Hi all
Ive been scratching my head over this for a while. I have an analog input circuit, using an ADC1208 ADC. There is some filtering on the input, and the first part of the circuit has a simple voltage follower amp, ie signal into + of op amp, - connected to Vout. +/-12V supply to op amp.
My analog signal in is obviosuly the range 0 - 5V, where im using the full 12 bit resolution of the ADC. My signal can go very low, right down to below 100mV which i need to detect.
What i need is some protection on the input to avoid the condition of +24V being inadvertantly applied to my analog input. And have it not interferring with the normal operation of the ADC at low voltages.. I tried a transistor and zener diode circuit but it obviously wont pass low voltages. I need the protection because the device is being installed by muppets in industrial situations and they are good at making cock ups...
any simple diode arrangement that may work?
Ive been scratching my head over this for a while. I have an analog input circuit, using an ADC1208 ADC. There is some filtering on the input, and the first part of the circuit has a simple voltage follower amp, ie signal into + of op amp, - connected to Vout. +/-12V supply to op amp.
My analog signal in is obviosuly the range 0 - 5V, where im using the full 12 bit resolution of the ADC. My signal can go very low, right down to below 100mV which i need to detect.
What i need is some protection on the input to avoid the condition of +24V being inadvertantly applied to my analog input. And have it not interferring with the normal operation of the ADC at low voltages.. I tried a transistor and zener diode circuit but it obviously wont pass low voltages. I need the protection because the device is being installed by muppets in industrial situations and they are good at making cock ups...
any simple diode arrangement that may work?