V I S H AY I N T E R T E C H N O L O G Y, I N C . esd protection and emi filter arrays INTRODUCTION With the increasing use of integrated circuits in mobile and wired communication devices and consumer products, it is more important than ever to protect sensitive electronics from high transient voltages or unintentional frequencies. High-voltage spikes with various waveforms and durations can damage or even destroy electronic circuits, and the interference of unintentional frequencies can influence the system in a negative way. These transient voltages have various sources. One of the most common types is electrostatic discharge (ESD). For example, a person can inadvertently discharge accumulated static electricity on a phone merely by touching the device. A sudden power surge can also occur when lightning strikes a power line, potentially harming devices connected to the line. ESD protection diodes combined with an electromagnetic interference (EMI) filter network serve as unobtrusive but strong “bodyguards” against these hazards. Protection devices such as very fast Zener and Avalanche diodes draw a very low leakage current when placed in front of sensitive electronic gates. But above the defined voltage working range, any transient voltage that approaches the breakdown voltage will be short-circuited by the diodes so it cannot reach the gate. Vishay offers a wide range of surface-mount, plastic packaged protection diodes, arrays, and EMI filters designed especially for space-sensitive electronic products such as mobile electronics. One of the World’s Largest Manufacturers of Discrete Semiconductors and Passive Components Capabilities 1/8 VMN-PL0431-1411 THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 d V I S H AY I N T E R T E C H N O L O G Y, I N C . esd protection and emi filter arrays How ESD Protection Diodes Work Equivalent Circuitry of an ESD Protection Diode 80 I 70 ESD 40 Ideal Z-diode with junction capacitance Forward Current Reverse Clamping Range Reverse Working Range In this range the diode behaves like a closed switch characterized by: In this range the diode behaves like an open switch characterized by: – – – – – – – – Breakdown voltage (VBR) Clamping voltage (VC) Peak pulse current (IPP) Maximum peak pulse current (IPPM) – Peak pulse power Rs = Series resistance VBR 50 Ls = Series inductance made by bond wires & package leads VBR + VRS VBR + VRS + VLS Voltage drop at a protection diode during 8kV ESD 60 Typical Current Voltage Diagram of an ESD Protection Diode VC Capacitance (CD) Leakage current (IR) Applied reverse voltage (VR) Maximum appliable reverse working voltage (VRWM) VBR VRWM VR 30 IR Reverse Voltage Inductive voltage component Forward Voltage VF Forward Clamping Range 20 The diode behaves like a closed switch and clamps voltage transients close to ground level. Resistive voltage component 10 V BR = Avalanche breakdown level 0 IF 0 10 20 30 40 50 60 70 80 – Forward voltage (VF) – Forward current (IF) 90 IPP Time axis (ns) The clamping voltage of an ESD protection diode is determined by three major components: IPPM Reverse Curren nt • Zener or avalanche breakdown voltage level: VBR = defined by chip design • Voltage drop at the series resistance of the diode: VRs = IESD * RS • Voltage drop at the bondwire and lead inductance: VLs = L S * (dIESD /dt) How EMI Filters Work LWire Out In Ground One EMI filter channel is made of a symmetrical π device with two identical Perspective)Z-diodes and a resistor Expand Appearance, between the input and Rotate 2º output pin. R In ZD ZD Cd Out LGND Out Ground Within the voltage working range the Z-diodes can be Out considered as a voltage In dependent capacitance. Ground Capabilities LWire RLine Cd In For higher frequencies in the GHz range, wire inductances and particularly the ground inductance have an influence on the filter performance. R Cd Out Cd Ground 2/8 VMN-PL0431-1411 THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 V I S H AY I N T E R T E C H N O L O G Y, I N C . esd protection and emi filter arrays Bode Diagram The most important characteristics for a filter is its signal attenuation over the frequency, the relation of the output to the input signal. The result depends on the source and load impedances and is usually defined with 50 Ω. In Out LWire ZSource VIN LWire RLine Cd Cd VOUT High Frequency Current LGND ZLoad Low Frequency Current Ground VOUT VIN In the low-frequency range,the whole signal current is flowing across the series resistance RLine and the load impedance ZLoad . Above the cut-off frequency (f 3dB), the diode capacitance Cd shorts the signal to ground. The higher the frequency, the lower the “short-impedance” to ground. [log] 1 f3 dB Capabilities It is the ground inductance LGND which lets the “short impedance” grow again. The increasing impedance of the line inductances LWire blocks the incoming EMI signal. frequency [log] 3/8 VMN-PL0431-1411 THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 V I S H AY I N T E R T E C H N O L O G Y, I N C . esd protection and emi filter arrays Basic ESD Protection Functions An ESD protection device with a BiAs clamping characteristic clamps transient voltage signals: BiAs BiAs BiAs BiAs Bidirectional Asymmetrical BiSy BiAs An ESD protection device with a BiSy clamping characteristic clamps transient voltage signals: BiSy BiSy Uni BiSy • at different voltage levels • in a positive direction just above the Zener or avalanche breakdown levels • in negative direction just below the ground level • like a single Z-Diode with forward and reverse modes BiSy Bidirectional Symmetrical • in positive and negative directions • at the same voltage levels in both directions • like two equal Z-Diodes with a common cathode in series Uni Uni An EMI filter device filters with: BUS Uni BUS BUS EMI Filters • • • • low-pass characteristic low attenuation of low-frequency data signals high attenuation of high frequencies additional overvoltage protection BUS EMI EMI EMI For further information... ...please contact ...please visit [email protected] [email protected] http://www.vishay.com/diodes/protection-tvs-esd/arrays/ http://www.vishay.com/diodes/protection-tvs-esd/emi-filter/ EMI Capabilities 4/8 VMN-PL0431-1411 THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 V I S H AY I N T E R T E C H N O L O G Y, I N C . esd protection and emi filter arrays NOTES Capabilities 5/8 VMN-PL0431-1411 THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 V I S H AY I N T E R T E C H N O L O G Y, I N C . esd protection and emi filter arrays NOTES Capabilities 6/8 VMN-PL0431-1411 THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 V I S H AY I N T E R T E C H N O L O G Y, I N C . esd protection and emi filter arrays NOTES Capabilities 7/8 VMN-PL0431-1411 THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 V I S H AY I N T E R T E C H N O L O G Y, I N C . esd protection and emi filter arrays WORLDWIDE SALES CONTACTS THE AMERICAS EUROPE UNITED STATES GERMANY VISHAY AMERICAS ONE GREENWICH PLACE SHELTON, CT 06484 UNITED STATES PH: +1-402-563-6866 FAX: +1-402-563-6296 VISHAY ELECTRONIC GMBH DR.-FELIX-ZANDMAN-PLATZ 1 95100 SELB GERMANY PH: +49-9287-71-0 FAX: +49-9287-70435 ASIA FRANCE SINGAPORE VISHAY INTERTECHNOLOGY ASIA PTE LTD. 37A TAMPINES STREET 92 #07-00 SINGAPORE 528886 PH: +65-6788-6668 FAX: +65-6788-0988 VISHAY S.A. 199, BD DE LA MADELEINE 06003 NICE, CEDEX 1 FRANCE PH: +33-4-9337-2727 FAX: +33-4-9337-2726 P.R. CHINA UNITED KINGDOM VISHAY CHINA CO., LTD. 15D, SUN TONG INFOPORT PLAZA 55 HUAI HAI WEST ROAD SHANGHAI 200030 P.R. CHINA PH: +86-21-22315555 FAX: +86-21-22315551 VISHAY LTD. SUITE 7A, TOWER HOUSE ST. CATHERINE’S COURT SUNDERLAND ENTERPRISE PARK SUNDERLAND SR5 3XJ UNITED KINGDOM PH: +44-191-516-8584 FAX: +44-191-549-9556 JAPAN VISHAY JAPAN CO., LTD. SHIBUYA PRESTIGE BLDG. 4F 3-12-22, SHIBUYA SHIBUYA-KU TOKYO 150-0002 JAPAN PH: +81-3-5466-7150 FAX: +81-3-5466-7160 Capabilities 8/8 VMN-PL0431-1411 THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000