Microchip PIC specific D2A
Ubicom SX specific D2A
Analog to Digital Conversion
Don Hyde says:
An R-2R ladder can be used to turn a group of [digital] output pins into a DAC for a few cents. Below is a 3-bit DAC. Using 3 [digital] output pins (beware of the odball open drain pins, they're no good for this), this circuit will provide 0 - Vcc*(7/8) volts out, with a 2R source impedence.
It can be extended to more bits by replicating the MSB R-2R end of the ladder.
Up to 4 bits can be achieved with 5% resistors.
Up to 6 bits can be achieved with 1% resistors.
In many applications, it would be advisable to buffer the output with an op-amp.
A circuit like this can achieve waaay higher output frequencies than PWM, and can be easier to filter, at the expense of using up a bunch of pins.OUT o--+-/\/\/\/\----o MSB | 2R \ / \ R / | +-/\/\/\/\----o Middle bit | 2R \ / R \ / +-/\/\/\/\----o LSB | 2R \ / \ 2R / | --- ///
PICList Thread '[EE]: high res DA challenge'
|file: /Techref/io/d2a.htm, 2KB, , updated: 2013/7/22 16:20, local time: 2014/11/23 03:54,
|©2014 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?|
<A HREF="http://www.massmind.org/techref/io/d2a.htm"> D2A, Sigma Delta, Digital to Analog Conversion</A>
|Did you find what you needed?|
Welcome to massmind.org!
Welcome to www.massmind.org!