### FT201XS-R: Full-Speed USB to I2C Bridge IC The **FT201XS-R** is a compact, power-efficient USB-to-I2C interface bridge developed by FTDI Chip. It is part of the **FT-X series**, specifically designed to reduce component count and PCB space by integrating many functions that previously required external components. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **USB Interface** | USB 2.0 Full Speed (12Mbps) | | **I2C Interface** | Standard (100kHz), Fast (400kHz), Fast Plus (1MHz) | | **Package** | 16-pin SSOP (Small Outline Package) | | **Operating Voltage** | +3.3V to +5.25V | | **I/O Voltage Range** | +1.8V to +3.3V (VCCIO) | | **EEPROM** | Internal 2048-byte MTP memory | | **Clocking** | Fully integrated internal clock (No crystal required) | --- ### 2. Core Electronic Components & Features The FT201XS-R is more than just a converter; it contains several internal subsystems: * **Integrated Clock Circuitry:** It does not require an external crystal or resonator, which reduces EMI and saves board space. * **MTP Memory (Multi-Time Programmable):** It includes 2KB of internal memory used to store USB Vendor ID (VID), Product ID (PID), device serial strings, and power descriptor information. * **Voltage Regulator:** An integrated +3.3V LDO regulator powers the USB transceiver and provides a reference for the I/O pins. * **CBUS I/O Pins:** It features multi-function configurable I/O pins that can be used for: * Driving status LEDs (TX/RX). * Battery charger detection (detecting if the USB port is a dedicated charging port). * Clock output (6MHz, 12MHz, or 24MHz). * **BCD (Battery Charger Detection):** A hardware feature that detects the presence of a USB charging port to allow higher current draw for battery charging. --- ### 3. Pinout Configuration The 16-pin SSOP layout is optimized for simple routing: | Pin Name | Function | Description | | :--- | :--- | :--- | | **VCC** | Power | Main power supply (+5V or +3.3V) | | **VCCIO** | I/O Power | Sets the logic level for I2C and CBUS pins | | **USBDM/USBDP** | Data | USB differential pair (D- and D+) | | **SCL / SDA** | I2C Bus | Serial Clock and Serial Data lines | | **RESET#** | Input | Active low hardware reset | | **CBUS(0-3)** | Configurable | I/O for LEDs, Sleep, or Power Enable | --- ### 4. Implementation Example (Basic Circuit) ```markdown USB Connector FT201XS-R I2C Peripheral ------------- ------------ -------------- VBUS (5V) ------> VCC (Pin 10) D- ------> USBDM (Pin 15) D+ ------> USBDP (Pin 14) GND ------> GND (Pin 13) SDA (Pin 1) -----> SDA (with 2.2k Pull-up) SCL (Pin 5) -----> SCL (with 2.2k Pull-up) ``` --- ### 5. Common Use Cases 1. **USB Dongles:** Adding USB connectivity to existing I2C-based sensors or displays. 2. **System Debugging:** Using a PC to communicate directly with an I2C bus on a prototype board. 3. **Battery Charging:** Utilizing the BCD pin to signal a microcontroller to switch to high-current charging mode.