Pages: [1]   Go Down
Author Topic: Voltage Divider Array as a DAC...  (Read 982 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
Edison Member
*
Karma: 29
Posts: 2444
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I watch Collin on youtube make his own 8bit DAC!!! Using resistors to divide the voltage (or just watch the video)

 


-- 8bit shift register should do the job nicely, so what about 2 shift registers? 16bit DAC?? surely not? right?
Logged

Offline Offline
Edison Member
*
Karma: 29
Posts: 2444
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

P.S if you want a giggle, turn on the CC (like teletext) "english automatic settings" option smiley-grin

Collin talks about Bit Burgers at some point lol (it's google's speech to text engine at fault lol)
Logged

Global Moderator
Netherlands
Online Online
Shannon Member
*****
Karma: 216
Posts: 13673
In theory there is no difference between theory and practice, however in practice there are many...
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset


Quote
so what about 2 shift registers? 16bit DAC?? surely not? right?
Works in just the same way

There exist complete R2R components like
- http://www.ece.uidaho.edu/ee/classes/ECE340/Notes/R2R.pdf -
or - http://www.newark.com/bourns/4310r-r2r-103lf/resistor-ladder-n-w-10-10kohm-2/dp/75K9799 -

16 bitters too
- http://www.semiconwell.com/r_net/swr2r16b.htm

Logged

Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

Offline Offline
Edison Member
*
Karma: 116
Posts: 2205
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

That's what people meant when they said R2R.

It is practically impossible to build a 8-bit or higher R2R: the resistors required would be too expensive / impossible to get.

Logged

Global Moderator
Netherlands
Online Online
Shannon Member
*****
Karma: 216
Posts: 13673
In theory there is no difference between theory and practice, however in practice there are many...
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

@dhenry
Is that also true for the components that have a build in R2R? I assume they are calibrated?
Logged

Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

Dallas, TX
Offline Offline
Sr. Member
****
Karma: 10
Posts: 318
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

When you have the luxury of being able to laser trim the R2R network, as a semiconductor fab would have, they are very practical. You can buy 0.1% resistors which will get you a little past 8 bits for around $1.50 each. Home building a 16 bit R2R network would likely take hours of hand sorting with a VERY precise resistor bridge or lots of $$$.
Logged

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 534
Posts: 26970
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

The English closed captioning is pretty funny - lots of errors there.

DACs with R2Rs can be laser trimmed at the factory for accurate level at the output:

http://www.analog.com/en/digital-to-analog-converters/audio-da-converters/ad1851/products/product.html

A part like that can be purchased for ~$12 at Digikey
http://www.digikey.com/product-detail/en/AD1851RZ/AD1851RZ-ND/936661

There's also some good information links there too, such as
http://dkc1.digikey.com/us/en/tod/ADI/DataConverterFundamentals/DataConverterFundamentals.html
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 534
Posts: 26970
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

This one on DAC architecture is pretty interesting.
http://dkc1.digikey.com/us/en/tod/ADI/DACArchitectures/DACArchitectures.html
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Dallas, TX
Offline Offline
Sr. Member
****
Karma: 10
Posts: 318
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

DACs without voltage output, i.e. current output DACs, are essentially just precisely trimmed R2R networks, and can be had for less than you can build your own. Much more compact, too.  smiley
Logged

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 534
Posts: 26970
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Can find all kinds of interesting things here:

http://www.digikey.com/PTM/PTMMaster.page?site=us&lang=en

Digi-Key’s library of more than 1600 exclusive Product Training Modules (PTM) Online… On Demand® product training modules is a collection of training tools created with you – the busy design engineer – in mind. They are provided with the cooperation of participating supplier partners. From this one source, you can learn about the latest products and technologies, download datasheets, check inventory, contact our technical staff, and place an order for same-day shipment.

These modules are available in audio and non-audio formats and listed by supplier in easy-to-find alphabetical order. Simply locate the module that interests you and click on your format of choice. We hope you find these tools useful, and with new modules added continuously, we invite you to stop back often to see what’s new.

Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Pages: [1]   Go Up
Jump to: