Tektronix has moved the some of the active signal-conditioning to the tip to develop a probe for oscilloscopes that can handle bandwidths up to 20GHz and with less need for de-embedding techniques.
“The P7700 is the first probe technology that has the chip at the end of the probe tip,” claimed Dean Miles, EMEA technical marketing manager for Tektronix. “The approach minimises signal loss and noise.”
The company has used IBM’s silicon germanium technology to develop the amplifiers and active signal-conditioning circuitry for the probes. The design is in two parts: a cable section and a removable probe tip. The chip at the tip means the remote amplifier is normally less than 4mm from the connection point.
One of the probe tips is a ‘browser’, using two teeth to attach to the PCB. The other type is a solderable tip, costing about $50 apiece. This tip is designed to be removable and reusable up to a point. Depending on soldering technique, the company reckons each probe tip can handle around 10 solder-desolder cycles on average. One of the solderable tips is based on a flexible circuit board, the other is built into a coaxial cable.
To help with removability and to connect to traces in densely packed PCBs, the approach recommended by Tektronix is to solder three short wire stubs onto the target board, thread them through eyes in the solder tip and then solder those connections.