"John Larkin"
"Phil Allison"
** Shame how that figure is not typical.
For the non inverting mode, with 600 ohms load, gain of 1000 ( as used in a
mic pre-amp ), frequency 20 kHz - the THD figure rises by 1000 times to
a mediocre 0.1%.
Sure. 75 MHz / 1000 is only 75 KHz of available gbw. Two stages of
gain, 32x each, and the distortion would be back in the single-digits
of ppm.
I use these opamps in nmr gradient amps, to amplify the current shunt
signals. To reduce thermal effects in the shunts, it's best to keep
their resistance and hence voltage drop as low as possible, and we
need ppm wideband noise, so a good opamp really pays off. My first
stage out of the shunt is an LT1028 running gains like 15. The
feedback resistor values are so low (to keep the Johnson noise down)
that the 1028 would have to source a lot of current into them and
transiently self-heat, so I put another, cheaper follower opamp inside
that loop, so it's the one that gets hot. At that point, one
appreciates the fact that the 1028 has a compensation adjust pin. Nice
amp.
Maxim made a MAX1028 for a while, but LTC made them drop it, somehow.
Analog Devices now has a similar part.
John