AD/DA conversion

Which is a characteristic of the current-steering architecture often used in high-speed DA converters?

  1. AIt is slow because it integrates the input for a long time
  2. BIt produces the output by slowly discharging a capacitor
  3. CIt produces the output by switching where the currents of many current sources go, so it suits high-speed operation
Show answer and explanation

Answer: C. It produces the output by switching where the currents of many current sources go, so it suits high-speed operation

A current-steering DAC has many current sources and, according to the digital input, switches each current to either the output or a dummy path, forming the output from the summed current. Because the current sources keep running and only their destination switches, it is fast and is used in high-speed DACs for communication equipment.

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More AD/DA conversion questions

  1. Which metric converts the performance of a real AD converter, including noise and distortion, into the bit count of an ideal ADC?
  2. Which AD converter splits conversion into several stages processed like an assembly line, combining high speed with medium to high resolution?
  3. With simple oversampling and no noise shaping, how much does quantization noise improve when the sampling frequency is quadrupled?
  4. Why does timing fluctuation (jitter) of the sampling clock become a problem when converting high-frequency signals?
  5. When a microcontroller produces an analog voltage by passing a PWM signal through a low-pass filter, what determines the output voltage?