SiT-AN6722EB Manual Rev. 2.0
Page 3 of 8
SiT6722EB Evaluation Board User Manual
3.1.1
I
2
C Support
The two pull up resistors (R10 and R11 with 4.7 kOhm value) need to be assembled to support the I
2
C
configuration. If requested, the EVB will ship with these resistors.
3.2
Waveform Capturing Using Active Probe
SiTime Elite Super-TCXO is a high speed logic output device. It is critical that the proper logic and high
frequency measurement techniques are used along with the high quality active probe in order to ensure
best measurement results.
SiTime recommends the following minimum equipment for proper clock waveform measurement
1)
GHz or higher active probe with capacitance <1 pF, such as an Agilent1134A;
2)
Oscilloscope with 4GHz bandwidth or higher such as a DSA90604A.
A passive voltage probe should not be used as it adds a high capacitive load to the part and the long
ground lead clip is not suitable for high frequency measurement applications. The inductance of the long
ground lead coupled with the input capacitance of the probe results in a resonant circuit. The
consequence of this resonance results in the distortion of the clock signal. Typical manifestations of this
distortion include ringing, overshoot, and undershoot of the clock signal.
Eliminating such distortion requires a probe with the lowest input capacitance and a low inductance
ground lead. In addition, SiTime Super-TCXOs are typically configured for fast rise and fall times (1 ns or
less) with 15 pF load. It is therefore critical that the probe tip ground be as short as possible, lowest
inductance, and the return path for the ground be located as close as possible to the trace carrying the
RF logic signal. Please refer to
for test point locations on the SiT6722EB and an example of
proper probing.
