Class Exercise Solution
Exercise 13: What is the largest value of output voltage one can
expect from an 8-bit DAC that produces 1 V for a digital input
of 00110010?
Solution: 00110010 = 5010
1 V = K x 50 => K = 20 mV
Vout(max) = 255 x 20 mV = 5.1 V
Exercise 14: In the op amp summer DAC discussed, let Rf =
250Ω. Determine the DAC resolution and full scale (f.s) output
voltage ⎛ 5 ⎞
K =⎜ ⎟ = 0.1563
Solution: ⎝ 4×8 ⎠
V V V V
Vout = −( D + C + B + A ) = 2.344
4 ×1 4 × 2 4 × 4 4 × 8
University of KwaZulu-Natal 1
13-1
ENEL2EBH2 2010
, References for Digital & Analog Conversion
Wakerly doesn’t cover this section
For the notes we used Rizzoni, (Principles and Applications of
Electrical Engineering, Giorgio Rizzoni, 3rd, revised 4th or 5th
edition) and Tocci/Widmer (Digital Systems – Principles &
Applications, Ronald J Tocci & Neal S Widmer, 8th edition).
Copies of Rizzoni are available in the library.
University of KwaZulu-Natal 2
13-2
ENEL2EBH2 2010
Exercise 13: What is the largest value of output voltage one can
expect from an 8-bit DAC that produces 1 V for a digital input
of 00110010?
Solution: 00110010 = 5010
1 V = K x 50 => K = 20 mV
Vout(max) = 255 x 20 mV = 5.1 V
Exercise 14: In the op amp summer DAC discussed, let Rf =
250Ω. Determine the DAC resolution and full scale (f.s) output
voltage ⎛ 5 ⎞
K =⎜ ⎟ = 0.1563
Solution: ⎝ 4×8 ⎠
V V V V
Vout = −( D + C + B + A ) = 2.344
4 ×1 4 × 2 4 × 4 4 × 8
University of KwaZulu-Natal 1
13-1
ENEL2EBH2 2010
, References for Digital & Analog Conversion
Wakerly doesn’t cover this section
For the notes we used Rizzoni, (Principles and Applications of
Electrical Engineering, Giorgio Rizzoni, 3rd, revised 4th or 5th
edition) and Tocci/Widmer (Digital Systems – Principles &
Applications, Ronald J Tocci & Neal S Widmer, 8th edition).
Copies of Rizzoni are available in the library.
University of KwaZulu-Natal 2
13-2
ENEL2EBH2 2010
