Output voltage : ADA4870

Hi team

I am going to design using ADA4870.
The voltage range is shown in 10 to 40V.
Is plus, minus 20V the maximum?

One question more,
The figure below shows "Up to 60 Vpp 1A with external BJT."
Is the range plus,  minus 30 volts?
Please share the BJT circuit.

Thanks

Damon