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Semiconductor Switch ICs
IC Analog Switch Chip. An Analog Switch is a Linear CMOS Integrated Circuit [IC]. The actual switch is normally produced using a MOSFET, while the control pin [or pins] is a TTL or CMOS digital input used to open or close the switch [turn on or off the FET]. The Control pins in the example below are IN1 and IN2.
The Analog Switch offers high switching speed and very low on resistance,
and very low leakage current when off. The 'on' resistance determines how well the device approximates a closed mechanical switch, and the 'leakage' current determines how well the device approximates an open mechanical switch.
DPDT Analog Switch Chip
Analog switches are classified just like mechanical switches; in the example above the circuit is a Dual Double Pole Double Throw [DPST], note the differences; they are either both open/closed in the first case, or one open one closed in the second case.
The same style switch is also available as two separate switches; Single Control Analog Switches [14-pin DIP package].
Analog Multiplexer are Analog switches that receive more than one analog input and place one of those inputs on the output pin based on the condition of the control pins [which are normally digital controls].
Commercial and Industrial temperature ranges [IC Temp Ranges].
At higher frequencies the capacitance coupling define isolation, while at low frequencies leakage current become more important. Leakage currents must be summed from all 'off' channels that are multiplexed in the same circuit. Leakage current also doubles for every 10 degree C increase in temperature.
Design hint; First select the required switch function. Then select the operational frequency requirements for the circuit function. Next select a part based on the 'on' and 'off' [leakage] resistance. Finally select the component based on package style. Analog Switch Manufacturers.
Index > Logic Design > IC Design > IC Schematics > Analog Switch
