The following figure shows the simplified diagram of the TDP7700 Series TriMode probe input architecture with the
P77C292MM SMA adapter. Because there are no active components within the adapter the A and B inputs are passed
through directly to the probe amplifier.
Figure 5: TDP7700 Series TriMode probe input architecture with the P77C292MM SMA adapter
TriMode operation
The TriMode feature of the TDP7700 Series probes is designed for improved convenience and enhanced capability in
measuring differential signal quality. Because a differential signal is composed of two complementary single-ended signals,
full characterization of a differential signal requires more than a simple differential measurement.
A TriMode probe features four input modes that allow a differential signal to be fully characterized with four measurements:
• Differential
• Positive polarity, single-ended
• Negative polarity, single-ended
• Common mode
A TriMode probe provides improved efficiency and convenience by enabling full differential signal characterization from a
single soldered connection.
TekFlex active probe solder tips support the TriMode functionality of a TDP7700 Series probe by buffering a matched pair of
input signals from a DUT differential signal connection. These active solder tips support the transmission of high-frequency
return currents through a probe tip ground path referenced to the DUT ground connection.
Using any of the TekFlex solder-in tips, probe connections are made to the two complementary signals (the A signal and the
B signal) and a ground reference. From this single DUT connection, the internal electronic switching control of the TriMode
probe allows any one of the four probe input modes to be selected at a time. The TriMode probe inputs are routed to an
ASIC (application-specific integrated circuit) inside the probe to a set of four independent input amplifiers that perform the
following signal calculations:
• A – B (for differential signal measurement)
• A – GND (for A input single-ended measurement)
• B – GND (for B input single-ended measurement)
Theory of operation
TDP7700 Series TriMode™ Probes Technical Reference
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