I want to use the ESD protection circuit(as shown below) for the I/O signal
But one input signal is just current mode signal, I am wondering for the ESD protection of current mode signal, is this circuit still applicable, because there will be a voltage drop on this series current limiting resistor
Or should I remove this series resistance for the current mode input signal?
Secondary protection is normally only necessary when you need to protect the gate of an internal MOS. If your internal signal does not touch a gate but just sources/drains, then you should be o.k. without the secondary protection. I say this without knowing your exact ESD requirements or what kind of primary protection you have, so it's only a generalization where the primrary protection sufficiently protects your pin.
As far as your input current goes, if your circuit can live with the drop, then you don't need to remove it. You're actually in a better scenario having current mode input because the resistor will not affect your frequency response. In voltage mode the resistor limits the charging current, in current mode it does not. So if you can afford the voltage drop, keep the resistor.
For current mode input, I think your circuit input is source, am I right ?
If the circuit input is source, I suggest you can remove the resistor and secondly ESD protect. But you need to layout yout input circuits by ESD rules.
katrin ,
there are two person major in ESD design in innios and taiwan , another person ,is called :
''Ming-Don Ker'', you can also search his paper o the internet. maybe it is more useful
Can you be more specific ? Layout can help quite a bit on ESD issue and it depends on your requirement.
For achieving CE standard ( 4KV contact descharge, 8KV air discharge ) with a relative good ic. It's simply by adding a cap to gnd with a inductor.( can achieve around 5.5KV contact discharge and around 10KV for air discharge ) A more expensive way to solve the problem is to use ESD suppressor.