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Inductor at ANT input for EDS protection

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7rots51

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inductor prevent esd

Hello

In boks it is recommended that an inductor be used at receiver ANT input for EDS protection of circuit,for a specified frequecy how we can calculate the vlue of inductor? Is there any formula?
 

Grig

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esd protection shunt inductor

Hi
Try L=500/2/pi/f(Hz)
 

biff44

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Yeah, in general it is a good idea. It would not work down at 10 MHz, since the inductance would be so large that the esd spike would go right by it. It would work fine at microwaves, since the inductor would be < 20 nH, and would effectively snub out the ESD spike.
 

RF-OM

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This is common practice in receiver design. usually impedance of the choke about 10 times higher that the receiver input impedance. Choke will work well for all RF band from 12 kHz to GHz if it is right designed. Usually it should be done with progressive winding in order to reduce parasitic capacitance and increase the SRF. Sometimes resistor with 1 to 10K value may be used instead of such choke.

Best regards
 

sergio mariotti

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The use of a shunt inductor at the front-end is a good idea to prevent ESD demage.
But, Since its the spectral response, it's effective only in order to reduce low frequency, high voltage sparks coming from antenna.
It means that the inductor may protect front-end only if the source (the antenna) is high impedance at DC (i.e open dipole). The inductance is useless if the receiving antenna is a folded dipole (or every kind of loop).
Also, it's useless for high energy spikes, a gas discharge tube is much better!
Also it's useless for frequencies higher few GHz because practically a differential spark cannot enter trough the antenna, shunt back to back diodes are better.
 

7rots51

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Is needed such protection for transmitter output(output of power amplifier)?

Do we need ESD protection at output of transmitter(PA)? how we can do it?
 

Joel-Tang

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Protecting the output of a power amplifier may be necessary depending on the topology and the devices used. If you must protect it you need to choose a protection device that will not attenuate the desired output signal. Just calculate the peak voltage of your output waveform and ensure the clamping diode does not activate under those conditions. The difference between that voltage and the voltage that will damage your PA is were problem can arrise.
 

patriot

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Protecting the output of a power amplifier may be necessary depending on the topology and the devices used. If you must protect it you need to choose a protection device that will not attenuate the desired output signal. Just calculate the peak voltage of your output waveform and ensure the clamping diode does not activate under those conditions. The difference between that voltage and the voltage that will damage your PA is were problem can arrise.
I met a strange phenomenon, the diode does not attenuate the output power and the clamping diode does not activate under the maximum Pout (I am sure), but the harmonics (odd number, such as 3rd, 5th, 7th....) will be worsen,
What 's the reason?
 

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