F81438 Datasheet, PDF (4/20 Pages) Feature Integration Technology Inc. – Single 5V RS232/RS422/RS485 Multiprotocol

F81438
1 General Description
The F81438 is programmable, monolithic multi-protocol transceiver device that contains RS-232
and RS-485 / RS-422 drivers and receivers. The F81438 can be reconfigured into four operating
modes including RS-232 only (3TX/5RX), one RS-485 (1TX/1RX) driver (TX) half duplex mode, one
RS-485 (1TX/1RX) receiver (RX) half duplex mode, and RS-422 (1TX/1RX) full duplex mode which
can be selected whenever you need by changing the logic state of the 2 mode selection pins. The
device can implement a dual-mode serial port, mixed mode ports or as an interface signal translator.
The extra charge pumps deliver true RS-232 driver output voltage from a single power supply at 5V.
A slew rate control pin configures driver outputs for either high data rate or slew-controlled data rates.
Slew-controlled outputs minimize the problems that caused by the reflections and ringing on long or
un-terminated cables.
All RS-485 receivers or transceivers feature high impedance which allow up to 256 transceivers
on a shared bus. When configured in RS-485/RS-422 mode, each driver may be individually enabled
or put into tri-state, simplifying use on shared buses or bidirectional communication. All receivers
have advanced failsafe protection to prevent oscillation when inputs are un - connected. In RS-232
mode each receiver input has a 5kΩ pull-down to ground. Differential Receivers will default to output
logic 1 if inputs are floating, shorted or open but terminated. All driver outputs and receiver inputs are
protected against ESD strikes up to ±15,000 volts (IEC 61000-4-2 Air Gap).
2 Feature List
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5V Single Supply Operation
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Robust ±15kV ESD Protection (IEC 61000-4-2 Air Gap)
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Mixed RS-232 / RS-485 Modes
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Adjustable Slew Rate for Minimize EMI Error
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RS-485 Advance Failsafe on Open, Short or Terminated Lines
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28 Pin TSSOP Packaging
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Flexible 4 Operation Modes Selected by 2 Configuration Pins
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One set of 3T5R RS-232 V.28 Drivers & Receivers
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One Set of RS-485 Drivers (Half Duplex Configuration)
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One Set of RS-485 Receivers (Half Duplex Configuration)
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One set of RS-422 Driver & Receiver (Full Duplex Configuration)
4
Jan, 2012
V0.11P