Pre-amp at the probe tip boosts scope probe performance, to 20 GHz

March 15, 2016 // By Graham Prophet
A range of oscilloscope probes is designed to tackle today’s smaller, faster designs: Tektronix’ P7700 Series Tri-Mode Probes are constructed to minimise probe loading, improve access to tight test locations, and lower costs

P7700 TriMode offer up to 20 GHz bandwidth, and support efficient test and debug of the latest standards from LPDDR4 to MIPI D-PHY and C-PHY requires probes that minimise signal loss to cope with the combination of high-performance and low power. The name represent the concept that differential and single-ended measurements can be made with one probe, and with a single connection to theunit under test.


Unlike other probe designs that use long tip cables connected to a remote amplifier, the P7700 Series probes introduce a new design. By placing a bare-die analogue IC very close to the tip of the probe, the input amplifier is located less than 4 mm from the connection point, minimising signal loss, probe tip capacitance and noise. The amplifier IC is fabricated in IBM’s 8HP silicon-germanium technology, for maximum high-frequency response. The signal path of the P7700 probes is fully characterised and automatically de-embedded from measurement results.

Tek has also addressed physical access to the measurement point; connections to high speed signals often require engineers to attach probe tips by soldering to a small component or feature on a circuit board. As the size of these features shrink, they become more fragile and attaching a probe tip can add stress to the component or the circuit board. In addition, multiple probe connections are often required to capture signals on multiple lanes of a MIPI bus or for LPDDR memory, the data, strobe, and clock signals. The P7700 series probes use compact solder tips that fit into tight spots to minimise the impact on the small size components on the board.


P7700 series probes introduce the a connector called TekFlex that supports a wide range of accessories. The TekFlex connector and accessories are designed to be easy to attach and at the same time provide the user with a reliable, secure connection including a small LED that lights up to confirm connectivity from