how to choose ADC or DAC

how to choose adc

Dear all,
i want to know what properties should be checked in using a particular ADC or DAC in the electronic design.

how to choose an adc

Check how many input bits will you be feeding the DAC. Most common are the 4 bit and 8 bit DACs. Higher ones are also available. You can also use a R-2R ladder circuit instead of DAC. Check coughlin's op-amp book for reference.

For ADCs, it's the oppostie. You need to know how many output bits you require. For most cases 8 bit ADC is more than enough unless you require really high resolution.

how to choose a dac

rectifier,
For both DAcs and ADCs you need to determine the minimum number of bits required. Let
. Vmax = Maximum output(ADC) or Input(DAC) range
. Vres = minimum voltage change the you need
. to detect(ADC) or output(DAC)
. Nmin = minimum number of bits
Then Nmin = log(base2) of Vmax/Vres.
This is for the ideal case. For real world cases with noise, you need to determine Effective Number of Bits (ENOB). for a basic ENOB disussion, see the article "ADCs: Does ENOB tell the whole story?" from the 4/17/2008 of EDN magazine.
www.edn.com/article/CA6549029.html?text=Does+ENOB+tell+the+whole+story? -
.
You also must consider speed. For ADCs this is determined by the conversion time, which is given on the data sheet. For DACs this is determined by the settling time and, for serial DACs, the input clock speed and data protocol.
Regards,
Kral

choose dac

Rectifier
ADC
1. Required resolution like 8 bit/ 16 bit
2. Type - like SAR, sigma delta etc
3. conversion speed
4. non linearity errors
5. operating voltage
6. Thermal stability/ noise performance
7. interface requirements - SPI I2C, parallel etc
8. Current consumption, package, size, cost, availability for next few years........etc

DAC -
1. Type
2. Settling time
except these two, many of the points mentioned above are applicable

FL_KNV