Texas Instruments BQ29729DSER

Overview

BQ29729DSER 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 (1.25 s OVP, 20 ms UVP, 8 ms OCD/OCC, 250 µs SCP). It operates from –40°C to +85°C with 4 µA normal-mode current and 100 nA shutdown current in a 1.50 mm × 1.50 mm WSON-6 package, used in mobile handsets for cell-level FET gate control.

For engineers reviewing the BQ29729DSER datasheet, BQ29729DSER pinout, BQ29729DSER application, or BQ29729DSER equivalent, this page delivers verified electrical parameters, validated fault detection accuracy (±10 mV at 25°C), confirmed WSON-6 package mapping, and two field-validated alternative parts with documented threshold and timing differences - all extracted from TI's SLUSBU9I (August 2024) production datasheet.

Technical Context

The BQ29729DSER implements analog voltage sensing across external power FETs (V_DS monitoring on V–/VSS) to detect overcurrent conditions without a sense resistor, with ±10 mV typical accuracy at 25°C for both OCC and OCD. Its internal oscillator drives fixed-duration fault timers - including 1.25 s overcharge delay and 250 µs short-circuit response - all factory-programmed and non-adjustable.

It supports zero-voltage charging initiation at ≥1.7 V BAT–V– and inhibits charging below 0.75 V, enabling safe recovery of deeply depleted cells. The device operates in NORMAL mode (4 µA ICC) or ultra-low-power SHUTDOWN (100 nA I_Q) without requiring an external charger controller, making it suitable for always-on battery protection in portable systems.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar single-cell Li-ion battery protection applications.

Compared with BQ29729DSER, BQ29728DSER raises UVP to 2.800 V with 144 ms delay for robustness against load-induced voltage sag, while BQ29732DSER increases OCD to 0.190 V for reduced false triggering in high-current discharge paths - both retain identical WSON-6 packaging and 250 µs short-circuit response.

Availability

BQ29729DSER is available at Aetrix Electronics and suitable for mobile handsets, tablet PCs, and handheld data terminals requiring stable component supply, long-term lifecycle support, and guaranteed TI original material traceability.

Supply support for BQ29729DSER 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 solutions.

The BQ297xx family is designed specifically for cost-sensitive, space-constrained single-cell Li-ion/Li-polymer battery packs requiring autonomous, resistorless overcurrent protection and factory-configured safety thresholds.

FAQ

What is the overcharge detection voltage and delay for BQ29729DSER?

The BQ29729DSER has a factory-programmed overcharge detection voltage of 4.275 V with ±10 mV accuracy at 25°C and a fixed detection delay of 1.25 seconds. Once triggered, the COUT output pulls low to disable the charge FET. The overcharge release hysteresis is 100 mV, meaning the cell voltage must drop to 4.175 V before recovery. This value is laser-trimmed and not user-adjustable.

Does BQ29729DSER support zero-voltage charging, and what are the thresholds?

Yes, BQ29729DSER supports zero-voltage charging initiation when BAT–V– ≥ 1.7 V, allowing safe charging of fully depleted cells. Charging is inhibited if BAT–V– falls below 0.75 V to prevent lithium plating. These thresholds are fixed at wafer test and do not require external configuration - they are integral to the BQ29729DSER's protection architecture.

What package type and dimensions does BQ29729DSER use?

BQ29729DSER uses the WSON-6 (DSE) package: 1.50 mm × 1.50 mm × 0.75 mm body size with wettable flanks and an exposed thermal pad. Pinout is NC/COUT/DOUT/VSS/BAT/V– in top-view order. This package is RoHS-compliant, halogen-free, and qualified for reflow per JEDEC J-STD-020.

How does BQ29729DSER detect overcurrent without a sense resistor?

BQ29729DSER performs V_DS-based sensing across external NMOS FETs using the V– and VSS pins. It measures the voltage drop between these terminals to detect charge overcurrent (VOCC = –0.100 V) and discharge overcurrent (VOCD = 0.130 V) with ±10 mV accuracy at 25°C - eliminating the need for a discrete sense resistor and associated board area and power loss.

What are the key differences between BQ29729DSER and BQ29728DSER?

BQ29729DSER uses 4.275 V OVP, 2.300 V UVP, and 20 ms UVP delay, while BQ29728DSER uses 4.280 V OVP, 2.800 V UVP, and 144 ms UVP delay. Both share identical WSON-6 packaging, 250 µs short-circuit response, and V_DS-based overcurrent sensing. The UVP difference makes BQ29728DSER more tolerant of voltage sag during high-current pulses.