Question

Which of the following logic families has the highest maximum clock frequency?

(a) S-TTL

(b) AS-TTL

(c) HS-TTL

(d) HCMOS

I have been asked this question during a job interview.

This interesting question is from Digital Integrated Circuits in section Boolean Algebra and Minimization Techniques and Logic Gates of Digital Circuits

Answer 1

Right choice is (b) AS-TTL

The explanation is: AS-TTL (Advanced Schottky) has a maximum clock frequency of 105 MHz. S-TTL (Schottky High Speed TTL) has 100 MHz. Found nothing as HS-TTL. There are H and S separate TTL. HCMOS has 50 MHz clock frequency.