Texas Instruments BQ2944L9DRBR

Overview

BQ2944L9DRBR from Texas Instruments is a second-level overvoltage protection IC for 2-, 3-, or 4-series Li-ion battery packs, featuring ±25 mV overvoltage detection accuracy (0°C to 60°C), 4.30 V fixed OVP threshold, latch-enabled OUT pin, and <2 µA typical supply current. It operates across –40°C to +110°C and is used in notebook computers and power tools to prevent cell overcharge during charging cycles.

For engineers reviewing the BQ2944L9DRBR datasheet, BQ2944L9DRBR pinout, BQ2944L9DRBR application, or BQ2944L9DRBR equivalent, key selection considerations include latch behavior, external capacitor–controlled delay timing, 4.30 V OVP threshold, QFN-8 DRB package compatibility, and thermal performance under high-temperature battery pack conditions.

Technical Context

The BQ2944L9DRBR implements precision per-cell voltage monitoring using internal reference comparators on VC1–VC4 inputs, triggering an externally timed overvoltage response via CD pin current source (140 nA typical) charging a capacitor to 1.2 V threshold. Its latch function holds OUT high indefinitely after timeout until CD is shorted to GND.

It supports 2-/3-/4-series configurations with independent cell voltage ranges up to 5 V per differential pair (VCx–VCx+1), operates from 4 V to 25 V VDD, and maintains OVP accuracy within ±0.4 mV/°C drift over 0°C–60°C - critical for reliable secondary protection in thermally variable battery systems.

Key Specifications

Pinout & Package

Package: 8-pin QFN (DRB), 3.0 mm × 3.0 mm, 0.5 mm pitch, exposed thermal pad - requires soldering to PCB thermal plane for junction-to-board thermal resistance of 19.3°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ2944L9DRBR, BQ29449DRBR offers identical functionality and can be substituted without design change, whereas BD1400GUL lacks latch and thermal robustness - making it unsuitable for high-reliability or high-temperature applications requiring persistent fault indication.

Availability

BQ2944L9DRBR is available at Aetrix Electronics and suitable for notebook computers, power tools, and portable medical devices requiring stable component supply across extended product lifecycles.

Supply support for BQ2944L9DRBR 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 specializing in analog, embedded processing, and power management technologies, with decades of experience in battery management solutions.

The bq2944x family was designed specifically for secondary overvoltage protection in multi-cell Li-ion battery packs, emphasizing accuracy, ultra-low power, and latch-based fault persistence for safety-critical applications.

FAQ

What is the overvoltage protection threshold of the BQ2944L9DRBR?

The BQ2944L9DRBR has a fixed overvoltage protection threshold of 4.30 V, specified with ±25 mV accuracy over 0°C to 60°C. This value is factory-trimmed and does not require external configuration. The BQ2944L9DRBR uses this threshold to detect overvoltage conditions across any monitored cell in 2-, 3-, or 4-series Li-ion battery configurations.

Does the BQ2944L9DRBR provide latch functionality on its OUT pin?

Yes, the BQ2944L9DRBR features a latched OUT pin: once an overvoltage condition persists beyond the programmed delay time, OUT transitions high and remains latched in that state until the CD pin is manually shorted to GND. This behavior distinguishes it from non-latch variants like BQ29440DRBR and ensures persistent fault signaling in safety-critical systems.

How is the overvoltage delay time set for the BQ2944L9DRBR?

The overvoltage delay time for the BQ2944L9DRBR is set using an external capacitor connected to the CD pin. A nominal 140 nA current source charges the capacitor; when voltage reaches ~1.2 V, OUT asserts. With a scale factor of 9.0 s/µF, a 0.33 µF capacitor yields ~3 s delay. The BQ2944L9DRBR supports Customer Test Mode (CTM) for accelerated validation using reduced delay scaling.

What package type and thermal characteristics does the BQ2944L9DRBR use?

The BQ2944L9DRBR is housed in an 8-pin QFN (DRB) package measuring 3.0 mm × 3.0 mm with 0.5 mm pitch and an exposed thermal pad. Its junction-to-board thermal resistance is 19.3°C/W, and it requires soldering the thermal pad to a PCB copper plane for optimal thermal performance - essential for reliable operation in high-temperature battery environments up to +110°C.

Can the BQ2944L9DRBR monitor 4-series Li-ion battery packs?

Yes, the BQ2944L9DRBR fully supports 4-series Li-ion battery packs using its five dedicated voltage sense inputs: VC1 (top cell), VC2, VC3, VC4 (bottom cell), and GND. The device reconstructs individual cell voltages differentially (e.g., VC1–VC2, VC2–VC3, etc.) and triggers protection if any cell exceeds 4.30 V - making the BQ2944L9DRBR suitable for quad-cell configurations in power tools and industrial equipment.