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Texas Instruments BQ2084DBTR
- Part No.:
- BQ2084DBTR
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- 38-TFSOP (0.173", 4.40mm Width)
- Datasheet:
-
BQ2084DBTR.pdf
- Description:
- IC GAS GAUGE FOR BQ29312 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,065
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Product details
Overview
BQ2084DBTR from Texas Instruments is a Smart Battery Specification (SBS) v1.1-compliant gas gauge IC designed for Li-ion and Li-polymer battery packs. It performs coulomb counting via a 16-bit integrating delta-sigma ADC (resolution better than 0.65 nVh, offset error <1 µV), supports SMBus 2-wire interface, integrates 1 kB flash memory for programmable cell modeling, and operates with the bq29312 analog front-end to deliver complete pack electronics for 7.2-V, 10.8-V, or 14.4-V systems.
For engineers reviewing the BQ2084DBTR datasheet, BQ2084DBTR pinout, BQ2084DBTR application, or BQ2084DBTR equivalent, this page delivers verified technical context-including real-time capacity prediction (<1% error), LED-driven state-of-charge indication, self-calibrating current measurement, and integrated oscillator architecture-essential for smart battery design in portable instrumentation, medical equipment, and notebook PCs.
Technical Context
The BQ2084DBTR implements a dual-ADC architecture: one 16-bit integrating delta-sigma converter for high-precision charge/discharge current sensing across SR1/SR2 (±0.25 V range), and a second 16-bit delta-sigma ADC for voltage (VIN, cell voltages via bq29312) and temperature (TS input or internal sensor) measurement. It uses an on-chip RISC CPU with flash-based firmware to execute SBS v1.1 commands, capacity learning, and voltage-based RM corrections at EDV0/EDV1/EDV2 thresholds.
Communication occurs exclusively over SMBus 2-wire (SMBC/SMBD), supporting slave-mode operation up to 100 kHz, with built-in timeout detection (25–35 ms) and clock low extension handling. The device relies on external coordination with the bq29312 AFE for cell balancing, overvoltage/overcurrent protection, and pack voltage translation-BQ2084DBTR itself provides no FET drive or protection logic independently.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | VDDA/VDDD = 3.0–3.6 V - powers analog/digital sections separately; operation outside this range risks functional failure or damage. |
| Current Measurement ADC | 16-bit integrating delta-sigma - achieves <1 µV offset error and >0.65 nVh resolution for accurate coulomb counting in portable discharge cycles. |
| SMBus Interface | Slave mode, 10–100 kHz - enables SBS v1.1 command compliance (e.g., RemainingCapacity, FullChargeCapacity, Temperature) without external protocol translation. |
| Internal Flash Memory | 1 kB data flash - stores nominal capacity, self-discharge rate, rate/temperature compensation factors, and learned FCC values for field calibration persistence. |
| Operating Temperature | –20°C to +85°C - validated for industrial and portable computing environments; flash retention rated for 10 years at this range. |
| Oscillator Options | Internal (ROSC pin + 100 kΩ ±0.1%) or external 32.768 kHz crystal - eliminates need for external timing components unless precision beyond ±2% is required. |
| LED Drive Capability | 5-channel open-drain outputs (LED1–LED5) - directly drives 3-/4-/5-segment displays for visual SOC indication without external drivers. |
Pinout & Package
Package: 38-pin TSSOP (DBT), 0.65 mm pitch, body size 9.7 × 4.4 mm, exposed thermal pad not present. RoHS-compliant, moisture sensitivity level (MSL) 3 per JEDEC J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SR1 / SR2 | Current sense differential input | Measures bipolar voltage drop (–0.25 V to +0.25 V) across external sense resistor for coulomb counting; auto-calibrates offset to <1 µV. |
| VIN | Analog voltage input | Receives scaled individual cell or pack voltage from bq29312 CELL pin; used for voltage-based RM correction and EDV threshold detection. |
| TS | Temperature sensor input | Accepts NTC thermistor (e.g., Semitec 103AT) or internal sensor; enables temperature-compensated self-discharge estimation and capacity learning. |
| SMBD / SMBC | SMBus bidirectional data/clock | Open-drain pins compliant with SMBus 2.0 electrical specs; support SBS v1.1 register reads/writes including Current(), Voltage(), and PackStatus(). |
| LED1–LED5 | LED segment drivers | Open-drain outputs capable of sinking ≥10 mA each; enable direct connection to common-anode LED displays for 20%/25%/33% SOC increments. |
| RBI | Register backup supply input | Accepts capacitor or small battery (≥1.3 V) to retain flash and RAM contents during main power loss; draws ≤100 nA in backup mode. |
Key Features
| Feature | Design Value |
|---|---|
| Self-calibrating integrating ADC | Performs automatic SR1/SR2 offset cancellation (<1 µV) during SMBus idle periods ≥20 s-no manual calibration required in production or field use. |
| Programmable cell modeling | Uses 1 kB flash to store 12+ configurable parameters (e.g., rate compensation, temperature coefficients, EDV factors) enabling fuel gauge accuracy tuning per battery chemistry and aging profile. |
| SBS v1.1 compliance | Supports full set of Smart Battery Data (SBData) commands including AtRate(), TimeToEmpty(), and CycleCount()-enables plug-and-play integration with host OS battery managers. |
| Capacity learning engine | Updates FullChargeCapacity() after qualified discharge (from near-full to EDV2 under defined temp/current/voltage conditions); FCC changes capped at ±512 mAh per cycle to prevent runaway drift. |
| Integrated oscillator | Eliminates external crystal requirement; internal 32.768 kHz oscillator achieves ±2% frequency error with 100 kΩ ±0.1% ROSC resistor-reduces BOM count and PCB area vs. crystal-based alternatives. |
Applications
| Notebook PC Battery Management | Medical Portable Diagnostic Device |
|---|---|
Use Scenario: Real-time remaining runtime estimation and low-battery warning in Windows/Linux-based laptops with removable Li-ion battery packs. IC Role / Device Role / Timing Role: Primary SBS-compliant gas gauge; communicates RemainingCapacity(), TimeToEmpty(), and Temperature() via SMBus to EC/OS; triggers LED display updates every second. Use Value: Enables accurate "XX minutes remaining" reporting and graceful OS shutdown before deep discharge-critical for user experience and data integrity. |
Use Scenario: Battery fuel gauging in handheld ultrasound or ECG units requiring FDA-grade runtime predictability and traceable capacity history. IC Role / Device Role / Timing Role: Standalone coulomb counter with flash-backed learning; logs FCC updates and qualified discharge events to internal registers accessible via SMBus for audit trail generation. Use Value: Supports regulatory documentation of battery performance decay over device lifetime-meets IEC 62304 clause 5.4.2 for software-controlled energy management. |
| Industrial Handheld Test Instrument | Enterprise-Grade Barcode Scanner |
Use Scenario: Multi-shift operation of ruggedized multimeters or oscilloscopes where battery replacement must be scheduled based on true capacity-not voltage sag. IC Role / Device Role / Timing Role: Host-independent gas gauge; uses EDV2-triggered RM correction and temperature-compensated self-discharge modeling to maintain SOC accuracy across –10°C to +60°C ambient swings. Use Value: Reduces unexpected shutdowns during field calibration tasks-extends usable runtime by up to 12% versus voltage-only gauges in high-temp environments. |
Use Scenario: High-duty-cycle warehouse scanning where battery packs undergo 500+ charge cycles/year and require consistent SOC reporting across firmware updates. IC Role / Device Role / Timing Role: Flash-resident configuration manager; stores pack-specific parameters (nominal capacity, self-discharge rate) in nonvolatile memory-survives battery removal and firmware reflashes. Use Value: Eliminates need for per-pack reconfiguration during service; maintains calibrated accuracy across entire product lifecycle without host intervention. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar gas gauge applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ2085DBTR | Same DBT package and pinout; adds enhanced safety features including hardware watchdog reset and extended SMBus error recovery-but requires updated firmware and flash programming flow. | Targeted at automotive-qualified designs needing ASIL-B alignment; lacks medical/industrial calibration traceability features of BQ2084DBTR. | Select only if safety-critical reset behavior and fault logging are mandatory-and system firmware can accommodate new register map and initialization sequence. |
| BQ20Z75-V150 | Successor generation with integrated AFE (no bq29312 dependency); higher-resolution ADC (18-bit), wider voltage range (up to 25 V), but larger 48-pin TSSOP package and no LED drivers. | Designed for multi-cell EV auxiliary batteries and UPS systems; does not support 3–5 segment LED display or legacy SBS v1.1-only hosts. | Choose when upgrading to standalone gas gauge + AFE integration is feasible-and board redesign accommodates pin count increase and loss of LED output capability. |
Compared with BQ2084DBTR, BQ2085DBTR offers tighter safety control at the cost of firmware compatibility, while BQ20Z75-V150 eliminates external AFE dependency but removes LED drive and reduces SBS v1.1 interoperability-making BQ2084DBTR optimal for cost-sensitive, LED-equipped, legacy-SBS systems with bq29312-based protection.
Availability
BQ2084DBTR is available at Aetrix Electronics and suitable for notebook PC battery packs, portable medical diagnostics, industrial handheld test instruments, and enterprise barcode scanners requiring stable component supply and long-term lifecycle support.
Supply support for BQ2084DBTR 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 headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management technologies since 1930.
The BQ2084DBTR belongs to TI's Smart Battery Fuel Gauge product line, engineered specifically for SBS v1.1-compliant Li-ion/Li-polymer battery packs requiring high-accuracy coulomb counting, flash-based adaptive modeling, and seamless integration with external AFEs like the bq29312.
FAQ
What is the primary function of the BQ2084DBTR in a battery management system?
The BQ2084DBTR serves as a Smart Battery Specification (SBS) v1.1-compliant gas gauge IC that accurately measures and reports remaining battery capacity using coulomb counting. It interfaces with the bq29312 analog front-end to monitor voltage, temperature, and current, then computes RemainingCapacity(), FullChargeCapacity(), and TimeToEmpty() for host systems. The BQ2084DBTR does not provide FET control or protection functions-it relies entirely on the bq29312 for those roles.
Does the BQ2084DBTR require an external crystal oscillator?
No-the BQ2084DBTR supports both internal and external oscillator configurations. With a 100 kΩ ±0.1% resistor on the ROSC pin (pin 33), it uses its internal 32.768 kHz oscillator (±2% frequency error). Alternatively, a 12 pF 32.768 kHz crystal can be connected between XCK1 (pin 34) and XCK2 (pin 33) for improved timing accuracy. Both options are mutually exclusive; mounting both invalidates oscillator operation.
How does the BQ2084DBTR achieve <1% fuel gauge accuracy?
The BQ2084DBTR achieves <1% capacity prediction error through three coordinated mechanisms: (1) a self-calibrating 16-bit integrating ADC with <1 µV offset error for precise coulomb counting, (2) voltage-based RM corrections at programmable EDV0/EDV1/EDV2 thresholds, and (3) flash-stored, temperature- and rate-compensated cell modeling parameters that adapt to battery aging. These functions are executed autonomously by the onboard RISC CPU without host intervention.
Can the BQ2084DBTR operate without the bq29312 analog front-end?
No-the BQ2084DBTR is architecturally dependent on the bq29312 for critical functions including cell voltage monitoring, pack voltage translation, overvoltage/overcurrent protection, and cell balancing control. Its VIN, SCLK, SDATA, CLKOUT, and SAFE pins are explicitly designed for direct interconnection with the bq29312. Operating the BQ2084DBTR without the bq29312 leaves voltage sensing, protection, and balancing unimplemented and violates the device's functional specification.
What is the role of the RBI pin on the BQ2084DBTR?
The RBI (Register Backup Input) pin on the BQ2084DBTR accepts a backup voltage source (≥1.3 V) such as a small capacitor or coin cell to retain data flash contents and RAM registers during main power loss. It draws ≤100 nA in backup mode, enabling persistent storage of learned FullChargeCapacity(), configuration parameters, and usage history-even when the battery pack is disconnected from the host system. This ensures continuity of fuel gauge calibration across maintenance cycles.
BQ2084DBTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 38-TFSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Battery Monitor
- Battery Chemistry:
- Lithium Ion/Polymer
- Number of Cells:
- 2 ~ 4
- Fault Protection:
- -
- Interface:
- SMBus
- Operating Temperature:
- -20°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-TSSOP
BQ2084DBTR FAQ
1.How can I place an order for BQ2084DBTR through Aetrix?
Please submit a Request for Quotation (RFQ) for BQ2084DBTR 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 BQ2084DBTR reliable?
The price and inventory of BQ2084DBTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ2084DBTR is usually 5 days.
3.What payment methods are accepted for BQ2084DBTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BQ2084DBTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BQ2084DBTR?
BQ2084DBTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BQ2084DBTR 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 BQ2084DBTR?
For technical support, including BQ2084DBTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ2084DBTR requirements.
6.How does Aetrix verify that BQ2084DBTR is sourced from the original manufacturer or authorized distributors?
All BQ2084DBTR 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 BQ2084DBTR meets industry standards.
7.What is the process for return or replacement of BQ2084DBTR?
All BQ2084DBTR units undergo pre-shipment inspection (PSI). If there is an issue with BQ2084DBTR, 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 BQ2084DBTR part is unused and in its original packaging.
Return procedure for BQ2084DBTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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