Hello there,
To add a little to what Eric posted...
There are different versions of the same IC chip, some with better specifications
than others. The A version has better specs than the C version. It probably
costs more too.
As Eric pointed out, 0.3Mohms is the same as 300Kohms. To find out what value to
use, you would first note what IC version you are using, A or C, etc. Then under
that set of columns (and only that set) you would look for the spec.
You also see different rows even under one version of the IC. You also see major
rows and minor rows. The major rows are separated by a thicker horizontal line.
The major rows at the top of the blue section are labeled on the left starting with
either TA=25 deg C or TAMin<=TA<=TAMax. Thus the top major row is made up of three
rows, and the next major row down is made up of five rows. The top three blue rows
are for Ta=25 deg C and RL>=2k ohms. The bottom 5 rows are for TAMin<=TA<=TAMax and
also RL>=2k ohms.
Of the top three blue rows, the second and third refer to two different supply voltages
and their corresponding output voltages. The gain is 50v/mv which works out to 50000
for a source voltage set of plus and minus 20v and output voltage swing plus and minus
15 volts. For a source voltage of 15 volts (and swing plus and minus 10v) we see
a different value for two of the versions, where one is 50v/mv and the other is 200v/mv
which is 50000 and 200000 respectively, and the other is 20 and 200 which is for the
other version. The reason for the two numbers is because they are giving a typical
value and a minimum value. If you want to make sure the design is going to function
properly you have to use the worst case value which here is the min value.
The second major blue row is the five rows that start with TAmin<=TA<=TAmax. They
are giving the values of the gain again for all three versions, and for three different
values of source (plus and minus) voltages.
So understanding this data sheet means breaking up the rows and columns and reading the
values found there.
TA means "Ambient Temperature"
Vs means "Source Voltage(s)"
Rs in this context would mean the equivalent resistance in series with the source voltage(s).
To calculate the gain from the units of V/mV just divide the volts given by 0.001, so a
V/mV of 20 means a gain of 20000. This just means simply "Volts per Millivolt" which would
refer to volts output per millivolt of input.