Practical Approximations
For small-signal analysis the current mirror can be approximated by its equivalent Norton impedance .
In large-signal hand analysis, a current mirror is usually and simply approximated by an ideal current source. However, an ideal current source is unrealistic in several respects:
- it has infinite AC impedance, while a practical mirror has finite impedance
- it provides the same current regardless of voltage, that is, there are no compliance range requirements
- it has no frequency limitations, while a real mirror has limitations due to the parasitic capacitances of the transistors
- the ideal source has no sensitivity to real-world effects like noise, power-supply voltage variations and component tolerances.
Read more about this topic: Current Mirror
Famous quotes containing the word practical:
“There are certain queer times and occasions in this strange mixed affair we call life when a man takes this whole universe for a vast practical joke, though the wit thereof he but dimly discerns, and more than suspects that the joke is at nobody’s expense but his own.”
—Herman Melville (1819–1891)
Related Phrases
Related Words