onsemi FUSB303BTMX

Overview

FUSB303BTMX from onsemi is a fully autonomous USB Type-C port controller optimized for ≤15 W applications, supporting Source, Sink, and DRP roles with Dead Battery operation, 2.85–5.5 V supply, ultra-low ICC < 10 µA standby current, and 4 kV HBM ESD protection on CC/ID/VBUS_DET pins - deployed in smartphones, power banks, and industrial USB-C interfaces.

For engineers reviewing the FUSB303BTMX datasheet, pinout, applications, or equivalent options, key selection criteria include CC logic detection accuracy, I²C address configurability (42h/62h), GPIO-mode port role control, 28 V DC tolerance on CC1/CC2/VBUS_DET, and support for Try.SRC/Try.SNK state machines in DRP implementations.

Technical Context

The FUSB303BTMX implements dual-mode operation: autonomous GPIO-based port role configuration (via PORT/DEBUG_N and ADDR/ORIENT pins) or I²C slave-controlled operation with programmable address (42h or 62h). Its CC detection logic complies with USB Type-C Specification Release 1.3, including Ra/Rd threshold detection (e.g., vRa−SRCdef = 0.20 V, vRd−3.0A = 2.11 V) and orientation decoding via ORIENT output.

It integrates dedicated hardware state machines for SRC, SNK, DRP, and accessory detection (Audio/Debug), with built-in remedial actions (REMEDY_EN), AUTOSNK mode for weak-battery sink enforcement, and configurable debounce timing (TCCDEB[2:0] = 011 → 130 ms typical). All functions operate within −40°C to +85°C ambient and tolerate up to 28 V on CC/VBUS_DET pins.

Key Specifications

Pinout & Package

Package: 12-lead QFN (1.6 mm × 1.6 mm × 0.375 mm, Case 722AG), thermally enhanced with exposed pad.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar USB-C port controller applications.

Compared with STUSB4500QTR and TUSB320LAR, the FUSB303BTMX uniquely delivers full autonomous operation with Dead Battery support, GPIO-mode simplicity, and 28 V CC tolerance - making it optimal for compact, battery-constrained USB-C endpoints without PD complexity.

Availability

FUSB303BTMX is available at Aetrix Electronics and suitable for smartphones, power banks, and industrial USB-C interfaces requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for FUSB303BTMX 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

onsemi is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, and IoT applications.

The FUSB303BTMX belongs to onsemi's USB Type-C port controller product line, designed specifically for autonomous, low-power, ≤15 W USB-C endpoint applications with robust fault tolerance and minimal host processor dependency.

FAQ

What is the operating voltage range for the FUSB303BTMX?

The FUSB303BTMX operates from 2.85 V to 5.5 V on its VDD supply pin. This range supports direct connection to single-cell Li-ion batteries (nominal 3.7 V, 3.0–4.2 V range) and standard 3.3 V or 5 V system rails. The device maintains full functionality across this range, including CC detection thresholds and I²C communication, with typical ICC < 10 µA in unattached standby - making it ideal for battery-powered USB-C endpoints like power banks and portable devices. The FUSB303BTMX also features 28 V DC tolerance on CC1, CC2, and VBUS_DET pins independent of VDD level.

Does the FUSB303BTMX support Dead Battery operation, and how does it work?

Yes, the FUSB303BTMX supports Dead Battery operation: when VDD = 0 V and the device is attached to a USB-C source, the FUSB303BTMX activates its internal Rd pull-down on the connected CC line, allowing the source to detect attachment and initiate VBUS. This occurs without any external power - the source's VBUS supplies operating current through the CC line. The FUSB303BTMX then transitions to Sink mode and asserts VBUSOK once VBUS exceeds 3.67 V. This feature is essential for emergency charging of powered-off devices such as laptops or tablets. The FUSB303BTMX implements this autonomously; no host processor or firmware is required to enable or manage Dead Battery mode.

How does the FUSB303BTMX handle USB-C cable orientation detection?

The FUSB303BTMX detects cable orientation via its ADDR/ORIENT pin and STATUS.ORIENT[1:0] register bits. When configured in GPIO mode (ADDR/ORIENT = float at power-up), the pin becomes a push-pull ORIENT output: LOW indicates CC1 (A5) is active, HIGH indicates CC2 (B5) is active. In I²C mode, orientation is reported in Status register bitfield ORIENT[1:0], updated after each attach event. The FUSB303BTMX decodes orientation based on Ra/Rd detection patterns on both CC lines - for example, SNK.Rp on CC1 + SNK.Open on CC2 yields ORIENT = 01. This real-time orientation signal enables firmware to route USB 2.0 or audio signals correctly without relying on host-side enumeration delays. The FUSB303BTMX does not require external mux control logic for orientation handling.

Can the FUSB303BTMX be used without an I²C host processor?

Yes, the FUSB303BTMX supports full autonomous operation without an I²C host processor using its GPIO mode. Port role (Source/Sink/DRP) is set at power-up by the voltage level on PORT/DEBUG_N (HIGH = Source, LOW = Sink, float = DRP), while I²C address and mode are selected via ADDR/ORIENT (float = GPIO mode). Current advertisement (80/180/330 µA) is controlled by GPIO[1:2] states or CONTROL register HOST_CUR[1:0]. Interrupts and status are indicated on INT_N/OUT3 (LOW = Audio accessory) and ID (LOW = Source). All state machines - including Try.SRC/SNK, AUTOSNK, and remedial attach recovery - run entirely in hardware. The FUSB303BTMX requires only VDD, GND, CC1/CC2, VBUS_DET, and optional EN_N - no I²C lines needed for basic USB-C functionality.

What are the ESD and overvoltage protection ratings for the FUSB303BTMX connector pins?

The FUSB303BTMX provides 4 kV HBM ESD protection on CC1, CC2, and VBUS_DET pins per JEDEC JESD22-A114, and 28 V DC overvoltage tolerance on those same pins - exceeding USB-C specification requirements. This eliminates the need for external TVS diodes in most consumer and industrial applications. The 28 V rating protects against misbehaving or non-compliant USB-C sources that may drive excessive VBUS or CC voltages. For systems requiring >28 V tolerance (e.g., automotive 48 V domains), an external 900 kΩ resistor plus TVS can extend protection - but the FUSB303BTMX itself sustains 28 V continuously. Note that ID and EN_N pins have lower 6 V tolerance (per Table 7), so they must remain within VDD ±0.3 V.