How to Choose the Right Tektronix IsoVu Probe
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If the gate waveform on the high side of your GaN or SiC half-bridge looks like ringing instead of switching, the cause is often the probe, not the design. A Tektronix IsoVu probe is built for this problem. It measures a small differential signal while the node it sits on swings thousands of volts in nanoseconds.
Choosing one takes some care. IsoVu is a family of voltage probes (TIVP) and current probes (TICP), each sold in several bandwidths and used with different sensor tips.
This guide explains how IsoVu works, compares the specifications from Tektronix datasheets and gives a short checklist for picking the right combination. It is written for power electronics engineers, test engineers and the buyers who support them.
Short answer: Choose a TIVP IsoVu probe to measure voltage and a TICP to measure current through a shunt. Then match the model's rise time to your fastest edge and pick the lowest-range sensor tip that fits your signal.
What an IsoVu probe does differently
A conventional differential probe shares a ground path with the oscilloscope, so a fast-moving common mode voltage leaks into the reading. On a half-bridge, that leakage buries the gate-source and drain-source detail you are trying to see.
IsoVu removes that path. The TIVP voltage probes use power-over-fibre and an optical analog signal path, so the sensor head floats with no galvanic connection to the oscilloscope. The TICP current probes use RF isolation between the tip and the scope for the same reason.
The benefit is common mode rejection that stays high across the bandwidth. Tektronix specifies up to 160 dB (100 million to 1) at DC for the TIVP series, falling to about 80 dB (10,000 to 1) at 1 GHz, with a common mode range of ±60 kV. The TIVP datasheet describes accurate measurements while the reference node slews at 100 V/ns or faster.
Tektronix IsoVu TIVP vs TICP: specifications compared
The TIVP series measures voltage. The TICP series measures current by reading the voltage across a shunt resistor, so it needs a shunt in your circuit. Both series are sold in three bandwidths.
Excellous supplies the Tektronix IsoVu isolated voltage probes (TIVP) and the IsoVu isolated current probes (TICP) . Full ratings are in the Tektronix TICP datasheet .
| Model | Measures | Bandwidth | Rise time | Common mode range | Compatible oscilloscopes |
|---|---|---|---|---|---|
| TIVP1 | Voltage | 1 GHz | 450 ps | ±60 kV | 4, 5 and 6 Series MSO |
| TIVP05 | Voltage | 500 MHz | 850 ps | ±60 kV | 4, 5 and 6 Series MSO |
| TIVP02 | Voltage | 200 MHz | 2 ns | ±60 kV | 4, 5 and 6 Series MSO |
| TICP100 | Current (shunt) | 1 GHz | 400 ps | Up to 1.8 kV | 4, 5 and 6 Series MSO, including B models |
| TICP050 | Current (shunt) | 500 MHz | 700 ps | Up to 1.8 kV | 4, 5 and 6 Series MSO, including B models |
| TICP025 | Current (shunt) | 250 MHz | 1.4 ns | Up to 1.8 kV | 4, 5 and 6 Series MSO, including B models |
Voltage tips: choose the range, not the model
The three TIVP models share the same ±2,500 V maximum. The sensor tip cable sets the differential and offset range you actually get.
| TIVP tip cable | Differential range | Offset range |
|---|---|---|
| TIVPMX1X | ±5 V | ±25 V |
| TIVPMX10X | ±50 V | ±200 V |
| TIVPMX50X | ±250 V | ±250 V |
| TIVPSQ100X | ±500 V | ±500 V |
| TIVPWS500X | ±2,500 V | ±2,500 V |
The usable differential range is derated with frequency. The MMCX tips give the best bandwidth and CMRR.
Current tips: range trades against CMRR
| TICP tip | Differential range | Input impedance | CMRR at 1 MHz | CMRR at 1 GHz |
|---|---|---|---|---|
| TICPSMA | ±0.5 V | 50 Ω | 90 dB | 35 dB |
| TICPMM1 | ±0.5 V | 50 Ω | 90 dB | 50 dB |
| TICPMM10 | ±5 V | 500 Ω | 70 dB | 20 dB |
| TICPMM100 | ±50 V | 5,000 Ω | 50 dB | 6 dB |
The TICPMM100 tip is an optional accessory. Choose the lowest-attenuation tip your shunt voltage allows, because it gives the lowest noise and the highest CMRR.
How to choose a Tektronix IsoVu probe in six steps
Decide what you are measuring. Use a TIVP to see voltage, such as gate-source or drain-source. Use a TICP to see current through a shunt on a floating node.
Match bandwidth to your fastest edge. As a rule of thumb, choose a probe whose rise time is at most one-third of your signal's rise time, which keeps rise-time error near 5%. On that basis the TIVP1 (450 ps) suits edges of about 1.4 ns or slower, the TIVP05 (850 ps) about 2.6 ns or slower, and the TIVP02 (2 ns) about 6 ns or slower.
Pick the tip for your signal level. Choose the smallest range that holds your signal plus its offset, with some headroom. A 400 V bus swing, for example, needs the TIVPSQ100X (±500 V) at minimum, not the ±250 V TIVPMX50X.
Check the common mode voltage. The TIVP series is rated for ±60 kV and the TICP series for up to 1.8 kV, so a high-voltage floating node may rule out the current probe.
Read CMRR at your switching frequency. The DC figure flatters every probe. For the TICP, tip choice changes CMRR sharply, as the table above shows.
Confirm the oscilloscope, cable and connections. Both series need a Tektronix 4, 5 or 6 Series MSO. The standard cable is 2 m, and the TIVP series also comes in 10 m versions (TIVP1L, TIVP05L, TIVP02L) for chambers and test cells. MMCX tips give the best performance, and adapters cover 0.100" square-pin headers.
Where IsoVu probes earn their price
| Application | Typical pairing | Why it fits |
|---|---|---|
| Half-bridge gate and drain voltage (SiC, GaN, IGBT) | TIVP1 with a low-range tip for the gate, a higher-range tip for the drain | High CMRR at 1 GHz as the switch node slews |
| Double pulse testing | TICP100 with a low-ohm shunt | Isolated high-side current measurement |
| Switching supplies, inverters and motor drives | TIVP05 or TIVP02 | Slower edges need less bandwidth |
| EMI and ESD troubleshooting | TIVP series | Listed by Tektronix as a target use |
| Low-power rail current, such as sleep-to-active transitions | TICP with the 1X tip | Noise below 4.7 nV/√Hz in the 1X configuration |
Tektronix gives two worked examples in the TICP datasheet. In an 800 V SiC circuit switching 40 A through a 125 mΩ shunt, the signal is 5 V, so the 10X tip is used with 0.3 V of offset. The noise floor is 2.2 mA RMS at 250 MHz.
On a 48 V rail drawing 3 mA through a 1 Ω shunt, the signal is only 3 mV. The 1X tip in its ±20 mV range resolves it with a noise floor of 21.2 µA RMS.
The datasheet rates tip cables and adapters from -40°C to +85°C, which helps when the device under test sits in a temperature chamber.
Tektronix IsoVu probe FAQ
The TIVP series measures differential voltage directly, with up to ±2,500 V of range and a ±60 kV common mode rating. The TICP series measures current by reading the voltage across a shunt, with a common mode rating of up to 1.8 kV.
No. Tektronix lists the 4, 5 and 6 Series MSO oscilloscopes as the supported instruments, and the TICP datasheet also names the B models.
Fast GaN edges often call for a 1 GHz probe such as the TIVP1 or TICP100. Apply the one-third rise-time rule from step 2 to your own measured edge before you decide.
No. The TICP series needs a shunt resistor or current-voltage resistor in the circuit. The measurable current then depends on the shunt, from microamps up to hundreds of amps.
The common mode rejection ratio shows how much of the common mode voltage the probe removes from the reading. A CMRR of 160 dB means the common mode signal is reduced by a factor of 100 million.
Excellous lists Tektronix IsoVu voltage and current probes. Contact our team for availability and a quote.
Get the right IsoVu probe for your bench
The model you pick sets the bandwidth, and the tip you pick sets the voltage range and much of the CMRR. Decide on voltage or current first, match the rise time to your fastest edge, then choose the lowest-range tip that fits your signal.
If you want help matching a probe and tip to your design, request a quote and tell us your signal levels and oscilloscope. You can also browse the IsoVu voltage probes , the IsoVu current probes and the full Tektronix range.