Which Digital POT to use?

[jayanth.devarayanadurga]

I want to know which MAXIM digital pot to use for my circuit? The device should be in production. I need to adjust the ADC input using a digital pot i.e., I need to vary the ADC input from 0 to 5V using digital pot.

 

[alexan_e]

Does it have to be specifically a maxim product? Microchip has digital posts too https://ww1.microchip.com/downloads/en/DeviceDoc/22017a.pdf

 

[jayanth.devarayanadurga]

Hi alexan

I need Digital Pot in DIP package. I can use Microchip MCP41XXX devices also. I need algorithm to adjust resistance from min to max when buttons are pressed. I have two buttons INC and DEC. Dallas pots have 256 steps and microchip has only 64 steps.


I found that Microchip has only 6-bit digital pots in Up/Down type and 256-bit pots in SPI type. I will go for MCP41010 (10k) digital pot SPI interface. I need algorithm to increment and decrement the resistance.

 

[alexan_e]

There are both 6bit and 8bit chips in the Microchip line.

MC41010/50/100 and MCP42010/50/100 have 256 steps , check page 7 of the document I have linked above

 

[betwixt]

As you are only producing a voltage, have you considered using a DAC as a digital pot?

Ground the negative reference, connect the positive reference to +5V and the digital input will select the voltage you get out. A standard 8-bit DAC will give you 256 steps.

Brian.

 

[jayanth.devarayanadurga]

Now I am finding if there are any 10-bit pot in DIP package. Analog devices have in TSOP package. If anybody find 10-bit pot in DIP package please mention its part number. Can I use SPI DAC 10 bit or higher. I think LTC have some 12 or 16 bit SPI DACs.

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Yes, they are 256 bit but not UP/Down type. They are SPI type.


Edit: Thank you betwixt. I ordered 12 bit SPI DACs in DPI package. I will use them as Digital Pots.