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Agilent
Reliable Electronic Component Evaluation
and Circuit Design with the 4294A
110 MHz Precision Impedance Analyzer
Product Note 4294-1
Introduction
With the trend toward lower power theory) only under certain conditions. expected. Component and circuit
consumption, smaller size and higher The characteristics under other condi- impedance characterization under
performance in electronic equipment, tions are not ideal due to a variety of actual operating conditions is very
it is crucial to evaluate electronic com- causes that are dependent on compo- important to circuit design. This prod-
ponents and circuits used in electronic nent structure. If the design of elec- uct note describes how to perform reli-
equipment. Electronic components tronic equipment, operating over a able component and circuit evaluation
such as inductors, capacitors, or resis- wide frequency or signal level range, with the 4294A precision impedance
tors behave as ideal components with only includes component characteris- analyzer.
theoretical impedance characteristics tics specified under certain conditions,
(as mentioned in the basics of circuit the actual performance might not be as
Agilent 4294A
Profile Review
The 4294A is a modern impedance (1) Accurate impedance The built-in floating power supply
enables grounded device measure-
analyzer, succeeding and expanding
the main features of the 4194A measurement up to 110 MHz ments with the 42941A impedance
impedance/gain-phase analyzer. probe kit or the 42942A terminal
The 4294A enables impedance mea- adapter. In particular, the
Note that the 4294A does not have
surement using the auto-balancing impedance of components mounted
Gain-Phase measurement capability.
bridge technique over the frequency on a printed circuit board can be
range 40 Hz to 110 MHz, while the easily measured with the 42941A.
Agilent 4194A covers only to 40 The 4194A is a very old impedance
MHz. This advantage permits accu- analyzer with many weak points in
rate evaluation of impedance charac- terms of data analysis. For example,
teristics for a wide variety of elec- since the built-in programming func-
tronic devices within a wide fre- tion called the Auto Sequential
quency range (power line through Programming (ASP) function is
FM frequencies). Typical devices unique to this instrument, and since
include capacitors, inductors, resis- a keyboard cannot be connected, it is
tors, resonators, varactor diodes, very hard to sequentially program
dielectric materials (such as ceramic), for automatic measurement and data
and electronic circuits such as an analysis. Only two markers are avail-
amplifier circuit (where input and able on the display and the marker
output impedance characterization movement is very slow, thereby making
is performed) analysis of data more troublesome. Data
manipulation on a PC is also incon-
(2) Variety of analysis venient because there is no floppy
disk.
functions and interface
The 4294A is equipped with a Local
types Area Network (LAN) interface, an
The 4294A graphically displays GPIB interface, as well as a floppy
impedance measurement results. disk drive. These standard features
This permits easy analysis of the res- simplify data transfer and analysis
onant frequency and impedance val- with a PC. Moreover, measurement
ues of electronic components using and instrument state (setup) data
the marker and the line cursor func- can be stored in the 10 Mbyte built-
tions. The wide signal-level ranges in non-volatile memory. These ease-
enable device evaluation under of-use features make data analysis
actual operating conditions. The test more efficient. Versatile and high-
signal level range is 5 mVrms to 1 speed automatic testing is possible
Vrms or 200