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Category: Hardware

I would like to use the dual voltage setup, and I also want to utilize both channels of the AD7383 simultaneously. Both analog input signals have an amplitude of +/- 2.5 V. Could you assist me with the input connection setup? In the 'Figure 33. Typical Application Circuit,' where does the -2.5 V voltage connect? What is the power supply configuration to allow dual input signals of +/-2.5 V?

## Top Replies

• The -2.5V will be supplied through the negative pin of the amplifier.

On the other hand, you are right. If you use a 3.2V Vref. Then your range would be from -1.6V to 1.6V. I would also…

• Hello  ,

To answer your question, the negative 2.5V should be connected to the negative supply rail of your amplifier from the analog front end. This will solve foot room issues that may cause signal degradation.

On the other hand, I just noticed that you mentioned your amplitude. So, does +/- 2.5V here means you will have a range of -2.5V to 2.5V? If this would be the case, the analog input range from its datasheet is only from -Vref/2 to Vref/2. And the Vref used is 2.5V.

Regards,
Jo

• Thanks for your response, so I am trying to understand your response.

(1) "To answer your question, the negative 2.5V should be connected to the negative supply rail of your amplifier from the analog front end. This will solve foot room issues that may cause signal degradation."

In (1) you mean -2.5 V to feed the operational amplifier before the high-pass filter, which is before the Analog signal positive input of the AD7383.

"(2) On the other hand, I just noticed that you mentioned your amplitude. So, does +/- 2.5V here means you will have a range of -2.5V to 2.5V? If this would be the case, the analog input range from its datasheet is only from -Vref/2 to Vref/2. And the Vref used is 2.5V."

Sorry, I have already converted the signal +/- 2.5 V to +/- 1.6 V range between the inputs A+ and A-. So,  to use this range -Vref/2 to Vref/2, should Vref have a value of 3.2 V?

• Hello  ,

The -2.5V will be supplied through the negative pin of the amplifier.

On the other hand, you are right. If you use a 3.2V Vref. Then your range would be from -1.6V to 1.6V. I would also like to add, that for external reference, you will have a range from 2.5V to 3.3V

Exceeding these ratings would not guarantee you an optimal performance. Or worse case, it could damage the device. Thus, you need to check the absolute maximum rating of the device.

Warm regards,
Jo