R-2R Ladder DAC

[PG1995]

Hi

Could you please help me with this query?

Regards
PG

Reference:
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/dac.html

 

[ericgibbs]

Hi

Could you please help me with this query?

Regards
PG

Reference:
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/dac.html

Hi PG,
Look up the datasheet for HEF4066 for starters.

E

 

[PG1995]

Thanks a lot, Eric.

So, this is what each switch is made up of.

Regards
PG

 

[Mike odom]

you can't use the 4066 as it is like a SPST, on or off. You need to either have the Rs connected to +V or Gnd, so you'd need a SPDT type switch. Like the original text says, it can be a TTL gate... yes, your original question was correct, you can use a TTL gate to drive each resistor high or low, if your +V is 5v. You'd need a 4000 series cmos gate to go higher.

 

[PG1995]

Thank you, Mike.

So, then I can use CD4081BMS. The four AND gates can work as four switches. A standard TTL circuits operate with a 5-volt power supply. A TTL input signal is defined as "low" when between 0 V and 0.8 V with respect to the ground terminal, and "high" when between 2.2 V and 5 V.

Regards
PG

 

[crutschow]

You can use a CD4081 but note that accuracy will depend upon the accuracy of the power supply which now becomes Vref.

 

[dr pepper]

You can use a 7805 or 7812 5v and 12v to generate you a stable supply.

 

[crutschow]

You can use a 7805 or 7812 5v and 12v to generate you a stable supply.

Or for the most stable supply you could use a voltage reference IC.

 

[PG1995]

Thank you, Carl, dr pepper.

Regards
PG

 

[PG1995]

Re: "F" flip-flop

Hi

Could you please help me with this query? Thank you.

Regards
PG

 

[PG1995]

Would someone please comment on the post above? Thanks.

 

[vtech]

Hard to tell exactly where the etch resistors are but I think this is what you have based on the schematic. E1/A1, E2/A2 could be on either side.

 

[rumpfy]

Hi PG,
When you have an analog to digital converter for say, a digital voltmeter, you have to be able to put the digital codes on to a display to give you the readout of the values.
The usual output code from a digital counter is to have 4 digital (0 or 1) outputs and the weighting of these is in a 1-2-4-8 progression. To count to 10 requires 4 bits, and these are usually denoted as D0, D1, D2, and D3. If the weighting of D0 is 1 and the weighting of D3 is 4, then the number 6 is represented by having Do = 0; D1 = 1; D2 = 1; and D3 = 0.
This code weighting can allow a number range of 0 to 15. There is another code weighting which is sometimes used and that is a 1-2-4-2 weighting; this gives a count range of 0 to 9.
Your original post asked about the D's and many of the answers referred to the actual hardware. My post is intended as complimentary to the prior posts.

 

[rumpfy]

You asked for a response to post 10.
PG, the manufacture of this stuff is a black art and your book is just pointing out the incredible increase in complexity and function in modern IC's over the 60 counterparts.
The original stuff tried to duplicate the circuit designs and components but the modern stuff tries to do away with components and rather uses controlled doping to provide resistance; controlled semiconductor dimensions to give varying current gain and constant current values to allow a wide range of functions and for the device to have stable characteristics. The modern IC design is driven by using as few masking processes as possible. Earlier designs of say audio operational amplifiers were specific designs. Instrumentation type IC op-amps were designed differently, but now, the masking process for an audio op amp is the same as for an instrumentation op amp; the only difference being the bias points and perhaps doping levels.
I reckon you will find it difficult to get a decent text book on the design/manufacture of modern IC's because much of what is done is highly proprietary.
I dont know what is a 'F' flip flop. My knowledge of F-F's is ; J-K; R-S; and D type flip flops.
Hope this helps

 

[large_ghostman]

This might be interesting for you

not exactly what your asking but the explanation of the R 2R DAC is good