Texas Instruments BQ7790503PW

Overview

BQ7790503PW 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, 160 mV overcurrent discharge 2 threshold, and 320 mV short-circuit discharge detection - enabling robust protection for 18.5-V nominal power tool battery packs.

For engineers reviewing the BQ7790503PW datasheet, BQ7790503PW pinout, BQ7790503PW application, or BQ7790503PW equivalent, key selection considerations include its 20-pin TSSOP package, 6 µA normal-mode quiescent current, 3-series-to-5-series scalability, independent CHG/DSG low-side NMOS drivers, and support for load-removal detection via LD pin in high-reliability portable power systems.

Technical Context

The BQ7790503PW operates as a standalone analog protector with no firmware or configuration interface. Its protection logic uses internal comparators with fixed thresholds and programmable delays - including 1-s undervoltage delay, 350-ms overcurrent discharge 2 delay, and 350-ms short-circuit delay - all implemented via on-chip timers without external components.

It supports cascaded stacking via CTRC/CTRD control pins and CHGU output to extend protection to ≥6-series configurations. The device integrates dedicated thermistor bias (VTB), cell voltage sensing (VC1–VC5), and dual current sense inputs (SRP/SRN) with ±20% accuracy for OCD2/SCD thresholds above 20 mV across –40°C to +85°C.

Key Specifications

Pinout & Package

Package: 20-pin TSSOP (PW), 6.50 mm × 4.40 mm body size, 0.65-mm pitch, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ7790502PW and BQ7790505PW, the BQ7790503PW offers balanced trade-offs: 4200-mV OV threshold aligns with standard 4.2-V Li-ion, 160-mV OCD2 provides robust overload margin, and load-removal recovery enables automatic resumption after temporary faults - making it optimal for mid-tier power tools and garden equipment.

Availability

BQ7790503PW is available at Aetrix Electronics and suitable for power tools, garden tools, and start-stop battery packs requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing for industrial OEM programs.

Supply support for BQ7790503PW 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 90 years of innovation in industrial and automotive electronics.

The BQ77905 family belongs to TI's high-reliability battery monitor and protector product line, designed specifically for standalone, MCU-free protection of multi-cell lithium-based battery packs in demanding portable and motive applications.

FAQ

What is the factory-programmed overvoltage threshold for BQ7790503PW?

The BQ7790503PW has a factory-programmed overvoltage threshold of 4200 mV with ±10 mV accuracy at 25°C. This value is laser-trimmed during production and cannot be modified in the field. The threshold remains stable across –40°C to +85°C with ±40 mV total error, ensuring reliable cell protection for standard 4.2-V Li-ion chemistry. BQ7790503PW maintains this specification without external calibration components.

Does BQ7790503PW support stacking beyond 5-series configurations?

Yes, BQ7790503PW supports stacking up to 20-series configurations using its CTRC, CTRD, and CHGU pins. In a cascade, the upper device's CHGU drives the lower device's CTRC to synchronize CHG control, while CTRD handles DSG coordination. Each BQ7790503PW manages its local 5-cell segment, and the architecture requires no inter-device communication protocol - only wired signal propagation. BQ7790503PW is validated for 4-device stacks in TI reference designs.

What is the purpose of the LD pin on BQ7790503PW?

The LD (Load Detection) pin on BQ7790503PW monitors PACK– disconnection to enable intelligent fault recovery. When a protection event occurs (e.g., OCD2), BQ7790503PW holds DSG/CHG off until LD detects voltage drop indicating load removal - then automatically recovers after configured delay. This prevents repeated tripping during intermittent faults and eliminates need for external microcontroller intervention. BQ7790503PW uses internal 250-kΩ pull-down on LD for reliable detection.

How does BQ7790503PW achieve functional safety compliance?

BQ7790503PW includes built-in self-test (BIST) circuits that verify comparator functionality, timer accuracy, and signal path integrity during power-up and periodically in NORMAL mode. TI provides FMEDA reports, diagnostic coverage data, and safety manual documentation supporting ISO 26262 ASIL-B integration. BQ7790503PW achieves >90% single-point fault coverage for voltage/current/temperature protections without external diagnostics - a key enabler for automotive start-stop systems.

What are the absolute maximum ratings for VCx pins on BQ7790503PW?

The VCx pins (VC1–VC5) on BQ7790503PW have an absolute maximum rating of –0.3 V to 36 V relative to VSS, matching the device's 36-V cell-input rating. This allows direct connection to high-voltage battery strings without level-shifting. However, recommended operating range is 0–5 V per cell differential (VCn–VCn−1), and exceeding 5 V risks violating common-mode limits. BQ7790503PW includes internal ESD protection on all VCx pins rated to ±1000 V HBM.