Current Sources and Voltage References

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Quality dual transistors

Table 5.3 Manufacturers of dual and quad BJT transistors.

Quad transistors are available from Fairchild Semiconductor, Central Semiconductor,

Crystalonics, ON Semiconductor, Diodes Inc., Microsemi, and others. Most products

contain either all-NPN or all-PNP devices. Some examples include the PQ-3904 (four

NPNs with similar specs to a 2N-3904) and the PQ-3906 (four PNPs with similar

specs to a 2N-3906). Some are dual-complementary (two NPN and two PNP in the

same package), such as the PQ-6002 and the PQ-6502 (two NPNs and two PNPs

with specs based on 2N3904/3906), which can provide a simple current source and

current sink ...