STMicroelectronics STW4102IQT

Overview

STW4102IQT from STMicroelectronics is a dual-input (USB/wall adapter) standalone linear Li-ion battery charger with integrated gas gauge and 4.7 V LDO regulator. It delivers up to 1 A fast charge current from wall adapter and 500 mA from USB, supports programmable charge voltage (4.1–4.35 V ±1%), includes thermal regulation, end-of-charge detection, and I²C interface for system monitoring - used in cellular phones, portable navigation devices, and USB-powered appliances.

For engineers reviewing the STW4102IQT datasheet, STW4102IQT pinout, STW4102IQT application, or STW4102IQT equivalent, key selection considerations include dual-input power path management, 13-bit gas gauge ADC accuracy (±3% uncalibrated), I²C register control of charge parameters, and QFN-24 package thermal performance under 1 A load.

Technical Context

The STW4102IQT implements independent CC/CV charge control paths for MAIN (wall adapter, up to 16 V, 1 A) and USBPWR (4.25–5.5 V, ≤500 mA) inputs, with automatic priority given to MAIN when both are present. Charge termination uses EOCHG open-drain output triggered at 10% of programmed current, with 5% hysteresis.

Its gas gauge subsystem employs a 13-bit signed ADC (23.5 µV LSB) measuring current via external sense resistor (e.g., 30 mΩ), while battery voltage monitoring uses a separate 7–12-bit ADC (1.42 mV LSB at 12-bit). The 4.7 V LDO regulator is driven by LDODRV and regulated via LDOFB using an external PMOS.

Key Specifications

Pinout & Package

STW4102IQT is housed in a thermally enhanced QFN-24 (4 × 4 mm, 0.5 mm pitch) package with exposed thermal pad for PCB heat dissipation. Pin numbering follows top-view layout with pins 1–12 on top row (left to right), 13–24 on bottom row (right to left).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-input Li-ion charger applications.

Compared with BQ24075RGTR and MAX1555ESA+, STW4102IQT uniquely integrates dual-input power path selection, 13-bit gas gauge, 4.7 V LDO, and I²C configurability - making it the only option among the three that supports full autonomous battery management in space-constrained portable systems.

Availability

STW4102IQT is available at Aetrix Electronics and suitable for cellular phones, portable navigation devices, digital cameras, and Bluetooth headsets requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial and consumer OEM programs.

Supply support for STW4102IQT 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.

The STW4102 belongs to ST's battery management IC product line, engineered specifically for single-cell Li-ion charging in portable electronics with integrated fuel gauging and system power rail generation - targeting space-constrained, cost-sensitive, and thermally demanding applications.

FAQ

What is the maximum allowable input voltage on the MAIN pin?

The absolute maximum rating for MAIN is 20 V, but the recommended operating range is 4.25–16 V per datasheet Table 3. Exceeding 16 V risks violating operating conditions and may trigger overvoltage protection or damage internal circuitry. Thermal regulation remains active within this range to limit die temperature to 125 °C.

How does the STW4102IQT handle simultaneous connection of MAIN and USBPWR inputs?

When both MAIN and USBPWR are present, the device automatically selects MAIN as the primary charge source and disables USBPWR charging. This behavior is hardwired and cannot be overridden via I²C. PWRDETECTN reflects the first detected input, and EOCHG status reflects only the active (MAIN) charge path.

Can the gas gauge function operate independently of charging?

Yes - the gas gauge subsystem (13-bit ADC, accumulator, and current sense circuitry) operates continuously when enabled via CG_ENA bit, regardless of whether charging is active. It draws only 90 µA during operation and 1 µA in off-mode, enabling accurate runtime estimation even during system sleep or battery-only operation.

What external components are mandatory for basic operation?

Mandatory components include: (1) ISET resistor (12–120 kΩ) to set MAIN charge current; (2) 1 µF CVIS decoupling capacitor (C2); (3) 1 µF internal supply capacitor (C1); (4) 30 mΩ sense resistor between ICG+ and ICG−; (5) 0.1–1 µF decoupling capacitors on MAIN and USBPWR inputs (C4, C5). LDO and high-current extensions require additional external FETs and feedback components.