Need an advice on output protection

Thread Starter

olebon

Joined Feb 29, 2012
2
Sorry about a question probably stupid for analog guys , I am a firmware engineer, but very enthusiastic in circuit design.

I use a 3V DAC MCP4822 output to send some modulated signal to a receiver. The receiver is using same media to reply with a 30V signal that will definitely burn my DAC outputs. The delay between sent and received messages is about 20ms, however there is a risk of unexpected 30V signal too. One solution that I figured out myself could be a MOSFET right after the DAC output, but it will not help with an unexpected 30V message. Is there any ready IC or something to protect my DAC? The DAC is operated under control of an MCU, so some digitally controlled IC with an 'overvoltage' output would be a good option. I assume something like this is used in oscilloscope when 50V unexpected signal does not harm 10mV input circuit.
 
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