STMicroelectronics STBC21FTR

Overview

STBC21FTR from STMicroelectronics is a programmable constant-current/constant-voltage Li-ion battery charger IC for single-cell applications, featuring I²C-configurable floating voltage (default 4.2 V), pre-charge current up to 72 mA, fast-charge current up to 1.1 A via external resistor, thermal regulation per JEITA/PSE, and reverse-battery polarity protection. It integrates all power path control in HTSSOP-14, eliminating external MOSFETs, sense resistors, or blocking diodes.

For engineers reviewing the STBC21FTR datasheet, STBC21FTR pinout, STBC21FTR application, or STBC21FTR equivalent, key selection considerations include I²C-programmable charge parameters, ±2 kV HBM ESD rating, -25 °C to 125 °C junction temperature operation, thermal shutdown at 115 °C, and dual open-drain LED status outputs with configurable flash patterns.

Technical Context

The STBC21FTR implements a three-phase charging algorithm: low-voltage pre-charge (<3.0 V, timeout 60 min), fast-charge (programmable up to 1.1 A), and constant-voltage termination (4.2 V ±0.7% tolerance). It uses an internal NVM to store floating voltage, termination current (40–190 mA in 10 mA steps), and auto-recharge thresholds.

Thermal regulation is enforced via an external NTC connected to the TEMP pin, with programmable high/low temperature thresholds (e.g., 10 °C and 45 °C default safety range) and hysteresis; outside this range, floating voltage is dynamically reduced. The I²C interface supports sequential register read/write for full configuration and real-time status monitoring.

Key Specifications

Pinout & Package

HTSSOP-14 (5 mm × 4.4 mm, 0.65 mm pitch) with exposed thermal pad (not electrically connected). Package supports high-power dissipation with R_thJA = 37.6 °C/W on standard 1S2P PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ24195RGER and MP2617GQ-Z, the STBC21FTR uniquely combines nonvolatile I²C-programmable parameters, hardware-enforced JEITA compliance, and integrated reverse-polarity blocking - making it optimal for unattended, safety-critical, or thermally variable deployments.

Availability

STBC21FTR is available at Aetrix Electronics and suitable for portable medical devices, industrial handheld terminals, smart home security cameras, and wearable health monitors requiring stable component supply, long-lifecycle support, and production-ready qualification.

Supply support for STBC21FTR 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 microcontrollers, power management ICs, sensors, and analog chips for industrial, automotive, and consumer markets.

The STBC21 product line delivers highly integrated, safety-certified Li-ion charging solutions targeting space-constrained, thermally demanding, and regulatory-sensitive applications such as medical wearables and ruggedized IoT endpoints.

FAQ

What is the maximum allowable input voltage for STBC21FTR?

The absolute maximum VCC rating is 10 V, but the functional operating range is 2.6 V to 9.0 V. Overvoltage protection triggers at 8.55–9.45 V (typ. 9.0 V), clamping the input and halting charging. Sustained operation above 9.0 V risks permanent damage and voids warranty compliance.

How does the STBC21FTR handle a reversed battery connection?

The device incorporates dedicated hardware reverse-polarity protection on the BAT pin. If the battery is inserted backward, internal circuitry blocks current flow and prevents damage to the IC or external components - no external diode or MOSFET is required. This feature is active at all times, including during standby.

Can the STBC21FTR operate without an external NTC thermistor?

Yes - the TEMP pin can be left unconnected or tied to a fixed voltage to disable thermal regulation. In that mode, the device operates with fixed 4.2 V floating voltage and full charge current, but loses JEITA/PSE compliance and thermal safety features. Default behavior assumes NTC is present.

What is the purpose of the PHC pin, and what external component is required?

The PHC pin drives an external photo-coupler (e.g., PC817) to provide isolated feedback to an AC-DC adapter's primary-side controller. It sinks up to 10 mA and requires a series current-limiting resistor (typically 1 kΩ) between PHC and the optocoupler anode. No pull-up is needed - the driver is active-low open-drain.