DS96176 RS-485/RS-422 Differential Bus Transceiver General Description The DS96176 Differential Bus Transceiver is a monolithic integrated circuit designed for bidirectional data communication on balanced multipoint bus transmission lines. The transceiver meets EIA Standard RS-485 as well as RS-422A. The DS96176 combines a TRI-STATE ® differential line driver and a differential input line receiver, both of which operate from a single 5.0V power supply. The driver and receiver have an active Enable that can be externally connected to function as a direction control. The driver differential outputs and the receiver differential inputs are internally connected to form differential input/output (I/O) bus ports that are designed to offer minimum loading to the bus whenever the driver is disabled or when VCC = 0V. These ports feature wide positive and negative common mode voltage ranges, making the device suitable for multipoint applications in noisy environments. The driver is designed to handle loads up to 60 mA of sink or source current. The driver features positive and negative current-limiting and thermal shutdown for protection from line fault conditions. Thermal shutdown is designed to occur at junction temperature of approximately 160˚C. The receiver features a typical input impedance of 15 kΩ, an input sensitivity of ± 200 mV, and a typical input hysteresis of 50 mV. Connection Diagram The DS96176 can be used in transmission line applications employing the DS96172 and the DS96174 quad differential line drivers and the DS96173 and DS96175 quad differential line receivers. Features n n n n n n n n n n n n n n Bidirectional transceiver Meets EIA Standard RS-422A and RS-485 Designed for multipoint transmission TRI-STATE driver and receiver enables Individual driver and receiver enables Wide positive and negative input/output bus voltage ranges Driver output capability ± 60 mA Maximum Thermal shutdown protection Driver positive and Negative current-limiting High impedance receiver input Receiver input sensitivity of ± 200 mV Receiver input hysteresis of 50 mV typical Operates from single 5.0V supply Low power requirements Receiver 8–Lead DIP Differential Inputs Enable Output A-B RE R VID ≥ 0.2V L H VID ≤ −0.2V L L X H Z H = High Level L = Low Level X = Immaterial Z = High Impedance (off) DS009630-1 Top View Order Number DS96176CN See NS Package Number N08E Function Table Driver Input Enable DI DE A Outputs H H H L L H L H X L Z Z B TRI-STATE ® is a registered trademark of National Semiconductor Corporation. © 1998 National Semiconductor Corporation DS009630 www.national.com DS96176 RS-485/RS-422 Differential Bus Transceiver May 1998 Absolute Maximum Ratings (Note 2) Recommended Operating Conditions If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage (VCC) Voltage at Any Bus Terminal (Separately or Common Mode) Differential Input Voltage (VID) Output Current HIGH (IOH) Driver Receiver Output Current LOW (IOL) Driver Receiver Operating Temperature (TA) Storage Temperature Range Molded DIP −65˚C to +150˚C Lead Temperature Molded DIP (soldering, 10 sec.) 265˚C Maximum Power Dissipation (Note 1) at 25˚C Molded Package 930 mW Supply Voltage 7.0V Differential Input Voltage +15V/−10V Enable Input Voltage 5.5V Min Typ Max 4.75 5.0 5.25 −7.0 0 12 Units V ± 12 V V −60 −400 mA µA 60 16 70 mA mA ˚C 25 Note 1: Derate molded DIP package 7.5 mW/˚C above 25˚C. Electrical Characteristics (Notes 3, 4) Over recommended temperature, common mode input voltage, and supply voltage ranges, unless otherwise specified Symbol Parameter Conditions Min Typ Max Units DRIVER SECTION VIH Input Voltage HIGH VIL Input Voltage LOW VOH Output Voltage HIGH VOL Output Voltage LOW VIC Input Clamp Voltage |VOD1| Differential Output Voltage |VOD2| Differential Output Voltage ∆|VOD2| Change in Magnitude of 2.0 V 0.8 IOH = −20 mA IOL = 20 mA 3.1 0.85 II = −18 mA IO = 0 mA V −1.5 6.0 RL = 100Ω, Figure 1 RL = 54Ω, Figure 1 and Figure 2 RL = 54Ω Differential Output Voltage (Note 5) VCM = 0V Figure 1 and Figure 2 RL = 100Ω Figure 1 VOC Common Mode Output Voltage (Note 6) RL = 54Ω or 100Ω, Figure 1 ∆|VOC| Change in Magnitude of 2.0 2.25 1.5 2.0 V V V V V ± 0.2 V 3.0 V ± 0.2 V 1.0 mA Common Mode Output Voltage (Note 5) IO Output Current (Note 5) Output Disabled (Includes Receiver II) IIH Input Current HIGH IIL Input Current LOW IOS Short Circuit Output Current (Note 10) ICC Supply Current VO = 12V VO = −7.0V −0.8 VI = 2.4V VI = 0.4V VO = −7.0V µA µA −250 VO = 0V VO = VCC VO = 12V No Load 20 −100 −150 mA 150 250 Outputs Enabled 35 Outputs Disabled 40 mA RECEIVER SECTION VTH Differential Input High VO = 2.7V, IO = −0.4 mA 0.2 V Threshold Voltage VTL Differential Input Low VO = 0.5V, IO = 8.0 mA −0.2 V Threshold Voltage (Note 7) VT+ − VT− Hysteresis (Note 8) VIH Enable Input Voltage HIGH VIL Enable Input Voltage LOW VIC Enable Input Clamp Voltage www.national.com VCM = 0V 50 mV 2.0 II = −18 mA 2 V 0.8 V −1.5 V Electrical Characteristics (Notes 3, 4) (Continued) Over recommended temperature, common mode input voltage, and supply voltage ranges, unless otherwise specified Symbol Parameter Conditions Min Typ Max Units RECEIVER SECTION VOH VOL Output Voltage HIGH VID = 200 mV, IOH = −400 µA, Output Voltage LOW Figure 3 VID = −200 mV, 2.7 V IOL = 8,0 mA Figure 3 IOL = 16 mA VO = 0.45V to 2.4V Other Input = VI = 12V 0V VI = −7.0V IOZ High Impedance State Output II Line Input Current (Note 9) IIH Enable Input Current HIGH IIL Enable Input Current LOW RI Input Resistance IOS Short Circuit Output Current (Note 10) ICC Supply Current (Total Package) No Load 0.45 V 0.50 ± 20 µA 1.0 mA 0.8 VIH = 2.7V VIL = 0.4V 20 µA −100 µA 12 kΩ −15 Outputs Enabled −85 mA 40 mA Outputs Disabled Driver Switching Characteristics VCC = 5V, TA = 25˚C Symbol Parameter tDD Differential Output Delay Time tTD Differential Output Transition Time tPLH Propagation Delay Time, Conditions RL = 60Ω, Figure 4 RL = 60Ω, Figure 4 RL = 27Ω, Figure 5 Min Typ Max Units 15 25 ns 15 25 ns 12 20 ns RL = 27Ω, Figure 5 12 20 ns RL = 110Ω, Figure 6 RL = 110Ω, Figure 7 RL = 110Ω, Figure 6 RL = 110Ω, Figure 7 25 35 ns 25 35 ns 20 25 ns 29 35 ns Typ Max Units 16 25 ns 16 25 ns 15 22 ns 15 22 ns 14 30 ns 24 40 ns Low-to-High Level Output tPHL Propagation Delay Time, High-to-Low Level Output tPZH Output Enable Time to High Level tPZL Output Enable Time to Low Level tPHZ Output Disable Time from High Level tPLZ Output Disable Time from Low Level Receiver Switching Characteristics VCC = 5.0V, TA = 25˚C Symbol tPLH Parameter Propagation Delay Time, Low-to-High Level Output tPHL Conditions VID = 0V to 3.0V CL = 15 pF, Figure 8 Propagation Delay Time, Min High-to-Low Level Output tPZH Output Enable Time to High Level tPZL Output Enable Time to Low Level tPHZ Output Disable Time from High Level tPLZ Output Disable Time from Low Level CL = 15 pF, Figure 9 CL = 5.0 pF, Figure 9 Note 2: “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the devices should be operated at these limits. The tables of “Electrical Characteristics” provide conditions for actual operation. Note 3: Unless otherwise specified min/max limits apply across the 0˚C to +70˚C range for the DS96176. All typicals are given for VCC = 5V and TA = 25˚C. Note 4: All currents into the device pins are positive; all currents out of the device pins are negative. All voltages are referenced to ground unless otherwise specified. Note 5: ∆|VOD| and ∆|VOC| are the changes in magnitude of VOD and VOC, respectively, that occur when the input is changed from a high level to a low level. Note 6: In EIA Standards RS-422A and RS-485, VOC, which is the average of the two output voltages with respect to ground, is called output offset voltage, VOS. Note 7: The algebraic convention, where the less positive (more negative) limit is designated minimum, is used in this data sheet for common mode input voltage and threshold voltage levels only. Note 8: Hysteresis is the difference between the positive-going input threshold voltage VT+, and the negative-going input threshold voltage, VT−. 3 www.national.com Receiver Switching Characteristics (Continued) Note 9: Refer to EIA Standard RS-485 for exact conditions. Note 10: Only one output at a time should be shorted. Parameter Measurement Information DS009630-2 FIGURE 1. Driver VOD and VOC DS009630-3 FIGURE 2. Driver VOD with Varying Common Mode Voltage DS009630-4 FIGURE 3. Receiver VOH and VOL DS009630-5 DS009630-6 FIGURE 4. Driver Differential Output Delay and Transition Times DS009630-7 DS009630-8 FIGURE 5. Driver Propagation Times www.national.com 4 Parameter Measurement Information (Continued) DS009630-10 DS009630-9 FIGURE 6. Driver Enable and Disable Times (tPZH, tPHZ) DS009630-12 DS009630-11 FIGURE 7. Driver Enable and Disable Times (tPZL, tPLZ) DS009630-14 DS009630-13 FIGURE 8. Receiver Propagation Delay Times 5 www.national.com Parameter Measurement Information (Continued) DS009630-15 DS009630-17 DS009630-16 DS009630-19 DS009630-18 Note 11: The input pulse is supplied by a generator having the following characteristics: PRR = 1.0 MHz, 50% duty cycle, tr ≤ 6.0 ns, ZO = 50Ω. Note 12: CL includes probe and stray capacitance. Note 13: DS96176 Driver enable is Active-High. Note 14: All diodes are 1N916 or equivalent. FIGURE 9. Receiver Enable and Disable Times Typical Application DS009630-20 Note: The line length should be terminated at both ends of its characteristic impedance. Stub lengths off the main line should be kept as short as possible. FIGURE 10. www.national.com 6 Typical Performance Characteristics Driver Differential Propagation Delay vs VCC vs Temperature Driver Differential Propagation Delay vs VCC vs Temperature DS009630-22 Driver Differential Rise Time vs VCC vs Temperature DS009630-23 Driver Differential Fall Time vs VCC vs Temperature DS009630-24 DS009630-25 Driver Skew vs VCC vs Temperature (|tPLDH–tPHLD|) DS009630-26 7 www.national.com Typical Performance Characteristics (Continued) DS009630-27 FIGURE 11. Typical Curve Driver Propagation Delay Test Circuit DS009630-28 FIGURE 12. Typical Curve Driver Differential Propagation Delay Timing www.national.com 8 Typical Performance Curves DS009630-29 FIGURE 13. Typical Curve Driver Differential Rise and Fall Times Receiver Propagation Delay vs VCC vs Temperature Receiver Propagation Delay vs VCC vs Temperature DS009630-30 DS009630-31 Receiver Skew vs VCC vs Temperature (|tPLH–tPHL|) DS009630-32 DS009630-33 FIGURE 14. Typical Curve Receiver Differential Propagation Delay Test Circuit 9 www.national.com Typical Performance Curves (Continued) DS009630-34 FIGURE 15. Typical Curve Receiver Propagation Delay Timing www.national.com 10 11 DS96176 RS-485/RS-422 Differential Bus Transceiver Physical Dimensions inches (millimeters) unless otherwise noted Molded Dual-In-Line Package (N) Order Number DS96176CN NS Package Number N08E LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 2. A critical component in any component of a life support 1. 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