The difference in accuracy between the PTO-350 and PTO-500 is primarily manifested in their signal reproduction capabilities within the high-frequency range and their stability against interference-rather than in their static accuracy specifications alone. Both probes demonstrate excellent performance in terms of basic accuracy; however, the higher-end model achieves superior dynamic accuracy through an optimized design:
1. Static Accuracy (Typical Values)
Under standard conditions, the typical gain accuracy for both probes is ±1% + 5mV, with a guaranteed maximum error of ±1.5% + 5mV.
This implies that during measurements of low-frequency or steady-state signals, the absolute error levels of both models are essentially identical.
2. Dynamic Accuracy (High-Frequency Signal Reproduction)
PTO-350: With a bandwidth of 350 MHz and a rise time of 1 ns, this model may exhibit slight rise-edge broadening or overshoot when measuring fast-switching waveforms.
PTO-500: The bandwidth is increased to 500 MHz, and the rise time is reduced to 0.7 ns. This allows for a more faithful reproduction of the rise edges and oscillation details of nanosecond-scale pulses, resulting in lower dynamic error in high-frequency scenarios.
3. Impact of Anti-Interference Capability on Accuracy
Both models feature a high Common Mode Rejection Ratio (CMRR); however, in high-frequency environments with strong interference, the PTO-500 benefits from a superior front-end attenuation and shielding design. This design effectively suppresses common-mode currents induced by high dv/dt rates, thereby reducing the risk of signal distortion.
In practical testing, when measuring the switching nodes of GaN devices, the PTO-500 demonstrated an average reduction of approximately 30% in waveform jitter and noise interference, thereby enhancing both measurement repeatability and credibility.
4. Usage Recommendations
For medium-to-high frequency applications-such as analyzing standard IGBT drive signals or debugging inverter systems-the accuracy provided by the PTO-350 is entirely sufficient to meet requirements.
For scenarios demanding high-fidelity measurements-such as analyzing the dynamic characteristics of GaN/SiC devices or testing power supply loop stability-the PTO-500 offers more credible measurement results, thanks to its wider bandwidth and superior immunity to interference.
