Texas Instruments BQ294705DSGR

Overview

BQ294705DSGR from Texas Instruments is a dedicated 4-series Li-ion battery overvoltage protection IC with factory-programmed 4.45 V OVP threshold, ±10 mV accuracy, external capacitor-programmed delay timer (1–2 s), and CMOS active-high output drive. It independently monitors up to four cell voltages in notebook and UPS battery packs to prevent thermal runaway during charging faults.

For engineers reviewing the BQ294705DSGR datasheet, BQ294705DSGR pinout, BQ294705DSGR application, or BQ294705DSGR equivalent, this page delivers verified technical context, real-world timing behavior, validated package mapping, confirmed leakage and supply current specs, and two rigorously cross-checked alternative parts for second-level battery pack protection design.

Technical Context

The BQ294705DSGR implements independent analog voltage comparators per cell input (V1–VSS through V4–V3), each referenced to a factory-trimmed 4.45 V overvoltage threshold with 300 mV hysteresis. Detection triggers an external RC-based delay timer on the CD pin, where capacitor discharge governs fault response timing.

Its CMOS active-high OUT pin drives an NMOS FET gate directly to short the fuse to ground upon timeout, enabling battery- or charger-powered fuse blow. The device operates across –40°C to +110°C with <1 µA quiescent current when all cells remain below VOV and <100 nA per-cell input leakage.

Key Specifications

Pinout & Package

8-pin WSON (DSG) package, 2.00 mm × 2.00 mm footprint with exposed thermal pad connected to VSS. Compact size enables integration into space-constrained battery management modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ294704DSGR and BQ294706DSGR, the BQ294705DSGR provides the optimal balance of safety margin and cycle life for standard 4S Li-ion packs charged to 4.45 V, avoiding premature cutoff while maintaining robust thermal safety.

Availability

BQ294705DSGR is available at Aetrix Electronics and suitable for notebook battery packs, UPS backup systems, and industrial portable test equipment requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.

Supply support for BQ294705DSGR 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 company specializing in analog and embedded processing technologies, with leadership in battery management, power conversion, and precision analog ICs.

The BQ2947 family was designed specifically for second-level hardware overvoltage protection in multi-cell Li-ion battery packs, delivering autonomous, low-power, and highly accurate cell monitoring without MCU dependency.

FAQ

What is the exact overvoltage protection threshold of the BQ294705DSGR?

The BQ294705DSGR has a factory-programmed overvoltage protection threshold of 4.45 V with ±10 mV accuracy at 25°C. This value is laser-trimmed during manufacturing and does not require external components to set. The BQ294705DSGR maintains this specification across its full operating temperature range of –40°C to +110°C, with drift bounded by ±54 mV at 110°C.

How does the external delay capacitor affect BQ294705DSGR timing behavior?

The BQ294705DSGR uses the CD pin to connect an external capacitor (typically 0.1 µF) that sets the overvoltage delay time between detection and OUT assertion. With a 0.1 µF capacitor, the BQ294705DSGR delivers a nominal 1.5 s delay, ranging from 1 s to 2 s depending on capacitor tolerance. The BQ294705DSGR also detects open or shorted CD capacitors and forces immediate OUT activation to ensure fail-safe behavior.

Can the BQ294705DSGR be used in 2-series or 3-series battery configurations?

Yes, the BQ294705DSGR supports 2S, 3S, and 4S Li-ion configurations. For 2S use, V3 and V4 pins are shorted to V2; for 3S, V4 is shorted to V3. All unused sense inputs must be tied to the adjacent lower potential to maintain valid voltage ranges. The BQ294705DSGR's internal comparators remain fully functional regardless of stack count, with identical OVP accuracy and delay timing.

What is the maximum supply voltage the BQ294705DSGR can tolerate on VDD?

The BQ294705DSGR supports a VDD supply range of 3 V to 20 V, with absolute maximum rating of 30 V. This wide input range allows direct connection to the full battery stack voltage in 4S Li-ion applications (up to ~16.8 V fully charged), eliminating the need for external regulators. The BQ294705DSGR maintains specified performance across the entire 3–20 V operating window.

Does the BQ294705DSGR require external passive components for basic operation?

Yes, the BQ294705DSGR requires external RC filters on all Vx sense inputs (1 kΩ + 0.1 µF typical) and a 0.1 µF capacitor on the CD pin to set the delay timer. A 100 Ω resistor is recommended on VDD for current limiting, and a 0.1 µF bypass capacitor is required between VDD and VSS. These components are mandatory for stable operation and noise immunity-omitting them degrades BQ294705DSGR accuracy and reliability.