Texas Instruments BQ2028YZGT

Overview

BQ2028YZGT from Texas Instruments is a 4-Kb serial EEPROM IC with integrated 2.5-V LDO regulator, single-wire HDQ interface, and die-temperature sensor-designed for battery pack-side nonvolatile storage and thermal monitoring in single-cell fuel gauge systems such as the bq27505-E1. It delivers 512 × 8-bit EEPROM, ±5°C temperature sensing range (–40°C to 85°C), and ultra-low 1-µA shutdown current.

For engineers reviewing the BQ2028YZGT datasheet, BQ2028YZGT pinout, BQ2028YZGT application, or BQ2028YZGT equivalent, this page provides verified technical context, validated pin functions, confirmed power-mode behavior, real-world use cases in battery management, and two documented alternative parts with explicit functional and application-level differences.

Technical Context

The BQ2028YZGT implements a dual-oscillator architecture (32.768-kHz LFO and 8.389-MHz HFO) to support configurable ADC conversion timing (7.8–125 ms) and HDQ communication with auto-timeout shutdown. Its HDQ interface uses asynchronous return-to-one encoding with break-pulse wakeup and CRC-8 data integrity checking across command/data packets.

It integrates a 2.5-V LDO regulator (2.4–2.6 V output, 10-mA max load) powered from REGIN (2.45–4.5 V), decoupled by 0.47-µF ceramic at VDD–VSS. The internal 10-bit ADC reads die temperature via VTEMP channel (–1.986 mV/°C slope), with raw conversion results stored in ADHI/ADLOW registers and processed externally.

Key Specifications

Pinout & Package

12-pin wafer-level chip-scale package (WCSP, YZG) with bottom-view layout: 4×3 grid (A1–D3). Requires conductive foam handling due to limited ESD protection. Ground pins (VSS) occupy A1, B1, D1, B2, C2 for low-impedance return path.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar nonvolatile memory with integrated sensing and regulation applications.

Compared with bq2027YZGT and bq2025YZGT, the BQ2028YZGT uniquely combines 4-Kb EEPROM, on-die temperature sensing, and integrated 2.5-V LDO in a single 12-pin WCSP-reducing component count, simplifying layout, and enabling true pack-side autonomy for smart battery applications.

Availability

BQ2028YZGT is available at Aetrix Electronics and suitable for smart battery packs, portable medical devices, and industrial handheld instruments requiring stable component supply, long-term lifecycle support, and qualified automotive-grade temperature performance.

Supply support for BQ2028YZGT 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 expertise in battery management ICs and precision analog design.

The BQ2028YZGT belongs to TI's battery fuel gauge companion IC product line, engineered specifically to provide reliable, low-power, pack-integrated nonvolatile memory and thermal telemetry for single-cell lithium-based energy systems.

FAQ

What is the primary function of the BQ2028YZGT in a battery management system?

The BQ2028YZGT serves as a pack-side nonvolatile memory and thermal monitor, providing 512-byte EEPROM storage for fuel gauge calibration data, manufacturing information, and operational history-while also delivering die-temperature readings via its integrated ADC. It communicates exclusively over the HDQ interface with system-side fuel gauges like the bq27505-E1, eliminating the need for separate EEPROM, LDO, and temperature sensor components.

How does the HDQ interface on the BQ2028YZGT differ from I²C or SPI?

The BQ2028YZGT uses a proprietary single-wire, open-drain HDQ interface defined by Texas Instruments-not I²C or SPI. It relies on precise timing (e.g., 190-µs break pulse, 211–233-µs response) and CRC-8 checksums for error detection, with no clock line or address byte. Communication is asynchronous and return-to-one encoded, requiring only one signal wire plus ground, making it ideal for space- and cost-constrained battery pack interconnects.

Can the BQ2028YZGT operate without an external pull-up resistor on the HDQ pin?

No-the BQ2028YZGT HDQ pin is open-drain and requires an external pull-up resistor (10–22 kΩ to VDD) for proper logic-level definition and bus arbitration. Without it, HDQ signals cannot transition high, breaking all communication-including wakeup from SHUTDOWN mode. TI specifies 10-kΩ ±5% as the recommended value for reliable timing and noise immunity.

What is the role of the REGIN and VDD pins on the BQ2028YZGT?

REGIN is the input to the internal 2.5-V LDO regulator and must be connected to the battery's CELL+ node (2.45–4.5 V). VDD is the regulated 2.5-V output, powering the IC's digital core, HDQ I/O, and ADC-requiring a 0.47-µF ceramic capacitor to VSS for stability. This integrated regulation removes the need for an external LDO in battery-pack designs.

How is temperature data obtained from the BQ2028YZGT?

The BQ2028YZGT contains an internal die-temperature sensor whose analog output is digitized by a 10-bit ADC. Raw conversion results are stored in ADHI (high byte) and ADLOW (low byte) registers, accessible via HDQ. Host firmware must apply the known slope (–1.986 mV/°C) and perform linear conversion-TI does not embed temperature calculation in the device; it provides raw ADC data only.