THS4521 decoupling

Hi Michael,

There is no comparable scheme that uses less parts, but the 10uF electrolytic capacitors are the largest, so it would save the most space to cut down to one 6.8uF capacitor per supply rail.  Using a lower value in place of two capacitors may sound odd, but lower value capacitors have less parasitic resistance and inductance, so when you eliminate a parallel capacitor you may need to reduce the value of the one you use. 

If you can run the part on a single supply you can eliminate 1/2 of the decoupling capacitors. 

The reason for using two capacitors in parallel is to reduce the ESR of the capacitor, the additional capacitance is a side benefit.  

If you have multiple amplifiers on one board you can share the 10uF capacitors between the various amplifiers. 

The 0.1uF capacitors need to be located near the amplifier power pins and should not be shared among amplifiers.  These are the most important capacitors for high frequency performance.  If you want to get rid of one of your 0.1uF capacitors I'd suggest you switch the remaining capacitor to 0.01uF. 

Are your requirements lower than specified in the datasheet?  Using fewer bypass capacitors will degrade HD2 as well as high frequency slew rate.  Most other specifications will not be changed much. 

Regards,

Loren

My signal bandwidth is only 10kHz, do you think it would be acceptable to use a 6.8u and a 0.01u ceramic capacitors instead of two 10u and 0.1u capacitors?

Hi Michael,

For your purposes a 6.8u and a 0.1u would be fine.  The 0.01uF caps are for signal bandwiths in the Megahertz range. 

Loren