On page 4 of the data sheet there are schematics for each gate in the chip. The LS04 and S04 schematics include a symbol that looks like a BJT transistor, but the "base" component has what looks like Zenner symbol attached.
Please advise what this means or how it is referenced.
Rgds br
Hello,
The symbol you are referring to is called a Schottky transistor. Its equivalent circuit is shown below:
This design prevents the transistor from saturating allowing for a faster switching speed.
The voltage drop across the diode of .3V plus the voltage drop across the transistor of .2V gives a .5V base-emitter voltage, Since this .5V is less than the .8V required for the transistor to go into saturation, the Schottky transistor never goes into saturation. BJT's take a long time switch out of the saturation region and so if they cannot be in the saturation region, they are able to switch much faster.
Thanks!
-Karan
