Texas Instruments BQ294705DSGT

Overview

BQ294705DSGT from Texas Instruments is a precision overvoltage protection IC for 2- to 4-series Li-ion battery packs, featuring factory-programmed 4.45 V OVP threshold, ±10 mV accuracy at 25°C, external capacitor-programmed delay (1–2 s with 0.1 µF), and CMOS active-high output drive. It operates across –40°C to +85°C and supports notebook and UPS battery backup systems.

For engineers reviewing the BQ294705DSGT datasheet, BQ294705DSGT pinout, BQ294705DSGT application, or BQ294705DSGT equivalent, this page delivers verified specifications, validated pin functions, confirmed thermal and leakage performance, and real-world implementation guidance for second-level cell voltage monitoring and fuse-triggered shutdown.

Technical Context

The BQ294705DSGT implements independent per-cell voltage sensing across four differential inputs (V1–VSS to V4–V3), compares each against a fixed 4.45 V overvoltage threshold, and initiates an external RC-based delay timer on any violation. Its internal timeout detection ensures fault response even if the CD capacitor is open or shorted.

It operates in two functional modes: Normal mode (all cells < 4.45 V, OUT low) and Overvoltage mode (any cell ≥ 4.45 V, OUT transitions high after t_CD delay). The device supports customer test mode via CD-to-VSS shorting, reducing delay to ≤170 ms for production-line verification.

Key Specifications

Pinout & Package

Package: 8-pin WSON (DSG), 2.00 mm × 2.00 mm, exposed thermal pad (PowerPAD™) recommended to be connected to VSS.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar overvoltage protection applications.

Compared with BQ294704DSGT and BQ294706DSGT, the BQ294705DSGT provides the optimal balance for standard 4.45 V Li-ion cells-offering tighter alignment with common charger termination voltages while maintaining full compatibility with shared PCB layouts and test procedures.

Availability

BQ294705DSGT is available at Aetrix Electronics and suitable for notebook battery management, UPS backup systems, and industrial portable equipment requiring stable component supply, long-lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for BQ294705DSGT 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 and embedded processing solutions, with over 90 years of innovation in power management and battery protection ICs.

The BQ2947 family was designed specifically for second-level overvoltage protection in multi-cell Li-ion battery packs, emphasizing precision, low power, and fail-safe timing behavior in safety-critical energy storage systems.

FAQ

What is the exact overvoltage protection threshold of the BQ294705DSGT?

The BQ294705DSGT has a factory-programmed overvoltage protection threshold of 4.45 V, with ±10 mV accuracy at 25°C and ±54 mV maximum drift across –40°C to +110°C. This value is laser-trimmed during production and cannot be adjusted externally - it is fixed for this specific variant within the BQ2947 family.

Does the BQ294705DSGT support 2-cell, 3-cell, and 4-cell battery configurations?

Yes, the BQ294705DSGT supports 2S, 3S, and 4S Li-ion configurations. For 2S operation, V3 and V4 pins are shorted to V2; for 3S, V4 is shorted to V3. All configurations use the same BQ294705DSGT device and maintain full overvoltage monitoring on active cells without firmware or hardware modification.

How does the external delay capacitor affect timing in the BQ294705DSGT?

The BQ294705DSGT uses an external capacitor on the CD pin to set the overvoltage delay: t_CD = K × C_CD, where K = 10–20. With a typical 0.1 µF capacitor, delay ranges from 1 s (min) to 2 s (max). The device also detects CD pin faults - an open or shorted capacitor forces immediate OUT assertion, ensuring fail-safe behavior.

What is the purpose of the Customer Test Mode in the BQ294705DSGT?

The Customer Test Mode in the BQ294705DSGT is activated by shorting the CD pin to VSS, reducing the overvoltage delay to ≤170 ms. This mode enables rapid functional verification during production testing without altering the main timing circuit - it preserves full protection functionality while accelerating QA throughput.

Can the BQ294705DSGT be used with both NMOS and PMOS external FETs?

The BQ294705DSGT is configured exclusively as CMOS active-high output and is optimized to drive an NMOS FET gate (e.g., to short a fuse to ground). It does not support direct PMOS drive; for active-low signaling required by PMOS, a different variant like BQ294707 (open-drain active-low) must be selected instead of the BQ294705DSGT.