SigOFIT optically isolated fiber optic voltage probes
The Micsig SigOFIT series is a state-of-the-art line of optically isolated probes designed specifically for precise measurements in high-frequency and high-voltage applications. These probes utilize Micsig's exclusive SigOFIT™ technology to deliver exceptional common-mode rejection ratio (CMRR) and isolation voltage performance. With a bandwidth of up to 1 GHz and a CMRR of up to 180 dB at DC and 108 dB at 1 GHz, the SigOFIT probes are ideal for the precise measurement of differential signals in the presence of large common-mode voltages.
Key features and functions:
Optical isolation technology: SigOFIT probes use optical fiber connections to ensure complete galvanic isolation between the measuring instrument (such as an oscilloscope) and the test circuit. This enables safe measurements in high-voltage environments while minimizing the risk of interference from common-mode voltages.Wide range of applications: The SigOFIT series probes are versatile and suitable for applications including the development of motor drives, power converters, electronic ballasts, and the analysis of GaN and SiC semiconductor devices. They are also ideal for safety testing in high-voltage and high-frequency applications.
High precision: With a DC gain accuracy of 1% and a noise reduction of less than 450 µV RMS, SigOFIT probes offer extremely high measurement accuracy. This enables the precise acquisition and analysis of even the smallest signal details.
Versatile attenuation tips: The SigOFIT series probes are available with various attenuation tips offering attenuation ratios from 10:1 to 10,000:1. This allows them to measure a wide range of differential voltages from ±0.01 V to ±8000 V. Additionally, the probe's gain function can amplify the signal by a factor of 10, providing each attenuation tip with two attenuation ranges. However, it should be noted that using the gain function can also amplify interference and noise.
Fast calibration and easy handling: SigOFIT probes feature an automatic calibration function that is completed in less than one second and can be performed without disconnecting the test circuit. This ensures efficient and easy handling, especially for repeated measurements.
Robust and compact design: Despite their advanced technology, SigOFIT probes are compact and robust, making them suitable for use in laboratories as well as demanding industrial environments.
Overall, the SigOFIT series was developed with the highest safety standards in mind to provide users with a safe and reliable measurement environment, especially when working in high-voltage and high-frequency environments. These safety features make SigOFIT probes an excellent choice for demanding and hazardous measurement applications.
More detailed information about the features can be found on the respective product model page.

Series overview
| Model comparison | ![]() MOIP200P | ![]() MOIP350P | ![]() MOIP500P | ![]() MOIP1000P |
|---|---|---|---|---|
| bandwidth | 200 MHz | 350 MHz | 500 MHz | 1 GHz |
| Upward mobility | ≤1.75 ns | ≤1ns | ≤700 hp | ≤350 hp |
| SMA input impedance | 1 MΩ; || 10 pF | 1 MΩ; || 10 pF | 1 MΩ; || 10 pF | 1 MΩ; || 10 pF |
| Output voltage | ±0.5 V | ±0.5 V | ±0.5 V | ±0.5 V |
| Differential voltage range | 1X: ±0.5V 2X: ±1V 10X: ±5V 20X: ±10V 50X: ±25V 500X: ±250 V1000x: ±500 V 2000X: ±1000V 5000X: ±2500V 10000X: ±5000V
| 1X: ±0.5V 2X: ±1V 10X: ±5V 20X: ±10V 50X: ±25V 500X: ±250 V 1000x: ±500 V 2000X: ±1000V 5000X: ±2500V 10000X: ±5000V | 1X: ±0.5V 2X: ±1V 10X: ±5V 20X: ±10V 50X: ±25V 500X: ±250 V1000x: ±500 V 2000X: ±1000V 5000X: ±2500V 10000X: ±5000V | 1X: ±0.5V 2X: ±1V 10X: ±5V 20X: ±10V 50X: ±25V 500X: ±250 V1000x: ±500 V 2000X: ±1000V 5000X: ±2500V 10000X: ±5000V |
| Noise | <450μVrms | <450μVrms | <450μVrms | <450μVrms |
| Runtime delay | 15.42 ns (2 m cable length) | 15.42 ns (2 m cable length) | 15.42 ns (2 m cable length) | 15.42 ns (2 m cable length) |
| power supply | USB Type-C, DC current: 5 V | USB Type-C, DC current: 5 V | USB Type-C, DC current: 5 V | USB Type-C, DC current: 5 V |
| Accuracy of DC amplification | 1% | 1% | 1% | 1% |
| Common-mode voltage range | 60 kVpk | 60 kVpk | 60 kVpk | 60 kVpk |
| Cable length | 2 M (Std.) (customizable) | 2 M (Std.) (customizable) | 2 M (Std.) (customizable) | 2 M (Std.) (customizable) |



