Question 29.4: Construct a table showing the thermometer code necessary to ......

CMOS Circuit Design, Layout, and Simulation [1366181]

Construct a table showing the thermometer code necessary to generate the output shown in Fig. 29.11a for a 3-bit current-steering DAC constructed using unit current sources.

29.11

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The thermometer code can be seen in Fig. 29.11b. When the code is all zeros, the output is 0 volts. Therefore, only 7 bits are needed to represent the $2^{N}$ or 8 states of a 3-bit DAC. Note how the interface between all ones and all zeros actually resembles the output signal itself.

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