# AD5142A Divider mode and Rheostat mode

Hello all,

I assume the use of the following.
AD5124 has two potentiometers, one of the potentiometer is Divider Mode, one of the potentiometer is Rheostat Mode.

Q1.
In one of the potentiometer, can I use together Linear Gain Setting Mode and Rheostats Mode?

Q2.
Can I set the following?
In AD5142A, one of the potentiometer is Divider Mode.
In AD5142A, one of the potentiometer is Rheostat Mode.

Q3.
If I can set Q2, could you pls tell me how to set?

Q4.
Could you pls tell me the merit of  Linear Gain Setting Mode?

Best Regards,

Parents
• Hi daisu,

Apologies for the delay,

Q1: Both channels will be in Linear Gain Setting Mode, this creates two independent rheostats Raw and Rwb connected at a single point W.

Q2: Yes you can use one channel as a potentiometer and one as a rheostat. See page 27 of the datasheet

Q3:  Page 27 gives a detailed description of how to set up rheostat and voltage divider (potentiometer mode)

Q4: In this mode overall tolerance error is below 1%, without using external parallel or series resistance combinations.   This is achieved because the gain is set by the resistance ratios,  and the overall resistor tolerance error, as is common in both string arrays, can be disregarded. AN1169 gives a detailed description of the Linear Gain Setting Mode. http://www.analog.com/static/imported-files/application_notes/AN-1169.pdf

Regards,

David

• Hi daisu,

Apologies for the delay,

Q1: Both channels will be in Linear Gain Setting Mode, this creates two independent rheostats Raw and Rwb connected at a single point W.

Q2: Yes you can use one channel as a potentiometer and one as a rheostat. See page 27 of the datasheet

Q3:  Page 27 gives a detailed description of how to set up rheostat and voltage divider (potentiometer mode)

Q4: In this mode overall tolerance error is below 1%, without using external parallel or series resistance combinations.   This is achieved because the gain is set by the resistance ratios,  and the overall resistor tolerance error, as is common in both string arrays, can be disregarded. AN1169 gives a detailed description of the Linear Gain Setting Mode. http://www.analog.com/static/imported-files/application_notes/AN-1169.pdf

Regards,

David

Children
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