How to measure the bandwidth for a buffer?

[surianova]

bandwitdh for buffer

hi all,

Just want to confirm the way we measure the bandwidth for a buffer.
For buffer, the gain is normally almost 0 dB. Is it correct we measure
the bandwidth as 0-3dB= -3 dB. The frequency at gain -3dB is the
bandwidth, is it corerct?

Suria

 

[IanP]

Re: bandwitdh for buffer

Yes, It is used not only for buffers, but amplifiers too.
This magic -3dB....and bandwidth..
For amplifiers there is another parameter which is called full power frequency, and this one describes the bandwidth at the maximum output voltage and without amplitude distortions...

 

[gevy]

Re: bandwitdh for buffer

-3dB frequency is frequency of half power.
For voltage or current
dB=20*lg(K) -> K=10^(dB/20) -> Power ~ K²=(10^(-3/20))²≈0.5
For power
dBp=10*lg(Kp) -> Kp=10^(dBp/10) -> Power ~ Kp=10^(-3/10)≈0.5

 

[flatulent]

Re: bandwitdh for buffer

One thing to keep in mind is that buffers are intended for large amplitude signals into low impedance loads. You should measure and expect the bandwidth to be with a high level sine wave and lowest specified impedance load.

 

[segabird]

Re: bandwitdh for buffer

One thing to keep in mind is that buffers are intended for large amplitude signals into low impedance loads. You should measure and expect the bandwidth to be with a high level sine wave and lowest specified impedance load.

which is the relation between sine wave frequency and the bandwidth?