Texas Instruments BQ29441DRBT

Overview

BQ29441DRBT from Texas Instruments is a second-level overvoltage protection IC for 2-, 3-, or 4-series Li-ion battery packs, featuring fixed 4.40 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 delivers precise cell voltage monitoring in portable power tools and notebook computers.

For engineers reviewing the BQ29441DRBT datasheet, BQ29441DRBT pinout, BQ29441DRBT application, or BQ29441DRBT equivalent, key selection criteria include overvoltage threshold accuracy, latch vs. non-latch behavior, CD-pin delay capacitor scaling (9.0 s/µF nominal), thermal performance in DRB package, and compatibility with multi-cell stack topologies up to 4-series.

Technical Context

The BQ29441DRBT implements independent per-cell voltage sensing on VC1–VC4 inputs, comparing each against an internal reference to detect overvoltage. When any cell exceeds 4.40 V, a 140 nA current source charges the external CD capacitor until it reaches 1.2 V, triggering OUT high after a delay determined by CCD value and temperature-stable scale factor (5.5–13.5 s/µF).

No internal latch is present-OUT returns low once overvoltage clears and the CD capacitor discharges fully. The device supports Customer Test Mode (CTM) at elevated VDD–VC1 differential to reduce delay time via alternate 0.08 s/µF scaling, intended only for production verification-not functional operation.

Key Specifications

Pinout & Package

8-pin SON (DRB) package with exposed thermal pad; requires soldering to PCB thermal plane for optimal 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 BQ29441DRBT, BQ29442DRBT raises overvoltage trip point by 50 mV for wider chemistry compatibility, while BQ29449DRBT lowers it by 100 mV for enhanced margin with aging or low-tolerance cells-both retain identical delay programming, thermal specs, and PCB layout.

Availability

BQ29441DRBT is available at Aetrix Electronics and suitable for power tools, notebook computers, portable medical devices, and industrial handheld scanners requiring stable component supply and long-term lifecycle support.

Supply support for BQ29441DRBT 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 with emphasis on reliability, precision, and power efficiency.

The bq2944x family was designed specifically for secondary overvoltage protection in multi-cell Li-ion battery packs, targeting applications where hardware-level redundancy is mandated alongside primary BMS control.

FAQ

What is the overvoltage protection threshold of the BQ29441DRBT?

The BQ29441DRBT has a fixed overvoltage protection threshold of 4.40 V per cell, specified with ±25 mV accuracy over 0°C to 60°C. This value is factory-trimmed and not adjustable. The BQ29441DRBT does not support user-programmable thresholds-alternative variants like BQ29442DRBT (4.45 V) or BQ29449DRBT (4.30 V) must be selected for different trip points.

Does the BQ29441DRBT include an internal latch function?

No, the BQ29441DRBT is a non-latching device. When an overvoltage condition clears, the internal CD capacitor discharges and the OUT pin returns to low state automatically. Latching behavior is only available in the "L" variants (e.g., BQ2944L0, BQ2944L9), which hold OUT high until CD is shorted to GND. The BQ29441DRBT requires no external latch circuit but also offers no persistent fault indication.

How is the overvoltage delay time set on the BQ29441DRBT?

The BQ29441DRBT uses an external capacitor on the CD pin to set delay time. A nominal 140 nA current charges the capacitor; when voltage reaches ~1.2 V, OUT transitions high. Delay = CCD × xDELAY, where xDELAY is 9.0 s/µF nominal (range 5.5–13.5 s/µF). For example, a 0.33 µF capacitor yields ~3 s delay at 25°C. The BQ29441DRBT does not use resistors or digital configuration for timing.

What package type and thermal characteristics does the BQ29441DRBT use?

The BQ29441DRBT uses an 8-pin SON (DRB) package measuring 3.0 × 3.0 mm with 1.0 mm max height and an exposed thermal pad. Its junction-to-board thermal resistance (qJB) is 19.3°C/W, and junction-to-ambient (qJA) is 50.5°C/W on JEDEC-standard high-K board. The BQ29441DRBT requires soldering the thermal pad to a PCB copper plane for reliable thermal performance in continuous operation.

Can the BQ29441DRBT monitor 2-series, 3-series, and 4-series Li-ion battery configurations?

Yes, the BQ29441DRBT supports all three configurations via its four VCx inputs (VC1–VC4) and GND. For 2S: connect VC1, VC2, and GND; for 3S: add VC3; for 4S: use all four VC pins. Unused VC inputs must be left unconnected-not tied to GND or VDD. The BQ29441DRBT performs independent per-cell comparison and triggers if any monitored cell exceeds 4.40 V, regardless of stack size.