My Inquiry
My Account
Texas Instruments BQ20851DBTR-V1P2
- Part No.:
- BQ20851DBTR-V1P2
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- -
- Datasheet:
-
BQ20851DBTR-V1P2.pdf
- Description:
- IC SUPERVISOR PWR SUP SUPPORT
- Quantity:
- Payment:
- Shipping:
Inventory:4,000
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
BQ20851DBTR-V1P2 from Texas Instruments is a Smart Battery Specification (SBS) v1.1-compliant fuel gauge IC for Li-ion/Li-polymer battery packs. It performs coulomb counting via a self-calibrating 16-bit integrating ADC (≤1-µV offset, <3-nVh resolution), measures voltage/temperature with a 16-bit delta-sigma ADC, and interfaces with the bq29311 AFE over glueless analog links and SMBus 2.0 for full pack electronics in 10.8-V/14.4-V notebook battery systems.
For engineers reviewing the BQ20851DBTR-V1P2 datasheet, BQ20851DBTR-V1P2 pinout, BQ20851DBTR-V1P2 application, or BQ20851DBTR-V1P2 equivalent, this page delivers verified functional role, real-world accuracy specs (e.g., ±1-µV offset, 3-nVh resolution), SMBus timing compliance (10–100 kHz), LED display drive capability (3–5 segments), and integration constraints with bq29311 AFE - all critical for smart battery firmware validation and hardware co-design.
Technical Context
The BQ20851DBTR-V1P2 implements dual-path sensing: an integrating ADC on SR1/SR2 pins continuously samples battery current with <1-µV offset error and better than 3-nVh resolution for precise coulomb counting, while a separate 16-bit delta-sigma ADC digitizes VIN (cell voltage via bq29311), TS (NTC thermistor), and internal temperature sensor outputs. Its RISC CPU executes programmable cell modeling using 512 bytes of flash-stored coefficients (e.g., TS Const1–Const4) to correct RM register values for temperature, rate, and aging effects.
Operation is synchronized via an integrated 32.768-kHz oscillator (±2% frequency error, 275-µs start-up) bias-controlled by ROSC pin; CLKOUT drives bq29311; SMBus 2-wire interface (SMBC/SMBD) handles SBS command exchange (e.g., RemainingCapacity, FullChargeCapacity, VCELL1–VCELL4); DISP pin controls LED segment activation; SAFE provides safety-level output for fuse control or external shutdown.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 3.0–3.6 V (VDDA/VDDD); powers analog/digital domains independently |
| Current Measurement | Integrating ADC with ≤1-µV offset, <3-nVh resolution, −0.3 to +1.0 V input range on SR1/SR2 |
| Voltage/Temperature ADC | 16-bit delta-sigma converter for VIN, TS, and internal temp; updates every second |
| SMBus Interface | 2-wire open-drain, 10–100 kHz clock; supports SBS v1.1 commands including RemainingCapacity, VCELL1–VCELL4 |
| Internal Oscillator | 32.768 kHz ±2% accuracy; no external crystal required; ROSC pin sets bias |
| LED Drive | 5-segment push-pull outputs (LED1–LED5); supports 20%/25%/33% capacity increments |
| Operating Temp | −20°C to +85°C; self-discharge compensation scales per Table 4 (e.g., 2× at 35°C vs. 25°C) |
| Data Retention | 10 years for 512-byte flash memory storing nominal capacity, voltage, self-discharge rate, and cell-modeling coefficients |
Pinout & Package
38-pin TSSOP (DBT) package with exposed thermal pad; pin-compatible with other bq2085x family members. Pin functions validated per SLUS575 Rev. A (August 2003) Terminal Functions table.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Cell voltage input | Accepts single-cell voltage from bq29311 VCELL pin; used for voltage reporting and EDV threshold detection |
| TS | Temperature sense input | Connects to NTC thermistor (e.g., Semitec 103AT) or internal sensor; enables temperature-compensated self-discharge and capacity correction |
| SR1 / SR2 | Current sense differential inputs | Monitor voltage across 10–20 mΩ sense resistor; enable coulomb counting with <1-µV offset and <3-nVh resolution |
| LED1–LED5 | LED segment drivers | Push-pull outputs driving external LEDs; DISP pin selects 3-/4-/5-segment display mode for remaining capacity indication |
| SMBC / SMBD | SMBus interface | Open-drain bidirectional clock/data lines compliant with SMBus 2.0 (10–100 kHz); support SBS v1.1 command set |
| SAFE | Safety output | Active-high signal for secondary protection (e.g., fuse blow); asserted during overvoltage, undervoltage, or thermal fault |
| CLKOUT | Oscillator output | 32.768-kHz clock fed to bq29311; eliminates need for external crystal in AFE/gauge pair |
| RBI | Register backup supply | Accepts capacitor or battery input to retain data registers during low-VDD conditions (e.g., pack removal) |
Key Features
| Feature | Design Value |
|---|---|
| Self-calibrating integrating ADC | Autocalibrates offset down to ≤1 µV when SMBus idle ≥20 s; eliminates manual calibration in production |
| Programmable cell modeling | 512-byte flash stores 7+ coefficients (e.g., TS Const1–Const4) to adapt capacity estimation to specific Li-ion chemistry and aging |
| Glueless AFE interface | Direct analog links (CLKOUT, SCLK, SDATA, EVENT, SAFE) with bq29311 eliminate level shifters and reduce BOM count |
| Voltage-based capacity correction | Applies RM register corrections at EDV0/EDV1/EDV2 thresholds and VOC25/VOC50/VOC75 midrange points for improved SOC accuracy |
| Low-power operation | 1 µA hibernate current; 350 µA active current; extends battery runtime during gauge monitoring |
| Qualified discharge learning | Updates FullChargeCapacity only after verified discharge (e.g., ≥FCC–Near Full to EDV2, no charge activity, temp stable) to prevent FCC drift |
Applications
| Notebook PC Battery Packs | Enterprise Tablet Smart Batteries |
|---|---|
Use Scenario: Integrated fuel gauge in removable 3S/4S Li-ion packs for Windows/Linux laptops with SMBus host communication. IC Role / Device Role / Timing Role: Primary gas gauge IC performing real-time coulomb counting, voltage/temperature sampling, and SBS-compliant data reporting to EC/BIOS. Use Value: Enables accurate remaining runtime prediction (<5% error over full cycle) and prevents premature shutdown via EDV2-triggered capacity correction. |
Use Scenario: High-reliability battery management in ruggedized tablets used in field service and healthcare environments. IC Role / Device Role / Timing Role: Core capacity estimator interfaced with bq29311 AFE; uses internal temp sensor and programmable self-discharge model for extended shelf-life accuracy. Use Value: Maintains ±2% SOC accuracy after 6-month storage at 25°C by applying temperature-scaled self-discharge compensation from flash-stored coefficients. |
| Medical Portable Monitor Packs | Industrial Handheld Scanner Batteries |
Use Scenario: UL-certified battery packs for portable ECG and vital sign monitors requiring fail-safe low-voltage cutoff. IC Role / Device Role / Timing Role: Safety-critical fuel gauge providing SAFE output assertion and Cell Under Voltage shutdown coordination with bq29311. Use Value: Guarantees shutdown before cell voltage drops below 2.75 V (Cell Under Voltage threshold), preventing irreversible Li-ion damage. |
Use Scenario: Drop-in smart battery modules for barcode scanners operating in warehouses with wide ambient temperature swings (−10°C to +60°C). IC Role / Device Role / Timing Role: Adaptive capacity estimator using temperature-compensated self-discharge (Table 4) and midrange VOC corrections to maintain accuracy across thermal cycles. Use Value: Delivers consistent 20%/25%/33% LED capacity steps despite daily thermal cycling, reducing user-reported "jumping" SOC behavior. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fuel gauge applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ2084DBTR-V1P2 | Same pinout and core architecture; lacks internal oscillator - requires external 32.768-kHz crystal | Higher BOM cost and PCB area due to crystal + load caps; identical SBS v1.1 register map and flash programming flow | Select when legacy designs already include crystal or when tighter oscillator tolerance (<±1%) is required via external source |
| BQ20Z75-V150 | Enhanced 32-bit RISC core; supports SBS v1.1 + v1.2; adds SHA-1 authentication; 2 kB flash; higher SMBus speed (up to 400 kHz) | Enables secure battery authentication and longer-term firmware extensibility; not drop-in - requires updated host driver and flash configuration | Select for new designs requiring cryptographic security, extended data logging, or future-proofing beyond SBS v1.1 |
Compared with BQ20851DBTR-V1P2, BQ2084DBTR-V1P2 increases system cost and layout complexity due to external timing, while BQ20Z75-V150 introduces architectural upgrades (security, speed, memory) that necessitate firmware redesign but deliver long-term scalability.
Availability
BQ20851DBTR-V1P2 is available at Aetrix Electronics and suitable for notebook PC battery packs, medical portable monitor batteries, enterprise tablet smart batteries, and industrial handheld scanner batteries requiring stable component supply and long-lifecycle support.
Supply support for BQ20851DBTR-V1P2 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor company specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and battery management ICs.
The BQ20851DBTR-V1P2 belongs to TI's Smart Battery Fuel Gauge product line, designed specifically for high-accuracy Li-ion/Li-polymer capacity estimation in portable computing and medical devices using SBS v1.1 compliance and integrated AFE co-design.
FAQ
What is the primary function of the BQ20851DBTR-V1P2 in a smart battery system?
The BQ20851DBTR-V1P2 serves as the core fuel gauge IC in SBS v1.1-compliant smart battery packs. It performs real-time coulomb counting using a self-calibrating integrating ADC, measures cell voltage and temperature via delta-sigma conversion, stores and applies programmable cell-modeling coefficients in 512-byte flash, and reports RemainingCapacity, FullChargeCapacity, and VCELL1–VCELL4 over SMBus. Its design centers on delivering <5% end-of-discharge capacity error in notebook and medical battery applications when paired with the bq29311 AFE.
Does the BQ20851DBTR-V1P2 require an external crystal oscillator?
No, the BQ20851DBTR-V1P2 integrates a 32.768-kHz oscillator with ±2% frequency accuracy, eliminating the need for an external crystal. The ROSC pin connects to an 113-kΩ ±0.1% resistor to ground (VSSA) to bias the internal oscillator. This oscillator drives the CLKOUT pin, which synchronizes the bq29311 AFE - enabling a crystal-free, glueless AFE/gauge solution that reduces BOM count and PCB area.
How does the BQ20851DBTR-V1P2 achieve high-accuracy coulomb counting?
The BQ20851DBTR-V1P2 achieves high-accuracy coulomb counting through a dedicated 16-bit integrating ADC on SR1/SR2 pins, featuring ≤1-µV offset error and better than 3-nVh resolution. It performs continuous sampling of the sense-resistor voltage (10–20 mΩ), supports autocalibration when SMBus is idle ≥20 s, and applies digital filtering to suppress noise below programmable thresholds. These capabilities enable sub-1% accumulated charge error over full discharge cycles in notebook battery applications.
Can the BQ20851DBTR-V1P2 operate with an internal temperature sensor instead of an external NTC thermistor?
Yes, the BQ20851DBTR-V1P2 can be configured to use its internal temperature sensor by setting bit 7 of Misc Configuration (DF 0x2a) and updating TS Const1–Const4 flash locations (DF 0xa4–0xad) to zero or prescribed internal-sensor values. This mode eliminates the NTC circuit but trades off absolute accuracy (±3°C typical) for reduced component count - suitable for applications where relative temperature trends matter more than absolute measurement, such as shelf-life self-discharge modeling.
What safety features does the BQ20851DBTR-V1P2 provide in coordination with the bq29311 AFE?
The BQ20851DBTR-V1P2 coordinates safety functions with the bq29311 AFE via dedicated pins: SAFE (active-high output for fuse blow or secondary shutdown), EVENT (input from bq29311 XALERT), and SCLK/SDATA (analog control links). It triggers SAFE during detected overvoltage, undervoltage (EDV0/EDV1/EDV2), or thermal faults, and initiates coordinated shutdown when Cell Under Voltage (<2.75 V) is reached - ensuring Li-ion cells remain within safe operating limits and preventing permanent damage or thermal runaway.
BQ20851DBTR-V1P2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- -
- Battery Chemistry:
- -
- Number of Cells:
- -
- Fault Protection:
- -
- Interface:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
BQ20851DBTR-V1P2 FAQ
1.How can I place an order for BQ20851DBTR-V1P2 through Aetrix?
Please submit a Request for Quotation (RFQ) for BQ20851DBTR-V1P2 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for BQ20851DBTR-V1P2 reliable?
The price and inventory of BQ20851DBTR-V1P2 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ20851DBTR-V1P2 is usually 5 days.
3.What payment methods are accepted for BQ20851DBTR-V1P2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BQ20851DBTR-V1P2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BQ20851DBTR-V1P2?
BQ20851DBTR-V1P2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BQ20851DBTR-V1P2 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for BQ20851DBTR-V1P2?
For technical support, including BQ20851DBTR-V1P2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ20851DBTR-V1P2 requirements.
6.How does Aetrix verify that BQ20851DBTR-V1P2 is sourced from the original manufacturer or authorized distributors?
All BQ20851DBTR-V1P2 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BQ20851DBTR-V1P2 meets industry standards.
7.What is the process for return or replacement of BQ20851DBTR-V1P2?
All BQ20851DBTR-V1P2 units undergo pre-shipment inspection (PSI). If there is an issue with BQ20851DBTR-V1P2, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The BQ20851DBTR-V1P2 part is unused and in its original packaging.
Return procedure for BQ20851DBTR-V1P2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BQ20851DBTR-V1P2 Tags
-
BQ29700DSER
Texas Instruments
-
S-8241ABKMC-GBKT2G
ABLIC Inc.
-
S-8241ABPMC-GBPT2G
ABLIC Inc.
-
BQ27427YZFR
Texas Instruments
-
BQ27426YZFR
Texas Instruments
-
STC3117IJT
STMicroelectronics
-
STC3115IJT
STMicroelectronics
-
BQ76925RGER
Texas Instruments
-
NPM1100-QDAA-R
Nordic Semiconductor ASA
-
BQ27441DRZR-G1A
Texas Instruments
-
STC3115AIQT
STMicroelectronics
-
S-8252AAL-M6T1U
ABLIC Inc.
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
