I am currently trying to replace an obsolete part. The old datasheet does not have as much detailed information as the datasheet of the part that I am looking to use as a replacement. Attached is a copy of both the old part and the new part that I am trying to replace it with. The obsolete part DS0026 is designated in the attachment, and the new part is the M38510. The M38510 datasheet shows the propagation delay and rise and fall times with a graph. The DS0026 only has a chart. On the electrical parameters chart for the DS0026, what would be considered the tPHL, tPLH, tTHL, tTLH? These are the parameters that the M38510 part has and I need these values in order to determine if the M38510 is a good replacement for the DS0026.