AD5539 Datasheet, PDF (12/16 Pages) Analog Devices – Ultrahigh Frequency Operational Amplifier

AD5539
Figure 35. Differential Gain and Phase Measurement
Circuit
Figure 36. Differential Gain and Phase Test Setup
Figure 38. Differential Phase vs. Ramp Amplitude
MEASURING AD5539 SETTLING TIME
Measuring the very rapid settling times associated with AD5539
can be a real problem for the designer; proper component layout
must be used and appropriate test equipment selected. In addi-
tion, both cable dispersion (a function of cable losses) and the
quality of termination (SWR) directly affect the measurement.
The circuit of Figure 39 was used to make a “brute force”
AD5539 settling time measurement. The fixture containing the
circuit was connected directly—using a male BNC connector
(but no cable)—onto the front of a 50 Ω input oscilloscope
preamp. A digital mainframe was then used to capture, average,
and expand the error signal. Most of the small-scale waveform
aberrations shown on the figure were caused by the oscilloscope
itself, especially the glitch at 15 ns. The pulse source used for
this measurement was an EH-SPG2000 pulse generator set for a
1 ns rise-time; it was coupled directly to the circuit using 18" of
microwave 50 Ω hard line.
Figure 37. Differential Gain vs. Ramp Amplitude
Figure 39. AD5539 Settling Time Test Circuit
–12–
REV. B