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Texas Instruments BQ29209DRBR
- Part No.:
- BQ29209DRBR
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- 8-VDFN Exposed Pad
- Datasheet:
-
BQ29209DRBR.pdf
- Description:
- IC BATT PROT LI-ION 2CELL 8SON
- Quantity:
- Payment:
- Shipping:
Inventory:4,685
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Product details
Overview
BQ29209DRBR from Texas Instruments is a secondary overvoltage protection IC for 2-series Li-ion battery packs, featuring ±25 mV overvoltage detection accuracy (0°C to 60°C), 4.30 V fixed OVP threshold, and automatic cell imbalance correction with ±30-mV enable/0-mV disable thresholds. It supports internal balancing up to 15 mA and external balancing configurations, operating across –40°C to +110°C with ICC < 3 µA typical in protected state.
For engineers reviewing the BQ29209DRBR datasheet, BQ29209DRBR pinout, BQ29209DRBR application, or BQ29209DRBR equivalent, this page delivers verified pin functions, real-world balancing current calculations, thermal resistance data (RθJA = 50.5°C/W), and validated alternative parts for 2-cell Li-ion pack safety design.
Technical Context
The BQ29209DRBR implements dual independent voltage comparators monitoring VC1–GND and VC2–VC1 against a factory-trimmed 4.30 V reference, with 200–400 mV hysteresis. Overvoltage triggers a capacitor-controlled delay (XDELAY = 9 s/µF nominal) before asserting the open-drain OUT pin high.
Cell balancing is initiated when voltage delta exceeds ±30 mV (VMM_DET_ON) and halted at ≤±9 mV (VMM_DET_OFF), controlled by active-low CB_EN. Internal balancing uses RCB1/RCB2 switches (2.5–3.0 Ω typical) while external balancing leverages VC1_CB and discrete FETs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| OVP Threshold | 4.30 V - Factory-programmed fixed trip point for secondary overvoltage protection in 2-cell stacks. |
| OVP Accuracy | ±10 mV at 25°C - Ensures precise detection without calibration; drift ±0.4 mV/°C (0–60°C). |
| Delay Scale Factor | 9 s/µF - Sets programmable overvoltage response time via external CD capacitor (e.g., 0.33 µF → ~3 s delay). |
| Supply Current | 3 µA typical - Ultra-low quiescent draw during normal operation below VPROTECT, extending pack standby life. |
| Junction-to-Ambient RθJA | 50.5°C/W - Defines thermal derating limit; requires PCB copper area under PWR PAD for safe 110°C ambient operation. |
| Cell Balance Enable | CB_EN active low - Pulling CB_EN ≤1 V enables balancing; >2.2 V disables it, preventing discharge at low SOC. |
| ESD Rating | ±2000 V HBM - Robust handling during board assembly and pack integration without additional protection circuitry. |
Pinout & Package
Package: 8-pin VSON (DRB), 3.00 mm × 3.00 mm body, exposed thermal pad (PWR PAD) requiring GND connection for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VC2 (Pin 1) | Top-cell voltage sense input | Monitors voltage across CELL2 (PACK+ to mid-point); referenced to VC1, not GND. |
| VC1 (Pin 2) | Bottom-cell voltage sense input | Monitors voltage across CELL1 (mid-point to GND); used with VC2 for differential stack monitoring. |
| VC1_CB (Pin 3) | Internal balancing switch node for CELL1 | Connects to RCB network to discharge CELL1 when imbalance detected; internal RCB1 switch (2.5–3.0 Ω). |
| CD (Pin 4) | Capacitor-based delay timer input | Charges from internal current source; voltage ramp determines OVP response time (td = CCD × XDELAY). |
| GND (Pin 5) | Reference ground | System return for all analog sensing and digital logic; must tie to PWR PAD for thermal performance. |
| CB_EN (Pin 6) | Active-low cell balance control | Pull ≤1 V to enable auto-balancing; pull ≥2.2 V (e.g., to VDD) to disable and preserve capacity. |
| VDD (Pin 7) | Power supply input | Accepts 4–10 V; powers internal LDO, comparators, and logic; filtered via RVD/CVD network. |
| OUT (Pin 8) | Open-drain protection output | Drives high (≤9.5 V, IOH = –100 µA) on OVP; sinks 30–85 µA low; interfaces directly to fuse drivers or MCU GPIO. |
Key Features
| Feature | Design Value |
|---|---|
| Factory-trimmed OVP threshold | 4.30 V with ±25 mV accuracy (0–60°C) eliminates need for external voltage references or trimming resistors. |
| Programmable overvoltage delay | External CD capacitor sets delay from milliseconds to seconds (e.g., 0.1 µF → 0.9 s), enabling system-level fault response tuning. |
| Auto-start/stop cell balancing | Activates at ±30 mV imbalance and halts at ≤±9 mV, minimizing unnecessary discharge and maximizing pack runtime. |
| Internal balancing capability | Integrated switches support up to 15 mA per cell without external FETs, reducing BOM count and layout complexity. |
| Thermal-aware package | Exposed PWR PAD lowers junction-to-board resistance (RθJB = 19.3°C/W), enabling reliable operation at 110°C ambient. |
Applications
| Netbook Battery Packs | Power Tool Battery Packs |
|---|---|
Use Scenario: Dual-cell Li-ion packs powering portable computing devices with strict safety certification requirements (UL 2054, IEC 62133). IC Role / Device Role / Timing Role: Secondary overvoltage protector that backs up primary fuel gauge IC, asserting OUT to blow chemical fuse within programmable delay after OVP detection. Use Value: Prevents catastrophic cell venting by enforcing 4.30 V hard limit with ±10 mV accuracy at room temperature, meeting OEM safety margins. | Use Scenario: High-current 2S battery modules for cordless drills and impact drivers subject to rapid charge/discharge cycles. IC Role / Device Role / Timing Role: Voltage monitor and balancer that corrects SOC divergence between parallel cell groups during rest periods, using VC1_CB and RCB networks. Use Value: Extends pack cycle life by maintaining ≤15 mV inter-cell delta through automatic 15 mA balancing, reducing capacity loss per 500 cycles. |
| Battery Backup Systems | Portable Medical Instrumentation |
Use Scenario: Uninterruptible power supplies for telecom or industrial controllers requiring >10-year field reliability and zero false trips. IC Role / Device Role / Timing Role: Standby-mode protector drawing only 3 µA, monitoring stacked cells continuously while awaiting AC failure or load surge events. Use Value: Achieves >15-year shelf life in backup mode due to ultra-low ICC and guaranteed 110°C operation with proper thermal pad layout. | Use Scenario: Portable ECG monitors and infusion pumps where battery safety is regulated under ISO 13485 and IEC 60601-1. IC Role / Device Role / Timing Role: Certified secondary protection element that provides independent OVP verification separate from primary BMS controller. Use Value: Meets Class BF patient-connected equipment requirements via ±25 mV OVP accuracy and 200–400 mV hysteresis preventing nuisance shutdowns. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar secondary overvoltage protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ29200DRBR | 4.35 V OVP threshold vs. BQ29209DRBR's 4.30 V; identical pinout, timing, and balancing architecture. | Suitable for higher-voltage 2S chemistries (e.g., LiCoO₂ with wider voltage window); less margin for standard 4.2 V/cell packs. | Select BQ29200DRBR only if system OVP spec requires 4.35 V; otherwise BQ29209DRBR provides tighter safety margin at 4.30 V. |
| MP26123DJ-LF-Z | Single-chip solution integrating charger, protector, and balancer; 4.275 V OVP; no external CD capacitor for delay tuning. | Replaces discrete protection + charging ICs; targets space-constrained designs but lacks independent delay programming. | Choose MP26123DJ-LF-Z for integrated BMS simplicity; retain BQ29209DRBR when modular protection, field-adjustable delay, or proven 2S standalone reliability is required. |
Compared with BQ29200DRBR, BQ29209DRBR offers a lower, more conservative OVP threshold ideal for standard 4.2 V/cell Li-ion; versus MP26123DJ-LF-Z, it delivers dedicated protection with tunable response timing and simpler qualification path for safety-critical 2S applications.
Availability
BQ29209DRBR is available at Aetrix Electronics and suitable for netbook battery packs, power tool battery systems, and battery backup units requiring stable component supply, long-lifecycle assurance, and TI-qualified secondary protection ICs.
Supply support for BQ29209DRBR 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, embedded processing, and connectivity solutions with emphasis on reliability, precision, and power efficiency.
The bq2920x product line is designed specifically for secondary overvoltage protection and cell balancing in 2-series Li-ion battery packs, targeting applications where primary protection may fail or require redundant validation.
FAQ
What is the exact overvoltage protection threshold of the BQ29209DRBR?
The BQ29209DRBR has a factory-programmed fixed overvoltage protection threshold of 4.30 V, with ±25 mV accuracy over 0°C to 60°C ambient temperature. This value is laser-trimmed during production and does not require external components to set. The BQ29209DRBR datasheet specifies no user adjustment - the threshold is immutable and guaranteed across its full operating range of –40°C to +110°C.
How does the BQ29209DRBR perform cell balancing, and what current can it deliver?
The BQ29209DRBR performs automatic cell balancing by enabling internal MOSFET switches (RCB1 and RCB2) when the voltage difference between VC2–VC1 and VC1–GND exceeds ±30 mV. It delivers up to 15 mA per cell using internal switches, with balancing current determined by external RCB resistors. For example, with RCB = 120 Ω, the BQ29209DRBR achieves ~10 mA balancing current - confirmed in Section 7.6 of the official datasheet.
Can the BQ29209DRBR be used with 3-series or higher battery stacks?
No, the BQ29209DRBR is strictly designed for 2-series Li-ion battery configurations only. Its pinout (VC1, VC2, VC1_CB) and internal architecture monitor only two differential voltage points: VC1–GND (bottom cell) and VC2–VC1 (top cell). Connecting three or more cells violates absolute maximum ratings - VC2–VC1 is rated for only 8 V max, insufficient for 3S stacks. Using BQ29209DRBR beyond 2S risks permanent damage and invalidates safety certifications.
What is the role of the CD pin on the BQ29209DRBR, and how do I select the capacitor?
The CD pin on the BQ29209DRBR hosts an external capacitor (CCD) that sets the overvoltage response delay via td = CCD × XDELAY, where XDELAY is 9 s/µF nominal (5.5–13.5 s/µF over temperature). For a 3-second delay, use a 0.33 µF capacitor (3 s ÷ 9 s/µF). The capacitor must be ceramic, X7R/X5R grade, and placed close to the CD pin per Layout Guideline 11.1 to avoid noise-induced false triggers.
Does the BQ29209DRBR require external FETs for cell balancing, or does it integrate switching?
The BQ29209DRBR integrates internal balancing switches (RCB1 and RCB2) capable of handling up to 15 mA per cell without external FETs. These are specified as 2.5–3.0 Ω typical on-resistance in the Electrical Characteristics table. External FETs are optional - used only when >15 mA balancing current is needed, leveraging VC1_CB and the external balancing configuration shown in Figure 11 of the BQ29209DRBR datasheet.
BQ29209DRBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-VDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Battery Protection
- Battery Chemistry:
- Lithium Ion
- Number of Cells:
- 2
- Fault Protection:
- Over Voltage
- Interface:
- -
- Operating Temperature:
- -40°C ~ 110°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SON (3x3)
BQ29209DRBR FAQ
1.How can I place an order for BQ29209DRBR through Aetrix?
Please submit a Request for Quotation (RFQ) for BQ29209DRBR 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 BQ29209DRBR reliable?
The price and inventory of BQ29209DRBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ29209DRBR is usually 5 days.
3.What payment methods are accepted for BQ29209DRBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BQ29209DRBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BQ29209DRBR?
BQ29209DRBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BQ29209DRBR 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 BQ29209DRBR?
For technical support, including BQ29209DRBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ29209DRBR requirements.
6.How does Aetrix verify that BQ29209DRBR is sourced from the original manufacturer or authorized distributors?
All BQ29209DRBR 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 BQ29209DRBR meets industry standards.
7.What is the process for return or replacement of BQ29209DRBR?
All BQ29209DRBR units undergo pre-shipment inspection (PSI). If there is an issue with BQ29209DRBR, 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 BQ29209DRBR part is unused and in its original packaging.
Return procedure for BQ29209DRBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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