What does "bandgap" stand for ?

I saw a block called "Bandgap Voltage" from a transceiver datasheet.
Could any expert advise what the function it is?
Thanks a lot.

bandgap voltage generation is the way to generate reference voltage in integrated circuits.

it is named bandgap, because it is referenced to the bandgap energy of the transistors

It is a voltage Reference standard. Some of the pros & Cons are:

Pros: Cons:

Lower power consumption Moderate noise characterization

Accuracy is generally sufficient and Limited temperature drift trimming can improve it

Guaranteed operation down to 1V supply Larger package
voltage, ideal for portable applications


Bandgap tutorial:
http://amesp02.tamu.edu/~sanchez/689-bandgap-fikret.pdf

Thanks.
May I know what the main function of bandgap is in the chip ?
Is it a voltage reference(for comparison) or voltage source in the chip ?
Thanks a lot.

Exactly...

Bandgap volatge references are used to obtain "temperature independent" voltage/current sources. Even "multiplied or copied" sources are not really temperature independent, it's better than nothing...:D