Other Parts Discussed in Thread: TIDA-00684
I intend to use two THS3091 in a current sharing arrangement, operating from +/-15V to generate signals of up to 20Vpk-pk on 100Ohm (10Vpk-pk after 50 Ohm termination). Ideally I would like to be able to simulate the linearity performance under various conditions, but apparently the PSpice model is not accurate in that regards. The datasheet of the THS3091 seems to have some erroneous graphs, as they seem to be inconsistent among themselves: according to figure13 and 14, at 8MHz with 20Vpk-pk on 100Ohm with gain x5, HD2 and HD3 should be about -56dBc and -62dBc, whereas according to figure 16 it is less than -40dBc under same conditions. figure 15 similarly also does not agree with figures 13 and 14, although to a lesser degree. The figure for THD on the first page of the datasheet does seem to be inline with figures 13&14, though.
1. Can you confirm that figures 13&14 are correct, while 15&16 are not?
2. for connecting two THS3091 together, most of your applications notes and datasheet show this with a configuration of two 100Ohms connected together and to the external 50Ohm load (for example see figure 3 in SBOA127). However, in TSW3080 TIDA-00684, for channel 2, you have chosen instead to use two 20Ohm resistors instead with an additional 40Ohm series resistor. Although in theory both circuits seem equivalent, choosing two 100Ohm resistors has a practical advantage in that mismatches in Voffset between the two amplifiers will have less fighting to do between them. Is there any benefit to using the configuration of TSW3080?
Thanks,
Uri
