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Texas Instruments BQ29412DCT3R
- Part No.:
- BQ29412DCT3R
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- 8-LSSOP, 8-MSOP (0.110", 2.80mm Width)
- Datasheet:
-
BQ29412DCT3R.pdf
- Description:
- IC BATT PROT LI-ION 2-4CELL SM8
- Quantity:
- Payment:
- Shipping:
Inventory:1,575
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Product details
Overview
BQ29412DCT3R from Texas Instruments is a secondary overvoltage protection IC for 2-, 3-, or 4-cell Li-ion battery packs, featuring fixed 4.45 V per-cell overvoltage threshold, <2 µA supply current, and programmable delay via external capacitor on CD pin; used in notebook computers and portable instrumentation to prevent cell damage during charging.
For engineers reviewing the BQ29412DCT3R datasheet, BQ29412DCT3R pinout, BQ29412DCT3R application, or BQ29412DCT3R equivalent, this page delivers verified technical context, exact pin functions, real-world use scenarios, and validated alternative options for second-level battery safety design.
Technical Context
The BQ29412DCT3R implements precision voltage monitoring across up to four series-connected Li-ion cells using dedicated VC1–VC4 inputs, with internal reference accuracy of ±25 mV at 25°C and ±80 mV over –40°C to 110°C. It triggers protection only when any single cell exceeds 4.45 V, initiating a controlled delay via CD pin current source (0.18 µA) charging an external capacitor.
Upon CD pin voltage reaching 1.2 V, the open-drain OUT pin transitions high to activate an external N-channel FET for fuse blowing; recovery occurs only after all cells fall below 4.45 V – 320 mV hysteresis. The device operates from 4 V to 25 V supply and maintains stable operation during pulse-charge conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Overvoltage Threshold | 4.45 V per cell - precise fixed trip point for second-level protection against Li-ion overcharge. |
| Supply Current | <2 µA - ultra-low quiescent power enables long-term battery pack monitoring without significant drain. |
| Overvoltage Accuracy | ±80 mV over –40°C to 110°C - ensures reliable trip margin across industrial temperature range. |
| Delay Time Control | Programmable via CD pin and external capacitor (e.g., 0.22 µF yields 1–2 s delay) - allows tuning of response time to match system safety requirements. |
| Hysteresis | 320 mV - prevents oscillation during recovery by requiring cell voltage to drop significantly below trip point before reset. |
| Operating Voltage Range | 4 V to 25 V - supports full battery stack voltages up to 4-cell (17.8 V max nominal) with headroom for transients. |
| Cell Count Support | 2-, 3-, or 4-cell configurations - configurable via VC pin connections without external components. |
Pinout & Package
Package: SSOP-8 (DCT), 3.95 mm × 4.25 mm × 1.3 mm body, 0.65 mm pitch, RoHS-compliant SNBI lead finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VC1 | Sense input for most positive cell | Connects to top of battery stack; monitors highest-potential cell voltage. |
| VC2 | Sense input for second most positive cell | Monitors voltage between first and second cell in series string. |
| VC3 | Sense input for third most positive cell | Enables 3- or 4-cell monitoring; tied to VC2 for 2-cell configuration. |
| GND | Ground reference | System ground return for all internal circuits and voltage references. |
| VC4 | Sense input for least positive cell | Connects to bottom of stack (cell 4 cathode or cell 1 anode in 4S); defines lowest monitored node. |
| CD | Capacitor delay timing input | Internal 0.18 µA current source charges external capacitor; 1.2 V threshold triggers OUT activation. |
| VDD | Power supply input | Accepts 4–25 V; powers internal comparators and logic; decoupled with 0.1 µF capacitor. |
| OUT | Open-drain protection output | Drives external N-channel FET gate; sinks ≤5 µA low, sources ≤1 mA high (with pull-up). |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 4.45 V overvoltage threshold | Eliminates need for external resistor dividers or trimming; guarantees consistent trip point across production lots. |
| Programmable delay via CD pin | Enables system-specific response timing (e.g., 1.5 s delay avoids false trips during transient voltage spikes). |
| High ripple rejection | Stable operation under >100 mVpp supply ripple - critical for noisy battery management environments. |
| Stable during pulse charge | Maintains accurate monitoring even with intermittent high-current charging pulses that cause voltage droop/recovery. |
| Low-power shutdown mode | ICC < 2 µA enables multi-year operation on backup battery or parasitic cell monitoring without measurable drain. |
Applications
| Smartphone Battery Pack Protection | Notebook Computer Battery Management |
|---|---|
Use Scenario: Secondary overvoltage safeguard in 3-cell Li-ion packs where primary protection may fail or be bypassed during fast charging. IC Role / Device Role / Timing Role: Monitors individual cell voltages in real time and triggers irreversible fuse blow via OUT pin if any cell exceeds 4.45 V. Use Value: Prevents thermal runaway by enforcing hard voltage limit independent of host controller firmware or primary BMS decisions. |
Use Scenario: Redundant overvoltage detection in 4-cell laptop battery modules operating across –20°C to 60°C ambient. IC Role / Device Role / Timing Role: Acts as autonomous hardware-level watchdog, comparing VC1–VC4 inputs and asserting OUT after programmable CD delay. Use Value: Adds certified safety layer compliant with IEC 62133, enabling UL/CE certification without reliance on software-based checks. |
| Portable Medical Instrument Power | Industrial Handheld Scanner Battery |
Use Scenario: Safety-critical 2-cell Li-ion pack in FDA-regulated glucose meters requiring fail-safe charge termination. IC Role / Device Role / Timing Role: Senses VC1 and VC4 directly across two series cells; activates OUT within 1.5 s of overvoltage event. Use Value: Guarantees compliance with ISO 14971 risk management by providing deterministic, analog-based protection independent of microcontroller health. |
Use Scenario: Ruggedized 3-cell battery in warehouse barcode scanners subjected to repeated 0–50°C thermal cycling and vibration. IC Role / Device Role / Timing Role: Uses VC1–VC3 inputs to monitor each cell; tolerates 100 mVpp supply ripple from switching regulators. Use Value: Ensures field reliability over 5+ years by eliminating false trips during motor-driven load transients or RF interference. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar secondary overvoltage protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ29413DCTR | Higher 4.50 V overvoltage threshold; otherwise identical architecture, pinout, and timing behavior. | Suitable for higher-voltage Li-ion chemistries (e.g., LiCoO₂ with extended upper limit) but not drop-in for 4.45 V systems. | Select only if system requires tighter margin above standard 4.2 V nominal; verify cell chemistry compatibility. |
| MP26028DJ-LF-Z | Single-cell focused; integrates MOSFET driver and thermal shutdown; lacks multi-cell VC pin architecture. | Designed for 1S packs only; cannot monitor 2–4 series cells independently; no CD-programmable delay. | Use only for single-cell applications; not functionally equivalent for multi-cell battery packs. |
Compared with BQ29412DCT3R, BQ29413DCTR offers a +50 mV threshold for enhanced headroom in high-accuracy charging, while MP26028DJ-LF-Z provides integrated drive but sacrifices multi-cell monitoring capability - making BQ29412DCT3R uniquely suited for scalable 2–4S hardware-level redundancy.
Availability
BQ29412DCT3R is available at Aetrix Electronics and suitable for notebook computer battery packs, portable medical instruments, and industrial handheld scanners requiring stable component supply with guaranteed long-term traceability.
Supply support for BQ29412DCT3R 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 delivering analog and embedded processing solutions, with over 50 years of innovation in power management and battery safety ICs.
The bq2941x product line was designed specifically for hardware-based secondary overvoltage protection in multi-cell Li-ion battery packs, emphasizing precision, ultra-low power, and robustness in safety-critical portable applications.
FAQ
What is the exact overvoltage protection threshold of the BQ29412DCT3R?
The BQ29412DCT3R has a fixed, factory-trimmed overvoltage protection threshold of 4.45 V per cell, specified with ±80 mV accuracy over the full –40°C to 110°C operating temperature range. This value is unique to the BQ29412DCT3R variant and differs from other members of the bq2941x family such as BQ29410 (4.35 V) or BQ29413 (4.50 V). The BQ29412DCT3R does not support user adjustment of this threshold.
Can the BQ29412DCT3R be used in a 2-cell Li-ion configuration?
Yes, the BQ29412DCT3R supports 2-cell configurations by connecting VC1 and VC2 together to the top of the stack, VC4 to the bottom node, and leaving VC3 unconnected or tied to VC4. The device automatically adapts its monitoring window and maintains full accuracy. This configuration is explicitly validated in TI's application diagrams and requires no external components beyond the CD capacitor and OUT pull-up.
What is the function of the CD pin on the BQ29412DCT3R?
The CD pin on the BQ29412DCT3R hosts an internal 0.18 µA current source that charges an external capacitor to generate a programmable delay before OUT activation. When the CD pin voltage reaches 1.2 V, the protection sequence executes. A 0.22 µF capacitor yields a typical delay of 1–2 seconds. The CD pin also features an internal clamp that discharges the capacitor if overvoltage clears before timeout, preserving full delay for subsequent events.
Does the BQ29412DCT3R require external passive components for basic operation?
Yes, the BQ29412DCT3R requires three external components for functional operation: a 0.1 µF ceramic capacitor on VDD for supply decoupling, a timing capacitor on CD (e.g., 0.22 µF), and a pull-up resistor on OUT (typically 10 kΩ to VDD) to drive the external N-channel FET gate. No resistive dividers or calibration components are needed due to its direct cell-voltage sensing architecture.
Is the BQ29412DCT3R pin-compatible with other devices in the bq2941x family?
Yes, the BQ29412DCT3R is fully pin-compatible with all other bq2941x variants (e.g., BQ29410, BQ29413) in the same DCT or PW package, sharing identical pinout, electrical characteristics, and functional block diagram. The only difference is the factory-set overvoltage threshold - 4.45 V for BQ29412DCT3R - allowing direct substitution where that specific threshold is required.
BQ29412DCT3R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-LSSOP, 8-MSOP (0.110", 2.80mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- SM8
BQ29412DCT3R FAQ
1.How can I place an order for BQ29412DCT3R through Aetrix?
Please submit a Request for Quotation (RFQ) for BQ29412DCT3R 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 BQ29412DCT3R reliable?
The price and inventory of BQ29412DCT3R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ29412DCT3R is usually 5 days.
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Once your BQ29412DCT3R 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 BQ29412DCT3R?
For technical support, including BQ29412DCT3R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ29412DCT3R requirements.
6.How does Aetrix verify that BQ29412DCT3R is sourced from the original manufacturer or authorized distributors?
All BQ29412DCT3R 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 BQ29412DCT3R meets industry standards.
7.What is the process for return or replacement of BQ29412DCT3R?
All BQ29412DCT3R units undergo pre-shipment inspection (PSI). If there is an issue with BQ29412DCT3R, 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 BQ29412DCT3R part is unused and in its original packaging.
Return procedure for BQ29412DCT3R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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