Application note TH808x External ESD protection Application Hints for using external ESD protection of TH808x TH808x 1. Scope This application note describes the possibility to increase the ESD robustness level of TH8080x by using different external protection elements. To verify different external circuitries it was applied the standard LIN ESD test method described in the LIN EMC Test Specification Rev. 2.0 (DIN 61000-4-2). This test method is used for the IC related ESD verification of LIN devices. The value of this test method can correlate with the behaviour on module level, but in general the test conditions, pulse forms, rise times and the energy of the applied pulses are much different. Fig.1 shows the improvement of the ESD protection on TH808x by using different ESD protection elements. 15 KV 14 KV 13 KV 12 KV 11 KV 10 KV 9 KV 8 KV applicable 7 KV 6 KV 5 KV applicable 4 KV 3 KV 2 KV applicable 1 KV 0 KV without ESD protection ESD protection with varistor ESD protection with Peak Power Zener Transient Voltage Suppressors diode Figure 1 – Results of ESD test of Th808x with different external ESD protection elements Appl.Note – External ESD Protection 390110808001 Page 1 of 8 July 2007 Rev 003 Application note TH808x External ESD protection 2. Description of the ESD test according to DIN 6100061000-4-2 For the test according to DIN 61000-4-2 was used the following equipment: ESD simulator Discharge module Oscilloscope Function generator EM Test ESD 30C P 30C (150pF/ 330Ω, 150pF/2000Ω or 330pF/2000Ω) Tektronix TDS 544A HAMEG HM8130 Fig.2 shows the schematic of the ESD test setup and Fig.3 shows the test PCB. Figure 2 - Schematic of the ESD test setup Figure 3 - ESD test PCB TH808x Appl.Note – External ESD Protection 390110808001 Page 2 of 8 July 2007 Rev 003 Application note TH808x External ESD protection 3. Test Results In order to check to the device after applying the ESD stress it was monitored the pin I/V characteristics. With this pin characteristic measurement is it is possible to detect already a pre-damaging caused by ESD, also if the IC functional is still OK. 3.1 ESD protection using Varistor (TDK AVR-M1608C270MBABB 15pF), bus capacitor 180pF (Slave Module) and resistor 10Ω ESD protection using varistor Protection elements: Varistor: Bus Capacitor: Bus serial Element: TDK AVR-M1608C270MBABB (15pF) 180pF (slave module) 10 Ω TH8082 Resistor LIN Bus 10Ohm 180p Varistor Figure 4 - Schematic of the ESD protection with varistor The damage limit by using varistor and serial resistor as protection elements is 9 to 15kV. The result is sufficient for a robustness level of 8kV. ESD- Measurement: LIN- Bus, I/V characteristics Transceiver: TH8082 KDC 0352 Pin: LIN to GND Bus capacitor: 180pF / 10 Ohm plus Varistor Pin Current [mA] 1,2 1,0 0,8 0,6 0,4 0,2 0,0 -0,2 -0,4 -0,6 -0,8 -1,0 -1,2 -40 -30 Before test # 3 @ +6kV # 3 @ -6kV # 3 @ +7kV # 3 @ -7kV # 3 @ +8kV # 3 @ -8kV # 3 @ +10kV # 3 @ -10kV # 3 @ +12kV -20 -10 0 10 20 30 40 50 60 Pin Voltage [V] Figure 5 - I/V pin characteristic after applying different ESD pulses Appl.Note – External ESD Protection 390110808001 Page 3 of 8 July 2007 Rev 003 Application note TH808x External ESD protection 3.2 ESD protection using Back-to-Back Zener Diode (Onsemi MMB27VCLT1 30pF), bus capacitor 180pF (Slave Module) and resistor 10Ω Protection elements: Diode: Bus Capacitor: Bus serial Element: ON-Semi MMBZ27VCLT1 (30pF) 180pF (slave module) 10 Ω TH8082 Resistor LIN Bus 10Ohm 180p MMBZ27VCLT1 Figure 6 - Schematic of the ESD protection with Back-to-Back Zener Diode The damage limit by using Back-to-back zener diode and serial resistor as protection elements is >15kV. The result is sufficient for a robustness level of 15kV. ESD- Measurement: LIN- Bus, I/V characteristics Transceiver: TH8082 KDC 0352 Pin: LIN to GND Bus capacitor: Pin Current [mA] 1,2 1,0 0,8 0,6 0,4 0,2 0,0 -0,2 -0,4 -0,6 -0,8 -1,0 -1,2 -40 -30 180pF / 10 Ohm plus Peak Power Zener Transient Voltage Suppressors diode Before test # 3 @ +6kV # 3 @ -6kV # 3 @ +8kV # 3 @ -8kV # 3 @ +12kV # 3 @ -12kV # 3 @ +15kV # 3 @ -15kV -20 -10 0 10 20 30 40 50 60 Pin Voltage [V] Figure 7 - I/V pin characteristic after applying different ESD pulses Appl.Note – External ESD Protection 390110808001 Page 4 of 8 July 2007 Rev 003 Application note TH808x External ESD protection 3.3 ESD protection using Back-to-Back Zener Diode (Onsemi MMB27VCLT1 30pF), bus capacitor 1nF (Master Module) and SMD-ferrite (Würth: 742 792 097) Protection elements: Diode: Bus Capacitor: Bus serial Element: ON-Semi MMBZ27VCLT1 (30pF) 1nF (master module) SMD-ferrite Würth 742 792 097 TH8082 SMD-Ferrite LIN Bus 742 793 097 1n MMBZ27VCLT1 Figure 8 - Schematic of the ESD protection with Back-to-Back Zener Diode The damage limit by using Back-to-back zener diode and serial SMD-ferrite as protection elements is >15kV. The result is sufficient for a robustness level of 15kV. ESD- Measurement: LIN- Bus, I/V characteristics Transceiver: TH8082 KDC 0642 Pin: LIN to GND Bus capacitor: 1nF & MMBZ27VCLT1 to GND; Ferrite (Würth: 742 792 097) in line Pin Current [mA] 1,2 1,0 0,8 0,6 0,4 0,2 0,0 -0,2 -0,4 -0,6 -0,8 -1,0 -1,2 -40 -30 Before test LIN # LIN @ +4kV # LIN @ -4kV # LIN @ +8kV # LIN @ -8kV # LIN @ +15kV # LIN @ -15kV -20 -10 0 10 20 30 40 50 60 Pin Voltage [V] Figure 9 - I/V pin characteristic after applying different ESD pulses Appl.Note – External ESD Protection 390110808001 Page 5 of 8 July 2007 Rev 003 Application note TH808x External ESD protection 3.4 ESD protection using Back-to-Back Zener Diode (Onsemi MMB27VCLT1 30pF), bus capacitor 2,7nF (Master Module) and SMD-ferrite (Würth: 742 792 097) Protection elements: Diode: Bus Capacitor: Bus serial Element: ON-Semi MMBZ27VCLT1 (30pF) 2,7nF (master module) SMD-ferrite Würth 742 792 097 TH8082 SMD-Ferrite LIN Bus 742 793 097 2,7n MMBZ27VCLT1 Figure 10 - Schematic of the ESD protection with Back-to-Back Zener Diode The damage limit by using Back-to-back zener diode and serial SMD-ferrite as protection elements is >15kV. The result is sufficient for a robustness level of 15kV. ESD- Measurement: LIN- Bus, I/V characteristics Transceiver: TH8082 KDC 0642 Pin: LIN to GND Bus capacitor: 2,7nF & MMBZ27VCLT1 to GND; Ferrite (Würth: 742 792 097) in line Pin Current [mA] 1,2 1,0 0,8 0,6 0,4 0,2 0,0 -0,2 -0,4 -0,6 -0,8 -1,0 -1,2 -40 -30 Before test LIN # LIN @ +4kV # LIN @ -4kV # LIN @ +8kV # LIN @ -8kV # LIN @ +15kV # LIN @ -15kV -20 -10 0 10 20 30 40 50 60 Pin Voltage [V] Figure 11 - I/V pin characteristic after applying different ESD pulses Appl.Note – External ESD Protection 390110808001 Page 6 of 8 July 2007 Rev 003 Application note TH808x External ESD protection 4. Summary The recommended protection elements for the TH8080/82 LIN transceiver in order to guarantee an ESD robustness level of 8kV at module level is: Transceiver with external protection element varistor TDK AVR-M1608C270MBABB (15pF) or similar, 180pF Bus capacitor and 10Ω series resistor. In order to confirm the results and to check the influence of the external protection circuitry regarding the EMC behaviour (DPI and emission), the test was done by IBEE, please see EMC Test report Nr. 01-05-05 and 02-05-05. External protection devices can decrease the EMC performance due to additional resonances, clamping and demodulation effects! Both devices show an excellent EMC behaviour with the recommended circuitry. In applications with higher requirements to the ESD severity level (15kV pass), the varistor can be replaced by an MMB27VCLT1 (On semiconductor Peak Power Zener Transient Voltage Suppressor diode), or similar device. In some cases the 10Ω series resistor is not approved to ESD protection. In this case the 10Ω series resistor can be replaced by an SMD ferrite, for instance an 1800Ω@100MHz SMD ferrite (Würth: 742 792 097) with the same package. Appl.Note – External ESD Protection 390110808001 Page 7 of 8 July 2007 Rev 003 Application note TH808x External ESD protection Disclaimer Devices sold by Melexis are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. Melexis makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. Melexis reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with Melexis for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing by Melexis for each application. The information furnished by Melexis is believed to be correct and accurate. However, Melexis shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interrupt of business or indirect, special incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of Melexis’ rendering of technical or other services. © 2002 Melexis NV. All rights reserved. For the latest version of this document. Go to our website at www.melexis.com Or for additional information contact Melexis Direct: Europe and Japan: All other locations: Phone: +32 1367 0795 E-mail: [email protected] Phone: +1 603 223 2362 E-mail: [email protected] QS9000, VDA6.1 and ISO14001 Certified Appl.Note – External ESD Protection 390110808001 Page 8 of 8 July 2007 Rev 003