www.LaserFreak.net

Posted: **Mon 17 Jan, 2005 9:12 pm**

Hi,

I am evaluating the possibility to replace the default 8-bit DAC with a 12-bit DAC. I've found this one: MAX508 - Voltage-Output, 12-Bit DAC with Internal Reference and 12-Bit Interfacehttp://www.maxim-ic.com/quick_view2.cfm/qv_pk/1543.

The idea is to the use bILDA PCB, remove the two DACs and place a simple board (with minimum logic) onto the empty sockets.

Nice thing; you can order samples from MAXIM; you will get two DACs for free!

All thoughts are welcome.

Thanks.

Regards, Arjan

Posted: **Tue 18 Jan, 2005 5:26 pm**

Hi,

Nice Idea. Just please explain me something:

Where do you get the needet 12 Bit Input ? Did you wrote your own Firmware ? You need the Signals from 2 (1.5) Ports to "feed" the 508.
If you write your own Firmware search for an other DAC from Maxim ( I dont know the Part Nr, 12 Bit DAC with 8 Bit input and Latches )

If theese Problems are cleared you just have to change the I - Output Circuit from the 0832 against a Voltage - Amp.. Then you got your 12 Bit DAC

Posted: **Tue 18 Jan, 2005 10:04 pm**

Guido,

The MAX508 has a 8-bit-wide data bus interface. I would use PC3/4 for the additional input control logic.

I would not write my own firmware, but add the 12-bit support to bILDA. There is some pre-work already done:

bilda-output.cpp

Code: Select all

/*	case BILDA_XY_FORMAT_12BIT:
	    this->xy_func = bilda_xy_func_xy12;
	    break;
	case BILDA_XY_FORMAT_16BIT:
	    this->xy_func = bilda_xy_func_xy16;
	    break;
	    ...
*/

An alternative DAC is: DAC1232. This one is pin compatible with the DAC832 ....

Posted: **Wed 19 Jan, 2005 7:22 am**

Hi,

i think, DAC "AD7537KN" (Analog Device) should be possible as well. It contains two 12Bit DAC`s , 8Bit Data Bus. 24Pin DIP

FEATURES (Copy from Datasheet)
Two 12-Bit DACs in One Package
DAC Ladder Resistance Matching: 0.5%
Space Saving Skinny DIP and Surface Mount Packages
4-Quadrant Multiplication
Low Gain Error (1 LSB max Over Temperature)
Byte Loading Structure
Fast Interface Timing
APPLICATIONS
Automatic Test Equipment
Programmable Filters
Audio Applications
Synchro Applications
Process Control

But the firmware have to be changegd and some conections have to be added.

greetings
Erich

Posted: **Wed 19 Jan, 2005 3:37 pm**

fyi, the DAC1232 is not cheap: 1 Stück 57.68 EUR
found at http://www.hinkel-elektronik.de/shop/2705.html

Erich, do you have an electronics retailer for your AD7537KN?

Cheers, Arjan

Posted: **Wed 19 Jan, 2005 8:42 pm**

Hello,

RS-Components. 1 St. 32,16 Euro

http://www.rsonline.de
(edit)
das hab ich dumm gemacht. geht ja garnicht mehr. ALSO:
Open the link and serch "AD7537"
(end edit)

I found 2 in an old device

Greetings
Erich[/url]

www.LaserFreak.net

Replacing 8-bit with 12-bit DAC - with almost no cost..

Replacing 8-bit with 12-bit DAC - with almost no cost..

Max 508