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Design >> Mixed-Signal Design >> voltage follower speed
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Message started by cktlife on Aug 28^th, 2007, 8:51am

Title: voltage follower speed
Post by cktlife on Aug 28^th, 2007, 8:51am

Dear all,

It is known that DAC speed is limited by OPAMP if there is a voltage follower as a buffer at the output. The voltage follower reaches UGBW due to unity feedback. How fast can voltage follower operate?

Thanks,

Title: Re: voltage follower speed
Post by carlgrace on Aug 30^th, 2007, 1:11pm

It really depends on the technology. The voltage follower will operate the fastest of any feedback circuit because it has the lowest gain (and therefore the largest feedback factor). It is possible to design a follower without an op amp if you have the headroom, this may be faster. Also, if you have a current mode DAC you can try loading it with a resistor. This is probably the highest speed you can do in a given technology.