Electronics - Analog and Digital Converters - Discussion

Discussion Forum : Analog and Digital Converters - General Questions (Q.No. 2)
2.
A 4-bit R/2R digital-to-analog (DAC) converter has a reference of 5 volts. What is the analog output for the input code 0101.
0.3125 V
3.125 V
0.78125 V
–3.125 V
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
34 comments Page 3 of 4.

Vidya said:   1 decade ago
Vout = Resolution * Decimal equivalent of given No.
Where Resolution = Vref/(2^n)-1
Resolution = 5/(2^4)-1 = 5/7
And dec No = 5

So answer = 25/7 = 3.125.
(1)

Ashu said:   1 decade ago
Vo = 5(0/16+1/8+0/4+1/2).
Vo = 3.125.

SUMIT SHAH said:   1 decade ago
Main equation is,
Vo= Vref * (b0*2^(-1)+b1*2^(-2)+....)
Vo= 5 * (1*2^(-1)+0*2^(-2)+1*2^(-3)+0*2^(-4))
Vo=3.125V

Manjeet said:   1 decade ago
Vo = 5(Vi/16)

= 5(5/16)

= 1.5625
4-bit R/2R digital-to-analog....

Here what about R/2R...?

I think 1.5625 x 2 = 3.125V

Pushpinder kansal said:   1 decade ago
v=5(5/16)
=1.5625
now 1.5625*2=3.125ans

Ankur said:   1 decade ago
Formula= Vref/{(2^n)-1}(msb bit*2^0+nextbit*2^1+nextbit*2^2+lsb bit*2^3)
where, n= no. of bits

output= (5/2^4)(0*1+1*2+0*4+1*8)
= (5/15)(10)
= 3.125 V

Kiran said:   1 decade ago
It can b solved as =ref. voltage * binary equivalent/ total no of steps.

Thanihai said:   1 decade ago
Formula= Vref/2^n(msb bit*2^3+nextbit*2^2+nextbit*2^1+lsb bit*2^0)
where, n= no. of bits

output= (5/2^4)(0*8+1*4+0*2+1*1)
= (5/16)(5)
= 1.5625 V

This should be the correct answer for any type of DACs.

Nilima sinha said:   1 decade ago
Vo=Vref(0*2^0+1*2^-1+0*2^-2+1*2^-3)
=5(0.5+.25)
=3.125V

Anuradha awasthi said:   1 decade ago
Formula= Vref/2^n(msb bit*2^0+nextbit*2^1+nextbit*2^2+lsb bit*2^3)
where, n= no. of bits

output= (5/2^4)(0*1+1*2+0*4+1*8)
= (5/16)(10)
= 3.125 V


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