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| analog switch |
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| Mitalius:
I have a 2.5V DAC with two channels. I invert one of these with OpAmp. So I get: Channel A: 0V to 2.5V Channel B: -2.5V to 0V I would like to have an output on which I can switch these 2 channels at a frequency of 0.5MHz. I plan to use this to generate a signal for a current source. Now I use TS12A12511 analog switch to switch DAC channels, but it is very noisy. It is very important for me to have a good signal quality, but I can't figure out what else to do. |
| OwO:
SGM3157 BL1551 |
| OwO:
Noisy during steady state or while switching? Can you try stopping the switching action and see if the noise persists? What kind of noise? harmonics of the switching frequency or just white noise? |
| OM222O:
a slim fit relay is pretty analog :) it's less than ideal but provides 0 noise. also if you get the type that only needs current to switch and then latches mechanically, it probably consumes less power than a chip that's constantly powered on as well. |
| Kleinstein:
The CMOS switches mentioned so far are very low resistance. This usually comes with a relatively high charge injection. During switching here will be a charge pules going out from the switch. This could effect the DAC or inverting amplifier. Depending one the DAC signal bandwidth one could have a filter / ferrite there to avoid at least the very high frequency part. Another point is going for a higher impedance and possibly slower switch. So something like 74HC4053 (maybe single gate version of this). |
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