What Company(s) Make A DTV Converter Box With An Analog(NTSC) Pass

I use an external antenna for TV reception. The reason I need this
type of converter box is that some low-power TV stations do NOT have
to convert to digital(ATSC) next year and the ones in my area are NOT
going to convert to digital. The higher power stations in my area ARE
converting. Therefore, I'm looking for a DTV converter box with
analog(NTSC) pass through capability or at least a switch that will
let the analog signal pass through the box to the TV antenna input.
Does anyone know of specific companies that are making such a DTV
converter box?

Thanks for your help.