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The F81433A is a programmable, monolithic multi-protocol 1T/1R transceiver supporting RS-232 and RS-485 / RS-422 drivers and receivers in a 28 pin QFN package. Integrated cable termination and four 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 F81433A can be reconfigured into four operating modes including 1T/1R RS-232, 1T/1R RS-422 full duplex with termination resistor and bias resistor, 1T/1R RS-485 half duplex with termination resistor, bias resistor and auto sensing, low power shutdown. 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. The RS-485/RS-422 receiver inputs are high impedance (>96kΩ when termination is disabled), allowing up to 256 devices on a single communication bus (1/8th unit load). |
The F81433A operates from a single power supply, either 3.3V or 5V, with low idle current (5mA typical in RS-232 and 10mA typical in RS-422/RS-485). The shutdown mode consumes less than 30μA for low power standby operation. I/O power (minimum 1.8V) is for the controller side’s power.