Spark Logic

FT230X USB-to-UART bridge connection guide

FT230X USB-to-UART bridge QFN-16 wiring guide with power, signal assignments, and bench checks.

SSOP-16 16 contacts

QFN-16

17 contacts Current package

FTDI · FT230XQ with ground pad

Wire USB with the external series resistors

Required

Use the bus-powered circuit with VCCIO connected to 3V3OUT. Fit each 27 Ω series resistor and 47 pF capacitor as shown in Figure 6.1. Solder the exposed pad to ground on FT230XQ. Keep the differential routing short and continuous.

27 Ω between Connector D+ and Chip D+Connector D+27 ΩChip D+
27 Ω between Connector D− and Chip D−Connector D−27 ΩChip D−
47 pF between Connector D+ and ReturnConnector D+47 pFReturn
47 pF between Connector D− and ReturnConnector D−47 pFReturn
4.7 µF in parallel with 100 nF between Filtered 5 V and ReturnFiltered 5 V4.7 µF in parallel with 100 nFReturn
100 nF between 3.3 V I/O supply and Return3.3 V I/O supply100 nFReturn

Bench checks

  • Check the two USB data lines are neither shorted nor swapped.
  • Check VCC and the 3.3 V rail, then confirm enumeration.

FTDI FT_000566, version 1.7, Fig. 6.1 and §3.

Connection scenarios

Test the UART in loopback

Unplug USB and jumper the bridge transmit output to its own receive input. Plug USB back in, open the enumerated port and disable local echo and flow control.

Bench checks

  • Send a short string at 9,600 bit/s, 8 data bits, no parity and 1 stop bit. The received bytes should match the transmitted bytes.
  • Remove the jumper before connecting another UART. Cross the two data lines, share ground and check the logic levels first.

FTDI FT_000566, version 1.7, §3. Loopback is a bench test.

QFN-16 wiring map

Highlighted contacts are used in the required step or selected circuit. Select a contact to inspect it.

QFN-16
Top view. Match pin 1 to the package mark. The numbers advance counterclockwise. Scroll the map to reach all contacts.
Selected pin details

15 · TXD

Output · Outputs

Asynchronous transmit. Connect to the receiver of the external logic-level UART.

FTDI FT_000566, version 1.7, §3.1.1

Electrical limits · Pin in the reference

Models and documents

The interactive maps cover FT230XS in SSOP-16 and FT230XQ in QFN-16. Match the suffix and pad arrangement before placing the device.

FT230XQ
FT230XQ with ground pad