Texas Instruments BQ2944L9DRBT

Overview

BQ2944L9DRBT 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 overvoltage 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 for cell-level voltage monitoring and fault isolation.

For engineers reviewing the BQ2944L9DRBT datasheet, BQ2944L9DRBT pinout, BQ2944L9DRBT application, or BQ2944L9DRBT equivalent, key selection criteria include latch behavior, 4.30 V OVP threshold, external capacitor-controlled delay timing, QFN-8 (DRB) package compatibility, and thermal performance under high-temperature battery pack conditions.

Technical Context

The BQ2944L9DRBT implements independent per-cell voltage monitoring across four VCx inputs (VC1–VC4), comparing each against an internal reference to detect overvoltage. When any cell exceeds 4.30 V, a 140 nA current source charges an external capacitor on CD, triggering OUT after delay time determined by xDELAY = 9.0 s/µF nominal scale factor.

Unlike non-latch variants, the BQ2944L9DRBT holds OUT high indefinitely after overvoltage timeout; release requires externally shorting CD to GND. Its architecture supports Customer Test Mode (CTM), reducing delay scaling to 0.08 s/µF for accelerated production verification without altering core protection thresholds.

Key Specifications

Pinout & Package

Package: 8-pin SON (DRB), 3.0 mm × 3.0 mm, 1.0 mm maximum height, exposed thermal pad requiring solder connection to PCB ground plane for thermal and mechanical integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ2944L9DRBT, BQ29449DRBT offers identical OVP threshold and latch but omits CTM-reducing test flexibility-while BD14000GUL provides lower ICC and higher accuracy but lacks latch and demands PCB revision due to incompatible pin mapping.

Availability

BQ2944L9DRBT is available at Aetrix Electronics and suitable for notebook computer battery packs, power tool battery modules, and portable medical instrumentation requiring stable component supply and long-term lifecycle support.

Supply support for BQ2944L9DRBT 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 bq2944x family was designed specifically for secondary overvoltage protection in multi-cell Li-ion battery packs, targeting applications demanding high accuracy, ultra-low power, and hardware-enforced fault latching without MCU dependency.

FAQ

What is the overvoltage protection threshold of the BQ2944L9DRBT?

The BQ2944L9DRBT has a fixed overvoltage protection threshold of 4.30 V, factory-trimmed with ±25 mV accuracy over 0°C to 60°C. This value is specified in the Electrical Characteristics table of the SLUSA15C datasheet and applies to all four monitored cells (VC1–VC2, VC2–VC3, VC3–VC4, VC4–GND). The BQ2944L9DRBT does not support user-adjustable thresholds.

How does the latch function work on the BQ2944L9DRBT?

The BQ2944L9DRBT's OUT pin transitions high after overvoltage delay timeout and remains latched high until the CD pin is externally shorted to GND. This reset action discharges the internal timing capacitor and returns OUT to low. Unlike non-latch variants, the BQ2944L9DRBT will not auto-clear the fault condition-even if cell voltages return to safe levels-ensuring persistent fault signaling.

What external components are required for basic operation of the BQ2944L9DRBT?

The BQ2944L9DRBT requires an external timing capacitor on CD (e.g., 0.33 µF for ~3 s delay), a 0.1 µF supply filter capacitor on VDD (CVD), and optional RC filters (RIN/CIN) on each VCx input for noise immunity. No external resistors are needed for voltage division-the device measures differential cell voltages directly. The exposed thermal pad must be soldered to PCB ground.

Can the BQ2944L9DRBT be used in a 2-series Li-ion battery configuration?

Yes, the BQ2944L9DRBT supports 2-series, 3-series, and 4-series Li-ion battery configurations. For 2-series use, connect VC1 to top of stack, VC2 to midpoint, and GND to bottom; leave VC3 and VC4 unconnected (floating). The device automatically detects active sense lines and monitors only the connected cells, maintaining full accuracy and latch functionality.

What is Customer Test Mode (CTM) and how is it enabled on the BQ2944L9DRBT?

Customer Test Mode (CTM) reduces the overvoltage delay scale factor from 9.0 s/µF to 0.08 s/µF for rapid production verification. To enable CTM on the BQ2944L9DRBT, set VDD ≈ 9.5 V higher than VC1 (e.g., VC1 = 8.5 V, VDD = 18 V). Exit CTM by power-cycling the device. CTM does not affect OVP threshold accuracy or latch behavior-only delay timing.