Texas Instruments BQ29442DRBT

Overview

BQ29442DRBT from Texas Instruments is a second-level overvoltage protection IC for 2-, 3-, or 4-series Li-ion battery packs, featuring fixed 4.45 V overvoltage threshold, ±25 mV accuracy (0°C to 60°C), <2 µA typical supply current, and external capacitor-controlled delay timing. It operates across –40°C to +110°C and drives an open-drain OUT pin to signal cell overvoltage in portable power tools and notebook computers.

For engineers reviewing the BQ29442DRBT datasheet, BQ29442DRBT pinout, BQ29442DRBT application, or BQ29442DRBT equivalent, key selection criteria include its 4.45 V OVP threshold, QFN-8 (DRB) package with exposed thermal pad, programmable delay via CD pin capacitor, latch-free operation, and compatibility with multi-cell voltage monitoring topologies.

Technical Context

The BQ29442DRBT implements precision per-cell voltage monitoring using internal high-accuracy comparators referenced to a stable bandgap. Each VCx input (VC1–VC4) independently monitors inter-cell or cell-to-ground voltages up to 5 V, triggering detection when any exceeds 4.45 V ±25 mV.

Upon overvoltage detection, a 140 nA current source charges the external capacitor on the CD pin; when voltage reaches ~1.2 V, the OUT pin transitions high (up to 9.5 V) with 5 µs rise time and 2 kΩ output impedance-enabling direct interface with external FET gate drivers or system fault controllers.

Key Specifications

Pinout & Package

Package: 8-pin SON (DRB), 3.0 mm × 3.0 mm × 1.0 mm body with exposed thermal pad (JEDEC MO-229, TI DRB0008B). Requires soldering of thermal pad for thermal performance and mechanical reliability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ29442DRBT, BQ29441DRBT offers a 50 mV lower OVP threshold for stricter protection, while BQ29443DRBT provides 50 mV higher margin for enhanced charge tolerance-both retain identical delay programming, supply current, and thermal performance in the DRB package.

Availability

BQ29442DRBT is available at Aetrix Electronics and suitable for power tools, notebook computers, and portable medical devices requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial OEM programs.

Supply support for BQ29442DRBT 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, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.

The bq2944x family is designed specifically for secondary overvoltage protection in multi-cell Li-ion battery packs, emphasizing accuracy, ultra-low power, and flexible delay timing without microcontroller dependency.

FAQ

What is the overvoltage protection threshold of the BQ29442DRBT?

The BQ29442DRBT has a fixed overvoltage protection (OVP) threshold of 4.45 V with ±25 mV accuracy over 0°C to 60°C. This value is factory-trimmed and non-adjustable, making it suitable for 4-series Li-ion battery packs where precise secondary protection is required without external resistor networks. The BQ29442DRBT does not support user-programmable thresholds.

How does the BQ29442DRBT implement delay timing for overvoltage events?

The BQ29442DRBT uses an external capacitor connected to the CD pin to set overvoltage delay time. A 140 nA internal current source charges the capacitor; when voltage reaches ~1.2 V, the OUT pin asserts high. Delay = 9.0 s/µF × CCD value (e.g., 0.33 µF yields ~3 s). The BQ29442DRBT supports Customer Test Mode (CTM) for reduced 0.08 s/µF scaling during production verification.

Does the BQ29442DRBT include a latch function for the OUT pin?

No, the BQ29442DRBT does not include a latch function. It is a non-latching device: the OUT pin returns low when the overvoltage condition is removed and the CD capacitor discharges. Latch functionality is available only in the BQ2944L0 and BQ2944L9 variants. The BQ29442DRBT's behavior is defined by its "No" latch option in TI's ordering table.

What package type and thermal considerations apply to the BQ29442DRBT?

The BQ29442DRBT uses an 8-pin SON (DRB) package measuring 3.0 mm × 3.0 mm × 1.0 mm with an exposed thermal pad. TI specifies junction-to-board thermal resistance (qJB) of 19.3°C/W and requires soldering the thermal pad to PCB copper for mechanical integrity and thermal performance. The BQ29442DRBT operates from –40°C to +110°C ambient.

Can the BQ29442DRBT monitor 2-series and 3-series Li-ion configurations?

Yes, the BQ29442DRBT supports 2-series, 3-series, and 4-series Li-ion battery configurations. For 2S, connect VC1 and VC2 to top/bottom cell terminals and leave VC3/VC4 unconnected; for 3S, use VC1–VC2–VC3 and leave VC4 floating. All VCx pins tolerate 0–5 V differential input, and the BQ29442DRBT detects overvoltage on any active sense channel.