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Stand Alone UART - SIO7 IC

7 Bits Serial Input/Output

General Description

The SIO7 IC is designed to provide 7 bits of input and output data to connect to RS-232, USB, Ethernet or directly to your UART. Outputs can be used to drive relays, logic, optocouplers or a transistors. Inputs can be from switches, relay contacts, logic, optocouplers or a transistor switched to ground. The SIO7 has internal pull resistors on the inputs to minimize additional parts. The SIO7 IC transmits data anytime the inputs change or every of 100 mS. The serial format to the SIO7 is standard asynchronous format, using 8 bits, 1 stop and no parity at 9600 BPS. Other formats and encoding are available, contact the factory. A .1 uF bypass capacitor is suggested across the VDD and VSS pins. The part uses the standard 20 pin .3 inch width SOIC and DIP package. A full duplex data channel is required, do not use RS-485 or a half duplex data channel with this part. The SAIO7 IC may be used if your design requires a half duplex data channel.


  • Asynchronous serial control for 7 bits of input and 7 bits of output.
  • Can connect with RS-232, USB or Ethernet or UART.
  • Inputs can be switches, relay contacts, optocouplers, and logic.
  • On chip input pull up resistors on inputs.
  • Outputs can be used to drive relays, transistors, optocouplers, and logic.
  • No external parts required.
  • Low power consumption 5 mA typical.
  • Supply voltage 2.4 to 5.25 volts.
  • All timing internally generated.
  • TTL and CMOS compatible inputs and outputs.
  • Part is in full production.
  • SOIC and DIP 20 Pin Package.
  • ROHS Compliant.
  • Low EMI.

Example Circuits

Spec sheet: SIO7 Stand Alone UART - Serial Input/Output IC - 7 Bits Input, 7 bits output

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