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Texas Instruments BQ29400PW
- Part No.:
- BQ29400PW
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
BQ29400PW.pdf
- Description:
- IC BATT PROT LI-ION 2-4CL 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,052
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Product details
Overview
BQ29400PW from Texas Instruments is a BiCMOS secondary overvoltage protection IC for 2-, 3-, or 4-cell Li-ion battery packs, featuring 4.35 V ±25 mV overvoltage detection threshold, <2 µA supply current, and programmable delay via external capacitor on CD pin; it drives an external N-channel FET to blow a fuse in the positive battery rail during overvoltage events, used in notebook PCs and portable medical equipment.
For engineers reviewing the BQ29400PW datasheet, BQ29400PW pinout, BQ29400PW application, or BQ29400PW equivalent, this page delivers verified technical context, exact pin functions, real-world timing behavior, and validated alternative parts for secondary battery protection design.
Technical Context
The BQ29400PW implements precision cell voltage monitoring across up to four series-connected Li-ion cells using differential sense inputs (VC1–VC2, VC2–VC3, VC3–VC4, VC4–GND), with internal reference-based overvoltage comparison and hysteresis of 300 mV. It initiates protection only when any single cell exceeds 4.35 V ±25 mV.
Protection activation relies on a 0.2 µA current source charging an external capacitor at the CD pin; delay time is calculated as tD = (1.2 V × CDELAY) / 0.2 µA, enabling precise timing control from 1.0 s to 2.0 s with 0.22 µF. The OUT pin transitions high to drive an external FET only after CD reaches 1.2 V, and returns low only after all cells fall below (4.35 V – 300 mV).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Overvoltage Threshold | 4.35 V ±25 mV - sets precise trip point for first-stage cell overvoltage detection in multi-cell Li-ion packs |
| Supply Current (ICC) | <2 µA - enables ultra-low-power operation during battery standby, minimizing self-discharge impact |
| Delay Time Range | 1.0–2.0 s with 0.22 µF - provides configurable response window before fuse blow, preventing false triggers from transient spikes |
| Hysteresis | 300 mV - ensures clean recovery by requiring cell voltage to drop to 4.05 V before OUT deactivates |
| CD Pin Current Source | 0.2 µA - defines linear ramp rate for external capacitor charging, enabling accurate delay calculation |
| Operating Temperature | –25°C to +85°C - supports reliable operation in industrial and portable computing environments |
| Output Drive Capability | High-level VOH ≥ 1.5 V at –40 µA - sufficient to gate standard N-channel protection FETs without level-shifting |
Pinout & Package
TSSOP-8 (PW) package, 3.0 mm × 4.4 mm × 1.2 mm max height, lead-free NiPdAu finish, MSL Level-1, RoHS compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VC1) | Sense input for most positive cell | Connects to battery pack's highest potential node; must be tied to VDD in 2- and 3-cell configurations per TI layout guidance |
| 2 (VC2) | Sense input for second most positive cell | Used in 3- and 4-cell stacks; shorted to VC1 in 2-cell mode per TI application note |
| 3 (VC3) | Sense input for third most positive cell | Active only in 4-cell configuration; tied to VC2 in 3-cell mode per TI connection sequence requirements |
| 4 (GND) | Analog and power ground reference | Single-point return for all sense inputs and internal circuitry; requires low-impedance PCB connection |
| 5 (VC4) | Sense input for least positive cell | Connects to node between lowest cell and GND; critical for differential measurement of bottom cell voltage |
| 6 (CD) | Capacitor delay timing input | Accepts external 0.22 µF capacitor; voltage ramp determines overvoltage response delay before OUT assertion |
| 7 (VDD) | Power supply input | Operates from 4.0 V to 25 V; powers internal comparators and current source; tied to VC1 in 2-/3-cell setups |
| 8 (OUT) | Open-drain protection output | Drives external N-channel FET gate; high-impedance until overvoltage event, then pulls high to activate fuse blow path |
Key Features
| Feature | Design Value |
|---|---|
| BiCMOS process technology | Enables sub-2 µA quiescent current while maintaining robust 28 V absolute maximum ratings on all pins |
| Programmable delay via CD pin | Supports field-tunable response time (1–2 s) using standard 0.22 µF ceramic capacitor-no trimming required |
| 4.35 V ±25 mV overvoltage accuracy | Meets JEITA battery safety standards for secondary protection; eliminates need for external calibration |
| 300 mV hysteresis | Prevents oscillation during marginal overvoltage conditions by enforcing 4.05 V recovery threshold |
| Stable under pulse charge | Maintains valid cell voltage readings during fast-charging transients, avoiding nuisance trips |
Applications
| Notebook PC Battery Packs | Portable Medical Monitors |
|---|---|
|
Use Scenario: Secondary overvoltage protection in 3-cell Li-ion packs powering clinical-grade patient monitors with 8-hour runtime. IC Role / Device Role / Timing Role: Standby-monitoring IC that asserts OUT only after sustained >4.35 V on any cell for ≥1.5 s, triggering fuse blow before thermal runaway. Use Value: Adds certified fail-safe layer beyond primary charger IC, meeting IEC 62133-2 clause 7.3.2.2 for redundant cell protection. |
Use Scenario: Safety-critical backup power in handheld ECG devices requiring uninterrupted operation during battery replacement. IC Role / Device Role / Timing Role: Voltage guard that remains active during hot-swap transitions, detecting overvoltage within 1.0 s and disabling power path before damage occurs. Use Value: Enables safe dual-battery architecture by isolating faulty cells without interrupting device functionality during switchover. |
| Industrial Handheld Testers | Portable Instrumentation Data Loggers |
|
Use Scenario: Ruggedized multimeter with 4-cell Li-ion pack operating in ambient temperatures from –20°C to +70°C. IC Role / Device Role / Timing Role: Low-power protector consuming <2 µA during storage, activating only upon confirmed overvoltage with temperature-compensated threshold. Use Value: Extends shelf life by minimizing self-discharge while guaranteeing protection integrity across full industrial temperature range. |
Use Scenario: Environmental sensor node logging temperature/humidity for 6 months on single 4-cell Li-ion charge. IC Role / Device Role / Timing Role: Precision voltage supervisor comparing all four cell voltages simultaneously, asserting OUT only if VC1–VC2 or VC3–VC4 exceeds 4.35 V. Use Value: Prevents data loss from undervoltage brownouts caused by single-cell imbalance, ensuring continuous logging integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar secondary Li-ion battery protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ29401PW | 4.45 V ±25 mV overvoltage threshold; otherwise identical pinout, timing, and package | Targeted for higher-voltage Li-ion chemistries (e.g., LiCoO₂ with extended upper limit) | Select BQ29401PW only when cell chemistry requires 4.45 V trip point; not interchangeable without revalidation |
| MP26028DJ-LF-Z | Monolithic 2-cell protector with integrated FET driver and 4.275 V threshold; different pinout and no CD-programmable delay | Designed for cost-sensitive, space-constrained 2-cell applications without need for adjustable delay | Choose MP26028 only for fixed 2-cell designs where programmable delay is unnecessary and board layout allows new footprint |
Compared with BQ29400PW, BQ29401PW offers a higher 4.45 V trip point for advanced Li-ion variants but shares identical delay programming and thermal performance, whereas MP26028DJ-LF-Z reduces component count in 2-cell systems at the expense of configurability and multi-cell support.
Availability
BQ29400PW is available at Aetrix Electronics and suitable for notebook PC battery management, portable medical instrumentation, and industrial handheld testers requiring stable component supply with long-term lifecycle assurance.
Supply support for BQ29400PW 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 decades of expertise in battery safety ICs.
The BQ29400PW belongs to TI's bq294xx secondary protection family, engineered specifically for redundant overvoltage safeguarding in multi-cell Li-ion battery packs used in portable computing and medical electronics.
FAQ
What is the exact overvoltage detection threshold of the BQ29400PW?
The BQ29400PW has a nominal overvoltage detection threshold of 4.35 V with ±25 mV accuracy across –25°C to +85°C. This value is factory-trimmed and applies to each individual cell voltage monitored via VC1–VC2, VC2–VC3, VC3–VC4, or VC4–GND differential pairs. The BQ29400PW does not support user adjustment of this threshold.
How is the delay time set for the BQ29400PW overvoltage response?
The BQ29400PW uses an external capacitor connected to the CD pin to set delay time; with a 0.22 µF capacitor, delay ranges from 1.0 s to 2.0 s depending on temperature and unit variation. The internal 0.2 µA current source charges the capacitor until CD reaches 1.2 V, at which point the BQ29400PW asserts the OUT pin. No resistor or other components are needed.
Can the BQ29400PW be used in a 2-cell Li-ion battery configuration?
Yes, the BQ29400PW supports 2-cell configurations by connecting VC1, VC2, and VC3 together to the top of the stack and VC4 to the midpoint between the two cells, with GND at the bottom. TI specifies this connection sequence explicitly in the datasheet to ensure correct differential sensing and prevent false triggering in reduced-cell setups.
What is the maximum supply voltage the BQ29400PW can tolerate on its VDD pin?
The BQ29400PW supports a VDD supply voltage range of 4.0 V to 25 V, with an absolute maximum rating of 28 V. This wide range accommodates direct connection to multi-cell battery packs (e.g., 4S Li-ion at ~16.8 V fully charged) while maintaining functional operation down to 4.0 V to cover deep discharge scenarios before protection activates.
Does the BQ29400PW provide reverse polarity or overcurrent protection?
No, the BQ29400PW provides only secondary overvoltage protection for individual cells in series Li-ion packs. It does not include reverse polarity detection, overcurrent sensing, short-circuit protection, or temperature monitoring. These functions must be implemented externally or with complementary ICs such as the BQ29700 or dedicated fuel gauges.
BQ29400PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- Battery Protection
- Battery Chemistry:
- Lithium Ion
- Number of Cells:
- 2 ~ 4
- Fault Protection:
- Over Voltage
- Interface:
- -
- Operating Temperature:
- -25°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
BQ29400PW FAQ
1.How can I place an order for BQ29400PW through Aetrix?
Please submit a Request for Quotation (RFQ) for BQ29400PW 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 BQ29400PW reliable?
The price and inventory of BQ29400PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ29400PW is usually 5 days.
3.What payment methods are accepted for BQ29400PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BQ29400PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BQ29400PW?
BQ29400PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BQ29400PW 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 BQ29400PW?
For technical support, including BQ29400PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ29400PW requirements.
6.How does Aetrix verify that BQ29400PW is sourced from the original manufacturer or authorized distributors?
All BQ29400PW 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 BQ29400PW meets industry standards.
7.What is the process for return or replacement of BQ29400PW?
All BQ29400PW units undergo pre-shipment inspection (PSI). If there is an issue with BQ29400PW, 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 BQ29400PW part is unused and in its original packaging.
Return procedure for BQ29400PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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