AVR-Chat

The '7528 is over 30 years old...1970s technology.  I don't remember if 
it was invented by Precision Monolithics or Analog Devices with PMI as a 
second source, but it's old technology and if you're developing a 
product intending to use them you'll eventually have issues trying to 
buy them.  With their parallel interface they also require more lines to 
talk back and forth.

If you insist upon using the AD7528, the datasheet has fairly complete 
information as to how to interface with your controller.  If need be you 
can also go to the Analog Devices web site for application note 
information.  They generally have good information up there.  You might 
also check to see what the production status of the AD7528 is while 
you're there.

          http://www.analog.com/en/

However, the MCP4922 is only about 3 bucks in 1s...and Microchip used to 
be pretty liberal with their sample policy.


REB




huiyangdoh wrote:

>Yeah I know. In fact MCP4725 is my first choice but since I couldn't 
>get it from the shop here, I would go with AD7528. So, any 
>suggestion to design the 4X DAC using AD7528 for Atmega16? I crack 
>my mind to search for this topic using Google but to no avail. 
>
>
>--- In AVR-Chat@yahoogroups.com, "Roy E. Burrage" <RBurrage@...> 
>wrote:
>  
>
>>You might do better using something like a Microchip MCP4922.  It 
>>    
>>
>has a 
>  
>
>>serial SPI interface, 12 bit accuracy, 14 pin dip package, dual 
>>    
>>
>DAC, and 
>  
>
>>rail to rail outputs for starters.  We use the MCP4921 single DAC 
>>version here regularly with good results.  We have used the '4922 
>>    
>>
>in a 
>  
>
>>couple of applications with good results too.  This would give you 
>>    
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>a 
>  
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>>smaller package, higher accuracy module with better crosstalk, 
>>    
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>lower 
>  
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>>power consumption, and better temperature specifications.  They 
>>    
>>
>only 
>  
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>>operate at 5 volts, but if you need higher voltage operation you'd 
>>    
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>have 
>  
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>>to add interface circuitry anyway between your controller and your 
>>    
>>
>DAC.
>  
>
>>They're cheap, too.
>>
>>
>>REB
>>
>>
>>huiyangdoh wrote:
>>
>>    
>>
>>>I am trying to develop DAC circuitry for Atmega 16 since Atmega16
>>>doesn't have in-built feature of DAC. The circuitry design will 
>>>      
>>>
>be 4X
>  
>
>>>DAC design using AD7528 DAC Chips. To my understanding,the 4X DAC 
>>>circuit would be using 11 ports lines of Atmega16 where PortC0-
>>>      
>>>
>PortC7 
>  
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>>>would be input to the 8-bit parallel AD7528 chip and 3 ports 
>>>      
>>>
>lines 
>  
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>>>(PortD0-Port2)would be used as control line inputs. The 
>>>      
>>>
>requirement of 
>  
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>>>this DAC circuit is that it would produce variable voltage (0DVc -
>>>      
>>>
> 
>  
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>>>10DVc) at fix current of 25mA. I will plan to locate Op Amp in 
>>>      
>>>
>the 
>  
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>>>output of every AD7528 DAC chip. 
>>>
>>>I am not trying to ask anyone to do homework for me but I may 
>>>      
>>>
>treat
>  
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>>>here as a resource to gain ideas for the development I am working 
>>>      
>>>
>on.
>  
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>>>I will appreaciate anyone helping me by having discussions and 
>>>      
>>>
>making
>  
>
>>>suggestions related to this topic. Kindly show me any link 
>>>      
>>>
>related to 
>  
>
>>>this topic if u know any. Best Regards.  
>>>
>>>
>>> 
>>>
>>>      
>>>
>
>
>
>
> 
>Yahoo! Groups Links
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>
>  
>


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