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Advancements in technology
current source or a current sink. Figure 1.6 shows a simplified view of the LM134’s
internal circuitry, which incorporates both NPN and PNP bipolar transistors, as well as
some very-low-voltage P-channel JFETs, and an integrated capacitor. The JFETs are
used for start-up biasing and enable the internal BJT current mirrors. Uniquely, the
device also doubled as a linear temperature sensor, which made it even more attrac-
tive at the time. Carl Nelson later joined Linear Technology, once again working for his
former boss, Bob Dobkin. The LM134 family is still in production today and available
from both National Semiconductor ...