I've seen many datasheet about zener diode for regulator voltage.
And zener voltage depends on test current, right?
So I want to know how to manufacturing company choose test current?
The voltage of a zener diode is constant, it won't change if the current changes. The manufacturer does not "choose" the current of a zener, it is measured as the maximum amount of current that the zener will allow to flow through itself without being damaged.
Well, almost all manufacturers use 5mA as a test current.
Why it's 5mA I don't now. Maybe its has something to do with "knee" of a Zener diode.
And to make sure that the Zener diode will produce the Zener voltage the current must be at least equal to test current.
The manufacturers choose a convenient current that's well above the "knee" of the Zener, so the test is well into the flat portion of the zener voltage versus current region. Some small zeners have a low current knee, so they are tested at a lower current, whereas high power zeners are generally tested at a higher current.
The manufacturer does not "choose" the current of a zener, it is measured as the maximum amount of current that the zener will allow to flow through itself without being damaged.
The voltage of a zener diode is constant, it won't change if the current changes. The manufacturer does not "choose" the current of a zener, it is measured as the maximum amount of current that the zener will allow to flow through itself without being damaged.