Texas Instruments BQ771605DPJT

Overview

BQ771605DPJT from Texas Instruments is a precision overvoltage protection IC for 2- to 4-series Li-ion battery packs, featuring fixed 3.85 V OVP threshold, ±10 mV accuracy at 25°C, 250 mV hysteresis, N-channel active-low open-drain output, and external capacitor-programmed delay (1–2 s with 0.1 µF). It operates in eBike battery management systems where cell-level fault detection and robust delay timing prevent false trips during transient voltage spikes.

For engineers reviewing the BQ771605DPJT datasheet, BQ771605DPJT pinout, BQ771605DPJT application, or BQ771605DPJT equivalent, key selection criteria include its 3.85 V overvoltage threshold, NCH active-low output drive capability, 8-pin WSON package compatibility with high-density PCB layouts, and support for Customer Test Mode with ≤170 ms reduced delay for production-line validation.

Technical Context

The BQ771605DPJT independently monitors up to four cell voltages (V1–VSS through V4–V3) using internal precision comparators referenced to a 3.85 V OVP threshold. Upon detection of any cell exceeding this threshold, it initiates a CD-pin-based delay timer with built-in open/short fault detection on the external capacitor.

In OVERVOLTAGE mode, the device discharges the CD capacitor via a 100 nA current source; when CD falls below ~250 mV, the OUT pin actively pulls low (NCH open-drain). In NORMAL mode, OUT remains high-impedance, and supply current draws only ≈1 µA while maintaining <100 nA per-cell input leakage.

Key Specifications

Pinout & Package

Package: 8-pin WSON (DPJ), 3.00 mm × 4.00 mm, exposed thermal pad, moisture sensitivity level 1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ771602DPJT and BQ771604DPJT, the BQ771605DPJT provides the lowest OVP threshold (3.85 V) and highest hysteresis (250 mV) in the family-critical for safe operation with lithium iron phosphate or high-safety-margin Li-ion cells-while retaining NCH open-drain compatibility with legacy battery management hardware.

Availability

BQ771605DPJT is available at Aetrix Electronics and suitable for power tools, UPS battery backup systems, and light electric vehicles requiring stable component supply, long-lifecycle support, and automotive-grade temperature resilience.

Supply support for BQ771605DPJT 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 battery management, power conversion, and precision analog ICs.

The BQ7716 family is designed specifically for standalone overvoltage protection in multi-cell Li-ion battery packs, emphasizing accuracy, low power, and robust fault detection without requiring microcontroller intervention.

FAQ

What is the overvoltage protection threshold of the BQ771605DPJT?

The BQ771605DPJT has a fixed overvoltage protection threshold of 3.85 V per cell, with ±10 mV accuracy at 25°C and guaranteed performance across –40°C to +110°C. This value is factory-trimmed and non-adjustable, making the BQ771605DPJT suitable for lithium iron phosphate (LFP) and other low-threshold chemistries where tighter voltage guardbanding is required. The BQ771605DPJT does not support user-programmable thresholds.

How does the external delay capacitor affect BQ771605DPJT timing behavior?

The external capacitor on the CD pin sets the overvoltage delay time for the BQ771605DPJT using the formula tCD = K × CCD, where K ranges from 10 to 20. With a typical 0.1 µF capacitor, the delay spans 1–2 seconds. The BQ771605DPJT also detects CD pin faults: if the capacitor is open or shorted, the OUT pin activates immediately. This ensures fail-safe response regardless of capacitor integrity.

What output configuration does the BQ771605DPJT use, and how should it be interfaced?

The BQ771605DPJT features an N-channel open-drain, active-low output (OUT pin). During overvoltage, it sinks current to VSS; otherwise, it presents high impedance. An external pull-up resistor to PACK+ or system rail is mandatory. The BQ771605DPJT's IOUTH2 specification (0.5–14 mA sink current) determines minimum pull-up resistance to ensure reliable logic-level transition under all operating conditions.

Can the BQ771605DPJT monitor fewer than four cells, and how is it configured?

Yes, the BQ771605DPJT supports 2-series, 3-series, and 4-series configurations. For 2S operation, V3 and V4 pins are shorted to V2; for 3S, V4 is shorted to V3. All unused sense inputs must be shorted-not left floating-to maintain measurement integrity. The BQ771605DPJT's independent per-cell monitoring architecture ensures accurate voltage detection regardless of stack size.

What is Customer Test Mode on the BQ771605DPJT, and when is it used?

Customer Test Mode on the BQ771605DPJT is activated by shorting the CD pin to VSS, reducing overvoltage delay to ≤170 ms (tCHGDELAY). This mode enables rapid functional verification during manufacturing test without modifying hardware or firmware. The BQ771605DPJT retains full electrical specifications in this mode but requires strict adherence to absolute maximum ratings to prevent damage during accelerated testing.