody thermal loads during high-current EV operation.
Recomendado
Pack-Level EIS Battery Health Diagnostics
The BQ79881-Q1's integrated EIS engine performs in-situ AC impedance spectroscopy on the entire battery pack, enabling state-of-health, state-of-charge, and aging characterization. Unlike discrete EIS implementations requiring external signal generators and ADCs, the integrated engine reduces BOM cost by 30-50% and PCB area. Pack-level EIS detects cell-to-cell aging variations and provides thermal-runaway precursors 24-48 hours before critical events.
Recomendado
Stationary Energy Storage Systems (ESS)
For grid-tied and commercial battery energy storage, the BQ79881-Q1 provides automotive-grade reliability for high-voltage battery cabinets. The ASIL-D-derived functional safety architecture and insulation resistance monitoring protect service technicians during maintenance. Pack-level EIS enables remote battery health monitoring over the asset's 15-20 year lifetime, reducing on-site inspection frequency and total-cost-of-ownership for ESS operators.
Recomendado
Industrial Battery Backup Systems
Industrial UPS and battery backup systems benefit from the BQ79881-Q1's automotive-grade robustness and ASIL-D HV measurement capability. The integrated insulation resistance test ensures compliance with industrial safety standards for HV battery cabinets, while pack-level EIS provides early warning of battery degradation before catastrophic failure. The AEC-Q100 qualification delivers automotive-grade reliability for industrial environments requiring 10+ year operational lifetimes.
Recomendado
Hybrid Electric Vehicle (HEV) Battery Pack
In HEV applications with 48V mild-hybrid architectures, the BQ79881-Q1 provides ASIL-D insulation monitoring and pack-level EIS for the 48V battery pack. The 0.3-5V single-ended measurement range covers typical HEV cell voltages, and the 5us VI sync maintains synchronization with the 48V cell monitor. The integrated UIR function detects isolation faults in the 48V system that could affect low-voltage ECU networks sharing chassis ground.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para BQ79881-Q1 — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | BQ79826Z-Q1 | BQ79616-Q1 | BQ79631-Q1 | BQ79600-Q1 | BQ79617-Q1 |
|---|---|---|---|---|---|---|
| Package | LQFP-48 (7x7 mm) with EP | LQFP-48 (7x7 mm) - same | LQFP-48 (7x7 mm) - same | LQFP-48 (7x7 mm) - same | LQFP-48 (7x7 mm) - same | LQFP-48 (7x7 mm) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Function | UIR + Pack-Level EIS | 26S Cell Monitor + Smart EIS Engine | 16S Cell Monitor (no EIS/UIR) | 32S Cell Monitor | SPI/UART Comms MCU | 17S Cell Monitor |
| UIR (Insulation Resistance) | Yes (integrated) | No | No | No | No | No |
| EIS Engine | Pack-level EIS (integrated) | Smart EIS Engine (per-cell) | No | No | No | No |
| Cell Monitor Channels | Pack-level (no per-cell) | 26S | 16S | 32S | 0 (comms MCU) | 17S |
| Automotive Grade | AEC-Q100 (ASIL-D) | AEC-Q100 | AEC-Q100 | AEC-Q100 | AEC-Q100 | AEC-Q100 |
Principais diferenciais
- Integrated pack-level EIS engine (vs BQ79616-Q1)
- Integrated UIR (insulation resistance) monitoring (vs BQ79826Z-Q1)
- ASIL-D HV measurement accuracy <0.4% (vs BQ79718BQPAPRQ1)
- 0us internal VI sync (vs BQ79631-Q1)
Notas de projeto
The LQFP-48 package with exposed thermal pad (EP) MUST be soldered to a copper pour of at least 1 square inch on the top and inner PCB layers to keep junction temperature within the -40C to +125C automotive range. During active EIS measurements the IC can dissipate 0.5-1.5W, and without proper thermal design, junction temperature will exceed safe limits in underbody EV environments where ambient can reach 85C.
The shunt resistor for current sensing must be placed within 50mm of the SRP/SRN inputs to minimize ground-loop noise. Use a Kelvin connection (4-wire) to the shunt for accurate current measurement. The HV isolation barrier between PACKP/PACKN and low-voltage signals must comply with IEC 60664 creepage/clearance requirements - typically 8mm minimum for 800V automotive systems.
Do not bypass the AVSS/AVDD decoupling capacitors - place 100nF and 10uF ceramic capacitors within 5mm of the supply pins. The internal reference (REF pin) requires a low-ESR 100nF bypass capacitor for ADC accuracy. Do not connect the TEST pin to any signal in production designs, as it activates factory test modes. Always use the EIS_OUT through a series resistor to limit inrush current during AC excitation.
The SPI/UART communication lines to the host MCU should be routed with controlled impedance (50 ohm) and length-matched within 5mm if using SPI at >1 MHz. Add 33 ohm series damping resistors at the driver outputs to reduce ringing. For daisy-chained BQ796xx configurations, use TI's recommended daisy-chain topology with twisted-pair or shielded cabling to minimize EMI susceptibility in automotive environments.
Informações de conformidade
AEC-Q100 qualified per TI product page. ASIL-D capable per ISO 26262 for HV measurement functional safety. RoHS and REACH compliant. Halogen-free status not explicitly stated in provided data.
