Question
1) Using the AD7142 is it possible to put the buttons on another board
connected by a cable? Or is it better to have a short distance between the
buttons and the AD717x?
2) Do you have PCB layouts for buttons for the AD7147 with one electrode?
The examples for the AD7142 uses mostly two electrode .
3) What is the major difference between the AD7142 and AD7147?
Answer
1) Using the AD7142 is it possible to put the buttons on another board
connected by a cable? Or is it better to have a short distance between the
buttons and the AD717x?
It is not possible to put the buttons on another board connected by cable using
the AD7142, however this is possible with the AD7147. One of the new features
of the AD7147 is the active shield that allows the sensors to be located
remotely from the IC and provides shielding from another noise sources in the
application. The maximum distance between the AD7147 and the sensor is 50 cm.
2) Do you have PCB layouts for buttons for the AD7147 with one electrode?
The examples for the AD7142 uses mostly two electrode .
The AD7147 is going to be released next month. The datasheet is already
available online: http://www.analog.com/AD7147
I have attached the AD7147 sensor library in PADS format.
3) What is the major difference between the AD7142 and AD7147?
The only different between AD7142 and AD7147 is the analog front end. The
AD7142 has two electrodes and the AD7147 just one. The attached slides shows
how the electric field is created in each case. Some of the AD7147 advantages
are: Larger response, easier design and can tolerate thicker overlays.