Texas Instruments BQ29412DCTRG4

Overview

BQ29412DCTRG4 from Texas Instruments is a secondary overvoltage protection IC for 2-, 3-, or 4-cell Li-ion battery packs, featuring fixed 4.45 V overvoltage threshold, <2 µA supply current, and programmable delay via external capacitor on CD pin. 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 BQ29412DCTRG4 datasheet, BQ29412DCTRG4 pinout, BQ29412DCTRG4 application, or BQ29412DCTRG4 equivalent, key selection criteria include its precise 4.45 V protection threshold, ultra-low ICC (<2 µA), MSOP-8 (DCT) package compatibility, and support for 2–4 series cell configurations with differential voltage monitoring up to 5 V per cell segment.

Technical Context

The BQ29412DCTRG4 implements a precision voltage comparator architecture that independently evaluates VC1–VC2, VC2–VC3, VC3–VC4, and VC4–GND against a trimmed 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 design includes high power supply ripple rejection and stable operation during pulse charging. The device maintains ±80 mV overvoltage detection accuracy across –40°C to 110°C and supports configurable delay timing (e.g., 1–2 s with 0.22 µF capacitor), while consuming only 1.5–2.5 µA at 2.3 V cell stack voltage.

Key Specifications

Pinout & Package

Package: SSOP-8 (DCT), 3.0 mm × 3.0 mm, 1.3 mm max height, lead pitch 0.65 mm, RoHS-compliant NIPDAU 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 BQ29412DCTRG4, BQ29411DCTRG4 offers lower trip voltage for conservative protection, while BQ29413PWG4 provides higher thermal margin and alternate packaging - neither is pin-compatible with DCT, and both require PCB layout revision.

Availability

BQ29412DCTRG4 is available at Aetrix Electronics and suitable for notebook computer battery packs, portable instrumentation power systems, and industrial portable equipment requiring stable component supply with full traceability and long-lifecycle support.

Supply support for BQ29412DCTRG4 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, signal chain, and battery management technologies.

The BQ29412DCTRG4 belongs to TI's bq2941x family of secondary protection ICs, designed specifically for hardware-enforced overvoltage safety in multi-cell Li-ion battery packs used in portable and industrial applications.

FAQ

What is the overvoltage protection threshold of the BQ29412DCTRG4?

The BQ29412DCTRG4 has a fixed overvoltage protection threshold of 4.45 V per cell segment. This value is factory-trimmed and specified across –40°C to 110°C with ±80 mV accuracy. It is not adjustable via external components or programming, distinguishing it from the broader bq2941x family which includes variants ranging from 4.30 V to 4.60 V.

How does the BQ29412DCTRG4 implement programmable delay timing?

The BQ29412DCTRG4 uses an internal 0.18 µA current source to charge an external capacitor connected to the CD pin. When the CD voltage reaches 1.2 V, the OUT pin asserts high. Delay time is calculated as t_D = (1.2 V × C_DELAY) / 0.18 µA - for example, a 0.22 µF capacitor yields ~1.5 s typical delay. If overvoltage clears before 1.2 V is reached, the CD pin is actively discharged.

Which battery configurations does the BQ29412DCTRG4 support?

The BQ29412DCTRG4 supports 2-, 3-, and 4-cell Li-ion battery configurations. For 2-cell use, VC1, VC2, and VC3 are tied together; for 3-cell, VC1 and VC2 are shorted. All configurations retain independent VC1–VC2, VC2–VC3, VC3–VC4, and VC4–GND monitoring capability, enabling accurate per-cell voltage supervision without additional external circuitry.

What is the supply current consumption of the BQ29412DCTRG4 under typical operating conditions?

The BQ29412DCTRG4 consumes ≤2 µA supply current (ICC) across its full operating range. At TA = 25°C and VDD = VC1 with all cell voltages at 2.3 V, ICC is 1.5–2.5 µA; at 3.5 V, it is 2–3 µA. This ultra-low quiescent current ensures minimal impact on battery shelf life and makes the device suitable for always-on protection in long-storage applications.

Is the BQ29412DCTRG4 pin-compatible with other devices in the bq2941x family?

Yes, the BQ29412DCTRG4 shares identical pinout and package (SSOP-8 DCT) with all bq2941x variants including BQ29410DCTRG4, BQ29411DCTRG4, BQ29413DCTRG4, and BQ29414DCTRG4. However, overvoltage thresholds differ (4.35 V to 4.55 V), so substitution requires verification that the alternate threshold meets system safety requirements - no PCB changes are needed for same-package variants.