The spec sheet of this amplifier (https://www.analog.com/en/search.html?query=LTC6240) states in its title and in the tables that this OpAmp has a Gain Bandwidth product (GBW) of 18 MHz (typically) and 13 MHz minimum.
However:
- Why is that specified under the condition "Frequency = 20KHz"? Is the GBW dependent on frequency? Which frequency? And how?
- The graph in the middle of page 15 shows the open loop gain vs. frequency of the OpAmp, where the trace crosses the 0 dB line at 5 MHz (or 3 MHz for a 3 V total supply), that is nowhere near 18 MHz.
The simulation model concurs. In open loop the result is comparable to this graph, albeit the GBW is 5 MHz irrespective of supply voltage. In closed loop at various gains the traces also cross the 0 dB line at or near 5 MHz.
What's going on?
