Determining parameters for SN74LS02 TTL NOR schottky diode

Now, what would I get if I repeated the similar experiments (see previous blogs on standard TTL) with a schottky diode; meaning the V_OL ,V_OH , etc

This is what I got:

	As Measured	From Datasheet
VOH	3.2 V	3.4 V (Test conditions: Vcc=4.75V, IOH= - 0.4 mA)
VOL	0.12 V	0.4V (Test conditions: Vcc=4.75V, IOL= 4 mA)
tPLH	13.86 nS	10 – 15 nS
tPHL	1.52 nS	10 – 15 nS
Frequency	23.36 MHz	----
tP	7.13 nS	10 – 15 nS

Note the Schottky logics will have a better propagation delay as they contain Schottky diode clamp across the base-collector junction of the transistor, causing the transistor never go to saturation. This meant an improved turn-off period. But my measurement showed the Schottky NOR gate had more propagation delay (tpLH) which I would attribute to my experimental setup like length of the wires, breadboard connections etc introducing various parasitic capacitances. (The charging and discharging of these parasitic capacitances could have introduced the noted additional delays).

For the VTC parameters, it was noted that the speficied V_OLmax for the schottky logic was nearly double that for the standard TTL logic. That was because use of the Schottky diode clamped the output at 0.4 V instead of normal saturation value of 0.2 V. It meant the lower value of logic swing for Schottky logic, and subsequently the lower Fanout.