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 +12V Common-Mode Input Voltage Range * Allows up to 32 transceivers on the serial bus * Compatibility with industry standard 75176 pinout * Driver Output Short-Circuit Protection DESCRIPTION The SP3485 device is a +3.3V low power half-duplex transceiver that meets the specifications of the RS-485 and RS-422 serial protocols. This device is pin-to-pin compatible with the Exar SP481, 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 10Mbps under load. Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 510-668-7017 * www.exar.com SP3485_100_061912 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. VCC.....................................................................+6.0V Input Voltages Logic....................................-0.3V to +6.0V Drivers.................................-0.3V to +6.0V Receivers.........................................+/-15V Output Voltages Drivers.............................................+/-15V 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 TAMB = TMIN to TMAX and VCC = +3.3V +/-5% unless otherwise noted. 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 1 Differential Output Voltage 1.5 Vcc Volts With Load; R = 27 (RS-485); Figure 1 Change in Magnitude of Driver Differential Output Voltage for Complimentary states 0.2 Volts R = 27 or R = 50; Figure 1 Driver Common Mode Output Voltage 3 Volts R = 27 or R = 50; Figure 1 Input High Voltage 2.0 Volts Applies to DE, DI, RE 0.8 Volts Applies to DE, DI, RE Input Current +/-10 A Applies to DE, DI, RE Driver Short Circuit Current VOUT = HIGH +/-250 mA -7V VO +12V; Figure 8 Driver Short Circuit Current VOUT = LOW +/-250 mA -7V VO +12V; Figure 8 Input Low Voltage SP3485 DRIVER AC Characteristics Maximum Data Rate 10 Driver Input to Output, tPLH 20 40 60 Mbps ns RE = VCC, DE = VCC Figures 2 & 9 Driver Input to Output, tPHL 20 40 60 ns Figures 2 & 9 Differential Driver Skew 2 10 ns |tDO1- tDO2|, Figures 2 and 10 Driver Rise or Fall Time 5 20 ns From 10%-90%; Figures 3 and 10 Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 510-668-7017 * www.exar.com SP3485_100_061912 ELECTRICAL CHARACTERISTICS TAMB = TMIN to TMAX and VCC = +3.3V +/-5% unless otherwise noted. PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS SP3485 DRIVER AC Characteristics continued Driver Enable to Output High 52 120 ns Figures 4 and 11 Driver Enable to Output Low 60 120 ns Figures 5 and 11 Driver Disable Time from Low 40 120 ns Figures 5 and 11 Driver Disable Time from High 60 120 ns Figures 4 and 11 +0.2 Volts -7V VCM +12V SP3485 RECEIVER DC Characteristics Differential Input Threshold -0.2 Input Hysteresis Output Voltage HIGH 20 mV Volts VID = +200mV, -1.5mA Output Voltage LOW 0.4 Volts VID = -200mV, 2.5mA Three-State (High Impedance) Output Current +/-1 A 0V VO VCC; RE = VCC k -7V VCM +12V Input Current (A, B); VIN = 12V +1.0 mA DE = 0V, VCC = 0V or 3.6V, VIN = 12V Input Current (A, B); VIN = -7V -0.8 mA DE = 0V, VCC = 0V or 3.6V, VIN = -7V 60 mA 0V VCM VCC Input Resistance Short Circuit Current Vcc-0.4 VCM = 0V 12 15 7 SP3485 RECEIVER AC Characteristics Maximum Data Rate 10 Receiver Input to Output, tPLH 40 70 Receiver Input to Output, tPLH Receiver Input to Output, tPHL 40 70 Receiver Input to Output, tPHL Mbps RE = 0V, DE = 0V 100 ns Figures 6 and 12 70 ns TAMB = +25C, Vcc = 3.3V, Figures 6 and 12 100 ns Figures 6 and 12 70 ns TAMB = +25C, Vcc = 3.3V, Figures 6 and 12 ns tRSKEW = |tRPHL- tRPLH|, Figures 6 and 12 Differential Receiver Skew 4 Receiver Enable to Output Low 35 60 ns Figures 7 and 13, S1 closed, S2 open Receiver Enable to Output High 35 60 ns Figures 7 and 13, S2 closed, S1 open Receiver Disable from Low 35 60 ns Figures 7 and 13, S1 closed, S2 open Receiver Disable from High 35 60 ns Figures 7 and 13, S2 closed, S1 open Supply Current , No Load 1000 2000 A RE, DI = 0V or VCC ; DE = VCC Supply Current , No Load 800 1500 A RE = 0V, DI = 0V or VCC, DE = 0V POWER REQUIREMENTS Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 510-668-7017 * www.exar.com SP3485_100_061912 Pin Function SP3485 PIN FUNCTION Pin 1 - RO - Receiver output Pin 2 - RE - Receiver Output Enable Active LOW Pin 3 - DE - Driver Output Enable Active HIGH Pin 4 - DI - Driver Input Pin 5 - GND - Ground Connection Pin 6 - A - Non-Inverting Driver Output/Receiver Input Pin 7 - B - Inverting Driver Output/Receiver Input Pin 8 - Vcc - Positive Supply Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 510-668-7017 * www.exar.com SP3485_100_061912 Test Circuits V DM R L = 27 R S1 D VOD D R Vcc GENERATOR (NOTE 1) VOC OUT 50 C L = 15pF (NOTE 2) V CC V OM = VOH + VOL 1.5V 2 Figure 1. Driver DC Test Load Circuit Figure 2. Driver Propagation Delay Test Circuit S1 CL D GENERATOR (NOTE 1) 50 D RL = OUT 60 OUT R L = 110 C L = 50pF (NOTE 2) GENERATOR (NOTE 1) VCC 50 VOM = VOH + VOL 1.5V 2 C L = 15pF (NOTE 2) Figure 3. Driver Differential Output Delay and Transition Time Circuit. Figure 4. Driver Enable and Disable Timing Circuit, Output High VCC R L = 110 S1 0V OR 3V D V ID GENERATOR (NOTE 1) OUT R OUT 50 C L = 15pF (NOTE 2) C L = 50pF (NOTE 2) GENERATOR (NOTE 1) 50 1.5V VOM = VCC 2 0V Figure 6. Receiver Propagation Delay Test Circuit Figure 5. Driver Enable and Disable Timing Circuit, Output Low 1.5V S1 S3 VCC 1k -1.5V VID R DE = 0 or Vcc S2 DI = 0 or Vcc A/Y C L = 15pF (NOTE 2) GENERATOR (NOTE 1) IOSD D B/Z 100 -7V to +12V V 50 Figure 7. Receiver Enable and Disable Timing Circuit Figure 8. Driver Short Circuit Current Limit Test NOTE 1: The input pulse is supplied by a generator with the following characteristics: PRR = 250kHz, 50% duty cycle, tR < 6.0ns, ZO = 50. NOTE 2: CL includes probe and stray capacitance. Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 510-668-7017 * www.exar.com SP3485_100_061912 SWITCHING WAVEFORMS 3V 1.5V 1.5V INPUT 3V 0V VOH tPLH IN tPHL 1.5V 0V VOM VOM Y OUTPUT 1.5V t DO1 t DO2 VOL VOH tPHL Z OUTPUT tPLH OUT VOM VOM 50% 10% 90% 90% 2.0V 50% 10% -2.0V VOL t TD t TD VOM = VOH + VOL 1.5V 2 Figure 10. Driver Differential Output Delay and Transition Time Waveforms Figure 9. Driver Propagation Delay Waveforms 3V 3V 1.5V 1.5V DE INPUT 0V VOH OUTPUT HIGH OUTPUT LOW tPHZ tPZH 0V 0.25V VOM VCC 0V VCC tPZL VOM 1.5V tRPLH tRPHL OUTPUT tPLZ VOL 1.5V 0.25V VOM = VCC 2 VOM = VOH + VOL 1.5V 2 Figure 11. Driver Enable and Disable Timing Waveforms 3V 0V VOH OUTPUT Figure 12. Receiver Propagation Delay Waveforms S1 is open S2 is closed S3 = 1.5V 3V 1.5V 1.5V RE tPRHZ 10% VOM VOM 0V S1 is closed S2 is open S3 = -1.5V 1.5V 1.5V RE 0V tPRZH tPRSH tPRLZ VCC 1.5V OUTPUT 1.5V VOL 0V tPRZL tPRSL 10% Figure 13. Receiver Enable and Disable Waveforms Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 510-668-7017 * www.exar.com SP3485_100_061912 DESCRIPTION The SP3485 is a member in the family of +3.3V low power half-duplex transceivers that meet the electrical specifications of the RS-485 and RS-422 serial protocols. This device is pin-to-pin compatible with the Exar SP481, SP483 and SP485 devices as well as popular industry standards. The SP3485 feature Exar's BiCMOS process allowing low power operation without sacrificing performance. Receiver The SP3485 receiver has differential inputs with an input sensitivity of 200mV. Input impedance of the receiver is typically 15k (12k minimum). A wide common mode range of -7V to +12V allows for large ground potential differences between systems. The receiver is equipped with a fail-safe feature that guarantees the receiver output will be in a HIGH state when the input is left unconnected. The receiver of the SP3485 operates up to 10Mbps. Driver The driver outputs of the SP3485 are differential outputs meeting the RS-485 and RS-422 standards. The typical voltage output swing with no load will be 0 volts to +3.3 Volts. With a load of 54 across the differential outputs, the drivers can maintain greater than 1.5V voltage levels. The receiver of the SP3485 has an enable control line which is active LOW. A logic LOW on RE (pin 2) will enable the differential receiver. A logic HIGH on RE (pin 2) of the SP3485 will disable the receiver. INPUTS The driver of the SP3485 has a driver enable control line which is active HIGH. A logic HIGH on DE (pin 3) will enable the differential driver outputs. A logic LOW on the DE (pin 3) will tri-state the driver outputs. The driver of the SP3485 operates up to 10Mbps. The 250mA ISC maximum limit on the driver output allows the SP3485 to withstand an infinite short circuit over the -7.0V to +12V common mode range without catastrophic damage to the IC. OUTPUTS RE DE DI Line Condition B A X 1 1 No Fault 0 1 X 1 0 No Fault 1 0 X 0 X X Z Z Table 1. Transmit Function Truth Table INPUTS OUTPUTS RE DE A-B R 0 0 +0.2V 1 0 0 -0.2V 0 0 0 Inputs Open 1 1 0 X Z Table 2. Receive Function Truth Table Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 510-668-7017 * www.exar.com SP3485_100_061912 Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 510-668-7017 * www.exar.com SP3485_100_061912 ORDERING INFORMATION Model Temperature Range Package Types SP3485CN-L........................................................................ 0C to +70C.................................................................................................8-pin NSOIC SP3485CN-L/TR.................................................................. 0C to +70C.................................................................................................8-pin NSOIC SP3485EN-L...................................................................... -40C to +85C..............................................................................................8-pin NSOIC SP3485EN-L/TR................................................................ -40C to +85C..............................................................................................8-pin NSOIC Note: /TR = Tape and Reel revision history DATE REVISION 10/15/02 -- 06/19/12 1.0.0 DESCRIPTION Legacy Sipex Datasheet Convert to Exar Format. Update ordering information and add new Figure 8 - Driver Short Circuit Current Limit Test Circuit. Remove EOL device SP3481. Notice EXAR Corporation reserves the right to make changes to any products contained in this publication in order to improve design, performance or reliability. EXAR Corporation assumes no representation that the circuits are free of patent infringement. Charts and schedules contained herein are only for illustration purposes and may vary depending upon a user's specific application. While the information in this publication has been carefully checked; no responsibility, however, is assumed for inaccuracies. EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, in writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized ; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. Copyright 2012 EXAR Corporation Datasheet June 2012 For technical support please email Exar's Serial Technical Support group at: serialtechsupport@exar.com Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 510-668-7017 * www.exar.com SP3485_100_061912