SP3490/SP3491 +3.3V Low Power Full-Duplex RS-485 Transceivers with 10Mbps Data Rate Full-Duplex RS-485 and RS-422 Transceivers 1 V CC Operates from a single +3.3V Supply 8 A 2 R R Interoperable with +5.0V logic 7 B Driver/Receiver Tri-state Enable Lines (SP3491) 6 -7V to + 2V Common-Mode Input Voltage Range Z 3 D D +/-200mV Receiver Input Sensitivity 5 Y Allows up to 32 transceivers on the serial bus 4 GND Compatability with LTC490 and SN75 79 ( SP3490) Compatability with LTC49 and SN75 80 ( SP3491) SP3490 DESCRIPTION The SP3490 and SP3491 devices are +3.3V low power full-duplex transceivers that meet the specifications of the RS-485 and RS-422 serial protocols. These devices are pin-to-pin compatible with the Exar SP490 and SP49 devices as well as popular industry standards. The SP3490 and SP3491 feature Exar s BiCMOS process, allowing low power operation without sacrificing performance. The SP3490 and SP3491 meet the electrical specifications of the RS-485 and RS-422 serial protocols up to 0Mbps under load. The SP3491 is identical to the SP3490 with the addition of driver and reciveiver tri-state enable lines. 14 1 VCC NC 13 NC 12 A 2 R R 11 B 3 REB 4 DE 10 Z 5 D D 9 6 Y GND 8 7 NC GND SP3491 Exar Corporation 48720 Kato Road, Fremont CA, 94538 50-668-70 7 www .exar.com SP3490 349 02 027 0 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.........................................+/- 4V Output Voltages Drivers.............................................+/-4V Receivers............................-0.3V to +6.0V Storage Temperature.......................-65C to +150C Power Dissipation 8-pin NSOIC...................................................600mW (derate 6.90mW/C above +70C) 4-pin NSOIC.................................................700mW (derate 8.33mW/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 SP3490 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 Input Low Voltage 0.8 Volts Input Current +/-0 A Driver Short Circuit Current V = HIGH +/-250 mA -7V V +12V Figure 8 OUT O V = LOW +/-250 mA -7V V +12V Figure 8 OUT O SP3490 DRIVER AC Characteristics Max. Transmission Rate 0 Mbps Driver Input to Output, t 20 40 60 ns R = 27, Figures 2 & 9 PLH Driver Input to Output, t 20 40 60 ns R = 27, Figures 2 & 9 PHL Differential Driver Skew 2 ns t (Y)- t (Y) , t (Z)- t (Z) , PHL PLH PHL PLH Figures 2 and 9 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 SP3490 349 02 027 0 2