Texas Instruments BQ771825DPJR

Overview

BQ771825DPJR from Texas Instruments is a dedicated overvoltage protection IC for 2- to 5-series Li-ion battery packs, featuring ±10 mV OVP accuracy, 3.950 V fixed overvoltage threshold, and N-channel open-drain active-low output with 3 s internal delay timer. It operates across –40°C to 110°C and consumes ≈1 µA quiescent current, enabling reliable cell-level monitoring in cordless power tools and e-bike battery management systems.

For engineers reviewing the BQ771825DPJR datasheet, BQ771825DPJR pinout, BQ771825DPJR application, or BQ771825DPJR equivalent, key selection criteria include its 3.950 V OVP threshold with 50 mV hysteresis, 3 s fault delay, NCH open-drain output drive capability, low 100 nA per-cell input leakage, and functional safety documentation support for ISO 26262-compliant designs.

Technical Context

The BQ771825DPJR independently monitors up to five differential cell voltages (V1–VSS through V5–V4) using precision internal references. Its overvoltage detection circuit compares each cell voltage against a fixed 3.950 V threshold with ±10 mV accuracy at 25°C and triggers an internal 3 s delay timer upon violation.

Upon timer expiration, the N-channel open-drain OUT pin pulls low to VSS (active-low), requiring an external pull-up resistor. The device supports Customer Test Mode (CTM) with sub-15 ms fault detection for production-line validation, and includes integrated RC filter interface support via RIN/CIN pins for noise-immune sensing.

Key Specifications

Pinout & Package

Package: 8-pin WSON (DPJ), 3.00 mm × 4.00 mm, wettable flank, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ771825DPJR, BQ771801DPJR and BQ771823DPJR offer identical timing and output architecture but differ in OVP threshold (4.275 V vs. 3.950 V) and hysteresis (50 mV vs. 300 mV), making them unsuitable drop-in replacements without revalidation of cell voltage margins and recovery behavior.

Availability

BQ771825DPJR is available at Aetrix Electronics and suitable for handheld power tools, e-bikes, and UPS battery backup systems requiring stable component supply, long-lifecycle support, and functional safety documentation.

Supply support for BQ771825DPJR 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 ICs and functional safety design resources.

The BQ7718 family is designed specifically for standalone overvoltage protection in multi-cell Li-ion battery packs, emphasizing precision, low power, and production-testability via Customer Test Mode.

FAQ

What is the overvoltage protection threshold of the BQ771825DPJR?

The BQ771825DPJR has a fixed overvoltage protection threshold of 3.950 V with ±10 mV accuracy at 25°C. This value is factory-trimmed and applies to each monitored cell voltage (V1–VSS through V5–V4). The device does not support user-programmable thresholds, and the 3.950 V setting is optimized for 3S Li-ion configurations where individual cell voltage must not exceed 3.95 V during charging or operation. BQ771825DPJR maintains this specification across its full operating temperature range.

Does the BQ771825DPJR support 2-cell, 3-cell, 4-cell, and 5-cell battery configurations?

Yes, the BQ771825DPJR supports 2- to 5-series Li-ion battery configurations. It monitors up to five differential cell voltages (V1–VSS, V2–V1, V3–V2, V4–V3, V5–V4) and remains fully functional with fewer cells by leaving unused Vx pins unconnected or tied appropriately. For example, in a 3S configuration, only V1, V2, V3, and VSS are used; V4 and V5 are left floating. The internal sensing circuitry automatically adapts without configuration changes. BQ771825DPJR's architecture eliminates the need for external multiplexing or reconfiguration between pack sizes.

What type of output driver does the BQ771825DPJR use, and how should it be interfaced?

The BQ771825DPJR uses an N-channel open-drain active-low output (OUT pin). When an overvoltage condition is detected and the 3 s delay expires, the OUT pin pulls low to VSS; otherwise, it presents high-impedance. An external pull-up resistor to PACK+ or another logic-rail voltage is mandatory. Typical values range from 10 kΩ to 100 kΩ depending on bus capacitance and noise immunity requirements. This output type enables wired-OR fault signaling across multiple protection devices and ensures compatibility with standard BMS microcontroller interrupt inputs. BQ771825DPJR does not provide active-high drive capability.

How does the Customer Test Mode (CTM) function in the BQ771825DPJR?

Customer Test Mode (CTM) in the BQ771825DPJR reduces the overvoltage fault detection delay from 3 s to less than 15 ms for production-line testing. CTM is activated by applying VDD at least 10 V higher than the V5 pin voltage - for example, if V5 = 12 V, then VDD ≥ 22 V. The mode exits automatically when the VDD-to-V5 differential falls below 10 V. CTM preserves all other functional behaviors, including OVP threshold and hysteresis, allowing full validation of timing performance without modifying hardware. BQ771825DPJR documentation confirms CTM is supported across all variants in the BQ7718xy family.

Is the BQ771825DPJR qualified for functional safety applications?

Yes, the BQ771825DPJR is functional safety-capable, with documentation available to aid ISO 26262 system-level design. Texas Instruments provides failure modes, effects, and diagnostic analysis (FMEDA) data, safety manuals, and diagnostic coverage reports for the BQ7718 family. While BQ771825DPJR itself is not ASIL-certified, its architecture - including independent cell monitoring, accurate OVP, and predictable timing - supports ASIL-B decomposition in battery management systems. Functional safety qualification requires system-level integration and validation; BQ771825DPJR serves as a foundational safety element within that architecture.