SP3485 +3.3V Low Power Half-Duplex RS-485 Transceiver with 10Mbps Data Rate RS-485 and RS-422 Transceiver Operates from a single +3.3V Supply Interoperable with +5.0V logic Driver/Receiver Enable -7V to +2V Common-Mode Input V oltage Range Allows up to 32 transceivers on the serial bus Compatibility with industry standard 75 76 pinout Driver Output Short-Circuit Protection DESCRIPTION The SP3485 device is a +3.3V low power half-duplex transceiver that meets the specifica - tions of the RS-485 and RS-422 serial protocols. This device is pin-to-pin compatible with the Exar SP48, SP483 and SP485 devices as well as popular industry standards. The SP3485 features the Exar BiCMOS process, allowing low power operation without sacrificing performance. The SP3485 can meet the electrical specifications of the RS-485 and RS-422 serial protocols up to 0Mbps under load. Exar Corporation 48720 Kato Road, Fremont CA, 94538 50-668-70 7 www .exar.com SP3485 00 06 9 2 ABSOLUTE MAXIMUM RATINGS These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. V .....................................................................+6.0V CC Input Voltages Logic....................................-0.3V to +6.0V Drivers.................................-0.3V to +6.0V Receivers.........................................+/-5V Output Voltages Drivers.............................................+/-5V Receivers............................-0.3V to +6.0V Storage Temperature.......................-65C to +150C Power Dissipation 8-pin NSOIC...................................................600mW (derate 6.90mW/C above +70C) ELECTRICAL CHARACTERISTICS T = T to T and V = +3.3V +/-5% unless otherwise noted. AMB MIN MAX CC PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS SP3485 DRIVER DC Characteristics Differential Output Voltage GND Vcc Volts Unloaded R = Figure 1 Differential Output Voltage 2 Vcc Volts With Load R = 50 (RS-422) Figure Differential Output Voltage .5 Vcc Volts With Load R = 27 (RS-485) Figure Change in Magnitude of Driver 0.2 Volts R = 27 or R = 50 Figure 1 Differential Output Voltage for Complimentary states Driver Common Mode Output 3 Volts R = 27 or R = 50 Figure 1 Voltage Input High Voltage 2.0 Volts Applies to DE, DI, RE Input Low Voltage 0.8 Volts Applies to DE, DI, RE Input Current +/-0 A Applies to DE, DI, RE Driver Short Circuit Current +/-250 mA -7V V +12V Figure 8 O V = HIGH OUT Driver Short Circuit Current +/-250 mA -7V V +12V Figure 8 O V = LOW OUT SP3485 DRIVER AC Characteristics Maximum Data Rate 0 Mbps RE = V , DE = V CC CC Driver Input to Output, t 20 40 60 ns Figures 2 & 9 PLH Driver Input to Output, t 20 40 60 ns Figures 2 & 9 PHL Differential Driver Skew 2 0 ns t - t , Figures 2 and 0 DO DO2 Driver Rise or Fall Time 5 20 ns From 0%-90% Figures 3 and 0 Exar Corporation 48720 Kato Road, Fremont CA, 94538 50-668-70 7 www .exar.com SP3485 00 06 9 2 2