Texas Instruments BQ24055DSST

Overview

BQ24055DSST from Texas Instruments is a 1-A single-cell Li-Ion/Li-Pol linear battery charger IC with integrated USB/adapter auto-detection, 1% voltage regulation accuracy, 10% current regulation accuracy, and JEITA-compliant thermal management via NTC thermistor interface. It delivers regulated 4.20 V ±1% charge voltage and supports programmable fast-charge current up to 1 A using an external ISET resistor, targeting compact wearable and audio accessories.

For engineers reviewing the BQ24055DSST datasheet, BQ24055DSST pinout, BQ24055DSST application, or BQ24055DSST equivalent, key selection considerations include its 2-mm × 2-mm WSON-10 package, automatic D+/D− source detection logic, TTDM (termination/timer disable mode) for thermistor-based battery absence handling, and dual-input current limit configuration (100 mA / 500 mA) via ISET2 pin control.

Technical Context

The BQ24055DSST implements a three-phase linear charging algorithm-preconditioning, constant-current, and constant-voltage-with internal thermal regulation at 125 °C and hard shutdown at 150 °C. Its input overvoltage protection triggers at 6.65 V (typ), and dynamic power management (DPM) maintains minimum 4.4 V input during USB operation to sustain system load while charging.

Charge termination and precharge thresholds are set by a single external resistor on the PRETERM pin, enabling simultaneous programming of both values (e.g., 10% termination and 20% precharge of fast-charge current). The TS pin supports either 10-kΩ or 100-kΩ NTC thermistors with bias currents of 50 μA or 5 μA respectively, and enters TTDM when pulled above 1.6 V.

Key Specifications

Pinout & Package

Package: 10-pin WSON (DSQ), 2.00 mm × 2.00 mm body size with exposed thermal pad electrically connected to VSS.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar single-cell Li-Ion linear charger applications.

Compared with BQ24055DSST, BQ24075TARGER offers simpler USB current limiting but omits D+/D− detection and JEITA, while MP2617GQBE provides higher current and digital control at the cost of NTC integration and increased BOM count.

Availability

BQ24055DSST is available at Aetrix Electronics and suitable for wireless headphones, smart wristbands, smart door locks, and low-power handheld devices requiring stable component supply across production lifecycles.

Supply support for BQ24055DSST 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 and embedded processing technologies, with decades of expertise in power management IC design.

The BQ2405x product line targets space-constrained portable electronics, delivering highly integrated, USB-friendly linear chargers with minimal external components and robust safety features.

FAQ

What is the maximum input voltage rating for the BQ24055DSST?

The BQ24055DSST has an absolute maximum input voltage rating of 30 V on the IN pin, with integrated 6.65-V overvoltage protection that clamps and disables charging if exceeded. This allows safe operation with low-cost unregulated AC adapters up to 28 V nominal input, as specified in the recommended operating conditions.

How does the BQ24055DSST handle battery absence during charging?

The BQ24055DSST enters Termination/Timer Disable Mode (TTDM) when the TS pin voltage exceeds 1.6 V, which occurs when the battery thermistor remains connected but the battery pack is removed. In TTDM, charge termination and the 10-hour safety timer are disabled, preventing false fault lockout and enabling safe reinsertion of the battery without power cycling.

Can the BQ24055DSST support both 10-kΩ and 100-kΩ NTC thermistors?

Yes - the BQ24055DSST supports both 10-kΩ (BQ24050 variant) and 100-kΩ (BQ24052 variant) NTC thermistors via different internal bias currents: 50 μA for 10-kΩ and 5 μA for 100-kΩ. The TS pin thresholds (e.g., 0.278 V at 45 °C) are calibrated for each type, and the datasheet specifies distinct resistor ranges to avoid unintended TTDM entry.

What is the purpose of the ISET2 pin on the BQ24055DSST?

The ISET2 pin configures the input current limit mode: HIGH selects 500-mA USB limit, FLOAT selects 100-mA USB limit, and LOW enables adaptor-mode current defined by the ISET resistor. This pin allows hardware-selectable USB compliance without firmware intervention and overrides initial D+/D− detection results once asserted.

Does the BQ24055DSST require external MOSFETs or diodes for operation?

No - the BQ24055DSST integrates all power switching, current sensing, and regulation circuitry internally. It requires only five external components for basic operation: two input/output bypass capacitors (1 μF each), one ISET resistor, one PRETERM resistor, and one NTC thermistor. No external FETs, diodes, or sense resistors are needed.