Hi Dear experts,
In datasheet, parameter measurement information, there is 50ohm resistor in front of Vi pin, may i know the function of 50ohm? Can user not connect 50ohm, and connect input directly?
in the Figure 5, typical application, there is no 50ohm connected.
thanks a lot for your reply in advance.
Best regards,
Joyce Li
Joyce,
What are you wanting to connect to the switch. You should be able to use this switch without any external components unless it is required by other devices in the signal path.
I believe the best explanation I can think of on why that 50 ohm resistor is in the test circuit is that it is a copy and paste error from a different datasheet for a device that needed to do some impedance matching.
The SN74CB3QXXXX family of switches is a basic N-FET switch with the gate of the FET biased with a charge pump. The series resistance for these types of devices is very linear and would not need impedance any impedance matching. You can find more information in this application note.
I will make a note to change this test circuit in the datasheet.
Thank you,
Adam
