Hello to everyone! I am currently designing a prototype of a two-way radio transceiver where I have incorporated SN74LVC1G3157DBV both in the audio and in the RF circuitry. I want to use this part to switch between audio signals or to select an attenuator p-pad in the RF front end or to switch balanced mixer ports between transmit and receive circuitry.
- As I have understood by reading the datasheet, any signal to be passed through this switch must have an amplitude ranging between the power rails (0 to +5 V in my case). This means that I have to use appropriate coupling capacitors ahead of a voltage divider in order to put a signal on a DC level (say +2.5 V DC for maximum swing, although not much of a concern in my case), and then I should route this signal in or out of the switch. My question is: Is it enough to bias the A-terminal of the switch (the "point" terminal") with a DC voltage to get the signals passed to B2 or B1 terminals (the "throw" terminals)? Or should I bias all terminals?
- The maximum frequency that I want to switch is 150 MHz. The datasheet states that the -3 dB bandwidth of the switch is 300 MHz. It seems that this switch is suitable for my application - power levels to be switched are really very small, -10 dBm@50 Ohm at most. Is there anything that I should take care of, apart from proper PCB layout, to use this switch without serious degradation of high-frequency signals?
Thanks,
George
