SP490/491 FullDuplex RS-485 T ransceivers FEATURES +5V Only Low Power BiCMOS Driver/Receiver Enable (SP49) RS-485 and RS-422 Drivers/Receivers Pin Compatible with LTC490 and SN75 79 (SP490) Pin Compatible with LTC49 and SN7580 (SP49 ) Now Available in Lead Free Packaging DESCRIPTION The SP490 is a low power differential line driver/receiver meeting RS-485 and RS-422 standards up to 5Mbps. The SP491 is identical to the SP490 with the addition of driver and receiver tri-state enable lines. Both products feature 200mV receiver input sensitivity, over wide common mode range. The SP490 is available in 8-pin plastic DIP and 8-pin NSOIC packages for operation over the commercial and industrial temperature ranges. The SP491 is available in 4-pin DIP and 4-pin NSOIC packages for operation over the commercial and industrial temperature ranges. BLOCK DIAGRAMS SP490 SP491 Exar Corporation 48720 Kato Road, Fremont CA, 94538 (5 0)668-707 www .exar.com SP490,49 0 0627 ABSOLUTEMAXIMUM RA TINGS 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 ....................................................................................................+7V CC Input Voltages Drivers................................................-0.5V to (V +0.5V) CC Receivers..................................................................4V Output Voltages Drivers......................................................................4V Receivers...........................................-0.5V to (V +0.5V) CC Storage Temperature....................................................-65C to +150 Power Dissipation.....................................................................000mW ELECTRICALCHARACTERISTICS T toT andV = 5V 5%unless otherwise noted. MIN MAX CC PARAMETERS MIN.TYP . MAX. UNITS CONDITIONS SP490 DRIVER DC Characteristics Differential Output Voltage GND V Volts Unloaded R = see figure 1 CC Differential Output Voltage 2 V Volts With Load R = 50 (RS422) CC see figure 1 Differential Output Voltage .5 V Volts With Load R = 27 (RS485) see CC figure 1 Change in Magnitude of Driver Differential Output Voltage for Complimentary States 0.2 Volts R = 27 or R = 50 see figure 1 Driver Common-Mode Output Voltage 3 Volts R = 27 or R = 50 see figure 1 Input High Voltage 2.0 Volts Applies to D Input Low Voltage 0.8 Volts Applies to D Input Current 0 A Applies to D Driver Short-Circuit Current V = HIGH 250 mA -7V V +12V OUT O V = LOW 250 mA -7V V +12V OUT O SP490DRIVER AC Characteristics Maximum Data Rate 5 Mbps Driver Input to Output 30 60 ns t R = 54, C = C = 00pF PLH DIFF L L2 see figures 3 and 6 Driver Input to Output 30 60 ns t R = 54, C = C = 00pF PHL DIFF L L2 see figures 3 and 6 Driver Skew 5 ns see figures 3 and 6, t = t - t SKEW DPLH DPHL Driver Rise or Fall Time 5 40 ns From 0% to 90% R = 54, DIFF C = C = 00pF see figures 3 and 6 L L2 SP490 RECEIVER DC Characteristics Differential Input Threshold -0.2 +0.2 Volts -7V V 12V CM Input Hysteresis 70 mV V = 0V CM Output Voltage High 3.5 Volts I = -4mA, V = +200mV O ID Output Voltage Low 0.4 Volts I = +4mA, V = -200mV O ID Input Resistance 12 15 k -7V V 12V CM Input Current (A, B) V = 2V .0 mA V = 2V IN IN Input Current (A, B) V = -7V -0.8 mA V = -7V IN IN Short-Circuit Current 85 mA 0V V V O CC Exar Corporation 48720 Kato Road, Fremont CA, 94538 (50)668-70 7 www .exar.com SP490,49 0 0627 2