Hi Cabe,
Did you investigate the circuit for unnecessary high impedance inputs? Noise susceptibility can most of the time easily be avoided by input filtering or choosing lower resistor values.
Best regards,
Enrico Migchels
Enrico,
The main issue is outside noise issues. It is a very delicate component.
Cabe
Hi Cabe,
I have 1 delicate component here also. A component with an input shutdown level of 500mV. If this input is high-ohmic, external noise will kill the function. If the input is low-ohmic (3kOhm, 1nF) there is no problem. That is why i asked. Shielding is changing the coupling between the transmitter (noise source) and the receiver (your IC). If you could fix the problem by improving the layout or external filtering this will save you a lot of trouble.
I use a nice tool to test the susceptibility of a circuit. It is a standard piezo ignitor (kitchen use) and there is a bnc connector at the top where the spark is. On that connector you can place a loop antenne (H) or plate (E). Just small antenna's for precise use. You can easily spot the weak circuits in your design by zapping in the air just a few cm's above the components.
Best regards,
Enrico Migchels
Hi Cabe,
If it is external noise, please try a metallic enclosure and ground it at a point nearest to the supply filter.
Regards,
Thomas