- #1
Hi, i need to know if this DAC-op-amp calculation is ok
- Thread starter NYAME EPHRAIM
- Start date
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Discussion Overview
The discussion revolves around the calculations related to a digital-to-analog converter (DAC) using an operational amplifier (op-amp). Participants are examining the accuracy of a provided diagram and calculations, specifically in the context of an R2R ladder DAC and a binary weighted network.
Discussion Character
- Homework-related
- Technical explanation
- Debate/contested
Main Points Raised
- Some participants question the validity of the output voltage calculations, noting that a 10V output cannot be achieved with power supplies of +/-9V.
- There is a request for clarification on a specific calculation involving Vout, which appears inconsistent with the provided values.
- One participant mentions that the resistor values in the table differ from those in the schematic, prompting further scrutiny.
- A participant acknowledges the use of a ladder circuit but indicates a need to adjust resistor values due to practical limitations.
- Another participant points out a potential issue with the units defined for Vout in the table, suggesting it is unclear.
- A distinction is made between a binary weighted network and a ladder network, with a reference to external resources for further learning.
Areas of Agreement / Disagreement
Participants express differing views on the accuracy of the calculations and the interpretation of the circuit diagram. There is no consensus on the correctness of the calculations or the definitions used.
Contextual Notes
Limitations include unclear definitions of resistor values and output voltage units, as well as discrepancies between the schematic and the provided table. The discussion does not resolve these issues.
- #2
berkeman
Admin
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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?
Are you trying to make an R2R ladder DAC?
- #3
NYAME EPHRAIM
- 10
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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!berkeman said:
Yeah it,s ladder
- #4
berkeman
Admin
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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?
Vout = (9V x 470/4700) = 900mV = 800mV = 8V
And why are the resistor values in your table different from the schematic?
- #5
NYAME EPHRAIM
- 10
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- #6
Tom.G
Science Advisor
Gold Member
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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)
To learn more, try a Google search for both terms.
Cheers,
Tom
What you have shown is a Binary Weighted network.
A Ladder network is shown below. (From: https://en.wikipedia.org/wiki/Resistor_ladder)
To learn more, try a Google search for both terms.
Cheers,
Tom
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