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AD7732 - basic functionality question

Question asked by WebsElec on Dec 9, 2015
Latest reply on Dec 9, 2015 by JellenieR

[Q1]  AD7732 channel 1

I'm looking at using the AD7732 (2-Channel, ±10 V Input Range, High Throughput,
24-Bit Σ-Δ ADC) for an application with a 5V Hall Sensor.

We want to connect the Hall Sensor output directly to the AD7732.

The Hall Sensor is powered from a 5V single ended supply (5V and 0V)

The Hall Sensor output is fixed at 2.5V (offset = power supply divided by 2)
and varies ±1V depending on current it senses (i.e. Output from Hall Sensor
between 1.5V and 3.5V).

I was planning to connect the ADC's negative input to GND and the ADC's
positive input to the Hall Sensor Output.

The data sheet shows that the AD7732 device accepts ±5V, and 0 to 5V.

I wanted to use the ADC in the 0 to 5V mode to accept this signal.

However I've seen the max input  dynamic range possible for the AD7732 is just
2.5V, so am a little confused.

Can you please help and let me know if I can use the AD7732 in this way?

[Q2] AD7732 Channel 2

I also want to measure a 0 to 5V output potential divider (accurately, right
down to 0.0V) using the 2nd channel of the AD7732.

Will this be possible using a single ended 5V supply (5V and 0V power for
AD7732)?

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