Application Note TH808x External ESD protection Application Hints for external ESD protection of TH808x 1. Scope This application note supplements the ESD part of the TH8080 and TH8082 datasheet. The used ESD test method describes the ESD severity level for handling and packaging of the IC itself. The result of this test method can correlate with the behaviour on module level, but in general the test conditions, pulse forms and rise times and the energy of the applied pulses are much different. By using external ESD protection the TH808x will be more robust against electrostatic discharges. Fig.1 shows the improvement of the ESD protection level of TH808x by using different external discrete 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 1 KV applicable 0 KV without ESD protection ESD protection with varistor ESD protection with Peak Power Zener Transient Voltage Suppressors diode Figure 1 - ESD protection level for TH808x by using different protection elements Author: MMT 390110808001 Page 1 of 6 Nov 2005 Rev 002 Application Note TH808x External ESD protection 2. Description of the ESD test according to DIN 61000-4-2 The used ESD method is described in DIN61000-4-2. This method is also part of the LIN EMC conformance test defined by the LIN Consortium. The following test equipment was used for the test: 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 and Fig.3 shows the block diagram of the ESD test set-up and the used PCB. Figure 2 - Block diagram of the ESD test setup Figure 3 - ESD test board TH808x Author: MMT 390110808001 Page 2 of 6 Nov 2005 Rev 002 Application Note TH808x External ESD protection 3. Test of different external discrete protection elements 3.1 ESD protection with varistor and series resistor Varistor: Bus capacitor: Serial resistor: TDK AVR-M1608C270MBABB with 15pF internal capacity 180 pF 10 Ohm Figure 4 - Schematic of the ESD protection with varistor With the above circuitry the damage limit is 9...15kV. The guarantied ESD protection level with this circuitry is 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 -20 -10 0 10 20 30 Before test # 3 @ +6kV # 3 @ -6kV # 3 @ +7kV # 3 @ -7kV # 3 @ +8kV # 3 @ -8kV # 3 @ +10kV # 3 @ -10kV # 3 @ +12kV 40 50 60 Pin Voltage [V] Figure 5 - Result of ESD test with varistor Author: MMT 390110808001 Page 3 of 6 Nov 2005 Rev 002 Application Note TH808x External ESD protection 3.2 ESD protection with bach-to-back zener diode and series resistor Back-to-back zener diode: MMB27VCLT1 (ON-Semiconductor) with 30pF internal capacity 10 Ohm 180 pF Series resistor: Bus capacitor: Figure 6 - Circuitry of the ESD protection with back-to-back zener diode With the above circuitry the damage limit is >15kV. The guarantied ESD protection level with this circuitry is 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 -20 -10 0 10 20 30 Before test # 3 @ +6kV # 3 @ -6kV # 3 @ +8kV # 3 @ -8kV # 3 @ +12kV # 3 @ -12kV # 3 @ +15kV # 3 @ -15kV 40 50 60 Pin Voltage [V] Figure 7 - Result of ESD test with back-to-back zener diode Author: MMT 390110808001 Page 4 of 6 Nov 2005 Rev 002 Application Note TH808x External ESD protection 4. Summary of ESD Test To archive different ESD protection levels of the TH808x it can be used different external circuitries. For protection level up to 8kV it is recommended to use a varistor TDK AVRM1608C270MBABB together with 180pF Bus capacitor and 10Ω series resistor between both. For higher ESD protection levels up to 15kV the varistor must be replaced by a back-toback zener diode ON-Semiconductor MMB27VCLT1 or a similar device. Some Vehicle manufacturer doesn’t allow the using of a 10 Ohm resistor. In this case it is also possible to replace it by a SMD ferrite, for instance a 1000Ω@100MHz type. ESD value Result without additional protection Result with varistor Result with back-to-back zener diode +2KV +3kV +4KV +6kV +8kV +9kV +12kV +15kV Pass Pass Fail Pass Pass Pass Pass Pass Pass Fail Pass Pass Pass Pass Pass Pass Pass Pass -2KV -3kV -4KV -6kV -8kV -9kV -12kV -15kV Pass Pass Fail Pass Pass Pass Pass Pass Pass Fail Pass Pass Pass Pass Pass Pass Pass Pass Table 1 - Summary of ESD test In order to confirm the results and to check the influence of the external protection circuitry on the EMC behaviour (DPI and emission) it was done verification by IBEE, please see EMC Test report Nr. 01-05-05 & 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. Author: MMT 390110808001 Page 5 of 6 Nov 2005 Rev 002 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: Phone: +32 1367 0495 E-mail: [email protected] All other locations: Phone: +1 603 223 2362 E-mail: [email protected] ISO/TS16949 and ISO14001 Certified Author: MMT 390110808001 Page 6 of 6 Nov 2005 Rev 002