Texas Instruments BQ29701DSER

Overview

BQ29701DSER from Texas Instruments is a single-cell Li-ion/Li-polymer battery protection IC that provides overvoltage (4.280 V), undervoltage (2.300 V), charge overcurrent (–0.100 V), discharge overcurrent (0.125 V), and short-circuit (0.5 V) detection with factory-programmed thresholds and fixed delay timers. It drives external CHG/DSG FETs, operates from –40°C to +85°C, and consumes only 4 µA in NORMAL mode - enabling long-term standby in portable power systems such as tablet PCs and handheld data terminals.

For engineers reviewing the BQ29701DSER datasheet, BQ29701DSER pinout, BQ29701DSER application, or BQ29701DSER equivalent, this page delivers verified technical context, exact pin functions, real-world protection timing behavior, and validated alternative options for battery pack safety design.

Technical Context

The BQ29701DSER implements analog voltage sensing across external FETs (V– to VSS differential path) to detect overcurrent conditions with ±5 mV typical accuracy, while using internal comparators and fixed-timer logic to trigger CHG/DSG gate drive outputs. Its fault recovery mechanism enforces 8 ms (UVP/OCC/OCD) or 12 ms (OVP) delays before re-enabling FETs after threshold clearance.

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 without a battery charger present and features factory-programmed thresholds - no external configuration or microcontroller interface required.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ29700DSER and BQ29702DSER, the BQ29701DSER offers a balanced trade-off: moderate OVP (4.280 V) for compatibility with standard CC/CV chargers, lower UVP (2.300 V) for aggressive energy extraction, and optimized OCD (0.125 V) for mid-range FET R_DS(on) use - making it ideal for cost-sensitive consumer electronics with defined thermal envelopes.

Availability

BQ29701DSER is available at Aetrix Electronics and suitable for tablet PCs, mobile handsets, and handheld data terminals requiring stable component supply, long-term lifecycle support, and guaranteed traceability for safety-critical battery systems.

Supply support for BQ29701DSER 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 experience in battery safety IC design.

The BQ297xx family was engineered specifically for single-cell Li-ion/Li-polymer pack protection - delivering factory-programmed, resistorless, ultra-low-power fault detection without software or external components.

FAQ

What protection functions does the BQ29701DSER provide?

The BQ29701DSER provides overcharge (OVP), over-discharge (UVP), charge overcurrent (OCC), discharge overcurrent (OCD), and load short-circuit (SCD) protection. Each function uses factory-programmed voltage thresholds and fixed delay timers - for example, OVP triggers at 4.280 V with 1.25 s delay, and SCD responds within 250 µs. All protections operate autonomously without host intervention, making BQ29701DSER a self-contained safety solution for single-cell Li-ion packs.

How does the BQ29701DSER detect overcurrent without a sense resistor?

The BQ29701DSER detects overcurrent by measuring the voltage drop (V_DS) across the external discharge or charge FET using its V– and VSS pins. For discharge overcurrent, it monitors V– relative to VSS; for charge overcurrent, it senses VSS relative to V–. With ±5 mV typical accuracy, this method leverages the FET's intrinsic on-resistance - eliminating the need for a separate current-sense resistor and reducing BOM cost and PCB area. This capability is integral to the BQ29701DSER architecture.

What is the purpose of the V– pin on the BQ29701DSER?

The V– pin on the BQ29701DSER serves as the differential sense input for overcurrent and short-circuit detection. It forms one side of the measurement path with VSS to monitor V_DS across the external FETs. A 2.2 kΩ resistor connects V– to PACK– in typical layouts to bias the internal current sink and enable accurate V_DS sampling. This pin is essential for the BQ29701DSER's resistorless protection scheme and must be routed with controlled impedance to maintain noise immunity.

Does the BQ29701DSER support zero-voltage charging?

Yes, the BQ29701DSER supports zero-voltage charging: it allows charging initiation when the cell voltage is near 0 V, provided the BAT–V– voltage is ≥1.7 V. Charging is inhibited if BAT–VSS falls below 0.75 V - preventing unsafe current injection into damaged or shorted cells. This dual-threshold behavior is hard-coded into the BQ29701DSER and requires no external configuration, enabling reliable recovery of deeply depleted batteries in consumer devices.

What package type and dimensions does the BQ29701DSER use?

The BQ29701DSER uses a 6-pin WSON (DSE) package with nominal dimensions of 1.50 mm × 1.50 mm × 0.75 mm. It features wettable flanks for automated optical inspection and is compatible with standard reflow profiles. This ultra-compact package minimizes PCB footprint - critical for space-constrained applications like smartphones and wearables - and is the only package option listed for the BQ29701DSER in TI's official documentation.