DS21FF44

The 4 x 4 and 4 x 3 MCMs offer a high-density packaging arrangement for the DS21Q44 E1 enhanced quad framer. Either three (DS21FT44) or four (DS21FF44) silicon die of these devices is packaged in a multichip module (MCM) with the electrical connections as shown in Figure 1-1.

All of the functions available on the DS21Q44 are also available in the MCM packaged version. However, in order to minimize package size, some signals have been deleted or combined. These differences are detailed in Table 1-1. In the 4 x 3 (FT) version, the fourth quad framer is not populated and thus all the signals to and from this fourth framer are absent and should be treated as no connects (NC). Table 2-1 lists all of the signals on the MCM and it also lists the absent signals for the 4 x 3.

The availability of both a 12-channel and a 16-channel version allow the maximum framer density with the lowest cost.