Texas Instruments BQ29400ADCT3E6

Overview

BQ29400ADCT3E6 from Texas Instruments is a BiCMOS secondary overvoltage protection IC for 2-, 3-, or 4-cell Li-ion battery packs, featuring 4.40 V ±25 mV precision overvoltage detection, programmable delay via external capacitor on CD pin, <2 µA supply current, and integrated high-accuracy voltage monitoring across four cell inputs (VC1–VC4). It drives an external N-channel FET to blow a fuse during overvoltage events in portable medical equipment.

For engineers reviewing the BQ29400ADCT3E6 datasheet, BQ29400ADCT3E6 pinout, BQ29400ADCT3E6 application, or BQ29400ADCT3E6 equivalent, key selection criteria include second-level protection threshold accuracy, CD-pin-based delay configurability, low-quiescent-current operation in battery-off states, and compatibility with TSSOP-8 (PW) and MSOP-8 (DCT) footprints for space-constrained pack designs.

Technical Context

The BQ29400ADCT3E6 implements a precision analog comparator bank that independently monitors differential voltages VC1–VC2, VC2–VC3, VC3–VC4, and VC4–GND against a trimmed internal reference. When any cell exceeds 4.40 V ±25 mV, a 0.2 µA current source charges an external capacitor on the CD pin until it reaches 1.2 V, triggering the OUT pin high.

Its architecture includes built-in hysteresis (300 mV), supply ripple rejection, and pulse-charge stability. The device resets only after all cells fall below (4.40 V – 300 mV), ensuring latch-free recovery without manual intervention or power cycling.

Key Specifications

Pinout & Package

Package: MSOP-8 (DCT), 3.0 mm × 3.0 mm × 1.0 mm body, lead pitch 0.65 mm, RoHS-compliant CuSnBi finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ29400ADCT3E6, BQ29401DCT3 raises protection sensitivity for newer high-capacity cells, while BQ29400DCT3 lowers it for long-life applications-both retain identical delay programming, quiescent current, and thermal performance but differ only in factory-trimmed reference voltage.

Availability

BQ29400ADCT3E6 is available at Aetrix Electronics and suitable for portable medical monitors, notebook PCs, and test & measurement equipment requiring stable component supply with guaranteed traceability and long-term lifecycle support.

Supply support for BQ29400ADCT3E6 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 headquartered in Dallas, Texas, delivering analog, embedded processing, and logic solutions for industrial, automotive, and consumer markets since 1930.

The BQ29400ADCT3E6 belongs to TI's battery management IC portfolio, designed specifically for hardware-level secondary protection in multi-cell Li-ion battery packs where firmware-independent safety is mandatory.

FAQ

What is the exact overvoltage detection threshold of the BQ29400ADCT3E6?

The BQ29400ADCT3E6 has a factory-trimmed overvoltage detection threshold of 4.40 V ±25 mV across the operating temperature range of –25°C to +85°C. This value applies to each monitored cell voltage (VC1–VC2, VC2–VC3, VC3–VC4, and VC4–GND) and is specified in the Electrical Characteristics table of the SLUS568C datasheet. The BQ29400ADCT3E6 does not support user adjustment of this threshold.

How is the delay time configured on the BQ29400ADCT3E6?

The delay time on the BQ29400ADCT3E6 is set by an external capacitor connected to the CD pin. With a fixed 0.2 µA internal current source charging the capacitor, delay time t_D = (1.2 V × C_DELAY) / 0.2 µA. For example, a 0.22 µF capacitor yields 1.0–2.0 s typical delay. The BQ29400ADCT3E6 requires no resistor network-only the capacitor determines timing.

Can the BQ29400ADCT3E6 be used in a 2-cell Li-ion configuration?

Yes, the BQ29400ADCT3E6 supports 2-cell configurations by connecting VC1, VC2, and VC3 together to the positive terminal of the top cell, and VC4 to the negative terminal of the bottom cell. The datasheet specifies this wiring in Figure 6 and mandates strict connection sequencing (GND → VC4 → VC1) to prevent false triggering during power-up.

What is the maximum continuous supply voltage the BQ29400ADCT3E6 can tolerate on VDD?

The BQ29400ADCT3E6 supports a VDD supply voltage range of –0.3 V to 28 V per Absolute Maximum Ratings. In normal operation, VDD is derived directly from the battery stack, and the recommended operating range is 4.0 V to 25 V. This allows use in 4-cell Li-ion packs up to ~16.8 V fully charged, with 11 V headroom for surge tolerance.

Is the BQ29400ADCT3E6 pin-compatible with the BQ29400DCT3?

Yes, the BQ29400ADCT3E6 is pin-compatible with the BQ29400DCT3-both use the MSOP-8 (DCT) package with identical pin assignments, electrical characteristics, and functional behavior except for the overvoltage threshold (4.40 V vs. 4.35 V). No PCB layout change is required when substituting between these two variants.