Active Differential Probes

BitScope Active Differential Probes

BitScope Active Differential Probe

Differential measurements can be very important but it is usually not possible to make such measurements using standard scope inputs, including those on BitScope.

There are standard solutions for normal oscilloscope channels (e.g. PRB-06) but they tend to be expensive, bulky and designed for higher voltage work.

We decided a better solution was needed, one that leverages BitScope's Smart Port Interface to support differential and other measurements packaged as a low cost accessory tailor made for BitScope. What we've come up with is a small active differential probe design that needs only twisted pairs to connect to your circuit.

The first model is DP01 which is designed for use with BitScope Mini as shown here.

Low Voltage Active Differential Probe and BitScope Mini

Powered by BitScope, it makes possible unreferenced measurements with excellent noise rejection even when using simple twisted pairs for probes.

It has fully compensated high impedance JFET inputs so it can be connected between high impedance nodes in a circuit without adversely affecting circuit operation and it offers many other unique test & measurement features such as optional AC coupling, selectable prescalers and single-ended operation. Read more about it here.

DP01 is designed for general purpose work over a working voltage range of ±13.8V and bandwidth up to 10MHz. It is designed primarily for differential measurements but this does not preclude its use for single ended measurements too. Likewise it's sometimes desirable to make AC coupled measurements so it has provision for this as well.

DP01 | Active Differential Probe Specifications

Attenuation/Gain Ratios 2:1 & 1:5 (prescale on)
Input Bandwidth DC to 10MHz (-3dB, prescale off)
DC to 3MHz (-3dB, prescale on)
Common Mode Rejection 100Hz: >1,000 : 1
1MHz: > 400 : 1
Input Resistance 20MΩ (differential)
10MΩ (common)
Input Capacitance 2.5pF (differential)
5pF (common)
Maximum Working Voltage 12.5Vp-p (differental)
±13.8Vpeak (common)
Power Requirement 5V & 3V3 (provided by BitScope)
DJ14A | E&OE 

Related Posts

Build a powerful mixed signal workstation with one simple 3D print !Sep 3
BitScope Blade for Raspberry Pi at Hannover Maker Faire!Jun 05
BitScope DSO 2.9 Now Available.Jun 02
Getting Started with BitScopeMay 08
BitScope Connection Ports ExplainedDec 19
BitScope Micro and Oscilloscope ProbesDec 10
Reducing Quantization Noise with BitScopeNov 08
Breadboard One, a typical Mixed Signal Circuit.Oct 17
Differential measurements matter, here's why...Oct 01