![Circuit from AN90](https://i.imgur.com/BkYU11E.png)

In this circuit from Jim Williams' AN90 the enable line pulls down the base of Q1 through Q2, through a Schottky diode (1n5712). Why is this Schottky diode there? I imagine it's a Schottky diode so it has a diode drop smaller than Q1's, so it's possible to turn off Q1... but why does it need to be there at all? It seems as if you could short over it and prevent Q1 from conducting just fine. It must be there for a reason! He even seems to omit it in an earlier figure (<http://cds.linear.com/docs/en/application-note/an90f.pdf> Fig. 2)