General Description

The F81434 is a programmable, monolithic multi-protocol 2T/2R transceiver supporting RS-232 and RS-485 / RS-422 drivers and receivers in a 28 pin QFN 4x4 package.

Integrated termination and eight configuration modes allow all three protocols to be used interchangeably over a single cable or connector with no additional switching components. Full operation requires only four external charge pump capacitors (0.1μF).

The high-speed drivers operate up to 20Mbps in RS-485/RS-422 modes (Max. Load 47pF), and up to 3 Mbps in RS-232 mode (Max. Load 100pF). All drivers can be slew limited to 250kbps in any mode to minimize Electromagnetic Interference (EMI).

The RS-232 receiver inputs include a 5KΩ pull-down to ground and allows up to 256 devices on a single communication bus (1/8th unit load).

The F81434 operates from a single power supply, either 3.3V or 5V, with low idle current. The shutdown mode consumes less than 20µA for low power standby operation. I/O power, 1.62V~5.5V, is for the controller side’s power.

  • Support single supply operation voltage from 3.3V to 5.5V
  • Support I/O power voltage from 1.62V to 5.5V on logic side.
  • RS 232 Data Rate 3Mbps (Max. Load 100pF)
  • RS-422/RS-485 Data Rate 20Mbps (Max. Load 47pF)
  • RS-485 Advance Failsafe on Open, Short or Terminated Lines
  • No External Biasing & Termination Resistors Are Required for RS-422/485 (could be disabled as well)
  • Provide shutdown function.
  • Adjustable Slew Rate for Minimize EMI Error
  • ±15kV ESD Protection (IEC 61000-4-2 Air Gap; ±8kV contact)
  • Flexible 8 Operation Modes Selected by 3 Configuration Pins
    • 2T/2R Pure RS-232 (6 Pin Cable) CTS# (pin 12) is from CTSN (pin 9) for 6 pin cable.
    • 2T/2R Pure RS-232 (4 Pin Cable) CTS# (pin 12) is from TX-(B) / RX-(B) (pin 13); RTS# (pin 7) and RX-(B) (pin 10) must be shorted when using this mode for 4 pin cable.
    • RS-422 Full Duplex without RTS# (TX always enable)
    • RS-422 Full Duplex (Multi-master). TX enable low active with auto sensing (also called auto direction control).
    • RS-422 Full Duplex (Multi-master). TX enable when RTS# is low.
    • RS-485 Half Duplex. TX enable when RTS# is low.
    • RS-485 Half Duplex. TX enable low active with auto sensing (also called auto direction control).
    • Low power shutdown. All I/O pins are High Impedance
  • Nominal ±10V Driving Output Swing for +5V lnput
  • ±16.5V Receiver Input Voltage Range
  • 28 QFN (4x4mm)
  • Operating Temperature : -40 to 85 'C

28-QFN (4x4mm)

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