Texas Instruments BQ29729DSET

Overview

BQ29729DSET from Texas Instruments is a single-cell Li-ion/Li-polymer battery protection IC that integrates overvoltage (4.275 V), undervoltage (2.300 V), charge/discharge overcurrent (–0.100 V / 0.130 V), and short-circuit (0.5 V) detection with factory-programmed thresholds and fixed timing delays. It drives external CHG/DSG FETs and supports zero-voltage charging for deeply depleted cells in portable power systems.

For engineers reviewing the BQ29729DSET datasheet, BQ29729DSET pinout, BQ29729DSET application, or BQ29729DSET equivalent, this device delivers verified ±10 mV OVP/UVP accuracy at 25°C, 4 µA NORMAL-mode current, 6-pin WSON (1.50 mm × 1.50 mm) packaging, and integrated V– sense node for high-accuracy V_DS-based current monitoring - critical for compact, low-power battery packs.

Technical Context

The BQ29729DSET implements analog comparator-based fault detection with internal reference trimming and fixed-delay timers for OVP (1.25 s), UVP (20 ms), OCC (8 ms), OCD (8 ms), and SCP (250 µs). Its dual FET gate drive outputs (COUT/DOUT) operate referenced to BAT and VSS respectively, enabling direct control of NMOS charge and discharge switches without level-shifting circuitry.

Voltage sensing occurs across external FETs via the V–/VSS differential pair, achieving ±5 mV typical OCP accuracy. The device operates from –40°C to +85°C with 4 µA quiescent current in NORMAL mode and enters 100 nA shutdown when BAT < 1.5 V - supporting long-term storage and ultra-low-power standby in handheld devices.

Key Specifications

Pinout & Package

Package: 6-pin WSON (DSE), 1.50 mm × 1.50 mm × 0.75 mm body size, wettable flank terminals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ29729DSET, BQ29728DSET offers higher UVP (2.800 V vs. 2.300 V) for conservative discharge management, while BQ29733DSET provides elevated OVP (4.400 V vs. 4.275 V) and tighter OCD (±10 mV vs. ±10 mV but lower nominal threshold), making it suitable for advanced Li-ion chemistries requiring stricter voltage margins.

Availability

BQ29729DSET is available at Aetrix Electronics and suitable for smartphone battery packs, tablet PC power systems, and handheld data terminals requiring stable component supply, full traceability, and lifecycle continuity assurance.

Supply support for BQ29729DSET 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 battery safety IP.

The BQ297xx family was designed specifically for cost-effective, highly integrated single-cell Li-ion/Li-polymer protection - targeting compact, low-power consumer and industrial portable electronics where reliability and minimal external components are essential.

FAQ

What is the overcharge protection voltage threshold for BQ29729DSET?

The BQ29729DSET has a factory-programmed overcharge detection voltage (VOVP) of 4.275 V with ±10 mV accuracy at 25°C. This threshold is fixed and cannot be adjusted externally. The device asserts COUT low after a 1.25-second delay when BAT–VSS exceeds this value, disabling the charge FET to prevent cell damage. Recovery occurs 12 ms after voltage drops below VOVP – 100 mV hysteresis.

Does BQ29729DSET support zero-voltage charging, and what is the activation condition?

Yes, BQ29729DSET supports zero-voltage charging. It enables charging of fully depleted cells when the charger voltage applied to the BAT pin reaches ≥1.7 V, as specified by the V0CHG parameter. This function is active only when the battery voltage is near 0 V and allows safe pre-charge initiation without external circuitry - a key feature for recovering stored devices.

How does BQ29729DSET detect discharge overcurrent, and what is the sensing method?

BQ29729DSET detects discharge overcurrent by measuring the voltage difference between the V– and VSS pins, which corresponds to the V_DS across the external discharge FET. When this differential exceeds the factory-set 0.130 V threshold (±10 mV at 25°C), the device triggers DOUT low after an 8 ms delay. This method eliminates the need for a separate current-sense resistor, reducing power loss and PCB area.

What is the quiescent current consumption of BQ29729DSET in normal operation?

BQ29729DSET draws 4 µA typical current in NORMAL mode at TA = 25°C and BAT = 3.8 V, with a maximum of 5.5 µA across temperature and voltage ranges. This ultra-low supply current ensures minimal impact on battery runtime during active protection monitoring - critical for always-on portable applications like smartphones and wearables.

What package type and dimensions does BQ29729DSET use?

BQ29729DSET is housed in a 6-pin WSON (DSE) package measuring 1.50 mm × 1.50 mm × 0.75 mm with wettable flanks. This compact, leadless封装 supports automated optical inspection (AOI) and provides excellent thermal performance (θJA = 190.5°C/W), making it ideal for space-constrained battery pack designs in consumer electronics.