Not quite "no external components", but Maxim has a chip that'll
do that with a couple external components.  It's a rectifier and a shunt
regulator.  You add a filter capacitor and a series current limit
capacitor that drops most of the AC line voltage.

Harold

On Fri, 4 Apr 1997 10:17:15 -0700 Scott Fink <Scott.Fink@MICROCHIP.COM>
writes:
>     Somewhere, sometime, a long time ago, at a job far, far away an
>ad for
>     a single IC which would convert line voltage to a low current +5V
>     supply with no external components, so it wasn't a buck converter
>     type.  Does anyone know who makes these parts and what the part
>number
>     is?
>
>     Scott Fink
>