Texas Instruments BQ7721612PWR

Overview

BQ7721612PWR from Texas Instruments is a fixed-threshold, 16-cell Li-ion battery voltage and temperature protection IC with integrated delay timers. It provides independent per-cell overvoltage (3.6 V) and undervoltage (2.0 V) detection, open-wire fault sensing, and overtemperature protection (75°C), consuming only ≈1 µA in quiescent state. It is deployed in cordless power tools and e-scooter battery packs to prevent cell damage during charge/discharge cycles.

For engineers reviewing the BQ7721612PWR datasheet, BQ7721612PWR pinout, BQ7721612PWR application, or BQ7721612PWR equivalent, key selection criteria include its active-low output drive configuration, 2-second OVP/UVP delay timing, ±20 mV overvoltage accuracy across 0°C–60°C, and TSSOP-24 package compatibility with high-density battery management layouts.

Technical Context

The BQ7721612PWR implements independent analog voltage comparators for each of 16 cell inputs (V1–V16), with fixed internal thresholds and hysteresis (0.2 V for both OVP and UVP). Its internal oscillator drives programmable delay timers-2 s for overvoltage and undervoltage events-before asserting fault outputs.

It uses ratiometric TS-pin monitoring with internal 20 kΩ pullup to detect overtemperature via external NTC thermistor resistance drop below 1915 Ω (75°C threshold); open-wire detection applies 50 µA pulsed sink current to each Vx input. COUT and DOUT are configured as active-low open-drain outputs, requiring external pull-up to VDD.

Key Specifications

Pinout & Package

Package: 24-pin TSSOP (PW), 4.40 mm × 7.80 mm body, 0.65 mm lead pitch, leaded, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Li-ion battery voltage and temperature protection applications.

Compared with BQ7721612PWR, BQ7721607PWR offers tighter voltage headroom for high-capacity NMC cells but lacks undertemperature response, while BQ7721613PWR adds cold-weather capability at the cost of longer OVP delay-making BQ7721612PWR optimal for cost-sensitive, room-temperature power tool applications requiring fast 2 s fault response.

Availability

BQ7721612PWR is available at Aetrix Electronics and suitable for handheld power tools, e-scooter battery packs, and cordless vacuum cleaner designs requiring stable component supply, long-lifecycle assurance, and automotive-grade reliability under industrial temperature stress.

Supply support for BQ7721612PWR 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 leader specializing in analog, embedded processing, and power management technologies, with decades of leadership in battery management ICs.

The BQ77216xx family is designed specifically for cost-optimized, fixed-threshold protection of 3–16 series Li-ion battery packs in consumer and light industrial applications-emphasizing simplicity, low power, and production-test efficiency.

FAQ

What is the overvoltage protection threshold and accuracy of the BQ7721612PWR?

The BQ7721612PWR has a fixed overvoltage protection threshold of 3.6 V, with accuracy of ±10 mV at 25°C and ±20 mV across 0°C to 60°C. This specification is factory-trimmed and does not require external calibration. The 0.2 V hysteresis ensures stable recovery after fault clearance. These values are confirmed in the Device Comparison Table and DC Characteristics section of the official BQ7721612PWR datasheet.

How does the BQ7721612PWR handle open-wire detection, and what is its impact on system design?

The BQ7721612PWR performs open-wire detection by applying a 50 µA pulsed sink current to each Vx input every 128 ms and monitoring for Vn < Vn−1 −200 mV. Open-wire detection is enabled by default and triggers both COUT and DOUT. This eliminates need for external continuity test circuitry but requires proper PCB routing to avoid false trips from parasitic capacitance-designers must limit trace length and avoid stubs on Vx lines. The BQ7721612PWR's built-in detection reduces bill-of-materials cost and improves field reliability.

What output drive configuration does the BQ7721612PWR use, and how should it be interfaced?

The BQ7721612PWR uses active-low open-drain outputs on both COUT and DOUT pins. Each output must be pulled up externally-typically to VDD via a resistor-to drive external MOSFET gates or optocouplers. The device sinks ≥0.3 mA when active, supporting direct interface with common N-channel high-side or low-side protection FETs. No level-shifting is required, and the open-drain architecture allows wired-OR fault signaling across multiple protection ICs in stacked configurations.

Can the BQ7721612PWR support temperature monitoring, and what external components are needed?

Yes, the BQ7721612PWR supports overtemperature monitoring via its TS pin, which features an internal 20 kΩ pullup resistor. A standard 10 kΩ NTC thermistor is connected between TS and VSS to form a voltage divider. At 75°C, the thermistor resistance drops to 1915 Ω, causing the TS voltage to cross the internal threshold and trigger both COUT and DOUT. No external biasing or ADC is required-the BQ7721612PWR performs ratiometric measurement internally, simplifying thermal safety implementation.

What is Customer Test Mode (CTM), and how is it activated on the BQ7721612PWR?

Customer Test Mode (CTM) reduces fault delay time from 2 s to 50 ms for rapid production-line validation. It is activated by raising VDD to at least 12 V above V16 (e.g., if V16 = 50 V, set VDD ≥ 62 V). CTM is automatically exited when the VDD–V16 differential falls below 10 V. This mode avoids stressing absolute maximum ratings-designers must ensure no pin exceeds its rated voltage during entry/exit. CTM is documented in Section 7.4.3 of the BQ7721612PWR datasheet and requires no OTP programming.