NMOS Current Sources and Sinks
Characteristics of Current Sources
· A well controlled output current
· Supplied current does not depend on output voltage and has High NortonResistance
· Connect a voltage source to the gate of another MOSFET:
Hence, IREF depends on the supply voltage VDD. If the supply is a battery or similar device, then this will change over time, causing the reference current to also vary with time.
IOUT scales with IREF by W/L ratios of two MOSFETs