Texas Instruments BQ29412DCTT

Overview

BQ29412DCTT from Texas Instruments is a secondary overvoltage protection IC for 2-, 3-, or 4-cell Li-ion battery packs, featuring fixed 4.45 V per-cell overvoltage threshold, programmable delay via external capacitor on CD pin, and ultra-low 2 µA supply current. It monitors individual cell voltages (VC1–VC4) and drives an external N-channel FET to blow the fuse during overvoltage events, used in notebook computers and portable instrumentation.

For engineers reviewing the BQ29412DCTT datasheet, BQ29412DCTT pinout, BQ29412DCTT application, or BQ29412DCTT equivalent, key selection factors include its precise 4.45 V overvoltage detection accuracy (±80 mV over –40°C to 110°C), 1–2 s delay time with 0.22 µF CD capacitor, MSOP-8 (DCT) package compatibility, and second-level protection role in high-reliability Li-ion battery management systems.

Technical Context

The BQ29412DCTT implements independent voltage monitoring across up to four series-connected Li-ion cells using dedicated VC1–VC4 inputs, comparing each against an internal reference. When any cell exceeds 4.45 V, a 0.18 µA current source charges the external CD capacitor until 1.2 V is reached, triggering OUT high.

Its architecture includes differential input tolerance (±0.3 V to ±8 V between adjacent VC pins), high ripple rejection, and stable operation during pulse charging. The OUT pin delivers ≥1.5 V at 40 µA high-level drive and sinks ≤5 µA low-level current, enabling direct interface with external protection FET gate drivers.

Key Specifications

Pinout & Package

Package: SSOP-8 (DCT), 3.0 mm × 4.9 mm, 1.3 mm max height, RoHS-compliant, NIPDAU lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ29412DCTT, BQ29411DCTT triggers 50 mV earlier and BQ29413DCTT 50 mV later-enabling precise matching to cell-specific overvoltage limits while maintaining identical board layout, timing behavior, and power consumption.

Availability

BQ29412DCTT is available at Aetrix Electronics and suitable for notebook computers, portable instrumentation, and medical portable devices requiring stable component supply and second-level battery overvoltage protection.

Supply support for BQ29412DCTT 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 delivering analog and embedded processing solutions, with leadership in power management and battery protection ICs.

The bq2941x family is designed specifically for secondary overvoltage protection in multi-cell Li-ion battery packs, providing hardware-enforced redundancy to complement primary BMS controllers.

FAQ

What is the exact overvoltage protection threshold for BQ29412DCTT?

The BQ29412DCTT has a fixed, factory-trimmed overvoltage detection threshold of 4.45 V per cell, with accuracy of ±80 mV over the full operating temperature range of –40°C to 110°C. This value is specific to the BQ29412 variant and differs from other members of the bq2941x family such as BQ29411 (4.40 V) or BQ29413 (4.50 V). The threshold is not user-adjustable and requires no external components to set.

How does the CD pin function in BQ29412DCTT?

The CD pin on the BQ29412DCTT connects to an external capacitor to program the overvoltage response delay. When an overvoltage condition occurs, an internal 0.18 µA current source charges this capacitor; once the CD voltage reaches 1.2 V, the OUT pin transitions high. With a 0.22 µF capacitor, the delay is 1–2 seconds. If the overvoltage clears before 1.2 V is reached, an internal switch discharges the capacitor, preserving full delay time for the next event.

Which battery configurations does BQ29412DCTT support?

The BQ29412DCTT supports 2-, 3-, and 4-cell Li-ion battery configurations by reconfiguring VC pin connections: for 4S, use VC1–VC4 individually; for 3S, tie VC1 and VC2 together; for 2S, tie VC1, VC2, and VC3 together. All configurations share the same DCT package and require no changes to the BQ29412DCTT's internal settings or external components beyond proper VC routing per TI's application diagrams.

What is the recommended decoupling for BQ29412DCTT's VDD pin?

A 0.1 µF ceramic capacitor placed as close as possible to the VDD pin (Pin 7) and GND (Pin 4) is recommended for BQ29412DCTT. This provides high-frequency noise suppression and stabilizes the internal reference during fast transients. TI's datasheet specifies CVD = 0.1 µF and RVD = 0–1 kΩ for the supply filter network, and layout guidelines emphasize short, low-inductance traces to minimize switching noise coupling into the sensitive voltage-monitoring circuitry.

Is BQ29412DCTT pin-compatible with other bq2941x variants?

Yes, the BQ29412DCTT is fully pin-compatible with all other bq2941x family members in the same DCT (SSOP-8) package, including BQ29410, BQ29411, BQ29413, BQ29414, BQ29415, and BQ29419. They share identical pinout, electrical characteristics (except overvoltage threshold), timing behavior, and package dimensions - enabling drop-in replacement solely by selecting the variant matching the required V(PROTECT) value.