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Texas Instruments BQ29740DSER
- Part No.:
- BQ29740DSER
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- 6-WFDFN
- Datasheet:
-
BQ29740DSER.pdf
- Description:
- LITHIUM-ION (LI-ION) AND LITHIUM
- Quantity:
- Payment:
- Shipping:
Inventory:2,909
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Product details
Overview
BQ29740DSER from Texas Instruments is a single-cell Li-ion/Li-polymer battery protection IC that integrates overvoltage (4.45 V), undervoltage (2.50 V), discharge overcurrent (100 mV), charge overcurrent (–100 mV), and short-circuit (300 mV) detection with factory-programmed thresholds and fixed timing delays (96 ms UVP, 8 ms OCD/OCC). It operates in NORMAL mode at 4 µA and supports zero-voltage charging for deeply depleted cells in portable power systems.
For engineers reviewing the BQ29740DSER datasheet, BQ29740DSER pinout, BQ29740DSER application, or BQ29740DSER equivalent, this device serves as a cost-effective, low-quiescent-current protector for space-constrained battery packs requiring precise, factory-set fault thresholds without external configuration circuitry.
Technical Context
The BQ29740DSER implements analog voltage sensing across external FETs to detect overcurrent conditions via differential VDS measurement on the V–/VSS node pair, with ±10 mV accuracy at 25°C and ±15 mV over –40°C to +85°C. Its dual gate-drive outputs (COUT and DOUT) independently control charge and discharge FETs using BAT-referenced CMOS-level signals.
It features a fixed internal oscillator driving programmable fault timers-96 ms over-discharge delay, 8 ms discharge/charge overcurrent delays, and 250 µs short-circuit response-with recovery timers (8 ms for UVP/OCC/OCD, 12 ms for OVP) initiating only after fault condition clearance. Zero-voltage charging activates when BAT–V– ≥ 1.7 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| OVP Threshold | 4.45 V ±10 mV at 25°C; triggers CHG FET disable to prevent cell damage during charging |
| UVP Threshold | 2.50 V ±50 mV at 25°C; disables DSG FET to avoid deep discharge and capacity loss |
| OCD Threshold | 100 mV ±10 mV at 25°C; detects excessive discharge current via V––VSS differential sensing |
| OCC Threshold | –100 mV ±10 mV at 25°C; monitors reverse current flow through CHG FET during overcharge events |
| SCD Threshold | 300 mV ±100 mV at 25°C; enables sub-millisecond load short-circuit shutdown using V––VSS sensing |
| Quiescent Current | 4 µA in NORMAL mode; ensures >1-year battery shelf life in always-connected portable devices |
| Operating Temp | –40°C to +85°C ambient; validated for consumer handheld and industrial battery pack environments |
Pinout & Package
The BQ29740DSER uses a 6-pin WSON (DSE) package measuring 1.50 mm × 1.50 mm × 0.75 mm, optimized for ultra-compact battery management layouts with exposed thermal pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| NC | No Connection | Electrically open; must remain unconnected to avoid unintended biasing or noise coupling |
| COUT | Charge FET Gate Drive Output | Drives CHG FET gate high (3.4–3.7 V) in normal operation; pulls low (≤0.5 V) during OCC/SCP faults |
| DOUT | Discharge FET Gate Drive Output | Drives DSG FET gate high (3.4–3.7 V); pulls low (≤0.5 V) during UVP/OCD/SCP faults |
| VSS | Ground Reference | Primary ground reference for all internal comparators, ADCs, and protection logic; connects to battery cell negative |
| BAT | Supply Input | Connects to battery pack positive terminal; powers internal circuitry and provides reference for COUT/DOUT drive levels |
| V– | Voltage Sense Node | Differential input (with VSS) for OCD, OCC, and SCD detection; interfaces with external 2.2 kΩ resistor to PACK– |
Key Features
| Feature | Design Value |
|---|---|
| Factory-programmed protection thresholds | Eliminates external resistor networks and configuration EEPROM; reduces BOM count and layout area by 30% vs. adjustable alternatives |
| ±5 mV typical OCP sensing accuracy | Enables precise current-limiting at <1 A with 10 mΩ sense resistors, minimizing power loss in compact battery packs |
| Zero-voltage charging support | Allows safe reactivation of fully depleted cells (BAT–V– ≥ 1.7 V) before enabling full charge cycles, extending usable battery life |
| 4 µA NORMAL mode current | Extends shelf life of sealed battery packs beyond 12 months without periodic maintenance or wake-up circuitry |
| 250 µs short-circuit response | Prevents thermal runaway in lithium cells by disabling DSG FET within one switching cycle of hard short detection |
Applications
| Tablet PCs | Mobile Handsets |
|---|---|
Use Scenario: Integrated into slim-profile tablet battery packs with single Li-ion cell and dual-MOSFET protection circuitry. IC Role / Device Role / Timing Role: Primary voltage/current protector monitoring cell voltage and FET VDS to enforce OVP/UVP/OCD limits with 96 ms UVP delay and 8 ms OCD delay. Use Value: Prevents irreversible capacity loss from over-discharge and thermal failure from short circuits while maintaining <4 µA standby drain. | Use Scenario: Embedded in smartphone battery modules where PCB space is constrained and zero-voltage recovery is required after deep discharge. IC Role / Device Role / Timing Role: Standalone protector managing CHG/DSG FETs via COUT/DOUT outputs; enables charging of 0 V cells once BAT–V– ≥ 1.7 V. Use Value: Restores functionality of accidentally drained batteries without requiring external boost circuitry or service intervention. |
| Handheld Data Terminals | Portable Medical Monitors |
Use Scenario: Used in ruggedized warehouse scanners with replaceable Li-ion battery packs subject to frequent high-current discharge pulses. IC Role / Device Role / Timing Role: Fault detector triggering DOUT low within 8 ms of 100 mV VDS threshold breach during motor-driven barcode scanning. Use Value: Maintains system uptime by preventing false trips during transient loads while ensuring fast shutdown during sustained overcurrent. | Use Scenario: Deployed in battery-powered ECG or pulse oximeter units requiring FDA-compliant safety margins and long shelf life. IC Role / Device Role / Timing Role: Safety-critical protector enforcing 4.45 V OVP and 2.50 V UVP with 12 ms/8 ms recovery timers to prevent hazardous cell states. Use Value: Meets IEC 62368-1 battery safety requirements with traceable, factory-set thresholds and no field-adjustable parameters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar battery protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ29733DSER | OVP = 4.40 V, UVP = 2.80 V, OCD = 120 mV, tUVPD = 20 ms | Better suited for higher UVP tolerance and faster UVP response in high-drain medical tools | Select BQ29733DSER when tighter over-discharge margin and quicker fault reaction are prioritized over zero-voltage charging capability |
| BQ29723DSER | OVP = 4.425 V, UVP = 2.50 V, OCD = 100 mV, tUVPD = 96 ms, OCC = –60 mV | Offers lower OCC threshold for enhanced charge-side fault sensitivity in USB-C PD applications | Choose BQ29723DSER when improved charge overcurrent detection resolution (–60 mV vs –100 mV) is critical for precision charging control |
Compared with BQ29740DSER, BQ29733DSER provides faster over-discharge response but lacks zero-voltage charging enablement, while BQ29723DSER improves charge overcurrent sensitivity at the expense of reduced short-circuit threshold margin (300 mV → 300 mV unchanged, but OCC shift affects overall fault hierarchy).
Availability
BQ29740DSER is available at Aetrix Electronics and suitable for tablet PCs, mobile handsets, and handheld data terminals requiring stable component supply with guaranteed long-term manufacturability and consistent factory programming.
Supply support for BQ29740DSER 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 leader specializing in analog, embedded processing, and power management technologies with over 50 years of innovation in battery management solutions.
The BQ297xx family was designed specifically for cost-sensitive, space-constrained single-cell Li-ion/Li-polymer battery packs in consumer electronics, delivering factory-configured protection without external components or firmware.
FAQ
What protection functions does the BQ29740DSER provide?
The BQ29740DSER provides overcharge protection (OVP at 4.45 V), over-discharge protection (UVP at 2.50 V), discharge overcurrent protection (OCD at 100 mV), charge overcurrent protection (OCC at –100 mV), and load short-circuit protection (SCD at 300 mV). All thresholds are factory-programmed and temperature-compensated, and each fault triggers dedicated timer-based responses before COUT or DOUT asserts low to disable the respective FET. The BQ29740DSER also supports zero-voltage charging initiation when BAT–V– ≥ 1.7 V.
What is the package type and pin configuration of the BQ29740DSER?
The BQ29740DSER uses a 6-pin WSON (DSE) package measuring 1.50 mm × 1.50 mm × 0.75 mm with an exposed thermal pad. Its pins are: NC (no connection), COUT (charge FET gate drive output), DOUT (discharge FET gate drive output), VSS (ground reference), BAT (battery positive supply input), and V– (differential voltage sense input for overcurrent detection). Pin 1 is NC, Pin 2 is COUT, Pin 3 is DOUT, Pin 4 is VSS, Pin 5 is BAT, and Pin 6 is V–, as confirmed in the official TI datasheet SLUSBU9I.
How does the BQ29740DSER implement zero-voltage charging?
The BQ29740DSER enables zero-voltage charging when the voltage difference between BAT and V– reaches or exceeds 1.7 V, allowing the COUT output to activate and permit charging of deeply depleted cells. This function is factory-enabled and requires no external configuration. Once activated, the BQ29740DSER monitors cell voltage and transitions to normal protection mode upon reaching safe operating thresholds. The BQ29740DSER does not regulate charging current or voltage-it only enables/disables the CHG FET based on sensed conditions.
What are the key timing parameters for fault detection in the BQ29740DSER?
The BQ29740DSER features fixed factory-programmed timing: overcharge detection delay (tOVPD) = 1 s, over-discharge detection delay (tUVPD) = 96 ms, discharge overcurrent detection delay (tOCDD) = 8 ms, charge overcurrent detection delay (tOCCD) = 8 ms, and short-circuit detection delay (tSCCD) = 250 µs. Recovery timers are 12 ms for OVP and 8 ms for UVP/OCC/OCD, beginning only after the fault condition clears. These values are immutable and verified per TI datasheet SLUSBU9I Rev. AUGUST 2024.
Can the BQ29740DSER be used with different MOSFET configurations?
Yes-the BQ29740DSER is designed to drive standard N-channel MOSFETs in both charge and discharge paths. Its COUT and DOUT outputs are BAT-referenced, supporting direct gate drive of high-side CHG and low-side DSG FETs without level-shifting circuitry. The BQ29740DSER senses overcurrent via V––VSS differential voltage, making it compatible with discrete FETs or integrated battery protection MOSFETs. Layout guidelines recommend 5 MΩ pull-down resistors from COUT/DOUT to PACK–/VSS for reliable FET turn-off.
BQ29740DSER Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- BQ297xx
- Package/Case:
- 6-WFDFN
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Battery Monitor
- Battery Chemistry:
- Lithium Ion/Polymer
- Number of Cells:
- 1
- Fault Protection:
- Over Current, Short Circuit
- Interface:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 6-WSON (1.5x1.5)
BQ29740DSER FAQ
1.How can I place an order for BQ29740DSER through Aetrix?
Please submit a Request for Quotation (RFQ) for BQ29740DSER 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 BQ29740DSER reliable?
The price and inventory of BQ29740DSER are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ29740DSER is usually 5 days.
3.What payment methods are accepted for BQ29740DSER?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BQ29740DSER transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BQ29740DSER?
BQ29740DSER orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BQ29740DSER 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 BQ29740DSER?
For technical support, including BQ29740DSER datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ29740DSER requirements.
6.How does Aetrix verify that BQ29740DSER is sourced from the original manufacturer or authorized distributors?
All BQ29740DSER 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 BQ29740DSER meets industry standards.
7.What is the process for return or replacement of BQ29740DSER?
All BQ29740DSER units undergo pre-shipment inspection (PSI). If there is an issue with BQ29740DSER, 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 BQ29740DSER part is unused and in its original packaging.
Return procedure for BQ29740DSER:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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