Hi all,
I have an application using an AFE5805 in a multibeam sonar, and have a query concerning the voltage control signals used for gain control.
The gain control signal are presented as a differential pair with a suggestion that a THS4130 be used as a buffer/filter. The datasheet also suggests 0.75V as a common mode voltage for this pair, but there is not so far as I can see any documentation as to what the acceptable range is.
This matters because the THS4130, when run from a single 5V supply (Which is what we have available) does not have sufficiently large output swing to allow operation with Vocm that close to the negative rail.
In the ideal case the common mode range would allow operation with a 2.5V common mode rail giving a swing from +3.25V to +1.75V.
The input circuit shown in the data sheet shows a pair of protection diodes, but does not specify which rail the upper one clamps to.
Can anyone point to some documentation giving the common mode range for these signals?
Push comes to shove, I can drive this single ended from an RC lowpass from the DAC, but I would rather have differential drive with a better filter.
Any pointers to a line in the datasheet I am mission would be appreciated.
Regards, Dan