Maxim Integrated Products introduced the MAX4580/MAX4590/MAX4600 dual SPST analog switches. They feature low on-resistances of only 0.9 W (1.25 W max), matched (inside the IC) to within 0.5 W max, and flat (over the specified signal range) to within 0.5 W max. All switches handle rail-to-rail analog signals.

The MAX4580 has two normally closed (NC) switches, the MAX4590 has two normally open (NO) switches, and the MAX4600 has one of each. Because these switches offer small space, low-power operation, and reliability higher than that of mechanical relays, they are preferred over mechanical relays for use in current-switching applications and automatic test equipment. They also excel in applications that require low distortion.

The low on-resistances are what makes these parts head for the commercial success that they deserve; and they are now at levels where their use in test equipment becomes guaranteed. Currently in automatic test equipment it is conventional to have two sets of relay contact for every closure; the first closure takes the current surge and the second, slightly later, allows the measurement path to be enabled at low resistance. The primary contacts to close age prematurely, of course, and are subject to frequent replacement; they are both a day-to-day replacement item and are a routine check area, both costing money. With a CMOS switch this process is not necessary and at these levels of predicted, specified resistance it can be designed in at a lower cost.