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Texas Instruments BQ29400ADCT3
- Part No.:
- BQ29400ADCT3
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- 8-LSSOP, 8-MSOP (0.110", 2.80mm Width)
- Datasheet:
-
BQ29400ADCT3.pdf
- Description:
- IC BATT PROT LI-ION 2-4CELL SM8
- Quantity:
- Payment:
- Shipping:
Inventory:3,937
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Product details
Overview
BQ29400ADCT3 from Texas Instruments is a BiCMOS secondary overvoltage protection IC for 2-, 3-, or 4-cell Li-ion battery packs, featuring 4.40 V ±25 mV precision overvoltage detection threshold, <2 µA quiescent current, and programmable delay via external capacitor on CD pin. It monitors individual cell voltages and triggers an open-drain OUT signal to activate an external fuse-blowing FET in notebook PC battery packs.
For engineers reviewing the BQ29400ADCT3 datasheet, BQ29400ADCT3 pinout, BQ29400ADCT3 application, or BQ29400ADCT3 equivalent, key selection criteria include second-level protection compliance, cell-count flexibility (2–4 series), low-power operation under battery standby, and compatibility with standard TSSOP-8 PCB footprints and thermal profiles.
Technical Context
The BQ29400ADCT3 implements independent voltage monitoring across up to four stacked cells using differential sense inputs (VC1–VC4), comparing each cell's voltage against a trimmed internal reference. Its overvoltage detection circuit includes 300 mV hysteresis to prevent chatter during recovery.
A precision 0.2 µA current source charges an external capacitor on the CD pin; when CD reaches 1.2 V, the OUT pin transitions high to initiate fuse blow. The device remains latched until all cell voltages fall below (V(PROTECT) – Vhys), ensuring robust fault containment.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VPROTECT | 4.40 V ±25 mV - precise second-level overvoltage trip point for each cell in multi-cell Li-ion packs |
| ICC | <2.0 µA - ultra-low supply current enabling years of standby operation on battery-backed systems |
| Vhys | 300 mV - fixed hysteresis prevents oscillation during voltage recovery after overvoltage event |
| tD1 | 1.0–2.0 s (with 0.22 µF CD cap) - externally programmable delay ensures immunity to transient spikes |
| VDD Range | 4.0 V to 25 V - supports full operating range of 2–4 cell Li-ion packs (8.4 V to 16.8 V nominal) |
| Input Voltage Range | –0.3 V to 28 V per VC pin - withstands reverse-bias and surge conditions during pack assembly or fault |
| OUT Drive | High-level output ≥1.5 V at –40 µA - sufficient to drive gate of N-channel fuse-control FET |
Pinout & Package
Package: 8-pin TSSOP (PW) / MSOP (DCT), 3.0 mm × 4.4 mm body, 0.65 mm pitch, 1.2 mm max height, RoHS-compliant Pb-free CU SNBI finish, JEDEC MO-153 / MO-187 compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VC1 | Sense input (most positive cell) | Connects to top of stack; enables monitoring of highest-potential cell in 2–4 series configuration |
| VC2 | Sense input (second most positive) | Used in 3- or 4-cell mode; tied to VC1 in 2-cell mode per TI connection sequence guidance |
| VC3 | Sense input (third most positive) | Active only in 4-cell mode; shorted to VC2 in 3-cell mode per TI application note |
| GND | Analog/digital ground reference | Common return for all sense inputs and internal circuitry; must be low-impedance path to pack negative |
| VC4 | Sense input (least positive cell) | Connects to node between lowest cell and pack GND; critical for bottom-cell overvoltage detection |
| VDD | Power supply input | Connected to pack positive rail; powers internal circuitry and provides bias for OUT driver |
| OUT | Open-drain output | Drives external N-channel FET gate; high-impedance when idle, pulled high during overvoltage fault |
| CD | Capacitor delay timing input | Accepts external 0.22 µF capacitor; voltage ramp determines programmable fault response delay |
Key Features
| Feature | Design Value |
|---|---|
| Cell-count agnostic architecture | Supports 2-, 3-, or 4-cell configurations via pin-strapping (VCx tie-offs), eliminating need for multiple BOM variants |
| Programmable overvoltage delay | Delay time set by single external capacitor (0.22 µF typical), enabling tuning for system-specific surge immunity |
| High ripple rejection | Stable operation under pulse charging waveforms without false triggering, verified per TI test conditions |
| Low-power fault retention | Maintains latch state with <2.5 µA ICC during fault condition, preserving battery charge during extended faults |
| Robust ESD protection | Qualified per JEDEC JS-001 Class 2 (2 kV HBM); requires conductive foam handling per TI notice |
Applications
| Notebook PC Battery Packs | Portable Medical Devices |
|---|---|
Use Scenario: Secondary protection layer in multi-cell Li-ion battery modules used in business-class laptops with fast-charge capability. IC Role / Device Role / Timing Role: Second-level overvoltage monitor that activates only if primary protection fails, preventing thermal runaway during AC adapter overvoltage events. Use Value: Adds fail-safe redundancy with <2 µA quiescent draw, extending shelf life and meeting UL 2054/IEC 62133 secondary protection requirements. | Use Scenario: Battery management in portable ultrasound or infusion pumps requiring certified safety margins and long field service life. IC Role / Device Role / Timing Role: Standby-mode cell voltage supervisor that initiates irreversible fuse blow upon sustained overvoltage, satisfying IEC 60601-1 leakage and fault isolation mandates. Use Value: Enables Class II medical device certification via deterministic, non-software-dependent hardware fault response with 300 mV hysteresis margin. |
| Industrial Handheld Testers | High-Accuracy Portable DMMs |
Use Scenario: Power management in ruggedized multimeters and oscilloscope probes powered by removable Li-ion packs. IC Role / Device Role / Timing Role: Cell-balancing-agnostic overvoltage detector that operates independently of pack BMS firmware, guarding against charger malfunction. Use Value: Eliminates need for microcontroller-based supervision; reduces BOM count while maintaining 4.40 V ±25 mV accuracy across –25°C to 85°C ambient. | Use Scenario: Precision digital multimeters with rechargeable battery packs used in calibration labs and field service. IC Role / Device Role / Timing Role: Hardware-enforced voltage ceiling that prevents cell degradation during overnight charging or lab power supply misconfiguration. Use Value: Preserves battery cycle life by limiting maximum cell voltage to 4.40 V with ±25 mV tolerance, directly traceable to TI's production test data. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar secondary overvoltage protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ29401DCT3 | Higher VPROTECT = 4.45 V ±25 mV; identical pinout, timing, and quiescent current | Targeted for higher-voltage Li-ion chemistries (e.g., LiCoO2 with extended voltage range) | Select when system requires tighter margin above 4.40 V nominal charge termination |
| BD1400GUL | Single-cell focused (max 2S), 4.25 V threshold, 1.5 µA ICC, different 6-pin WLCSP package | Limited to 2-cell stacks; lacks VC3/VC4 inputs and programmable CD delay | Consider only for space-constrained 2S designs where delay programming is unnecessary |
Compared with BQ29400ADCT3, BQ29401DCT3 offers a +50 mV overvoltage threshold for enhanced cell longevity in high-accuracy charging systems, while BD1400GUL trades multi-cell flexibility and delay programmability for ultra-small footprint and lower quiescent current in dedicated 2S applications.
Availability
BQ29400ADCT3 is available at Aetrix Electronics and suitable for notebook PC battery packs, portable medical instrumentation, and industrial handheld testers requiring stable component supply with long-lifecycle support.
Supply support for BQ29400ADCT3 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, delivering analog, embedded processing, and logic products for industrial, automotive, and personal electronics markets.
The BQ29400ADCT3 belongs to TI's battery management IC portfolio, designed specifically to provide hardware-based secondary protection for multi-cell Li-ion battery packs in safety-critical portable equipment.
FAQ
What is the exact overvoltage protection threshold voltage of the BQ29400ADCT3?
The BQ29400ADCT3 has a factory-trimmed overvoltage detection threshold of 4.40 V ±25 mV per cell, specified over the full operating temperature range of –25°C to 85°C. This value is confirmed in TI's SLUS568C datasheet Electrical Characteristics table and applies identically to all four sense inputs (VC1–VC4) when used in 2-, 3-, or 4-cell configurations. The BQ29400ADCT3 does not support user adjustment of this threshold.
How is the delay time programmed on the BQ29400ADCT3?
The BQ29400ADCT3 delay time is programmed by connecting an external capacitor between the CD pin and GND. With a 0.22 µF capacitor, the delay is 1.0–2.0 seconds, calculated as tD = (1.2 V × CDELAY) / 0.2 µA. The BQ29400ADCT3 uses an internal 0.2 µA current source to charge the capacitor; no resistor or additional components are required. TI validates this behavior in Figure 2 of the SLUS568C datasheet.
Can the BQ29400ADCT3 be used in a 2-cell Li-ion battery pack?
Yes, the BQ29400ADCT3 supports 2-cell configurations by connecting VC1, VC2, and VC3 together to the positive terminal of the top cell, and VC4 to the junction between the two cells. TI specifies this wiring in Figure 7 and the APPLICATION INFORMATION section of SLUS568C. The BQ29400ADCT3 maintains full overvoltage detection accuracy and delay functionality in 2-cell mode without performance degradation.
What is the function of the OUT pin on the BQ29400ADCT3?
The OUT pin on the BQ29400ADCT3 is an open-drain output that transitions from high-impedance to ~1.5 V (min) at –40 µA when an overvoltage condition is confirmed. It drives the gate of an external N-channel MOSFET to blow a fuse in the battery's positive rail. The BQ29400ADCT3 holds OUT active until all monitored cell voltages fall below (4.40 V – 300 mV), providing latched fault signaling without software intervention.
Is the BQ29400ADCT3 recommended for new designs?
No, the BQ29400ADCT3 is marked "Not Recommended for New Designs" (NRND) by Texas Instruments per their 2017 Packaging Addendum. TI continues manufacturing it to support existing customers but advises migration to newer alternatives like the BQ296xxx family for new projects. Aetrix Electronics maintains inventory and supply continuity for legacy BQ29400ADCT3 deployments in fielded equipment.
BQ29400ADCT3 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:
- Obsolete
- 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:
- SM8
BQ29400ADCT3 FAQ
1.How can I place an order for BQ29400ADCT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for BQ29400ADCT3 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 BQ29400ADCT3 reliable?
The price and inventory of BQ29400ADCT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ29400ADCT3 is usually 5 days.
3.What payment methods are accepted for BQ29400ADCT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BQ29400ADCT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BQ29400ADCT3?
BQ29400ADCT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BQ29400ADCT3 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 BQ29400ADCT3?
For technical support, including BQ29400ADCT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ29400ADCT3 requirements.
6.How does Aetrix verify that BQ29400ADCT3 is sourced from the original manufacturer or authorized distributors?
All BQ29400ADCT3 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 BQ29400ADCT3 meets industry standards.
7.What is the process for return or replacement of BQ29400ADCT3?
All BQ29400ADCT3 units undergo pre-shipment inspection (PSI). If there is an issue with BQ29400ADCT3, 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 BQ29400ADCT3 part is unused and in its original packaging.
Return procedure for BQ29400ADCT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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