LiquidOrb24
New Member
Hello,
I have a circuit working at roughly 13MHz and have several IC's within the circuit...However I'm having trouble understanding DC Blocking and Bypass Capcitors and the values I should be using.
I notice a common value for a bypass cap is .1uF which turns out to be .1175 Ohms impedance at 13MHz and the lower I go in cap value the larger the impedance gets and vice versa. So in order to bypass the AC signals from the DC lines going to the IC should I choose the smallest impedance possible < 1 Ohm or does it not matter...Also with bypass capcitors if I know the frequency I'm running at do I need multiple caps to work/bypass at a wider range of frequencies just incase.
The same question goes for the DC blocking cap...should I be using a value cap that gives an impedance lower than 1 Ohm or does the high impedance not affect the ac signal going throught he capacitor and only the DC? Or does the impedance/value of the capacitor not matter because no matter the value of the cap...all capacitors block DC?
I was thinking of just using a 10nF or .1uF capactor for DC blocking and a 10nF and .1uF capacitor for the shunt bypass capcitors...would this be a safe bet or should the values be somewhat differet.
Thank you for all your help
I have a circuit working at roughly 13MHz and have several IC's within the circuit...However I'm having trouble understanding DC Blocking and Bypass Capcitors and the values I should be using.
I notice a common value for a bypass cap is .1uF which turns out to be .1175 Ohms impedance at 13MHz and the lower I go in cap value the larger the impedance gets and vice versa. So in order to bypass the AC signals from the DC lines going to the IC should I choose the smallest impedance possible < 1 Ohm or does it not matter...Also with bypass capcitors if I know the frequency I'm running at do I need multiple caps to work/bypass at a wider range of frequencies just incase.
The same question goes for the DC blocking cap...should I be using a value cap that gives an impedance lower than 1 Ohm or does the high impedance not affect the ac signal going throught he capacitor and only the DC? Or does the impedance/value of the capacitor not matter because no matter the value of the cap...all capacitors block DC?
I was thinking of just using a 10nF or .1uF capactor for DC blocking and a 10nF and .1uF capacitor for the shunt bypass capcitors...would this be a safe bet or should the values be somewhat differet.
Thank you for all your help