A comparison of first and second-generation switched-current cells

The Switched-Current (SI) technique is a circuit method that enables analog sampled-data circuits to be realized with a standard digital CMOS process. At this time it is fair to say that SI circuits are realized from either first- or second-generation type current memory cells, with the latter cell being favored owing to its perceived better sensitivity behavior. Unfortunately, however, the second-generation current memory cell has some serious circuit drawbacks. These include large internal transient glitches that cause large linear and nonlinear circuit errors, as well, requires a more complicated circuit. When all factors are considered including the sensitivity issue, it is our opinion that the first-generation cell is superior to the second-generation memory cell. In this paper we shall present our arguments and experiments that back up these claims