Suggestions regarding selection of Isolator

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1

Hi Team,

We are designing a data acquisition system that shall comply with the DO-160 military standard. In our system, we will be reading the data from the following sensors:

  • 32x channel PZT sensor

  • 3x channel RTD sensor

  • 9x channel Strain gauge sensor

From a protection point of view, we are looking to add isolation in our system. While exploring the concept of isolation, we came across two types of isolation: digital isolation and analog isolation. As per our understanding, we will require analog isolation between the sensor and the ADC (unsure). Could you please help out select the best isolator that meets our isolation as well as our channel needs?

We are planning to use a single-ended ADC for the PZT sensor and a differential input ADC for the RTD & Strain gauge sensor. Attached is the block diagram of the sensor and ADC interfacing (without isolator).

AFE
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Please let me know if you require any further information to assist us.

Thanks & Regards,
Sahil Nayak

2

Hi Sahil,

From a cost perspective, using digital isolators and isolating between the ADC and MCU will be the cheapest method as the digital isolators have up to 6 channels of isolation which allows you to reduce the number of isolators needed in the system. Some of the products such as the MP27960 or MP27933. The MP27960 is 6 forward channels and 0 reverse channels, while the MP27933 is 3 forward and 3 reverse channels.

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