Hi, i need to know if this DAC-op-amp calculation is ok

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SUMMARY

The discussion centers on the calculation of output voltage for a Digital-to-Analog Converter (DAC) using an R2R ladder configuration. Participants identified a critical error in the output voltage calculation, noting that a maximum output of 10V is unattainable with a power supply of +/-9V. The conversation also highlighted discrepancies in resistor values between the schematic and the provided table, emphasizing the importance of accurate component specifications in DAC design.

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NYAME EPHRAIM
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ephraim summing amp.PNG

Homework Statement

Homework Equations

The Attempt at a Solution

 

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That doesn't look right to me. You also can't get 10V out if the power supplies are +/-9V.

Are you trying to make an R2R ladder DAC?
 
berkeman said:
That doesn't look right to me. You also can't get 10V out if the power supplies are +/-9V.

Are you trying to make an R2R ladder DAC?
Hi, thanks for the reply, the diagraim was presented that way for me to do the calculations, i have also seen related diagraim online for DAC!
Yeah it,s ladder
 
Well, can you explain this first line from your diagram? It doesn't make sense past the 900mV number...

Vout = (9V x 470/4700) = 900mV = 800mV = 8V

And why are the resistor values in your table different from the schematic?
 
berkeman said:
Well, can you explain this first line from your diagram? It doesn't make sense past the 900mV number...

Vout = (9V x 470/4700) = 900mV = 800mV = 8V

And why are the resistor values in your table different from the schematic?

Hi thanks for the reply. my target is to fill that table, those value of resistor in that ladder circuit we don't have most of the values practically, that's why i had to reduce the 9 to 8.
please take a look at this diagram and cross check.
FINAL CHECK EPHRAIM.PNG
 

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That looks very close. The only problem I see is maybe the units definition for Vout in the last column heading of the table. It is hard to read the image, it shows 'x (something) 100mV'. What does it actually say?

What you have shown is a Binary Weighted network.

A Ladder network is shown below. (From: https://en.wikipedia.org/wiki/Resistor_ladder)
336px-UnequalLadder.svg.png

To learn more, try a Google search for both terms.

Cheers,
Tom
 

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