Can I use the IES5501 bus buffer at TTL logic levels?
While not using TTL logic levels itself, the IES5501 will interface to TTL devices. The buffer will track (with some small input-output offset) any signal applied to it’s I/O pins which fall below 33% of the IC’s supply voltage. Therefore, as long as VIN + VOFFSET < TTL low level, the system is compatible.