The SQG60-AC is a 10:1 passive low impedance probe with AC coupling and a bandwidth above 6 GHz, the widest in the SQG series. Its SMA output connects to oscilloscopes and other instruments with a 50 Ω input, and the probe reaches the fastest digital and RF test points on the PCB without soldered wires.
The AC coupling blocks up to 50 V DC, so the probe draws no DC current at the test point and the bias of the circuit is left untouched. The response is flat within ±0.5 dB from 1.15 kHz to 4.8 GHz and the low-frequency cutoff is 536 Hz, so small high-frequency signals riding on a DC level can be viewed at full oscilloscope sensitivity.
With usable data rates up to 12 Gbps at the fundamental, the probe covers DC-biased serial lanes such as SuperSpeed USB at 10 Gbps, PCIe Gen 3, SATA III, DisplayPort up to HBR3 and HDMI 2.0 for activity, level and noise checks, along with ECL, PECL and LVPECL signaling. On the RF side it reaches the 5 GHz Wi-Fi band as well as 2.4 GHz, cellular and GNSS front-ends below 6 GHz, and it traces supply noise and decoupling problems on power and control lines. Besides oscilloscopes, the probe works with sampling oscilloscopes, network analyzers, spectrum and modulation analyzers, receivers, power meters and millivoltmeters with a 50 Ω input.
The nominal tip impedance is 333 Ω and the typical tip capacitance 0.35 pF. The return loss for the probed line is typically -23 dB to -6.2 dB from 0 to 6 GHz, and on a 50 Ω line the amplitude drops by about 0.63 dB without changing the waveform, so the loss is restored by scaling the result. The transition time is below 52 ps, ringing stays within 0.15 dB at 6 GHz and the additive noise is 180 µV.
The SQG60-AC is grounded with dual spring-loaded ground needles that fit its 5 mm (0.20 in) probe head. The needles sit 3 mm (0.12 in) on each side of the signal needle, 6 mm (0.24 in) apart, which gives a short and symmetrical ground return at 6 GHz. A spare spring-loaded test needle is included, and the needle can be replaced when it wears.
Each SQG60-AC has its own serial number (SPID), and the S-parameters measured on that probe can be downloaded for simulation or de-embedding. The insulated probe weighs 34 g (1.2 oz) with its 1.2 m (47 in) cable, and the low center of gravity keeps it in place in a PCBite holder through long captures or in the hand for quick checks. A storage case holds the probe together with the probe holder, an SMA wrench, color coded cable holders and a 5 mm tip protection cap.
The probe is rated CAT 0 under IEC 61010-031:2022 for circuits not directly connected to mains, with a maximum continuous input of 6.3 V AC RMS at the probe tip.
