Texas Instruments BQ29443DRBT

Overview

BQ29443DRBT from Texas Instruments is a second-level overvoltage protection IC for 4-series Li-ion battery packs, featuring fixed 4.50 V overvoltage threshold, ±25 mV accuracy (0°C to 60°C), <2 µA typical supply current, and external capacitor-controlled delay timing - deployed in power tools and portable instrumentation requiring fail-safe cell voltage monitoring.

For engineers reviewing the BQ29443DRBT datasheet, BQ29443DRBT pinout, BQ29443DRBT application, or BQ29443DRBT equivalent, key selection criteria include its 4.50 V OVP threshold, DRB 8-pin QFN package with exposed thermal pad, non-latching output behavior, and compatibility with 2–4 series cell configurations under –40°C to +110°C operating range.

Technical Context

The BQ29443DRBT implements independent per-cell voltage monitoring across four VCx inputs (VC1–VC4), comparing each against an internal precision reference. When any cell exceeds 4.50 V, a 140 nA current source charges the external CD capacitor until it reaches 1.2 V, triggering OUT high after a delay scalable via CCD capacitance (nominal 9.0 s/µF).

No internal latch is present - the OUT pin returns low once overvoltage clears and the CD capacitor discharges fully. The device operates from 4 V to 25 V supply, supports up to 5 V differential input per cell pair, and maintains ±0.4 mV overvoltage accuracy over 0°C to 60°C ambient.

Key Specifications

Pinout & Package

Package: DRB - 8-pin plastic small-outline no-lead (SON) with 3.0 mm × 3.0 mm body, 0.5 mm pitch, and exposed thermal pad (JEDEC MO-229, TI drawing DRB0008B). Requires soldering of thermal pad to PCB ground plane for thermal and mechanical reliability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ29443DRBT, BQ29442DRBT offers earlier overvoltage intervention at 4.45 V, while BQ29449DRBT provides maximum safety margin at 4.30 V - both retain identical timing control, low-power operation, and 4-series cell support but require system-level validation of new trip thresholds.

Availability

BQ29443DRBT is available at Aetrix Electronics and suitable for power tools, portable medical instrumentation, and industrial handheld scanners requiring stable component supply with guaranteed long-term sourcing.

Supply support for BQ29443DRBT 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, embedded processing, and power management technologies with broad industrial and automotive design expertise.

The bq2944x family was designed specifically for secondary overvoltage protection in multi-cell Li-ion battery packs, delivering precision, low-power, and capacitor-programmable timing in compact QFN packages.

FAQ

What is the overvoltage protection threshold of the BQ29443DRBT?

The BQ29443DRBT has a fixed overvoltage protection (OVP) threshold of 4.50 V, factory-trimmed with ±25 mV accuracy over 0°C to 60°C ambient temperature. This value is specific to the BQ29443 variant and is not adjustable via external components or programming. The BQ29443DRBT does not support user-configurable thresholds - alternative variants (e.g., BQ29442DRBT at 4.45 V) must be selected for different trip points.

Does the BQ29443DRBT provide latched or non-latched overvoltage output behavior?

The BQ29443DRBT implements non-latched output behavior: the OUT pin transitions high upon confirmed overvoltage and automatically returns low once the overvoltage condition is removed and the CD capacitor fully discharges. Unlike latched variants (e.g., BQ2944L3), no external reset (e.g., shorting CD to GND) is required. This behavior is inherent to the BQ29443DRBT part number and cannot be modified.

What package type and dimensions does the BQ29443DRBT use?

The BQ29443DRBT uses the DRB package - an 8-pin plastic small-outline no-lead (SON) measuring 3.0 mm × 3.0 mm with 0.5 mm pitch and 1.0 mm maximum height. It features an exposed thermal pad on the bottom for PCB soldering. The DRB package is JEDEC-compliant (MO-229) and requires adherence to TI's board layout guidelines, including thermal pad connection to ground and controlled solder paste volume.

How is the overvoltage delay time set on the BQ29443DRBT?

The overvoltage delay time on the BQ29443DRBT is set by an external capacitor (CCD) connected to the CD pin. A nominal 140 nA current charges CCD until it reaches 1.2 V, at which point OUT asserts. With a nominal scale factor of 9.0 s/µF, a 0.33 µF capacitor yields ~3 s delay. Delay time varies with temperature and capacitor tolerance; the BQ29443DRBT does not support digital delay configuration or internal trimming.

Can the BQ29443DRBT monitor fewer than four series-connected Li-ion cells?

Yes, the BQ29443DRBT supports 2-series, 3-series, and 4-series Li-ion configurations. For 2- or 3-cell stacks, unused VCx pins (e.g., VC3 and VC4 in a 2-cell setup) must be connected according to TI's recommended cell connection sequence - starting from GND upward - and left unconnected only if explicitly permitted by the datasheet. The BQ29443DRBT performs independent voltage comparisons on all enabled VCx inputs and triggers if any monitored cell exceeds 4.50 V.