| 摘要 |
<p>An analog-to-digital converter is provided with minimized metastability. Each of a plurality of bipolar comparators (13) provides from an analog data input a differential output signal. Each of a plurality of latch means (14, 15) provides from the signal of a corresponding comparator (15) a respective one of a plurality of preselected equal-step binary levels. Each latch means (14, 15) includes a dynamic latch (20) for sensing and amplifying a respective one of thesignals to CMOS level, a static latch (22), and transfer gate means (21) for transferring the respective one of the signals from the dynamic latch (20) to the static latch only (22) if such signal is not metastable. As illustrated, each of a plurality of AND gates (30) three inputs that consist of combinations of three adjacent binary levels that are output as a thermometer code by the plurality of latch means (14, 15) in combination for translating the data from thermometer code into a single one hot code. Each latch means (14, 15) also preferably comprises a second static latch (15) which receives the output of the first-mentioned static latch (22) to further decrease the probability of metastability and feeds the thermometer code to the AND gates (30). The binary output of each latch means (14, 15) is input to the dynamic latch (20) of the adjacent latch means; and selectable binary scan data corresponding to a desired thermometer code or code sequence can be input under control of a scan clock for facilitating level sensitive scan design testing. <IMAGE></p> |
