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What is fan-in and fan-out of different logic gates?
Fan-in refers to the maximum number of input signals that feed the input equations of a logic cell. Fan-out refers to the maximum number of output signals that are fed by the output equations of a logic cell.
Why fan-out of ECL gates is higher?
The ECL family is fastest of all logic families. ➢Based on BJT, but removes problems of delay time by preventing the transistors from saturating. transistors change states quickly, gate delays are low, and the fan out capability is high.
Does TTL have the biggest fan?
Fan-out is a term that defines the maximum number of digital inputs that the output of a single logic gate can feed. Most transistor-transistor logic ( TTL ) gates can feed up to 10 other digital gates or devices. Thus, a typical TTL gate has a fan-out of 10. A buffer of this type has a fan-out of 25 to 30.
Which of the following is fastest logic style?
Explanation: ECL is the fastest of all the logic families because of the emitters of many transistors are coupled together which results in the highest transmission rate.
What’s the difference between CMOS and TTL logic?
The TTL logic family uses bipolar transistors to perform logic functions and CMOS uses field effect transistors. CMOS generally consumes much less power, despite being more sensitive than TTL. CMOS and TTL are not really interchangeable, and with the availability of low power CMOS chips, TTL use in modern designs is rare.
What’s the difference between CMOS and ECL logic?
ECL (Emitter Coupled Logic) IC technology uses bipolar transistors configured as differential amplifier. Let us compare TTL vs CMOS vs ECL logic families in order to derive difference between TTL and CMOS and ECL based on various parameters such as fan-out, power consumption, noise immunity etc.
What’s the fan out of a TTL logic gate?
Going on these figures alone TTL logic gates are limited to perhaps 2 to 10, depending on the type of gate, while CMOS gates have DC fan-outs that are generally far higher than is likely to occur in practical circuits (e.g. using NXP Semiconductor specifications for their HEF4000 series CMOS chips at 25 °C and 15 V gives a fan-out of 34 000).
What is the difference between CMOS and pass-transistor logic?
In order to save a couple of transistors we can arrange them in such a way that we would need less transistors (to make that flip-flop) yet still be able to memorize that bit. That is what Pass transistor logic is about. But since modern CMOS transistors can be made so extremely small and cheap it isn’t really needed to save those few transistors.