As shown by the functional block diagrams, the PSW-1211 is very similar to the discontinued model of PSW-1111. Because of this similarity, with the addition of a 50Ω resistor at output #1, the PSW-1211 can be used in place of the PSW-1111.

Functional block diagrams:

Figure 1: PSW-1111, SPST switch.
Figure 2: PSW-1211, SPDT switch.
Figure 3: PSW-1211 with 50 ohm resistor at output #1.

With output #1 terminated in 50Ω, the PSW-1211 may be operated as either an absorptive or a reflective SPST switch.

For an absorptive application, both control #1 and #2 must be used. The logic is given in table 1.

Table 1: Logic of PWS-1211 used as SPST absorptive switch.

At stage 2, the signal path closes from the input (pin 5) to pin 2 and the signal is absorbed at the 50Ω termination.

For a reflective application, Control #1 can be either open or grounded. This will cause the signal to reflect back to the input source when Control #2 is 0V.

Our discussion has focused on using the PSW-1211 as a replacement for the PSW-1111 with pin 8 as the output. However, if the PC board layout is such that terminating pin 8 in 50Ω is more convenient, then this may be done and pin 2 can be used as the output with opposite logic.

Please direct any questions or comments on this article to our Applications Department.

Browse all RF switches