Texas Instruments BQ29704DSER

Overview

BQ29704DSER from Texas Instruments is a single-cell Li-ion/Li-polymer battery protection IC that integrates overvoltage (4.425 V), undervoltage (2.500 V), charge/discharge overcurrent (–0.100 V / 0.125 V), and short-circuit (0.5 V) detection with factory-programmed thresholds and fixed timing delays. It drives external CHG/DSG FETs via dedicated COUT/DOUT outputs and supports zero-voltage charging for deeply depleted cells in portable power systems.

For engineers reviewing the BQ29704DSER datasheet, BQ29704DSER pinout, BQ29704DSER application, or BQ29704DSER equivalent, this device delivers precise, low-quiescent-current (4 µA NORMAL mode) cell-level protection without requiring a host controller-ideal for space-constrained, cost-sensitive battery packs in handheld electronics.

Technical Context

The BQ29704DSER implements independent analog comparators with internal reference voltages to monitor BAT–VSS (OVP/UVP), V––VSS (OCD/SCP), and VSS–V– (OCC) with ±10 mV accuracy at 25°C. Fault detection triggers fixed-delay timers (e.g., 1.25 s OVP delay, 20 ms UVP delay, 8 ms OCD delay), after which COUT or DOUT transitions low to disable the respective FET.

It operates across –40°C to +85°C with input voltage range up to 8 V on BAT and tolerates up to BAT – 25 V on V–. The device enters 100 nA shutdown mode when both BAT and V– fall below 1.5 V, and features built-in 0 V charging enablement above 1.7 V BAT–V– differential.

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 BQ29704DSER, BQ29702DSER offers higher UVP (2.800 V) for conservative cell preservation but slower UVP response (96 ms), whereas BQ29703DSER provides lower UVP (2.300 V) for extended runtime at the cost of reduced safety margin-both share identical package, pinout, and core architecture.

Availability

BQ29704DSER is available at Aetrix Electronics and suitable for smartphone battery packs, tablet PC power management, and handheld data terminals requiring stable component supply with full industrial temperature support and long-lifecycle availability.

Supply support for BQ29704DSER 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, precision, and energy efficiency.

The BQ297xx family is designed specifically for cost-effective, standalone protection of single-cell Li-ion/Li-polymer battery packs in consumer portable electronics-prioritizing minimal external components, factory-trimmed accuracy, and ultra-low power consumption.

FAQ

What is the overvoltage protection threshold for BQ29704DSER?

The BQ29704DSER has a factory-programmed overvoltage protection (OVP) threshold of 4.425 V ±10 mV at 25°C. This value is fixed and cannot be adjusted externally. When the BAT–VSS voltage exceeds this threshold for 1.25 seconds, the BQ29704DSER pulls COUT low to disable the charge FET. Recovery occurs 12 ms after the voltage drops below 4.325 V (100 mV hysteresis).

Does BQ29704DSER support zero-voltage charging?

Yes, BQ29704DSER supports zero-voltage charging: it allows charging of fully depleted cells when the BAT–V– differential reaches ≥1.7 V. Charging is inhibited if BAT–V– falls below 0.75 V. This function is implemented entirely in hardware and requires no external configuration or host intervention-enabling safe recovery of deeply discharged Li-ion cells.

What are the key timing parameters for fault detection in BQ29704DSER?

BQ29704DSER uses fixed factory-programmed timing: overcharge detection delay is 1.25 s, over-discharge delay is 20 ms, discharge overcurrent delay is 8 ms, charge overcurrent delay is 8 ms, and short-circuit detection delay is 250 µs. All recovery delays are also fixed-12 ms for OVP, and 8 ms for UVP/OCC/OCD-ensuring deterministic, repeatable protection behavior without software dependency.

How does BQ29704DSER sense overcurrent conditions?

BQ29704DSER senses overcurrent by measuring voltage differentials across external FETs: V––VSS for discharge overcurrent (OCD) and VSS–V– for charge overcurrent (OCC). For example, an OCD event triggers when V––VSS exceeds 0.125 V for 8 ms. The device does not use a sense resistor; instead, it leverages the R_DS(on) of the external FET as the current-sensing element, reducing component count and board space.

What package type and dimensions does BQ29704DSER use?

BQ29704DSER uses a 6-pin WSON package labeled DSE, with nominal dimensions of 1.50 mm × 1.50 mm × 0.75 mm and wettable flank terminals. This ultra-compact, leadless package supports automated optical inspection (AOI) and is optimized for high-density portable PCB layouts. Pin 1 is NC (no connection), and the exposed thermal pad is not electrically connected.