DS1634 Datasheet, National Semiconductor

output transistor protection if the VCC supply is lost by forcing the output into the high impe- dance OFF state with the same breakdown levels as when VCC was applied P.

The DS1631 series of dual peripheral drivers was designed to be a universal set of interface components for CMOS circuits Each circuit has CMOS compatible inputs with thresholds that track as a function of VCC (approximately VCC) The inputs are PNPs .