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Texas Instruments BQ29411PW
- Part No.:
- BQ29411PW
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
BQ29411PW.pdf
- Description:
- IC BATT PROT LI-ION 2-4CL 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,366
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Product details
Overview
BQ29411PW from Texas Instruments is a secondary overvoltage protection IC for 2-, 3-, or 4-cell Li-ion battery packs, featuring fixed 4.40 V per-cell overvoltage threshold, <2 µA supply current, programmable delay via external capacitor on CD pin, and open-drain OUT pin for fuse-blowing control in notebook and portable instrumentation battery management systems.
For engineers reviewing the BQ29411PW datasheet, BQ29411PW pinout, BQ29411PW application, or BQ29411PW equivalent, this page delivers verified technical context, exact pin functions, real-world use scenarios, and validated alternative parts with documented functional differences for second-level Li-ion cell protection design.
Technical Context
The BQ29411PW implements precision voltage monitoring across up to four series-connected Li-ion cells using dedicated VC1–VC4 inputs, comparing each cell's voltage against an internal 4.40 V reference. An internal current source (0.18 µA) charges an external capacitor on the CD pin to generate a programmable delay before triggering protection.
Upon detection of any cell exceeding 4.40 V, the OUT pin transitions high (up to 2.5 V at 40 µA sink), enabling external N-channel FETs to blow a fuse in the positive battery rail. Recovery occurs only after all cell voltages fall below 4.40 V minus 320 mV hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Overvoltage Threshold | 4.40 V per cell - precise fixed trip point for second-level Li-ion protection, eliminating need for external resistor networks. |
| Supply Current | <2 µA - enables ultra-low-power operation in always-on battery pack monitoring without significant drain. |
| Delay Time Control | Programmable via CD pin capacitor (e.g., 0.22 µF → 1.5 s typical) - allows tuning of response time to avoid false triggers during transient charge spikes. |
| Input Voltage Range | VC pins: 0–25 V; differential cell range: 0–5 V - supports full operating window of 4-cell Li-ion stacks (0–16.8 V total). |
| Operating Temperature | –40°C to +110°C - qualified for industrial and portable equipment environments including hot battery compartments. |
| Overvoltage Accuracy | ±25 mV at 25°C, ±50 mV at –20°C to +85°C - ensures reliable margin above standard 4.2 V primary protection cutoff. |
| Hysteresis | 320 mV - prevents oscillation during recovery by requiring cell voltage to drop to 4.08 V before OUT deactivates. |
Pinout & Package
TSSOP-8 (PW) package, 3.0 mm × 4.4 mm, 1.2 mm max height, lead pitch 0.65 mm, RoHS-compliant NiPdAu finish, MSL Level-1 (260°C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VC1) | Most positive cell voltage sense | Connects to top of 4-cell stack (or shared with VDD in 2-/3-cell configs); must be wired first in sequence per datasheet. |
| 2 (VC2) | Second most positive cell sense | Inputs voltage between cells 1 and 2; used only in 3- or 4-cell configurations. |
| 3 (VC3) | Third most positive cell sense | Inputs voltage between cells 2 and 3; required for 4-cell operation, tied to VC2 in 3-cell mode. |
| 4 (GND) | Analog and power ground reference | Common return for all VC inputs, CD clamp, and OUT driver; requires low-impedance PCB connection. |
| 5 (VC4) | Least positive cell voltage sense | Connects to bottom of stack (cell 4 negative / cell 3 positive); tied to GND in 2-cell config. |
| 6 (CD) | Capacitor delay timing input | Internal 0.18 µA current source charges external capacitor; 1.2 V threshold triggers OUT activation. |
| 7 (VDD) | Power supply input | Accepts 4–25 V; powers internal circuitry; bypassed with 0.1 µF capacitor near pin per layout guidelines. |
| 8 (OUT) | Open-drain protection output | Drives external N-FET gate; sinks up to 1 mA; requires pull-up to VDD or higher rail for proper fuse-control logic. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 4.40 V overvoltage threshold | Eliminates calibration overhead and resistor tolerance drift in safety-critical secondary protection layer. |
| Programmable delay via CD pin | Enables system-specific immunity to charge-voltage transients without firmware or additional components. |
| High ripple rejection | Maintains stable detection under pulse charging or noisy DC-DC converter outputs common in portable systems. |
| Stable during pulse charge operation | Prevents nuisance tripping during fast-charge algorithms where cell voltage temporarily exceeds nominal limits. |
| Low 2 µA quiescent current | Extends shelf life and standby runtime in battery-powered devices with always-connected protection circuits. |
Applications
| Notebook Computer Battery Packs | Portable Instrumentation Power Systems |
|---|---|
Use Scenario: Monitors individual cell voltages in multi-cell Li-ion packs during AC charging and discharge cycles to prevent overvoltage damage. IC Role / Device Role / Timing Role: Second-level hardware protection device that activates only if primary charger fails to terminate at 4.2 V/cell. Use Value: Adds fail-safe redundancy with 4.40 V trip point and 320 mV hysteresis, ensuring cell integrity even during charger malfunction. | Use Scenario: Embedded in handheld test meters and data loggers with removable Li-ion battery modules requiring certified safety compliance. IC Role / Device Role / Timing Role: Standalone analog overvoltage detector with no MCU dependency, delivering deterministic response within programmable 1–2 s window. Use Value: Enables IEC 62133-compliant battery pack certification by providing independent, non-software-reliant protection layer. |
| Medical Portable Diagnostic Devices | Industrial Handheld Scanners |
Use Scenario: Integrated into sealed battery packs powering ultrasound probes and glucose monitors where thermal stress and long shelf life are critical. IC Role / Device Role / Timing Role: Low-power (<2 µA) voltage supervisor maintaining vigilance during multi-year storage without battery depletion. Use Value: Preserves battery state-of-charge during shelf life while guaranteeing immediate response to overvoltage events upon deployment. | Use Scenario: Used in warehouse barcode scanners operating in wide ambient temperatures (–20°C to +60°C) with frequent hot-swap battery usage. IC Role / Device Role / Timing Role: Robust cell monitor tolerant to voltage transients during battery insertion/removal and ESD-prone environments. Use Value: Prevents field failures due to contact bounce or connector arcing by rejecting short-duration spikes via internal filtering and hysteresis. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar secondary overvoltage protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ29412PW | 4.45 V overvoltage threshold vs. BQ29411PW's 4.40 V; otherwise identical pinout, specs, and timing. | Suitable for higher-voltage Li-ion chemistries (e.g., LiCoO₂ variants with extended charge profiles) requiring tighter margin above 4.2 V. | Select BQ29412PW only when system-level validation confirms safe operation at 4.45 V per cell without compromising cycle life. |
| BQ29410PW | 4.35 V overvoltage threshold; same package, pinout, and electrical behavior otherwise. | Used in cost-sensitive or legacy designs where lower trip point provides wider safety margin for aging cells or temperature derating. | Choose BQ29410PW when primary protection has looser tolerance or battery chemistry exhibits higher voltage drift over lifetime. |
Compared with BQ29412PW and BQ29410PW, the BQ29411PW offers the industry-standard 4.40 V secondary threshold-optimized for mainstream 4.2 V/cell Li-ion systems needing balanced safety margin and longevity, without requiring layout changes or firmware updates.
Availability
BQ29411PW is available at Aetrix Electronics and suitable for notebook computer battery packs, portable instrumentation power systems, and medical diagnostic devices requiring stable component supply and long-term lifecycle support.
Supply support for BQ29411PW 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 high-reliability IC design.
The BQ2941x family was developed specifically for redundant, hardware-based overvoltage protection in multi-cell Li-ion battery packs-addressing safety certification requirements (UL 2054, IEC 62133) and eliminating single-point failure modes in portable energy systems.
FAQ
What is the exact overvoltage protection threshold of the BQ29411PW?
The BQ29411PW has a fixed, factory-trimmed overvoltage detection threshold of 4.40 V per cell, specified with ±25 mV accuracy at 25°C and ±50 mV over –20°C to +85°C. This value is not adjustable and applies identically across all VC1–VC4 inputs for 2-, 3-, or 4-cell configurations. The BQ29411PW datasheet confirms this threshold is part of the device's silicon characterization and does not require external calibration.
Can the BQ29411PW be used in a 2-cell Li-ion configuration?
Yes, the BQ29411PW supports 2-cell operation by connecting VC1 and VC2 to the top of the stack (VDD), VC3 to the midpoint, and VC4 to the bottom (GND). The datasheet explicitly defines this wiring sequence in Figure 5 and mandates correct connection order to prevent false triggering. All other electrical parameters-including 4.40 V threshold, <2 µA ICC, and CD delay functionality-remain fully valid in 2-cell mode.
How is the overvoltage delay time set on the BQ29411PW?
The BQ29411PW delay time is set by an external capacitor connected to the CD pin, charged by an internal 0.18 µA current source. Delay = (1.2 V × CDELAY) / 0.18 µA; for example, a 0.22 µF capacitor yields ~1.5 s typical delay. The BQ29411PW datasheet specifies CD pin voltage threshold at 1.2 V (typical) and validates this calculation across temperature and process corners.
Does the BQ29411PW require external components for basic operation?
Yes-the BQ29411PW requires at minimum an external capacitor on the CD pin to set delay time and a pull-up resistor on the OUT pin to drive the external N-channel FET gate. Additionally, a 0.1 µF ceramic capacitor is recommended between VDD and GND. These components are mandatory per the BQ29411PW functional block diagram and layout guidelines in the datasheet; omission risks unreliable protection activation or latch-up.
What is the maximum operating voltage for the VC pins on the BQ29411PW?
The VC1–VC4 pins of the BQ29411PW support an absolute maximum voltage of 28 V, with recommended operating range of 0–25 V. Differential voltage between adjacent VC pins (e.g., VC1–VC2) is limited to 0–5 V, aligning with standard 4-cell Li-ion stack voltages (max 16.8 V total). This rating is confirmed in the Absolute Maximum Ratings table of the BQ29411PW datasheet and validated across temperature.
BQ29411PW 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:
- -40°C ~ 110°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
BQ29411PW FAQ
1.How can I place an order for BQ29411PW through Aetrix?
Please submit a Request for Quotation (RFQ) for BQ29411PW 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 BQ29411PW reliable?
The price and inventory of BQ29411PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ29411PW is usually 5 days.
3.What payment methods are accepted for BQ29411PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BQ29411PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BQ29411PW?
BQ29411PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BQ29411PW 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 BQ29411PW?
For technical support, including BQ29411PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ29411PW requirements.
6.How does Aetrix verify that BQ29411PW is sourced from the original manufacturer or authorized distributors?
All BQ29411PW 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 BQ29411PW meets industry standards.
7.What is the process for return or replacement of BQ29411PW?
All BQ29411PW units undergo pre-shipment inspection (PSI). If there is an issue with BQ29411PW, 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 BQ29411PW part is unused and in its original packaging.
Return procedure for BQ29411PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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