Texas Instruments BQ7790509PW

Overview

BQ7790509PW from Texas Instruments is a 3- to 5-series ultra-low-power lithium-ion battery protector IC implementing integrated voltage, current, temperature, and open-wire protection without MCU control. It features ±10 mV overvoltage/undervoltage accuracy, 100 mV overcurrent discharge 2 threshold, 200 mV short-circuit discharge threshold, and 70°C/50°C overtemperature discharge/charge thresholds - deployed in power tools and light electric vehicle battery packs.

For engineers reviewing the BQ7790509PW datasheet, BQ7790509PW pinout, BQ7790509PW application, or BQ7790509PW equivalent, key selection criteria include factory-programmed protection thresholds (OV = 4250 mV, UV = 2500 mV, OCD2 = 100 mV, SCD = 200 mV), TSSOP-20 package with stackable interface for ≥6-series scalability, and independent CHG/DSG low-side NMOS drivers with load-removal detection.

Technical Context

The BQ7790509PW operates in NORMAL mode at 6 µA quiescent current and SHUTDOWN mode at ≤0.5 µA, enabling multi-year battery pack standby life. Its protection logic uses factory-trimmed analog comparators with internal delay timers - no software or external timing components required.

It supports 3–5 series cell configurations natively via CCFG pin decoding and scales beyond 5 cells using cascaded CHGU→CTRC/CTRD signaling between stacked devices. All protections - OV, UV, OCD1/OCD2, SCD, OTD/OTC, UTD/UTC, OW - are independently configurable and latched with programmable recovery behavior.

Key Specifications

Pinout & Package

Package: 20-pin TSSOP (PW), 6.50 mm × 4.40 mm body size, JEDEC MO-153 compliant, rated for 36 V absolute maximum per cell input.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery protector applications.

Compared with BQ7790508PW and BQ7790512PW, the BQ7790509PW delivers optimal balance for NMC-based power tools: 4250 mV OV ensures full capacity utilization, 2500 mV UV prevents irreversible damage, and 100 mV OCD2 enables precise 20 A current limiting with standard 5 mΩ shunts - all while maintaining identical TSSOP-20 footprint and stackability.

Availability

BQ7790509PW 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 consistent factory-programmed protection thresholds.

Supply support for BQ7790509PW 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 automotive and industrial reliability heritage.

The BQ7790509PW belongs to TI's BQ77905 family of stackable battery protectors - designed specifically for cost-sensitive, high-volume Li-ion packs needing zero-MCU hardware safety enforcement in portable and motive applications.

FAQ

What is the factory-programmed overvoltage threshold for BQ7790509PW?

The BQ7790509PW has a factory-programmed overvoltage threshold of 4250 mV ±10 mV at 25°C, with temperature-compensated accuracy maintained across –40°C to +85°C. This value is permanently set during manufacturing and cannot be modified in-system. The BQ7790509PW uses this fixed threshold to trigger cell-level overvoltage protection after a 1-second delay, ensuring safe operation for standard NMC lithium-ion cells.

Does BQ7790509PW support 6-series or higher battery configurations?

Yes, the BQ7790509PW supports ≥6-series configurations through its stackable architecture: the CHGU output of an upper device connects to the CTRC/CTRD inputs of the device below, enabling coordinated CHG/DSG control across multiple ICs. While the BQ7790509PW itself is configured for 3–5 series, up to four BQ7790509PW devices can be cascaded to protect up to 20-series battery packs - verified in TI reference designs like TIDA-01003.

How does the load-removal detection (LD) pin function on BQ7790509PW?

The LD pin on BQ7790509PW detects disconnection of the PACK– terminal by monitoring voltage at the LD input; a threshold of 1.3 V initiates automatic recovery from undervoltage (UV) and undertemperature discharge (UTD) faults. When LD senses removal, the BQ7790509PW exits latched fault state without requiring external reset - critical for hot-swap battery applications like cordless power tools where users replace packs mid-operation.

What is the short-circuit discharge (SCD) response time of BQ7790509PW?

The BQ7790509PW detects short-circuit discharge events within 90 ms using its –200 mV SCD threshold (VSRP – VSRN), followed by a 1-second recovery delay before re-enabling the DSG FET. This timing is factory-programmed and unalterable; the 90 ms detection window meets IEC 62133 requirements for Li-ion cell safety, while the 1 s recovery prevents nuisance tripping during transient inrush currents.

Can BQ7790509PW operate without external passive components?

Yes, the BQ7790509PW requires only three external components for basic operation: a 1 µF VDD bypass capacitor, a 10 kΩ pull-up resistor on VTB for thermistor biasing, and a current-sense resistor between SRP/SRN. No external RC timing networks, voltage dividers, or configuration EEPROMs are needed - all protection thresholds, delays, and hysteresis values are factory-programmed and stored in nonvolatile memory inside the BQ7790509PW die.