Why is always prefered the value of 0.1u as decoupling capacitors that they placed very close to the chips? Why don't use larger, like 0.22u, 0.47u, 0.68u or 1u for example?
\$\begingroup\$
\$\endgroup\$
7
-
6\$\begingroup\$ It used to be 0.1uF ceramics were the biggest and cheapest devices available and were a nice physical size that matched the dip package. Today you can get and use larger values. \$\endgroup\$– Trevor_GSep 28, 2017 at 18:23
-
3\$\begingroup\$ related \$\endgroup\$– The PhotonSep 28, 2017 at 18:28
-
3\$\begingroup\$ also related \$\endgroup\$– The PhotonSep 28, 2017 at 18:29
-
5\$\begingroup\$ Modern tiny high capacitance caps lose a lot of capacity at typical DC bias values anyway. In fact the voltage rating has more to do with the capacitance loss than breakdown in many cases (you can think of it as analogous to saturation in inductors at higher currents). \$\endgroup\$– Spehro PefhanySep 28, 2017 at 19:18
-
4\$\begingroup\$ Larger capacitors are not, in general, good for decoupling because they have low self-resonant frequencies. \$\endgroup\$– dirac16Sep 28, 2017 at 19:27
|
Show 2 more comments
1 Answer
\$\begingroup\$
\$\endgroup\$
1
0.1uF capacitors may attenuate higher frequencies better than, say, a 1uF capacitor due to larger (SMD) capacitors having more inductance.
answered Sep 28, 2017 at 22:34
-
\$\begingroup\$ That was true in the 90's, but not today. 1µF is readily available in 0402 package. You can even get as high as 22µF in 0402 package(!) \$\endgroup\$ Apr 14, 2019 at 0:03