SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 CAN TRANSCEIVER FEATURES • • • • • • • • • Drop-In Improved Replacement for the PCA82C250 and PCA82C251 Bus-Fault Protection of ±36 V Meets or Exceeds ISO 11898 Signaling Rates(1) up to 1 Mbps High Input Impedance Allows up to 120 SN65HVD251 Nodes on a Bus Bus Pin ESD Protection Exceeds 14 kV HBM Unpowered Node Does Not Disturb the Bus Low Current Standby Mode . . . 200 µA Typical Thermal Shutdown Protection • • Glitch-Free Power-Up and Power-Down Bus Protection For Hot-Plugging DeviceNet Vendor ID # 806 APPLICATIONS • • • • • CAN Data Buses Industrial Automation – DeviceNet™ Data Buses – Smart Distributed Systems (SDS™) SAE J1939 Standard Data Bus Interface NMEA 2000 Standard Data Bus Interface ISO 11783 Standard Data Bus Interface DESCRIPTION The SN65HVD251 is intended for use in applications employing the Controller Area Network (CAN) serial communication physical layer in accordance with the ISO 11898 Standard. The SN65HVD251 provides differential transmit capability to the bus and differential receive capability to a CAN controller at speeds up to 1 megabits per second (Mbps). Designed for operation in harsh environments, the device features cross-wire, over-voltage and loss of ground protection to ±36 V. Also featured are over-temperature protection as well as -7 V to 12 V common-mode range, and tolerance to transients of ± 200 V. The transceiver interfaces the single-ended CAN controller with the differential CAN bus found in industrial, building automation, and automotive applications. Rs, pin 8, provides for three different modes of operation: high-speed, slope control, or low-power mode. The high-speed mode of operation is selected by connecting pin 8 to ground, allowing the transmitter output transistors to switch as fast as possible with no limitation on the rise and fall slope. The rise and fall slope can be adjusted by connecting a resistor to ground at pin 8; the slope is proportional to the pin's output current. Slope control with an external resistor value of 10 kΩ gives ~ 15 V/us slew rate; 100 kΩ gives ~ 2 V/us slew rate. If a high logic level is applied to the Rs pin 8, the device enters a low-current standby mode during which the driver is switched off and the receiver remains active . The local protocol controller reverses this low-current standby mode when it needs to transmit to the bus. The SN65HVD251 may be used in CAN, DeviceNet™ or SDS™ applications with the Texas Instruments' TMS320F241 and TMS320F243 DSPs with CAN 2.0B controllers. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. DeviceNet is a trademark of Allen-Bradley. SDS is a trademark of Honeywell. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2002–2003, Texas Instruments Incorporated SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 function diagram (positive logic) VCC D GND 1 8 Rs 2 7 Vcc 3 4 6 5 CANH CANL Vref R (1) (1)The 5 V ref 1 D RS 8 R (1) 3 7 CANH 6 CANL 4 ORDERING INFORMATION PART NUMBER PACKAGE MARKED AS SN65HVD251D 8-pin SOIC (Tube) VP251 SN65HVD251DR 8-pin SOIC (Tape & Reel) VP251 SN65HVD251P 8-pin DIP 65HVD251 signaling rate of a line is the number of voltage transitions that are made per second expressed in the units bps (bits per second). ABSOLUTE MAXIMUM RATINGS (1), (2) SN65HVD251 Supply voltage range, VCC -0.3 V to 7V Voltage range at any bus terminal (CANH or CANL) -36 V to 36 V Transient voltage per ISO 7637, pulse 1, 2, 3a, 3b ±200 V CANH, CANL Input voltage range, VI (D, Rs, or R) -0.3 V to VCC + 0.5 Human Body Model Electrostatic discharge (3) Charged-Device Model (4) CANH, CANL and GND 14 kV All pins 6 kV All pins 1 kV Continuous total power dissipation (see Dissipation Rating Table) Storage temperature range, Tstg -65C to 150°C Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds (1) (2) (3) (4) 260°C Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. All voltage values, except differential I/O bus voltages, are with respect to network ground terminal. Tested in accordance with JEDEC Standard 22, Test Method A114-A. Tested in accordance with JEDEC Standard 22, Test Method C101. ABSOLUTE MAXIMUM POWER DISSIPATION RATINGS PACKAGE SOIC (D) PDIP (P) (1) (2) (3) CIRCUIT BOARD MODEL TA = 25°C POWER RATING Low-K (2) 600 mW High-K (3) 963 mW DERATING FACTOR ABOVE TA = 25°C (1) TA = 85°C POWER RATING TA = 125°C POWER RATING 4.4 mW/°C 312 mW 120 mW 7.7 mW/°C 501 mW 193 mW Low-K (2) 984 mW 7.8 mW/°C 512 mW 197 mW High-K (3) 1344 mW 10.8 mW/°C 699 mW 269 mW This is the inverse of the junction-to-ambient thermal resistance when board-mounted and with no air flow. In accordance with the Low-K thermal metric definitions of EIA/JESD51-3. In accordance with the High-K thermal metric definitions of EIA/JESD51-7. THERMAL CHARACTERISTICS PARAMETER TEST CONDITIONS VALUE MIN Θ JB 2 Junction-to-board thermal resistance TYP D 78.7 P 56.5 UNITS MAX °C/W SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 THERMAL CHARACTERISTICS (continued) PARAMETER TEST CONDITIONS VALUE MIN Θ JC Junction-to-board thermal resistance PD Device power dissipation TSD Thermal shutdown junction temperature UNITS TYP D 44.6 P 54.5 MAX °C/W VCC = 5 V, Tj = 27 °C, RL = 60Ω, RS at 0 V, Input to D a 500-kHz 50% duty cycle square wave 97.7 mW VCC = 5.5 V, Tj = 130°C, RL = 60Ω, RS at 0 V, Input to D a 500-kHz 50% duty cycle square wave 142 mW °C 165 RECOMMENDED OPERATING CONDITIONS over recommended operating conditions (unless otherwise noted). PARAMETER MIN Supply voltage, VCC Voltage at any bus terminal (separately or common mode) VI or VIC High-level input voltage, VIH D input Low-level input voltage, VIL D input NOM V -7 (1) 12 V 0.7 VCC Input voltage at Rs for standby, VI(Rs) 0.3 VCC V 6 V 0 VCC V 0.75 VCC VCC V 0 100 kΩ Rs wave-shaping resistance Driver -50 Receiver mA -4 Driver 50 Receiver Operating free-air temperature, TA 4 -40 Junction temperature, Tj (1) V -6 Input voltage to Rs, VI(Rs) Low-level output current, IOL UNIT 5.5 Differential input voltage, VID High-level output current, IOH MAX 4.5 125 PDIP Package 145 SOIC Package 150 mA °C °C The algebraic convention, in which the least positive (most negative) limit is designated as minimum is used in this data sheet. DRIVER ELECTRICAL CHARACTERISTICS over recommended operating conditions (unless otherwise noted). PARAMETER TEST CONDITIONS CANH Figure 1 & Figure 2 , D at 0 V Rs at 0 V TYP (1) MIN 2.75 3.5 MAX UNIT 4.5 VO(D) Bus output voltage (Dominant) VO(R) Bus output voltage (Recessive) VOD(D) Differential output voltage (Dominant) Figure 1 , D at 0 V, Rs at 0 V VOD(D) Differential output voltage (Dominant) Figure 2 & Figure 3 , D at 0 V, Rs at 0 V 1.2 VOD(R) Differential output voltage (Recessive) Figure 1 & Figure 2 , D at 0.7 VCC -120 VOD(R) Differential output voltage (Recessive) D at 0.7 VCC, no load -0.5 VOC(pp) Peak-to-peak common-mode output voltage Figure 9, Rs at 0 V IIH High-level input current, D Input D at 0.7 VCC -40 0 µA IIL Low-level input current, D Input D at 0.3 VCC -60 0 µA (1) CANL CANH CANL Figure 1 & Figure 2 , D at 0.7VCC , Rs at 0 V 0.5 2 V 2 2.5 3 2 2.5 3 1.5 2 3 V 2 3.1 V 12 mV 0.05 600 V mV All typical values are at 25°C and with a 5-V supply. 3 SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 DRIVER ELECTRICAL CHARACTERISTICS (continued) over recommended operating conditions (unless otherwise noted). PARAMETER TEST CONDITIONS Figure 11, VCANH at -7 V, CANL Open IOS(SS) TYP (1) MIN MAX Figure 11, VCANH at 12 V, CANL Open Short-circuit steady-state output current 2.5 Figure 11, VCANL at -7 V, CANH Open mA -2 Figure 11, VCANL at 12 V, CANH Open 200 CO Output capacitance See receiver input capacitance IOZ High-impedance output current See receiver input current IIRs(s) Rs input current for standby Rs at 0.75 VCC IIRs(f) Rs input current for full speed operation ICC Supply current UNIT -200 -10 Rs at 0 V µA -550 0 µA 275 µA Standby Rs at VCC, D at VCC Dominant D at 0 V, 60Ω load, Rs at 0 V 65 Recessive D at VCC, no load, Rs at 0 V 14 mA DRIVER SWITCHING CHARACTERISTICS over recommended operating conditions (unless otherwise noted). PARAMETER tpLH TEST CONDITIONS Propagation delay time, low-to-high-level output TYP MAX Figure 4, Rs at 0 V MIN 40 70 Figure 4, Rs with 10 kΩ to ground 90 125 Figure 4, Rs with 100 kΩ to ground 500 800 85 125 Figure 4, Rs with 10 kΩ to ground 200 260 Figure 4, Rs with 100 kΩ to ground 1150 1450 Figure 4, Rs at 0 V tpHL Propagation delay time, high-to-low-level output Figure 4, Rs at 0 V tsk(p) Pulse skew (|tpHL - tpLH|) tr Differential output signal rise time tf Differential output signal fall time tr Differential output signal rise time tf Differential output signal fall time tr Differential output signal rise time tf Differential output signal fall time ten Enable time from standby to dominant Figure 4, Rs with 10 kΩ to ground Figure 4, Rs with 100 kΩ to ground Figure 4, Rs at 0 V Figure 4, Rs with 10 kΩ to ground Figure 4, Rs with 100 kΩ to ground 45 85 110 180 650 900 35 100 35 100 100 250 100 250 600 1550 600 1550 Figure 8 0.5 UNIT ns µs RECEIVER ELECTRICAL CHARACTERISTICS over recommended operating conditions (unless otherwise noted). PARAMETER TEST CONDITIONS VIT+ Positive-going input threshold voltage VIT- Negative-going input threshold voltage Vhys Hysteresis voltage (VIT+ - VIT-) VOH High-level output voltage Figure 6, IO = -4mA VOL Low-level output voltage Figure 6, IO = 4mA 4 Rs at 0 V, (See Table 1) MIN 500 TYP MAX 750 900 650 UNIT mV 100 0.8 Vcc V 0.2 Vcc V SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 RECEIVER ELECTRICAL CHARACTERISTICS (continued) over recommended operating conditions (unless otherwise noted). PARAMETER TEST CONDITIONS MIN TYP MAX CANH or CANL at 12 V II CANH or CANL at 12 V, VCC at 0 V Other bus pin at 0 V, Rs at 0 V, D CANH or CANL at -7 V at 0.7 VCC Bus input current CANH or CANL at -7 V, VCC at 0 V 715 -340 Input capacitance, (CANH or CANL) Pin-to-ground, VI = 0.4 sin (4E6πt) + 0.5 V, D at 0.7 VCC 20 CID Differential input capacitance Pin-to-pin, VI = 0.4 sin (4E6πt) + 0.5 V, D at 0.7 VCC 10 RID Differential input resistance D at 0.7 VCC, Rs at 0 V 40 RIN Input resistance, (CANH or CANL) D at 0.7 VCC, Rs at 0 V 20 Supply current µA -460 CI ICC UNIT 600 pF pF 100 kΩ 50 kΩ 275 µA Standby Rs at VCC, D at VCC Dominant D at 0 V, 60Ω Load, Rs at 0 V 65 Recessive D at VCC, No Load, Rs at 0 V 14 mA RECEIVER SWITCHING CHARACTERISTICS over recommended operating conditions (unless otherwise noted). PARAMETER TEST CONDITIONS tpLH Propagation delay time, low-to-high-level output tpHL Propagation delay time, high-to-low-level output tsk(p) Pulse skew (|tpHL - tpLH|) tr Output signal rise time tf Output signal fall time tp(sb) Propagation delay time in standby MIN TYP MAX 35 50 35 50 Figure 6 20 2 2 Figure 12, Rs at VCC 4 UNIT ns 4 500 VREF-PIN CHARACTERISTICS over recommended operating conditions (unless otherwise noted). PARAMETER VO Reference output voltage TEST CONDITIONS -5 µA < IO < 5 µA -50 µA < IO < 50 µA MIN TYP MAX 0.45 VCC 0.55 VCC 0.4 VCC 0.6 VCC UNIT V 5 SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 DEVICE SWITCHING CHARACTERISTICS over recommended operating conditions (unless otherwise noted). PARAMETER TEST CONDITIONS MIN TYP Figure 10, Rs at 0 V tloop1 tloop2 tloop2 Total loop delay, driver input to receiver output, recessive to dominant Total loop delay, driver input to receiver output, dominant to recessive Total loop delay, driver input to receiver output, dominant to recessive 60 100 Figure 10, Rs with 10 kΩ to ground 100 150 Figure 10, Rs with 100 kΩ to ground 440 800 Figure 10, Rs at 0 V 115 150 Figure 10, Rs with 10 kΩ to ground 235 290 Figure 10, Rs with 100 kΩ to ground 1070 1450 105 145 Figure 10, Rs at 0 V, VCC from 4.5 V to 5.1 V, PARAMETER MEASUREMENT INFORMATION IO(CANH) VO(CANH) D VOD II 60 1% IIRs Rs VI + VO(CANH) + VO(CANL) 2 VOC IO(CANL) VI(Rs) _ VO(CANL) Figure 1. Driver Voltage, Current, and Test Definition Dominant Recessive 3.5 V VO(CANH) 2.5 V 1.5 V VO(CANL) Figure 2. Bus Logic State Voltage Definitions CANH VI D VOD 330 1% 60 1% + _ RS CANL 330 1% Figure 3. Driver VOD 6 MAX –7 V VTEST 12 V UNIT ns ns ns SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 PARAMETER MEASUREMENT INFORMATION (continued) CANH D VI RL = 60 1% + VI(Rs) _ Rs (see Note A) CL = 50 pF 20% (see Note B) VO CANH VCC VCC/2 VI VCC/2 0V tPHL tPLH 0.9V VO 90% 10% tr VO(D) 0.5V VO(R) tf Figure 4. Driver Test Circuit and Voltage Waveforms CANH R VI(CANH) VI(CANH) + VI(CANL) VIC = 2 VI(CANL) IO VID VO CANL Figure 5. Receiver Voltage and Current Definitions CANH R VI CANL (see Note A) 1.5 V IO CL = 15 pF 20% (see Note B) VO 3.5 V VI 2.4 V 2V 1.5 V tPLH VO tPHL 0.7 VCC 10% 90% tr VOH 0.3 VCC 10% VOL tf A. The input pulse is supplied by a generator having the following characteristics: PRR ≤ 125 kHz, 50% duty cycle, tr≤ 6ns, tf≤ 6ns, ZO = 50Ω. B. CL includes instrumentation and fixture capacitance within ±20%. Figure 6. Receiver Test Circuit and Voltage Waveforms 7 SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 PARAMETER MEASUREMENT INFORMATION (continued) CANH R CANL 100 Pulse Generator 15 s Duration 1% Duty Cycle tr, tr 100 ns D at 0 V or VCC RS at 0 V or VCC A. This test is conducted to test survivability only. Data stability at the R output is not specified. Figure 7. Test Circuit, Transient Over-Voltage Test Table 1. Receiver Characteristics Over Common Mode Voltage INPUT MEASURED OUTPUT VCANH VCANL |VID| 12 V 11.1 V 900 mV L R -6.1 V -7 V 900 mV L -1 V -7 V 6V L 12 V 6V 6V L -6.5 V -7 V 500 mV H 12 V 11.5 V 500 mV H -7 V -1 V 6V H 6V 12 V 6V H open open X H DUT CANH 0V VI D 60 1% Rs CANL R + VO _ 15 pF 20% VCC 0.7 VCC VI 0V VOH 0.3 VCC VO ten 0.3 VCC VOL Figure 8. ten Test Circuit and Voltage Waveforms 8 VOL VOH SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 CANH 27 1% D VI CANL 27 1% RS VOC 50 pF 20% VOC(PP) VOC A. The input pulse is supplied by a generator having the following characteristics: PRR ≤ 125 kHz, 50% duty cycle, tr≤ 6ns, tf≤ 6ns, ZO = 50Ω. Figure 9. Peak-to-Peak Common Mode Output Voltage DUT CANH VI D 60 1% 10 k or 100 k 5% _ RS CANL VRs + R + VO _ 15 pF 20% VCC 50% D Input 0V tLoop2 tLoop1 VOH 0.7 Vcc R Output 0.3 Vcc VOL Figure 10. tLOOP Test Circuit and Voltage Waveforms 9 SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 IOS CANH D 0 V or VCC CANL Rs Vin –7 V or 12 V IOS(SS) IOS(P) 15 s 0V 12 V Vin 0V 10 s or 0V Vin –7 V Figure 11. Driver Short-Circuit Test CANH R VI (see Note A) CANL CL = 15 pF 1.5 V VO (see Note B) 3.5 V 2.4 V VI 1.5 V tp(sb) VOH VO 0.3 VCC VOL A. The input pulse is supplied by a generator having the following characteristics: PRR ≤ 125 kHz, 50% duty cycle, tr≤ 6ns, tf≤ 6ns, ZO = 50Ω. B. CL includes instrumentation and fixture capacitance within ±20%. Figure 12. Receiver Propagation Delay in Standby Test Circuit and Waveform 10 SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 DEVICE INFORMATION 5V R21% R11% CANH + R VID – CANL Vac R11% VI R21% VID R1 R2 500 mV 50 450 900 mV 50 227 12 V VI –7 V A. All input pulses are supplied by a generator having the following characteristics: f < 1.5 MHz, TA = 25oC, VCC = 5.0 V. Figure 13. Common-Mode Input Voltage Rejection Test FUNCTION TABLES Table 2. DRIVER INPUTS D Voltage at Rs, VRs OUTPUTS CANH BUS STATE CANL L VRs < 1.2 V H L Dominant H VRs < 1.2 V Z Z Recessive Open X Z Z Recessive X VRs > 0.75 VCC Z Z Recessive Table 3. RECEIVER (1) DIFFERENTIAL INPUTS [VID = V(CANH) - V(CANL)] OUTPUT R (1) VID≥ 0.9 V L 0.5V < VID < 0.9 V ? VID ≤ 0.5 V H Open H H = high level; L = low level; X = irrelevant; ? = indeterminate; Z = high impedance 11 SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 D Input R Output VCC VCC 100 k 5 1 k Input Output 9V 9V CANH Input CANL Input VCC VCC 110 k 110 k 9 k 45 k 9 k 45 k Input Input 40 V 40 V 9 k CANH and CANL Outputs 9 k Rs Input VCC VCC Output 40 V +_ Input Figure 14. Equivalent Input and Output Schematic Diagrams 12 SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 TYPICAL CHARACTERISTICS tLOOP1-LOOP TIME vs FREE-AIR TEMPERATURE tLOOP2-LOOP TIME vs FREE-AIR TEMPERATURE SUPPLY CURRENT (RMS) vs SIGNALING RATE 150 33 72 tLOOP2 – Loop Time – ns VCC = 4.5 V VCC = 5 V 70 68 66 VCC = 5.5 V VCC = 5.5 V VCC = 5 V 140 135 130 VCC = 4.5 V 64 125 62 –40 –25 –10 5 120 –40 –25 –10 5 20 35 50 65 80 95 110 125 32 31 30 29 28 27 26 25 0 35 50 65 80 95 110 125 VCC = 5 V, TA = 25°C, RS = 0 V, RL = 60 Ω, CL = 50 pF 250 500 750 1000 1250 1500 1750 2000 TA – Free-Air Temperature – C Signaling Rate – kbps Figure 15. Figure 16. Figure 17. DRIVER LOW-LEVEL OUTPUT CURRENT vs LOW-LEVEL OUTPUT VOLTAGE DRIVER HIGH-LEVEL OUTPUT CURRENT vs HIGH-LEVEL OUTPUT VOLTAGE DOMINANT DIFFERENTIAL OUTPUT VOLTAGE vs FREE-AIR TEMPERATURE 140 IOH – Driver High-Level Output Current – mA IOL – Driver Low-Level Output Current – mA TA – Free-Air Temperature – C 20 VCC = 5 V, TA = 25°C, RS = 0 V, D at 0V 120 100 80 60 40 20 0 0 1 2 3 4 VOCANL – Low-Level Output Voltage – V 5 80 VCC = 5 V, TA = 25°C, RS = 0 V, D at 0V 70 60 50 40 30 20 10 0 0 1 2 3 4 VOCANH – High-Level Output Voltage – V 5 VOD(D) – Dominant Differential Output Voltage – V tLOOP1 – Loop Time – ns 145 ICC – RMS Supply Current – mA RS = 0 V RS = 0 V 74 3 VCC = 5.5 V 2.5 2 VCC = 4.5 V VCC = 5 V 1.5 1 RS = 0 V, D at 0V, RL = 60 Ω 0.5 0 –55 –40 0 25 70 85 125 TA – Free-Air Temperature – C Figure 18. Figure 19. Figure 20. 13 SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 DIFFERENTIAL OUTPUT FALL TIME vs SLOPE RESISTANCE (Rs) DRIVER OUTPUT CURRENT vs SUPPLY VOLTAGE 50 40 30 20 10 0 TA = 25°C 900 800 VCC = 5.5 V VCC = 5 V 700 600 VCC = 4.5 V 500 400 300 200 2 3 4 VCC – Supply Voltage – V Figure 21. 5 6 −0.50 VCC = 5.5 V −1 −1.50 VCC = 5 V −2 VCC = 4.5 V −2.50 100 −3 0 1 Input Resistance Matching − % TA = 25°C, RS = 0 V, D at 0V, RL = 60 Ω tf - Differential Output Fall Time - ns IO – Driver Output Current – mA 0 1000 60 14 INPUT RESISTANCE MATCHING vs FREE-AIR TEMPERATURE 0 10 20 30 40 50 60 70 80 90 100 RS - Slope Resistance - k Figure 22. −50 0 50 100 TA − Free-Air Temperature − °C Figure 23. 150 SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 APPLICATION INFORMATION The basics of arbitration require that the receiver at the sending node designate the first bit as dominant or recessive after the initial wave of the first bit of a message travels to the most remote node on a network and back again. Typically, this sample is made at 75% of the bit width, and within this limitation, the maximum allowable signal distortion in a CAN network is determined by network electrical parameters. Factors to be considered in network design include the ≈ 5 ns/m propagation delay of typical twisted-pair bus cable; signal amplitude loss due to the loss mechanisms of the cable; and the number, length, and spacing of drop-lines (stubs) on a network. Under strict analysis, variations among the different oscil- lators in a system also need to be accounted for with adjustments in signaling rate and stub & bus length. Table 2 lists the maximum signaling rates achieved with the SN65HVD251 in high-speed mode with several bus lengths of category 5, shielded twisted pair (CAT 5 STP) cable. Table 4. Maximum Signaling Rates for Various Cable Lengths BUS LENGTH (m) SIGNALING RATE (kbps) 30 1000 100 500 250 250 500 125 1000 62.5 The ISO 11898 Standard specifies a maximum bus length of 40 m and maximum stub length of 0.3 m with a maximum of 30 nodes. However, with careful design, users can have longer cables, longer stub lengths, and many more nodes on a bus. (Note: Non-standard application may come with a trade-off in signaling rate.) A large number of nodes requires a transceiver with high input impedance such as the HVD251. The Standard specifies the interconnect to be a single twisted-pair cable (shielded or unshielded) with 120Ω characteristic impedance (Zo). Resistors equal to the characteristic impedance of the line terminate both ends of the cable to prevent signal reflections. Unterminated drop-lines connect nodes to the bus and should be kept as short as possible to minimize signal reflections. Connectors, while not specified by the Standard should have as little effect as possible on standard operating parameters such as capacitive loading. Although unshielded cable is used in many applications, data transmission circuits employing CAN transceivers are usually used in applications requiring a rugged interconnection with a wide common-mode voltage range. Therefore, shielded cable is recommended in these electronically harsh environments, and when coupled with the Standard's –2-V to 7-V common-mode range of tolerable ground noise, helps to ensure data integrity. The HVD251 enhances the Standard's insurance of data integrity with an extended –7-V to 12-V range of common-mode operation. NOISE MARGIN 900 mV Threshold RECEIVER DETECTION WINDOW 75% SAMPLE POINT 500 mV Threshold NOISE MARGIN ALLOWABLE JITTER Figure 24. Typical CAN Differential Signal Eye-Pattern 15 SN65HVD251 www.ti.com SLLS545B – NOVEMBER 2002 – REVISED SEPTEMBER 2003 An eye pattern is a useful tool for measuring overall signal quality. As displayed in Figure 24, the differential signal changes logic states in two places on the display, producing an eye. Instead of viewing only one logic crossing on the scope, an entire bit of data is brought into view. The resulting eye pattern includes all of the effects of systemic and random distortion, and displays the time during which a signal may be considered valid. The height of the eye above or below the receiver threshold voltage level at the sampling point is the noise margin of the system. Jitter is typically measured at the differential voltage zero-crossing during the logic state transition of a signal. Note that jitter present at the receiver threshold voltage level is considered by some to be a more effective representation of the jitter at the input of a receiver. As the sum of skew and noise increases, the eye closes and data is corrupted. Closing the width decreases the time available for accurate sampling, and lowering the height enters the 900 mV or 500 mV threshold of a receiver. Different sources induce noise onto a signal. The more obvious noise sources are the components of a transmission circuit themselves; the signal transmitter, traces & cables, connectors, and the receiver. Beyond that, there is a termination dependency, cross-talk from clock traces and other proximity effects, VCC & ground bounce, and electromagnetic interference from near-by electrical equipment. The balanced receiver inputs of the HVD251 mitigate most all sources of signal corruption, and when used with a quality shielded twisted-pair cable, help insure data integrity. Typical Application Bus Lines – 40 m max CANH 120 120 Stub Lines –– 0.3 m max CANL Vref RS VCC 5V SN65HVD251 0.1 F Vref RS VCC CANTX R CANRX 0.1 F SN65HVD251 GND D 5V RS VCC SN65HVD230 GND D CANTX R CANRX GND D CANTX R CANRX TMS320F243 TMS320F243 TMS320LF2407A Sensor, Actuator, or Control Equipment Sensor, Actuator, or Control Equipment Sensor, Actuator, or Control Equipment Figure 25. Typical HVD251 Application 16 Vref 3.3 V 0.1 F MECHANICAL DATA MPDI001A – JANUARY 1995 – REVISED JUNE 1999 P (R-PDIP-T8) PLASTIC DUAL-IN-LINE 0.400 (10,60) 0.355 (9,02) 8 5 0.260 (6,60) 0.240 (6,10) 1 4 0.070 (1,78) MAX 0.325 (8,26) 0.300 (7,62) 0.020 (0,51) MIN 0.015 (0,38) Gage Plane 0.200 (5,08) MAX Seating Plane 0.010 (0,25) NOM 0.125 (3,18) MIN 0.100 (2,54) 0.021 (0,53) 0.015 (0,38) 0.430 (10,92) MAX 0.010 (0,25) M 4040082/D 05/98 NOTES: A. All linear dimensions are in inches (millimeters). B. This drawing is subject to change without notice. C. Falls within JEDEC MS-001 For the latest package information, go to http://www.ti.com/sc/docs/package/pkg_info.htm POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and applications using TI components. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation. Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. Following are URLs where you can obtain information on other Texas Instruments products and application solutions: Products Applications Amplifiers amplifier.ti.com Audio www.ti.com/audio Data Converters dataconverter.ti.com Automotive www.ti.com/automotive DSP dsp.ti.com Broadband www.ti.com/broadband Interface interface.ti.com Digital Control www.ti.com/digitalcontrol Logic logic.ti.com Military www.ti.com/military Power Mgmt power.ti.com Optical Networking www.ti.com/opticalnetwork Microcontrollers microcontroller.ti.com Security www.ti.com/security Telephony www.ti.com/telephony Video & Imaging www.ti.com/video Wireless www.ti.com/wireless Mailing Address: Texas Instruments Post Office Box 655303 Dallas, Texas 75265 Copyright 2004, Texas Instruments Incorporated