AN-6609 Datasheet, PDF (1/53 Pages) Fairchild Semiconductor – Selecting the Best JFET for Your Application

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AN-6609
Selecting the Best JFET for Your Application
Introduction
This application note contains design curves for all of
Fairchild Semiconductor discrete JFET processes. JFET
process characteristics provide complete information on all
processes, including all parts manufactured from a particular
process. This can greatly aid device selection or
substitution. In all cases, temperature and V_GS(off)
distribution data is provided to facilitate worst-case design.
In addition, a complete list of all device types supplied from
this process is included to aid in cross reference searches
and the selection of preferred device types. Preferred parts
are shown with gray overprinting. The curves in this section
should be considered typical of the process supplied by
Fairchild Semiconductor. Every effort is made to keep the
process in tolerance with the published graphs, but the exact
distribution of any specific lot of material is not guaranteed.
How to use the Application Note
The following suggested procedure will help you find the
device you need.
Part Number Known: Go to the Fairchild web site and
type in the part number. If alternate type is required, refer to
the online cross reference guide.
Specification Known: Refer to Figure 2, "JFET Process
Family Tree" on page 4 of this application note to find the
most compatible process. Then turn to Figure 3, “JFET
Process Comparison Curves”, on page 6 to compare the
specifications of each process type. Finally, turn to page 16
for a detailed listing of process characteristics and specific
device type numbers available in that process. Take special
note of preferred part types. Full data sheets are available on
line.
Application Known: Turn to "Choose the Proper FET" and
Figure 2, "JFET Process Tree" on page 4. Also Table 2,
“Advantages of Using JFET by Application on page 3.
Finally, refer to 0, “Applications and Their Parameters in
Approximate Order of Importance” on page 2 as needed.
None of the Above: Contact local representative or regional
office for assistance.
JFET Application Guide
Fairchild Semiconductor manufactures a broad line of
silicon junction field effect transistors (JFETs). Fairchild’s
JFETs provide excellent performance in many application
areas such as RF amplifiers, analog switching low input
current amplifiers, ultra low noise amplifiers and
outstanding matched duals for operational amplifiers input
applications.
Table 1 is a guide to enable the user to determine what
parameters are important in each application. This followed
by a listing of JFET Parameter Relationships in Figure 1.
Table 2 lists many application advantages of JFETs by
application.
© 1977 Fairchild Semiconductor Corporation
Rev. 1.0 • 7/20/15
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