I need to bypass a circuit with some periphreals and a dsPIC chip (runs at 40MIPS with 80Mhz). I only have 10uF tantalum capacitors (and for some reason it's cheaper anyways if I buy those ones than the 0.1uF caps from the local store).
Anyways, is 10uF bypass caps too large for these frequencies? In theory, the larger the capacitor but better but in actuality the parasitic inductances of the capacitors can start to kick in, but I am not sure what at which frequencies and which capacitor values it will start to matter for. I just know that it has something to do with the parasitic inductances and resistances form a RLC network in the cap with a resonance frequency (with larger caps more likely to have a lower resonance frequency) and if you operate the capacitor above that frequency then the inductances start to kick in and the bypassing breaks down. Any insight would be nice.
ANd could I try and get the best of both worlds by using a large capacitor and a very small capacitor in parallel in order to maximize the capacitance and reduce the parasitic inductance? (I think the much smaller inductance of the small cap should dominate over the larger inductance of the large cap, if it is anything like resistors in parallel).
Thanks.
Anyways, is 10uF bypass caps too large for these frequencies? In theory, the larger the capacitor but better but in actuality the parasitic inductances of the capacitors can start to kick in, but I am not sure what at which frequencies and which capacitor values it will start to matter for. I just know that it has something to do with the parasitic inductances and resistances form a RLC network in the cap with a resonance frequency (with larger caps more likely to have a lower resonance frequency) and if you operate the capacitor above that frequency then the inductances start to kick in and the bypassing breaks down. Any insight would be nice.
ANd could I try and get the best of both worlds by using a large capacitor and a very small capacitor in parallel in order to maximize the capacitance and reduce the parasitic inductance? (I think the much smaller inductance of the small cap should dominate over the larger inductance of the large cap, if it is anything like resistors in parallel).
Thanks.
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