Agilent Technologies 93000 SOC Series - DAC Basics

Lesson 1 – The Training DAC
157
1-1 DAC Basics
A DAC converts a digital value, which is applied via n data lines,
into an analog voltage.
DAC Block Diagram
DAC Block Diagram
DAC Transfer Curve
Linear DACs have a transfer characteristic as shown below:
DAC Transfer Curves
Real DACs show minor or major non-linear deviations.
Vo =
Rf
R
( ++)
2
a
0
4
a
1
8
a
2
Vref
Vref
Vo
a
0
a
1
a
2
digital code
8R
4R
2R
Rf
Example of a 3-bit DAC
Digital input code
Discrete Analog
Output Voltage
Digital input code
Discrete Analog
Output Voltage
Ideal DAC
Non-Ideal DAC