- 28th August 2008, 15:35 #1

- Join Date
- Aug 2006
- Posts
- 42
- Helped
- 6 / 6
- Points
- 2,232
- Level
- 10

## r2r calculate

- 28th August 2008, 15:35

- 3rd September 2008, 17:03 #2

- Join Date
- Jan 2005
- Posts
- 100
- Helped
- 7 / 7
- Points
- 2,082
- Level
- 10

## r/2r dac equation

could you re-upload a more clear pic?

in generally, the r2r calculate is easy, please from the terminal close the vref,then one by one to the termal close the opamp.

- 3rd September 2008, 17:03

- 3rd September 2008, 19:05 #3
## caclulation of a R2R dac ladder

Google it. :)

- 3rd September 2008, 19:05

- 5th March 2010, 23:09 #4

- Join Date
- Jun 2008
- Location
- Hungary
- Posts
- 34
- Helped
- 1 / 1
- Points
- 1,429
- Level
- 8

## Re: caclulation of a R2R dac ladder

I do not understand the analysis of the R2R ladders. My main concern is that the different bits are seeing different resistances. If we look downwards all the resistances are 2R, but not upwards! For example the weight of b(n-2) should be (R+2R)||2R/((R+2R)||2R+2R)=3/8

For a 2 bit DAC the outputs would be:

0, 3/8, 4/8, 7/8

So looking upwards from the right end of a 2R resistor we see a resistance which depends on the distance of the output node. Thus the bits are not binary weighted.

Could somebody resolve this?

Added after 2 hours 20 minutes:

Originally Posted by**tzg6sa**