FT231XS-R - USB to Full UART Bridge IC, SSOP-20 | FTDI
Teilenummer: FT231XS-R ✓ Aktiv| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $4.2 | $4,20 |
| 10 | $3.78 | $37,80 |
| 100 | $3.25 | $325,00 |
| 500 | $2.8 | $1.400,00 |
| 1.000 | $2.34 | $2.340,00 |
FT231XS-R Übersicht
A USB-to-UART bridge IC is a class of interface device that converts USB signaling into a serial (asynchronous) UART protocol so that microcontrollers, microprocessors, and legacy serial peripherals can communicate with a host PC without an external MCU. Bridges belong to the broader category of USB interface ICs > interface ICs > integrated circuits, and the FT231X family specifically sits in the FT-X series second generation, succeeding the older FT232R. The FT231X family adds integrated MTP memory for user-configurable descriptor fields and is offered in three variants by feature set: FT230X (basic UART, fewer lines), FT231X (full modem UART, more GPIOs), and FT234X (TX/RX only).
Key features of the FT231XS-R include full hardware handshake support (RTS, CTS, DTR, DSR, DCD, RI), four GPIO pins multiplexed with modem-control functions, an integrated 1024-byte EEPROM (MTP, user-configurable for VID/PID/product string/serial number), a wide operating temperature range of -40C to +85C industrial grade, and low-power suspend current of approximately 125 uA when the USB host is in suspend mode. The chip is RoHS compliant and ships in a small SSOP-20 footprint that drops onto the same PCB land pattern used by the FT232R (SSOP-28 is the larger legacy). The device is supported by FTDI's royalty-free VCP (Virtual COM Port) and D2XX direct-driver libraries, allowing seamless integration with Windows, macOS, Linux, and Android.
Architecturally, the FT231XS-R uses an internal 48 MHz oscillator with on-chip PLL to derive the USB 12 MHz clock and the UART baud-rate generator, eliminating the external crystal that older USB-to-UART bridges required. The USB protocol stack is handled entirely in hardware/firmware on the chip, so no host-side USB stack or external MCU intervention is needed for basic UART pass-through. The integrated MTP memory (reprogrammable via USB from the host PC using FTDI's FT_PROG utility) lets OEMs customize VID/PID and descriptor strings without external EEPROM.
Typical applications include industrial RS-232 / RS-485 dongles, debug and console ports on development boards, point-of-sale (POS) terminals, microcontroller-to-PC debug bridges, USB instrumentation probes, embedded firmware-flashing fixtures, and any design that needs a reliable, driver-supported USB-to-serial port with full modem-control signals. Its small SSOP-20 footprint and absence of an external crystal make it a strong choice for compact, low-BOM-count boards.
When designing with the FT231X, ensure the USB D+/D- pair is routed as a 90 ohm differential trace and the VBUS pin is connected to +5V (or to a 3.3V rail for the FT231XQ variant). For designs migrating from the FT232R, note that the FT231X uses SSOP-20 (smaller than SSOP-28) so the PCB footprint must be redesigned, and the FT232R's external EEPROM is replaced by on-chip MTP memory.
This page synthesizes distributor pricing, verified drop-in alternatives (FT231XQ-R for 3.3V operation and the FT230X family for reduced GPIO), and practical PCB layout notes not consolidated in the manufacturer datasheet.
Drop-in-Alternativen für FT231XS-R – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Varianten dieser Serie
Modelle derselben Serie, die drop-in-kompatibel sind mit FT231XS-R (gleiche Bauform und Footprint) – abweichend in Function, Package.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
FT231XS-U
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
FT231XQ-R
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
FT230XS-R
✅ Drop-In✓ Auf Lager
$2.45 / Stück
Datenblatt ansehen →FT234XD-R
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
FT231XS-R Technische Daten
| Funktion | USB to Full Handshake UART Bridge |
| USB Standard | USB 2.0 Full Speed (12 Mbps) |
| UART Channels | 1 (TX, RX, RTS, CTS, DTR, DSR, DCD, RI) |
| Maximum Baud Rate | 3 Mbaud |
| Minimum Baud Rate | 300 baud |
| Supply Voltage (VBUS) | 4.5 V to 5.25 V |
| Internal LDO Output | 3.3 V (core supply) |
| Operating Current (Active) | 8 mA (typical) |
| Suspend Current | 125 uA (typical) |
| GPIO Pins | 4 (multiplexed with modem-control lines) |
| Integrated Memory | 1024-byte MTP (reprogrammable via FT_PROG) |
| External Crystal Required | No (internal 48 MHz oscillator + PLL) |
| Gehäuse | 20-pin SSOP (5.3 mm body) |
| Betriebstemperatur | -40 C to +85 C |
| Montageart | Surface Mount |
| MSL-Level | 3 |
| RoHS-Status | Compliant |
| Lead-Free | Yes |
FT231XS-R Pin-Konfiguration
| Pin 1 | VCC — +3.3V internal LDO output (bypass with 100nF cap) |
| Pin 2 | DCD — Data Carrier Detect modem control line / GPIO |
| Pin 3 | DSR — Data Set Ready modem control line / GPIO |
| Pin 4 | RI — Ring Indicator modem control line / GPIO |
| Pin 5 | GND — Ground |
| Pin 6 | CTS — Clear To Send hardware flow control input (active low) |
| Pin 7 | RTS — Request To Send hardware flow control output (active low) |
| Pin 8 | RXD — UART Receive (input to FT231X from MCU) |
| Pin 9 | TXD — UART Transmit (output from FT231X to MCU) |
| Pin 10 | DTR — Data Terminal Ready modem control line / GPIO |
| Pin 11 | NC — Not connected (per datasheet) |
| Pin 12 | NC — Not connected (per datasheet) |
| Pin 13 | VBUS — USB VBUS (+5V from USB connector) |
| Pin 14 | USBDP — USB D+ data line (90 ohm differential with USBDM) |
| Pin 15 | USBDM — USB D- data line (90 ohm differential with USBDP) |
| Pin 16 | RESET — Active-low reset input; tie to VCC via 10k for normal operation |
| Pin 17 | TEST — Factory test pin; tie to GND per datasheet |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | NC — Not connected (per datasheet) |
| Pin 20 | GND — Ground |
Typische Anwendungen
FT231XS-R ist geeignet für 6 Anwendungs: Industrial USB-to-Serial Dongle, Embedded Development Board Console Port, USB Instrumentation Probe / Data Acquisition Front-End, Point-of-Sale (POS) Terminal Connectivity, Microcontroller Firmware Flashing Fixture, IoT Sensor Gateway / Smart-Home Hub.
Industrial USB-to-Serial Dongle
The FT231XS-R's full handshake modem-control lines (RTS/CTS/DTR/DSR/DCD/RI) make it a strong fit for industrial USB-to-RS-232/485 dongles that must replace legacy DB-9 serial ports on factory PCs. With 300-baud-to-3-Mbaud support, the chip transparently passes legacy PLC, sensor, and instrumentation protocols. Designers route a 90-ohm USB D+/D- differential pair to USB Type-B or micro-B connector; the FT231X handles the USB protocol stack in hardware, leaving no MCU-side USB stack requirement. Compared to MCP2200 and CH340 alternatives, FTDI's mature VCP/D2XX driver base and global inventory reduce design risk for industrial deployments.
Empfohlen
Embedded Development Board Console Port
The FT231XS-R is widely used as a debug console on STM32, ESP32, NXP Kinetis, and Microchip PIC development boards. Its 3 Mbaud UART throughput is more than adequate for printf-style logging and firmware-flash bridges at 921600 baud. The integrated 48 MHz oscillator eliminates the external crystal that older USB-UART bridges needed, shrinking BOM count. Designers typically route the UART TX/RX to the target MCU's USART pins and break out RTS/CTS for hardware-flow-controlled bootloaders. The FT231X driver is pre-installed on modern Windows 10/11, macOS, and Linux kernels, so end users rarely need to install drivers manually.
Empfohlen
USB Instrumentation Probe / Data Acquisition Front-End
For USB-connected instrumentation such as oscilloscope probes, logic analyzers, and multimeter front-ends, the FT231XS-R provides a deterministic, low-latency UART path between the measurement front-end and host PC. The full modem-control lines enable hardware handshaking for high-throughput data streaming without software flow control. Internal MTP memory lets OEMs customize VID/PID and descriptor strings so Windows enumerates the device with a product-specific name. The -40C to +85C industrial temperature range supports use in lab and field environments.
Empfohlen
Point-of-Sale (POS) Terminal Connectivity
POS terminals, receipt printers, and barcode scanners rely on reliable USB-to-UART bridges to connect peripherals to the main terminal controller. The FT231XS-R's hardware modem-control signals enable proper handshaking with receipt printers that buffer data, while the integrated MTP memory supports OEM-specific VID/PID branding. The 8 mA active current and 125 uA suspend current are well-suited to battery and AC-powered POS hardware that must meet standby-power regulations. The royalty-free FTDI driver ecosystem keeps BOM costs predictable for POS OEMs.
Empfohlen
Microcontroller Firmware Flashing Fixture
Production firmware-flashing fixtures benefit from the FT231XS-R's 3 Mbaud UART capability, which supports fast bootloader-based flash programming for ESP32, STM32, nRF52, and other MCUs that expose UART bootloaders. The chip's hardware RTS line can drive the target MCU's BOOT/reset pin for hands-free enter-bootloader sequencing, while CTS provides back-pressure. Compared to slower CH340 or CP2102N bridges at 921600 baud, the FT231X at 3 Mbaud cuts production flashing time significantly. The integrated MTP lets fixtures carry custom VID/PID so flashing stations identify themselves to flashing software.
Empfohlen
IoT Sensor Gateway / Smart-Home Hub
IoT gateways and smart-home hubs that expose a USB-CDC serial console to the host for diagnostics and provisioning often use the FT231XS-R as the bridge between the hub MCU and the host USB port. The chip's industrial temperature range and proven driver support across Linux/Android Open Accessory mode enable reliable field deployments. The integrated clock and MTP reduce BOM count for cost-sensitive consumer IoT hardware. For hubs that also need USB Host mode, pair the FT231X with a USB Host controller like the MAX3421E; the FT231X handles the device-side UART console independently.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für FT231XS-R – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | FT231XS-U | FT231XQ-R | FT230XS-R | FT234XD-R |
|---|---|---|---|---|---|
| Brand | FTDI | FTDI | FTDI | FTDI | FTDI |
| Package | 20-pin SSOP | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same |
| Function | USB to Full Handshake UART | USB to Full Handshake UART | USB to Full Handshake UART (3.3V VBUS) | USB to Basic UART (TX/RX/RTS/CTS) | USB to TX/RX only |
| USB Speed | USB 2.0 Full Speed (12 Mbps) | USB 2.0 Full Speed (12 Mbps) | USB 2.0 Full Speed (12 Mbps) | USB 2.0 Full Speed (12 Mbps) | USB 2.0 Full Speed (12 Mbps) |
| Maximum Baud Rate | 3 Mbaud | 3 Mbaud | 3 Mbaud | 3 Mbaud | 3 Mbaud |
| Modem-control Signals | RTS/CTS/DTR/DSR/DCD/RI + 4 GPIO | RTS/CTS/DTR/DSR/DCD/RI + 4 GPIO | RTS/CTS/DTR/DSR/DCD/RI + 4 GPIO | RTS/CTS + 4 GPIO (no DCD/RI/DSR) | None (TX/RX only) |
| VBUS Voltage Range | 4.5 V to 5.25 V | 4.5 V to 5.25 V | 3.0 V to 3.6 V | 4.5 V to 5.25 V | 4.5 V to 5.25 V |
| External Crystal Required | No | No | No | No | No |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
Wichtigste Unterscheidungsmerkmale
- Full modem-control signals natively exposed (DCD/RI/DSR) plus 4 GPIO (vs. FT230XS-R)
- 5V VBUS operation matches desktop USB ports (vs. FT231XQ-R)
- Higher feature density in SSOP-20 vs FT234XD-R's TX/RX-only configuration (vs. FT234XD-R)
Designhinweise
Route the USB D+ (pin 14) and D- (pin 15) pair as a 90-ohm differential trace with matched length and keep them away from switching nodes and clock lines. Place a 100 nF decoupling capacitor as close as possible to pin 1 (VCC) and another 4.7 uF bulk cap on pin 13 (VBUS). The exposed SSOP-20 lead frame requires no thermal pad, but keep ground pours continuous under the chip to provide a low-impedance return path for the USB differential pair. Per the FTDI FT231X datasheet reference schematic, the TEST pin (pin 17) must be tied to GND; the RESET pin (pin 16) is normally tied to VCC through a 10 kohm resistor but can be left floating in production.
Do not assume the FT231XS-R is pin-compatible with the older FT232R. The FT232R uses a 28-pin SSOP package while the FT231XS-R uses a 20-pin SSOP, so PCB land patterns cannot be reused. Do not omit the VBUS 4.7 uF bulk capacitor; the internal 3.3 V LDO requires sufficient bulk capacitance on VBUS to handle USB hot-plug inrush. Do not tie RESET low permanently or the chip will be held in reset. When migrating from CH340 or CP2102 designs, verify that GPIO4..GPIO7 multiplex assignments match because FTDI's GPIO map differs from WCH and Silicon Labs bridges.
For EMI compliance, place a common-mode choke or ferrite bead on the USB D+/D- traces if the enclosure is non-shielded, and add a USBLC6-2SC6 ESD protection array near the USB connector. Keep high-speed digital signals (UART TX/RX at 3 Mbaud) away from the USB differential pair. The VCC pin decoupling cap (100 nF X7R) should be no more than 2 mm from the pin to minimize inductance. If the board will be USB-IF certified, follow the USB 2.0 Full Speed layout checklist in the FT231X datasheet, including 90-ohm differential impedance and matched trace lengths within 150 mil.
Compliance-Informationen
RoHS compliant per FTDI product page. MSL Level 3 per IC Directory specification page. Industrial temperature -40C to +85C. USB 2.0 Full Speed compliance handled by FTDI's certified USB stack.
