AND8410/D EMC Conducted Susceptibility, IEC 62132-4, Direct Power Injection http://onsemi.com APPLICATION NOTE Introduction The EMC conducted immunity can be significantly improved by terminating the LIN bus with a capacitor to ground. On one hand it will load the bus so the maximum value is limited to ensure t < 5 ms (see LIN Physical Layer Spec Rev. 2.0, paragraph 3.1 LINE characteristics). On the other hand the higher the capacitor level, the more power can be injected in the system. Terminating the LIN output with a capacitor CL to ground improves the EMC conducted susceptibility to the levels indicated in Table 1. Table 1. MEASURED LEVELS OF EMC CONDUCTED SUSCEPTIBILITY CL Power Injected Frequency Range 1 nF 3W 15 MHz − 300 MHz >4 W 17 MHz − 290 MHz 3W 6 MHz − 500 MHz >4 W 8 MHz − 500 MHz 2.2 nF Measurement Set−up Vbat +5 V 100 nF VBB VCC DPI Analyzer 7 8 3 INH 100 nF AMIS−30600 TxD RxD 20 pF RL 4 1 6 4.7 nF LIN 5 2 EN CL GND Figure 1. Schematic Diagram DUT © Semiconductor Components Industries, LLC, 2009 August, 2009 − Rev. 3 1 Publication Order Number: AND8410/D AND8410/D Figure 2. DPI Analyzer Details Table 2. LIST OF MEASUREMENT INSTRUMENTS USED Instrument Description RF Generator Rohde & Schwarz signal generator 5 kHz; 1.5 GHz SMT02 Switch Unit Agilent data acquisition / switch unit 34970A Switch Unit Module HP 20 channel actuator / general−purpose switch 34903A Amplifier research worldwide directional coupler MODEL DC3010 (10 KHz − 1000 MHz, 50 W CW/40 dB) Amplifier research worldwide microwave switches 8761A (DC−18 GHz, 10 W) Power load termination Narda MOD376BNM (DC−12.4 GHz, 50 W/40 W) RF Amplifier Amplifier research worldwide model 25A250A 25 Wats 10 kHz; 250 MHz Amplifier research worldwide model 30A1000B 30 Wats 10 kHz; 1000 MHz Switch Box Power switch AMIS including directional coupler amplifier research RF Power Meter Rohde & Schwarz power meter NRVD RF Attenuator Rohde & Schwarz 6 dB, input max. 50 W, DC−2 GHz URV Probes Rohde & Schwarz URV5−Z2 Accessories http://onsemi.com 2 AND8410/D Measurement Results Power injected in dBm and W in function of frequency with termination capacitor CL as a parameter. EMC susceptibility − disturbance on LIN bus 40 35 C_LIN = 2.2 n C_LIN = 1 n Power [dBm] 30 25 C_LIN = NA 20 15 10 5 0 1 10 100 1000 Frequency [MHz] Figure 3. Power Injected in dBm EMC susceptibility − disturbance on LIN bus 4.5 4 3.5 C_LIN = 2.2 n C_LIN = 1 n Power [W] 3 2.5 2 1.5 1 0.5 0 C_LIN = NA 1 10 100 Frequency [MHz] Figure 4. Power Injected in W http://onsemi.com 3 1000 AND8410/D Recommendation Company or Product Inquiries At the master node a capacitor CL can be connected between LIN and ground still fulfilling the maximum time−constant of the bus. Giving next equations: For more information about ON Semiconductor’s products or services, please visit our web site at http://www.onsemi.com. CBUS = CMASTER + n CSLAVE + C’LINE ⋅ LengthBUS t + CBUS @ RBUS RBUS + RMaster ø RSlave1 ø RSlave2 ø AAA ø RSlave_n As an example, one can calculate the maximum value for CL: • 1 master • 3 slaves • Line length = 10 m • C’line = 100 pF/m • Cslave = 220 pF • Rslave = 30 kW • Rmaster = 1 kW • t ≤ 4 ms This yields in CL = 2.74 nF. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. 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