STMicroelectronics STBC02AJR

Overview

STBC02AJR from STMicroelectronics is a highly integrated Li-Ion linear battery charger IC with embedded 150 mA LDO regulator, two 3 Ω SPDT load switches, smart reset/watchdog generator, and protection circuit module (PCM). It delivers up to 450 mA fast charge current, supports programmable floating voltage up to 4.45 V, and features automatic power path management and shipping mode with <10 nA battery leakage. It is designed for space-constrained wearable devices such as smartwatches.

For engineers reviewing the STBC02AJR datasheet, STBC02AJR pinout, STBC02AJR application, or STBC02AJR equivalent, key selection considerations include CC/CV charging compliance, dual SPDT switch integration, LDO output voltage option (3.0/3.1/3.3 V), battery overcharge/discharge thresholds (VOCHG = 4.275 V typ, VODC = 2.8 V typ), and Flip Chip 30 package compatibility with 0.4 mm pitch PCB layout.

Technical Context

The STBC02AJR implements a dual-stage CC/CV charging algorithm with independently programmable fast charge (via ISET) and pre-charge (via IPRE) currents using external resistors. End-of-charge termination is set at 5% of IFAST by default, with configurable timeout (14–22 s) and thermal warning (135 °C) / shutdown (155 °C) thresholds.

Its power architecture includes automatic input/battery source selection on SYS, bidirectional power path control, and SWIRE-controlled functional enablement (e.g., BATMS monitoring, shipping mode exit). The integrated PCM monitors battery voltage (BATSNS/BATSNSFV), temperature (NTC), and discharge current (IBATOCP = 900 mA), triggering protection events with defined deglitch timing (tOCD = 1.2 s, tODD = 60 ms).

Key Specifications

Pinout & Package

STBC02AJR is housed in a Flip Chip 30 package (2.25 × 2.59 mm, 0.4 mm pitch), optimized for ultra-thin wearable PCBs with bottom-side bump interconnects and minimal footprint.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Li-Ion linear charger with integrated LDO and protection applications.

Compared with BQ24075RGTR and MAX1555, STBC02AJR uniquely consolidates charging, regulation, switching, reset, and protection into one Flip Chip 30 package-reducing component count by ≥6, eliminating 3–4 external passives, and enabling sub-10 mm² power subsystem layouts essential for modern wearables.

Availability

STBC02AJR is available at Aetrix Electronics and suitable for smartwatches, fitness trackers, wireless earbud cases, and portable medical patches requiring stable component supply, long-term lifecycle support, and automotive-grade reliability in compact form factors.

Supply support for STBC02AJR 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 STBC02AJR belongs to ST's STBC family of highly integrated battery management ICs, engineered specifically for ultra-low-power, space-constrained wearable electronics requiring single-chip solutions for charging, regulation, protection, and system supervision.

FAQ

What is the maximum programmable floating voltage for STBC02AJR, and how is it set?

The STBC02AJR supports a maximum floating voltage of 4.45 V, set by connecting an external resistor between the BATSNSFV pin and the battery positive terminal. Using Equation 2 from the datasheet (Vfloatadj = 4.2 V × (1 + Rfloat / 1 MΩ)), a 35.7 kΩ resistor achieves 4.35 V; scaling Rfloat adjusts VFLOAT linearly up to 4.45 V. Default is 4.2 V when BATSNSFV is shorted to BATSNS.

How does the STBC02AJR manage power source selection between USB input and battery?

The STBC02AJR uses automatic power path management to prioritize IN (USB) when valid (4.55–5.4 V), powering SYS and charging the battery simultaneously. When IN is absent or invalid (<3.9 V), it seamlessly switches SYS to BAT without interruption. Table 7 in DS11617 confirms SYS sourcing logic depends on VIN, VBAT, and protection states-not software control-ensuring glitch-free transitions.

Can the two SPDT load switches be used independently, and what are their voltage/current limits?

Yes, SW1 (SW1_OA/SW1_OB) and SW2 (SW2_OA/SW2_OB) operate independently under SWIRE control. Each switch handles 1.8–5 V input (SWx_I) and supports 50 mA continuous current with R_ON of 2.0–3.8 Ω. They are not bidirectional; current flows only from input to selected output. Unused inputs/outputs must be tied to GND per datasheet guidance to prevent floating nodes.

What triggers the "shipping mode," and how is it exited?

Shipping mode activates automatically when VBAT drops below VODC (2.8 V) and VIN is absent, reducing battery leakage to <10 nA. It is exited by applying a valid high pulse (>1.6 V, >1.2 ms width) to the WAKE-UP pin-only if VBAT has recovered above VODCR (3.0 V). The internal 50 kΩ pull-down ensures robust noise immunity; no external circuitry is required for entry or exit.