How Do They Compare? Pitting the Analog Discovery 2 Against the New ADP3450

The Analog Discovery 2 has been the flagship of Digilent’s Test and Measurement line, as we have worked with our global customer base to refine and develop WaveForms over the past 10+ years to what it is today. As the world has changed, we have realized that while the Analog Discovery 2 is good enough for most things, we want to give you all more. And its 2021, so let’s shake things up! So, what exactly is the difference between the beloved Analog Discovery 2 and the new ADP3450, the first in our Analog Discovery Pro line?

Short answer: we kept everything you love and added a whole lot more.

Comparing the AD2 and ADP3450

Buffer Size:

This is a key point of feedback on all our devices – something that we are focusing on improving through the selection of larger Xilinx FPGAs and the addition of external memory. The Analog Discovery 2 logic analyzer and oscilloscope instruments provide 16k samples of memory depth which is then transferred via USB to the host PC.

The ADP3450 improves this by factors of magnitude in several different ways. Using the oscilloscope instrument in Record Mode, 128 Million samples can be captured, and in Repeated, Shift, and Screen modes over 32 thousand samples can be captured. When using the Logic Analyzer, in Record Mode 64 Million samples can be captured, and in other modes the same size applies as in the oscilloscope. In addition, when taking advantage of the new Linux Mode, data can be streamed onto an external storage device via one of the several available USB ports using WaveForms SDK.

Bandwidth and Sample Rate:

The Analog Discovery 2 device sample rate is 100 MS/s, supporting a 9MHz Bandwidth as is, and a 30MHz bandwidth with the addition of the BNC Adapter and probes on the oscilloscope, and 9 MHz and 12 MHz bandwidth respectively on the waveform generator instrument. The device sample rate is used on the logic analyzer.

The ADP3450 makes improvements to both the bandwidth and sample rate, increasing the oscilloscope bandwidth from 9MHz to 55 MHz (built-in, with BNC connectors standard), and a maximum sample rate of 0.5 GS/s for repeated signals. The maximum device sample rate is 125 MS/s and is the sample rate for the logic analyzer.

Number of Channels:

The ADP3450 doubles the number of channels to four oscilloscope channels, enabling measurements that require a minimum of three, and reducing the time spent resetting probes before taking measurements. For those that don’t need all four channels, the smaller ADP3250 offers everything the ADP3450 does, but with only two oscilloscope channels. The ADP3450 and ADP3250 both have 16 digital I/O, two waveform generator channels, and a digital power supply.

High-Resolution and Mixed Signals:

Resolution and the true mixed signal nature of the Analog Discovery 2 is something core to the product that we kept on the ADP3450.

The digital and analog channels are separate and dedicated as with the Analog Discovery 2, so there is no trade off when taking mixed signal measurement. In addition, the ADP3450 keeps the two dedicated trigger inputs/outputs so there is no need to lose a digital or analog channel to add an external trigger. This puts the total channel count at 24 channels, not including the power supplies.

The ADP3450 oscilloscope and waveform generator instruments are both 14-bit but can provide 16-bits of data with software enhancement, which is double what most benchtop oscilloscopes provide.

Configurable Digital I/O

The Analog Discovery 2’s digital I/O operates at 3.3V logic following the LVCMOS standard but is also 5V compatible. The ADP3450 takes the improved digital I/O from the Digital Discovery to vastly increase the types of digital systems that can be decoded with the device. The digital I/O on the ADP3450 can be configured to between 1.2 and 3.3V, are also 5V compatible, and offer a variety of settings including adjustable slew rate, configurable pull up and down resistors, and more!

Linux Mode and Standalone Operation

The Analog Discovery 2 is controlled by WaveForms running on a host PC and data is transferred via USB. The device itself has an FPGA image with a variety of “profiles” that can be configured in WaveForms. This method of operation is what we call “Standard Mode” (which has been unnamed, until now).

The ADP3450 introduces a new mode of operation called Linux Mode, where an embedded operating system is running on the device itself. When operating in Linux Mode, the device can be treated standalone, running scripts written with WaveForms SDK, or can be controlled from a host pc using WaveForms. Linux Mode enables the four USB ports on the back of the device that can be used to add WiFi dongles (more on that later), USB mass storage devices, or other USB peripherals. The ADP3450 comes loaded with Linux Mode and it is booted with the click of a button in WaveForms and connected to via serial terminal connection. I’m personally super excited to see what creative applications are created using Linux Mode.

For those of you that love the stability and simplicity of Standard Mode, don’t worry: these modes are separate and can be changed in WaveForms with the click of a button. If you get too creative in Linux Mode, it can be easily recovered in Linux Recovery Mode.

Networking

In both Standard Mode and Linux Mode the ADP3450 adds the ability to connect to the device to the network. This enables remote operation for working with teammates, deploying the device, checking on the status of a test, or simply running a test you forgot to start. With the right custom application, it could even go from your favorite coworker to your least favorite coworker by sending you superfluous emails (I kid, but not really – it could actually do that).

Signal Integrity Improvements

With every Test and Measurement design, we strive to improve our design to improve signal integrity in any way we can. In addition to this and the software filters available in WaveForms, the ADP3450 features a 20 MHz hardware filter that can be enabled for each channel. This is a feature in many high-end scopes that we wanted to include to give the best measurement opportunity.

Power Supplies

In order to make room for the many improvements listed above, we opted to include a digital power supply on the ADP3450 that can provide between 1.2 and 3.3 V on two available pins. You may notice that the ADP3450 is stackable, which could be used to stack multiple devices. I can neither confirm nor deny the existence of a stackable power supply designed to be used with the ADP3450 coming from Digilent in the future…

Form Factor

This is probably the most obvious change, but it’s definitely worth noting. To make room for the extra channels, improvements, protection circuits and layout the board in a way that’s best for signal integrity, the ADP3450 is bigger than the Analog Discovery 2. However, we still consider this to be a portable device as its smaller than an average laptop. Although data can be sent via USB, Ethernet, or WiFi (with the addition of a dongle) the device is powered by an external power supply. It also features BNC connectors for the triggers and analog inputs and outputs, but the familiar MTE connector for the digital I/O and power supplies. And last but certainly not least, in order to remain compact but ensure comfortable connecting of BNC cables, the ADP3450 has integrated feet that can be flipped out to tilt the device up.

Whew, we really thought of everything, didn’t we?

For a complete overview of the specifications of the ADP3450 and ADP3250 check out the specification sheet.

2 Comments on “How Do They Compare? Pitting the Analog Discovery 2 Against the New ADP3450”

  1. How about the BNC inputs on the ADP3450, are they differential or do they have all the same GND potential?
    The scope inputs on the AD2 are differential, this is the main reason why I’m using it all the time.

    1. The BNC inputs on the ADP3450 are singled ended; you usually need a secondary BNC connector to have differential BNC inputs. Like the AD2 though, they also handle an input range of -25 V to + 25 V with respect to ground (as per the specifications document on the ADP3450’s Resource Center).

      I’m curious what application you use the differential input capabilities of the AD2 for if you don’t mind sharing.

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