What is meant by emitter coupled logic?
A type of current mode logic that is commonly used to build logic gates in which emitters of two transistors are connected to a current carrying resistor so that only one transistor will work at a time. Here output of the transistor is taken from emitter instead of collector.
What is the biggest advantage of emitter coupled logic?
During voltage transitions, CMOS logic gates cause transient disturbances in the power-supply voltage. A major advantage of ECL is that the current-steering behavior of the input stage (i.e., Q1 and Q2) does not cause disturbances in the way that CMOS switching does.
What is MOS current mode logic?
MOS current mode logic (MCML) style is widely used as an alternative to CMOS logic style in mixed-signal applications. MCML circuits in contrast to the CMOS circuits provide an analog friendly environment to the sensitive analog circuits fabricated on same silicon chip.
Why ECL is fastest logic family?
Emitter-coupled-logic (ECL) is a BJT logic family that is generally considered the fastest logic available. ECL achieves its high-speed operation by employing a relatively small voltage swing and preventing the transistors from entering the saturation region. (Reduces the storage delay time).
What are the advantages and disadvantages of emitter coupled logic?
Following points summarize ECL advantages over TTL and CMOS: ➨It has fanout of 25 which is better than TTL and less then CMOS. ➨It has average propagation delay time ( 1 to 4 ns ) better compare to both TTL and CMOS. Hence it is known as fastest logic family.
Why is CML faster than LVDS?
The CML output transistors are permanently biased in the active region, resulting in the ability for much faster switching than technologies that use saturated transistor operation, such as CMOS or most LVDS implementations.
What is CML output?
The CML output consists of a differential pair with 50Ω collector resistors, as shown in Figure 3. The signal swing is supplied by switching the current in a common-emitter differential pair.
What are the characteristics of ECL?
In ECL, the transistors are never in saturation, the input/output voltages have a small swing (0.8 V), the input impedance is high and the output impedance is low. As a result, the transistors change states quickly, gate delays are low, and the fanout capability is high.
What are the characteristics of emitter coupled logic?
Emitter-coupled logic
- In electronics, emitter-coupled logic (ECL) is a high-speed integrated circuit bipolar transistor logic family.
- In ECL, the transistors are never in saturation, the input/output voltages have a small swing (0.8 V), the input impedance is high and the output impedance is low.
