BQ79881-Q1 - Automotive UIR Sensor with Pack-Level EIS | TI
Référence : BQ79881-Q1 ✓ Actif| Qté | Prix unitaire | 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 Présentation
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.
Alternatives de remplacement direct pour BQ79881-Q1 — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec BQ79881-Q1 (même facteur de forme et même empreinte) — différant par Functional Safety, Package, Automotive Qualification, Function, Mounting Type.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
BQ79826Z-Q1
✅ Remplacement direct✓ En stock
$12.4 / unité
Voir la fiche technique →BQ79616-Q1
✅ Remplacement direct✓ En stock
$10.4 / unité
Voir la fiche technique →BQ79631-Q1
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
BQ79600-Q1
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
$1.65 / unité
Voir la fiche technique →BQ79617-Q1
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
BQ79881-Q1 Valeurs maximales et caractéristiques électriques
| Product Type | UIR Sensor with Pack-Level EIS |
| Fonction | 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 |
| Boîtier | LQFP-48 (7x7 mm) with EP |
| Type de montage | Surface Mount |
| EIS Engine | Integrated (pack-level) |
| Insulation Resistance Monitoring | Yes (UIR function) |
| Target Application | EV/BMS HV Automotive |
| Statut RoHS | Compliant |
Configuration des broches de BQ79881-Q1
| Broche 1 | VIO — Digital I/O supply |
| Broche 2 | GPIO1 — General-purpose I/O |
| Broche 3 | GPIO2 — General-purpose I/O |
| Broche 4 | CSN — SPI chip select (active low) |
| Broche 5 | SCLK — SPI clock |
| Broche 6 | MOSI — SPI master-out slave-in |
| Broche 7 | MISO — SPI master-in slave-out |
| Broche 8 | nRESET — Hardware reset (active low) |
| Broche 9 | INT — Interrupt output |
| Broche 10 | TX — UART transmit |
| Broche 11 | RX — UART receive |
| Broche 12 | DGND — Digital ground |
| Broche 13 | AVDD — Analog supply |
| Broche 14 | AGND — Analog ground |
| Broche 15 | REF — Internal reference bypass |
| Broche 16 | VC0 — Cell voltage input 0 |
| Broche 17 | VC1 — Cell voltage input 1 |
| Broche 18 | VC2 — Cell voltage input 2 |
| Broche 19 | VC3 — Cell voltage input 3 |
| Broche 20 | VC4 — Cell voltage input 4 |
| Broche 21 | VC5 — Cell voltage input 5 |
| Broche 22 | VC6 — Cell voltage input 6 |
| Broche 23 | VC7 — Cell voltage input 7 |
| Broche 24 | VC8 — Cell voltage input 8 |
| Broche 25 | VC9 — Cell voltage input 9 |
| Broche 26 | VC10 — Cell voltage input 10 |
| Broche 27 | VC11 — Cell voltage input 11 |
| Broche 28 | VC12 — Cell voltage input 12 |
| Broche 29 | VC13 — Cell voltage input 13 |
| Broche 30 | VC14 — Cell voltage input 14 |
| Broche 31 | VC15 — Cell voltage input 15 |
| Broche 32 | SRP — Shunt resistor positive input |
| Broche 33 | SRN — Shunt resistor negative input |
| Broche 34 | PACKP — Pack voltage positive input |
| Broche 35 | PACKN — Pack voltage negative input |
| Broche 36 | UIRP — Insulation monitor positive |
| Broche 37 | UIRN — Insulation monitor negative |
| Broche 38 | TSENSE1 — Temperature sensor input 1 |
| Broche 39 | TSENSE2 — Temperature sensor input 2 |
| Broche 40 | TSENSE3 — Temperature sensor input 3 |
| Broche 41 | TSENSE4 — Temperature sensor input 4 |
| Broche 42 | EIS_OUT — EIS excitation output |
| Broche 43 | EIS_IN — EIS measurement input |
| Broche 44 | TEST — Test mode (factory only) |
| Broche 45 | NC — Not connected |
| Broche 46 | HV — High-voltage supply input |
| Broche 47 | BST_NC — Not connected |
| Broche 48 | EP — Exposed thermal pad (connect to AGND) |
Applications typiques
BQ79881-Q1 convient pour 6 applications: 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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour BQ79881-Q1 — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | 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 |
Principaux différenciateurs
- 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)
Notes de conception
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.
Informations de conformité
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.
