A 16-b D/A converter with increased spurious free dynamic range
- Analog Devices Semiconductor, Wilmington, MA (United States)
There are many sources of unwanted signals or spurs in the output of Digital to Analog Converters (DAC) used in the digital synthesis or reconstruction of analog waveforms. The sources of error or distortion can be divided into two broad categories. The first are static or dc errors. Characteristics such as the integral nonlinearity (INL) and differential nonlinearity (DNL) of the DAC are well-known examples of this kind of error. Methods such as segmentation of the bits and laser trimming of thin film resistors are often used to minimize these static errors. The second category of errors are dynamic or ac errors. Nonlinear settling, ringing, nonsymmetric slew, and glitch are examples of these dynamic errors. Thermometer decoding of the most significant bits along with high-speed process technologies are often employed to minimize dynamic effects. The work described here addresses the dynamic effects, mentioned above, through the use of a novel arrangement in the precision current switch used in the DAC. This approach to switching the DAC currents has led to improved switching symmetry and better time alignment between the individual bit switches. This has resulted in a 10-dB improvement in the spurious free dynamic range over the conventional n-p-n current switch used in D/A converters.
- OSTI ID:
- 6987588
- Journal Information:
- IEEE Journal of Solid-State Circuits (Institute of Electrical and Electronics Engineers); (United States), Vol. 29:10; ISSN 0018-9200
- Country of Publication:
- United States
- Language:
- English
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