Intersil – Dual-protocol transceiver can replace discrete RS-485 and RS-232 ICs


The ISL3333xE and ISL3335xE from Intersil are dual-protocol transceivers supporting both RS-485 and RS-232 communication networks.

The devices feature two independent ports: port 1 is set for RS-232 (with two transceivers) and port 2 is set for RS-485/RS-422 (one transceiver). This configuration is suitable for applications in which data communication over both RS-232 and RS-485 networks is needed. Here, two discrete transceiver chips may be replaced by one integrated ISL3333x or ISL3335x device, reducing the system’s component count and saving board space.

The parts are available in two package options: the 40-lead QFN package requires around 60% less board space than the equivalent SSOP part. In addition, the devices’ pin-out helps to simply board layout, since the receiver’s inputs and the transmitter’s outputs are on the same side.

In both package options, the transceivers are available in versions which support either a 5V or a 3.3V supply, giving the user flexibility to change their power-system design without having to change the communications-system design.


  • ±15kV ESD protection on bus pins
  • Full fail-safe RS-485/-422 port 2 receiver
  • User-selectable RS-485 data rates
  • Four 0.1μF charge-pump capacitors
  • 40μA current in shut-down mode


  • Gaming equipment
  • Single-board computers
  • Factory automation equipment
  • Security networks
  • Process control networks
  • Level translators
  • Point-of-sale equipment
Part NumberSupply VoltagePackageChannelsRS-485 Data Rate (kbits/)RS-232 Data Rate (kbits/s)
ISL33354E528-lead SSOP2115650
ISL33357E540-lead QFN2115650
ISL33334E3.328-lead SSOP2115400
ISL33334E3.340-lead QFN2115400