LTC6401-14 Linear Technology, LTC6401-14 Datasheet - Page 12

• Manufacturer Part Number: LTC6401-14
• Description: Low Distortion Differential ADC Driver
• Manufacturer: Linear Technology

LTC6401-14
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APPLICATIONS INFORMATION
Test Circuits
Due to the fully-differential design of the LTC6401 and
its usefulness in applications with differing characteristic
specifi cations, two test circuits are used to generate the
information in this datasheet. Test Circuit A is DC987B,
a two-port demonstration circuit for the LTC6401 family.
The silkscreen is shown in Figure 9. This circuit includes
input and output transformers (baluns) for single-ended-
to-differential conversion and impedance transformation,
allowing direct hook-up to a 2-port network analyzer.
There are also series resistors at the output to present
the LTC6401 with a 375Ω differential load, optimizing
distortion performance. Due to the input and output trans-
formers, the –3dB bandwidth is reduced from 1.95GHz to
approximately 1.4GHz.
Test Circuit B uses a 4-port network analyzer to measure
S-parameters and gain/phase response. This removes the
effects of the wideband baluns and associated circuitry,
for a true picture of the >1GHz S-parameters and AC
characteristics.
Figure 9. Top Silkscreen for DC987B. Test Circuit A
640114f
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