Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Quick DAC Question

Status
Not open for further replies.

jp1390

New Member
Hello, I was working on some problems that my prof had assigned but his solutions were pretty unclear and did not reason his answers very justly. I have finished most of the question but I'm wondering if someone can help me out.

Here is the question:

**broken link removed**

My solutions:

**broken link removed**

I finished the first part and received the correct solutions, but I have no idea how to to the second part, where they ask to find a value for resistor R that will cause the gain error to be zero, noting that all the switches have an on-resistance of 200 ohms in this case.

I am not sure what they are relating the gain error to, as the gain is not constant in the previous example. Am I to pick an R that meets specification with an ideal case?

The solution that Jaeger and Blalock (Q12.79 - 4th Edition) posted was R = 1.0742 kohms. No idea how they came to that though.

Can anyone lend a hand?

Thanks!
 
This isn't clear at all. Does he intend "zero gain error" to mean a gain of -1? That circuit can't swing positive. And if so, are we to assume the intended output range is -5V to 0V, because Vref is +5V?

If these assumptions are correct, that 1074.2Ω R won't do it - that gives a span of -3.63V to 0V, yielding a gain of -.726, which hardly seems like a "zero gain error" to me.

A 1477Ω R would get your -5V to 0V span... if THAT's what he means.
 
Last edited:
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top