Texas Instruments BQ27742YZFT-G1

Overview

BQ27742YZFT-G1 from Texas Instruments is a single-cell Li-ion battery fuel gauge IC with integrated hardware protection, featuring Impedance Track™ technology for ±1% state-of-charge accuracy, 16-bit high-side coulomb counting (5–20 mΩ sense resistor), and programmable overvoltage (4.45 V), undervoltage (2.438 V), overcurrent (OCD: 14 mV, OCC: 6 mV), and short-circuit (73 mV) protection - deployed in smartphones and tablets for runtime prediction and pack safety.

For engineers reviewing the BQ27742YZFT-G1 datasheet, BQ27742YZFT-G1 pinout, BQ27742YZFT-G1 application, or BQ27742YZFT-G1 equivalent, key selection considerations include its dual I²C/HDQ interface support, 15-ball NanoFree™ DSBGA (2.78 mm × 1.96 mm) package, integrated 2.5-V LDO regulator (2.3–2.6 V output), and flash-based reprogrammability of protection thresholds without firmware changes.

Technical Context

The BQ27742YZFT-G1 implements a dedicated coulomb counter with 14–15-bit integrating ADC (1 s conversion time, 10 µV offset) and dual-oscillator timing: 8.389 MHz high-frequency oscillator (±4.5% error over –40°C to 85°C) and 32.768 kHz low-frequency oscillator (±4.0% error) for accurate lifetime logging. Its protection logic operates independently of host communication using internal voltage comparators and fixed delay timers (e.g., tOVP = 1.00 s, tSCD = 312.5 µs).

Hardware protection thresholds are stored in data flash memory (20,000 write cycles, 10-year retention) and configurable via host commands; the device supports both SDA/SCL (400 kHz I²C) and HDQ (single-wire) interfaces with open-drain outputs and 10-kΩ pullup requirements. Temperature sensing uses an internal sensor (–2 mV/°C gain) and external thermistor input (TS pin) for dual-point thermal monitoring.

Key Specifications

Pinout & Package

Package: 15-ball NanoFree™ DSBGA (YZF), 2.78 mm × 1.96 mm body size, 0.4-mm ball pitch, bottom-side thermal pad not present.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery fuel gauge and protection applications.

Compared with BQ27426YZFT and BQ27742-G1YFFT, the BQ27742YZFT-G1 uniquely combines full hardware protection drive capability, dual-interface support, and 15-ball DSBGA packaging - making it optimal for integrated battery-pack designs demanding minimal external components and maximum configurability.

Availability

BQ27742YZFT-G1 is available at Aetrix Electronics and suitable for smartphone battery management, tablet power monitoring, handheld terminal safety systems, and portable media player gauging requiring stable component supply and long-term lifecycle support.

Supply support for BQ27742YZFT-G1 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 over 50 years of innovation in battery management solutions.

The BQ27742YZFT-G1 belongs to TI's bq27xxx fuel gauge product line, designed specifically for space-constrained, single-cell Li-ion applications requiring high-accuracy runtime prediction and autonomous hardware-level safety enforcement.

FAQ

What is the primary function of the BQ27742YZFT-G1?

The BQ27742YZFT-G1 is a single-cell Li-ion battery fuel gauge IC with integrated hardware protection. It provides highly accurate state-of-charge estimation using Impedance Track™ technology and autonomously enforces overvoltage, undervoltage, overcurrent, and short-circuit protection without host intervention. The BQ27742YZFT-G1 also supports I²C and HDQ communication for runtime reporting and configuration.

Does the BQ27742YZFT-G1 require an external sense resistor?

Yes, the BQ27742YZFT-G1 requires an external high-side sense resistor (5–20 mΩ) connected between SRP and SRN pins for coulomb counting. This resistor enables precise current measurement with 10 µV input offset and 14–15-bit resolution. The BQ27742YZFT-G1 does not include an internal sense element and relies on this external component for charge/discharge tracking accuracy.

What package type is used for the BQ27742YZFT-G1?

The BQ27742YZFT-G1 uses a 15-ball NanoFree™ DSBGA (YZF) package measuring 2.78 mm × 1.96 mm with 0.4-mm ball pitch. This ultra-compact, chip-scale package eliminates wire bonds and substrate, reducing thickness and thermal resistance - ideal for slim smartphone and tablet battery assemblies where vertical space is constrained.

Can the protection thresholds of the BQ27742YZFT-G1 be modified after manufacturing?

Yes, the BQ27742YZFT-G1 stores all protection thresholds (OVP, UVP, OCD, OCC, SCD) and timing delays in on-chip data flash memory, supporting up to 20,000 write cycles with 10-year retention. These values can be reprogrammed via I²C or HDQ interface using TI's bqStudio software, enabling field updates for different battery chemistries or end-equipment requirements without hardware changes.

How does the BQ27742YZFT-G1 handle temperature monitoring?

The BQ27742YZFT-G1 supports dual temperature sensing: an internal sensor with –2 mV/°C gain for ambient die temperature, and an external 103AT-type NTC thermistor connected to the TS pin for pack-level thermal profiling. Both inputs feed the Impedance Track™ algorithm to compensate SOC and protection thresholds for temperature-induced battery impedance shifts.