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Texas Instruments BQ7790521PW
- Part No.:
- BQ7790521PW
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
BQ7790521PW.pdf
- Description:
- IC BATT PROT LI-ION 3-5C 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:912
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Product details
Overview
BQ7790521PW from Texas Instruments is a 5-cell stackable lithium-ion battery protector IC implementing factory-programmed voltage, current, temperature, and open-wire protections without MCU control. It delivers ±10 mV overvoltage/undervoltage accuracy, 140 mV overcurrent discharge 2 threshold, and 320 mV short-circuit discharge threshold with 1-ms recovery, targeting 10.8-V to 36-V power tool and light EV battery packs.
For engineers reviewing the BQ7790521PW datasheet, BQ7790521PW pinout, BQ7790521PW application, or BQ7790521PW equivalent, key selection factors include its 5-series cell support, 6 µA normal-mode current, independent CHG/DSG low-side NMOS drivers, and load-removal detection for pack-level fault isolation in scalable battery management systems.
Technical Context
The BQ7790521PW operates as a primary hardware-based protector in the battery pack's protection circuit module (PCM), directly interfacing with cell voltage sense lines (VC1–VC5), current-sense differential inputs (SRP/SRN), thermistor network (TS/VTB), and dual FET gate drivers (CHG, DSG). Its stackable architecture enables cascaded configurations up to 20-series cells using CTRC/CTRD control signaling between devices.
It implements fixed-function analog comparators with internal delay timers for all protections - no firmware required. Thresholds are factory-programmed: OV = 3700 mV (1 s delay), UV = 2500 mV (1 s delay), OCD2 = 140 mV (20 ms delay), SCD = 320 mV (360 µs delay), OTD/OTC = 70°C/50°C, UTD/UTC = –20°C/0°C - all referenced to VTB bias output and calibrated for 103AT NTC thermistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Cell Count Support | Factory-configured for 5-series Li-ion/LiPo stacks; enables ≥6-series via cascading with CTRC/CTRD inter-device control. |
| Normal Mode Current | 6 µA typical - enables multi-year runtime on backup cell or low-leakage pack monitoring circuits. |
| Overvoltage Threshold | 3700 mV ±10 mV - protects against cell degradation at 3.7 V/cell while allowing full charge of high-capacity NMC cells. |
| OCD2 Detection | 140 mV threshold with ±20% accuracy ≤20 mV - supports precise mid-level discharge current limiting (e.g., 20 A @ 7 mΩ sense resistor). |
| Short-Circuit Delay | 360 µs detection time - ensures MOSFET turn-off before bond wire fusing in <100 ms fault events. |
| Thermal Thresholds | OTD = 70°C, UTC = 0°C - matches common NTC-based thermal cutoff profiles for safe discharge/charge in consumer power tools. |
| Shutdown Current | ≤0.5 µA - preserves pack self-discharge budget during storage or transport mode. |
Pinout & Package
Package: 20-pin TSSOP (PW), 6.50 mm × 4.40 mm body size, 0.65 mm pitch, exposed thermal pad (not electrically connected).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD (Pin 1) | Supply input | Accepts 3–25 V; powers internal regulators and logic; POR triggers at 4 V, shutdown at ≤3.25 V. |
| VC1–VC5 (Pins 3–7) | Cell voltage sense inputs | Differential sensing across 5 series cells; VC5 must connect to VC4 externally per BQ77905 spec. |
| SRP/SRN (Pins 9–10) | Current sense differential inputs | Measures (VSRP – VSRN) for OCD1/OCD2/SCD; supports bidirectional sensing with ±340 mV range. |
| CHG/DSG (Pins 13/11) | Low-side NMOS FET drivers | Drive external CHG/DSG FET gates; 12 V typical output swing; 1 kΩ CHG off-resistance prevents leakage turn-on. |
| CTRC/CTRD (Pins 18/19) | Stack control inputs | Accept CHGU/DSGU signals from upper device in cascade; deglitched with 7 ms filter to reject noise-induced false overrides. |
| TS/VTB (Pins 15/16) | Thermistor interface | TS accepts NTC voltage divider; VTB provides 3.0 V bias reference; thresholds defined as %VTB (e.g., 20.56% for 65°C OTD). |
| LD (Pin 14) | Load removal detection | Monitors PACK– disconnect; triggers fault if voltage drops below 1.3 V; 250 kΩ input resistance minimizes current draw. |
Key Features
| Feature | Design Value |
|---|---|
| Scalable stack architecture | Supports 3–5 series natively; up to 20 series via daisy-chained CTRC/CTRD control - eliminates need for external microcontroller coordination. |
| Independent CHG/DSG drivers | Separate gate drive outputs enable asymmetric protection: e.g., disable charging while permitting discharge during thermal faults. |
| Open-wire detection | 500 mV fault threshold with 100 mV hysteresis per cell - detects broken interconnects or solder joint failures before cell imbalance occurs. |
| Functional safety documentation | TI-provided FIT rate, failure mode analysis, and diagnostic coverage data aid ISO 26262 ASIL-B system-level certification. |
| Customer Test Mode (CTM) | Entry via VDD > VC5 + 10 V enables accelerated fault testing with configurable 100–200 ms delays - reduces validation time for production PCM qualification. |
Applications
| Power Tools | Light Electric Vehicles |
|---|---|
|
Use Scenario: Cordless drill/driver battery packs with 5S Li-ion configuration (18.5 V nominal) requiring robust overcurrent and thermal protection during burst-load operation. IC Role / Device Role / Timing Role: Primary hardware protector executing millisecond-scale SCD response and 1-second OV/UV decisions - bypassing software latency. Use Value: Prevents MOSFET destruction during stall-current events (e.g., 60 A @ 320 mV) while maintaining 6 µA quiescent draw for state-of-charge retention during idle. |
Use Scenario: 36-V e-bike or scooter battery modules where cell-level open-wire detection avoids catastrophic imbalance after vibration-induced connector failure. IC Role / Device Role / Timing Role: Stackable protector enabling 10S–20S scalability; CTRC/CTRD pins coordinate inter-device CHG/DSG sequencing without host intervention. Use Value: Detects VCx–VC(x−1) disconnection at 500 mV with 4.5 s delay - isolates faulty subpack before adjacent cells overcharge or overdischarge. |
| Start-Stop Automotive Batteries | Energy Storage Systems |
|
Use Scenario: 12-V LiFePO₄ replacement packs for automotive start-stop systems needing ultra-low shutdown current and reliable load-removal detection. IC Role / Device Role / Timing Role: LD pin monitors PACK– continuity; triggers immediate DSG disable upon disconnect - preventing reverse-current damage during jump-start scenarios. Use Value: 0.5 µA shutdown current extends shelf life; LD threshold at 1.3 V ensures detection before MOSFET body diode conduction compromises isolation. |
Use Scenario: Residential 48-V LFP battery banks requiring coordinated overtemperature protection across multiple parallel strings with independent charge/discharge thresholds. IC Role / Device Role / Timing Role: Implements separate OTD (70°C)/OTC (50°C) and UTD (–20°C)/UTC (0°C) thresholds - enabling differentiated thermal management for charge vs. discharge cycles. Use Value: Prevents lithium plating during low-temp charging while permitting higher discharge rates at elevated temperatures - extending cycle life by >20% in real-world cycling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar battery protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ7790522PW | OV = 4250 mV, UV = 2800 mV, OCD2 = 100 mV, OTD/OTC = 70°C/50°C, UTD/UTC = –20°C/–5°C | Higher OV/UV thresholds suit NMC cells with wider voltage range; –5°C UTC enables charging in colder climates. | Select BQ7790522PW when operating above 4.2 V/cell or requiring sub-zero charging capability. |
| BQ7790512PW | OV = 4175 mV, UV = 2800 mV, OCD2 = 150 mV, SCD = 300 mV, OTD/OTC = 65°C/45°C, UTD/UTC = –20°C/0°C | Lower OTD/OTC thresholds provide earlier thermal cutoff; 150 mV OCD2 targets higher-current applications (e.g., >30 A). | Choose BQ7790512PW for high-power industrial tools where aggressive thermal derating improves safety margin. |
Compared with BQ7790521PW, BQ7790522PW offers higher voltage tolerance and colder charging support, while BQ7790512PW prioritizes faster thermal shutdown and higher current handling - making each variant optimal for distinct cell chemistries and thermal environments.
Availability
BQ7790521PW is available at Aetrix Electronics and suitable for power tools, light electric vehicles, and energy storage systems requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial-grade battery packs.
Supply support for BQ7790521PW 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 management IC design.
The BQ77905 family belongs to TI's dedicated battery protector product line, engineered for standalone, MCU-free protection in cost-sensitive, high-reliability portable and motive battery applications - emphasizing ultra-low power, factory-programmed precision, and stackable scalability.
FAQ
What is the maximum supported cell count for BQ7790521PW?
The BQ7790521PW is factory-configured for 5-series Li-ion cells but enables expansion to 20-series stacks via cascaded configurations using CTRC and CTRD control pins. In a 4-device stack, each BQ7790521PW manages 5 cells, with upper devices feeding CHGU/DSGU signals to lower devices' CTRC/CTRD inputs to synchronize FET control - eliminating need for external arbitration logic.
Does BQ7790521PW require external microcontroller firmware to operate?
No, the BQ7790521PW operates autonomously without MCU firmware. All protections - including OV, UV, OCD1/OCD2, SCD, OTD/OTC, UTD/UTC, and open-wire - use factory-programmed analog comparators and internal delay timers. The BQ7790521PW only requires passive components (NTC thermistor, sense resistor, decoupling capacitors) and external CHG/DSG MOSFETs to function as a complete hardware protector.
How does the load removal detection (LD) pin function in BQ7790521PW?
The LD pin on BQ7790521PW monitors PACK– continuity by detecting voltage drop below 1.3 V (typical threshold). When triggered, it forces immediate DSG FET disable to isolate the pack - critical during jump-start or service disconnect events. Its 250 kΩ input resistance minimizes current draw, and 1.5 ms deglitch filter prevents false trips from transient noise on the PACK– rail.
What thermistor configuration is required for accurate temperature protection with BQ7790521PW?
The BQ7790521PW expects a 10-kΩ NTC thermistor (103AT type) connected between TS and VSS, with a 10-kΩ pull-up from VTB to TS. Temperature thresholds (e.g., 70°C OTD = 20.56% of VTB) are defined as ratios of VTB's 3.0 V bias output. Actual thresholds depend on this resistor network - calibration is performed at board level, not inside the BQ7790521PW.
Can BQ7790521PW be used in 3-cell or 4-cell battery packs?
Yes, the BQ7790521PW supports 3- to 5-cell configurations via the CCFG pin. For 3-cell use, tie CCFG to VSS (0 V); for 4-cell, apply 65–100% of AVDD; for 5-cell (default), leave CCFG floating (internally biased to 25–45% AVDD). The device auto-detects configuration at power-up and enables only the required VCx inputs - unused pins remain high-impedance.
BQ7790521PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Battery Protection
- Battery Chemistry:
- Lithium Ion
- Number of Cells:
- 3 ~ 5
- Fault Protection:
- Over Current, Over Temperature, Over/Under Voltage, Short Circuit
- Interface:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
BQ7790521PW FAQ
1.How can I place an order for BQ7790521PW through Aetrix?
Please submit a Request for Quotation (RFQ) for BQ7790521PW 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 BQ7790521PW reliable?
The price and inventory of BQ7790521PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ7790521PW is usually 5 days.
3.What payment methods are accepted for BQ7790521PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BQ7790521PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BQ7790521PW?
BQ7790521PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BQ7790521PW 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 BQ7790521PW?
For technical support, including BQ7790521PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ7790521PW requirements.
6.How does Aetrix verify that BQ7790521PW is sourced from the original manufacturer or authorized distributors?
All BQ7790521PW 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 BQ7790521PW meets industry standards.
7.What is the process for return or replacement of BQ7790521PW?
All BQ7790521PW units undergo pre-shipment inspection (PSI). If there is an issue with BQ7790521PW, 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 BQ7790521PW part is unused and in its original packaging.
Return procedure for BQ7790521PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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