Products > Test Equipment
PRP1 - Low cost 2GHz power rail probe
tszaboo:
I'm calling this PRP1. It's a power rail probe, that is oscilloscope agnostic and low cost.
I've started working on this because normal power rail probes cost around 10 times as much as entry level oscilloscopes. I hope to change that with this probe.
It's still very much in development, and I release some info about it, hoping to organize a group buy.
Below is an image of the first 2 working prototype. I've some promising measurements from the prototypes already.
Specifications:
Max voltage offset: ±24V
DC Input impedance: 50kΩ
High frequency input impedance: 50 Ohm
Signal attenuation of 1.3:1
Transfer function within 1dB to 2GHz
Estimated noise: 42 µVp-p RMS to 20MHz
Active signal range: +/-350mv
Course - Fine adjustment
USB Type C 5V power input - run it from your oscilloscope directly
SMA input and output. SMA to BNC cable to connect to oscilloscope
Typical power consumption of 20mA
(Specifications are yet to be verified by independent third party.)
tszaboo:
Example probing setup. PRP1 measuring power supply ripple of an ESP32 board with a Siglent oscilloscope, using external 50 Ohm termination.
Dual probing power supply ripple with PRP1 and standard oscilloscope probes. Siglent oscilloscope
CH2 is standard oscilloscope probe, CH3 is PRP1
Noise level of PRP1
CH2 is input terminated with 50 Ohm, CH3 is PRP1
Dual probing power supply ripple with PRP1 and standard oscilloscope probes. Keysight MSOX 1 GHz oscilloscope
CH1 is standard oscilloscope probe, CH3 is PRP1. Note the lower noise levels of the PRP1
tszaboo:
Low frequency transfer function:
Note this measures up to 10MHz, which includes the low frequency crossover point of the probe.
High frequency transfer function:
Some TODO, to declare the status of the project:
Some trivial changes to the PCB, that are patched on the prototype
Prototype only reached 23.6V, needs a slight adjustment to the references
If possible, bring U6 underneath the internal shielding can
Going from 2 PCB solution (potentiometers) and wiring to one PCB
2 Potentiometers too big to fit on front panel, second potentiometer should be fine adjust type
Maybe go from end-launch SMA to TH, to bring the connector closer to the middle of the enclosure. On the other hand it's ascetic only, and it would reduce performance.
Drawings of enclosure to outsource the cutouts. So the end product doesn't look like I hacked some holes on it with a drill and some files. I've contact with the manufacturer
Quality SMA to BNC cable is needed. I've found half the time the cable, and the BNC connector made 4x the noise than the PRP1
tautech:
Nice, OP image needs resizing....good you've done it.
Dunno what it is but we have one coming soon too, a 4 GHz version.
Wanna know the specs of what you're up against ?
tszaboo:
--- Quote from: tautech on August 23, 2024, 10:05:33 am ---Nice, OP image needs resizing....good you've done it.
Dunno what it is but we have one coming soon too, a 4 GHz version.
Wanna know the specs of what you're up against ?
--- End quote ---
Thanks. I'm eager to find out.
There are many benefits of using a factory built probe, it tells you on the screen what the voltage you are looking at, and with the active probe it's a better interface.
Still, I hope people with low-end scopes or budget will be able to use a probe like this.
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