The UM3035B is highly integrated, robust and advanced multiprotocol transceiver supporting RS-232, RS-422 and RS-485 serial standards. The device offers three transmitters and five receivers in RS-232 mode to support 3T5R DB9 RS-232 connector. The device also integrates one transmitter and one receiver to support half and full duplex RS-485 communication. MODE selection pins enable shared bus and logic pins for the protocols to share a common single connector. Integrated termination resistance for RS-485 bus pins and for RS-232 receiver inputs need no external components to realize a fully-functional and switchable communication port.

The UM3035B operates up to 20Mbps in RS-485/RS-422 modes, and up to 1Mbps in RS-232 mode. What’s more, based on the SLR pin setting, the UM3035B can be limited to 0.25Mbps low-speed RS-485 mode and 0.25Mbps low-speed RS-232 mode.

The device features integrated robust IEC ESD protection. What’s more, diagnostic loopback mode for RS-232 is provided to check for logic to bus and bus to logic path functional integrity and check for cable and connector shorts. The RS-485 receiver fail-safe feature drives logic high on received logic output when the bus inputs are open or shorted together or when the bus is idle.

The UM3035B needs 3.0V to 5.5V supply that fully powers four external charge pump capacitors for RS-232 and the drivers/receivers for both RS-232 and RS-485. The device also features nSHDN pin to achieve extremely low current consumption when the system disables the device.

- Meets or exceeds the requirements of the TIA/EIA-485A and TIA/EIA-232F standards

- 3V to 5.5V supply voltage

- RS-485 differential output exceeds 2.1V for PROFIBUS compatibility with 5V supply

- 3 transmitters, 5 receivers for RS-232 port

- 1 transmitter, 1 receiver for RS-485 port

- Integrated switchable 120Ω termination resistor for half and full duplex RS-485 mode

- Integrated charge-pump for RS-232

- Large output swing (typical ±8.5V) for RS-232 mode with VCC = 5V supply

- Diagnostic loopback for RS-232 mode

- Open, short, and idle bus failsafe for RS-485 receiver

- Selectable Data Rates with SLR Pin:

-- RS-232 mode: 250kbps and 1Mbps

-- RS-485 half-duplex and full-duplex mode: 250kbps and 20Mbps

- Glitch-free power-up/down for hot plug-in capability

- Bus short-circuit protection, thermal Shutdown

- Extended ambient temperature range: -40°C to 125°C

- Space-saving QFN40 6.0×6.0 package

- Industrial

- Factory automation and control

- HAVC systems

- Building automation

- Point-of-sale terminals

- Grid infrastructure