Question on a feature for the Analog Discovery Model 410-394

[Clyde]

Hi,

This model has a built in power supply.   Does this power supply have the ability to set the current limit?  Is the output current protected against an excessive  current draw?

 

Thanks.

[JColvin]

Hi @Clyde,

I have moved your question to a more appropriate section of the Forum where the engineer most familiar with the Analog Discovery Pro 3450 will be able to give accurate insight into this.

I know that the trigger DIO signals themselves are protected by ESD diodes and PTC thermistors, but I am uncertain about digital supplies themselves regarding overcurrent protection.

Thanks,
JColvin

[Clyde]

I was speaking of the adjustablle power supply, not digital I/Os.

[attila]

Hi @Clyde

On ADP3X50 the Digital IO voltage is adjustable between 1.2V and 3.3V
The VIO output of this, first 2 pins of the DIO connector, is protected and can deliver up to 300mA.
The 4 USB host ports are available in Linux mode. 2 of this can deliver 500mA and the other 2 900mA.
The device has no other power supplies. Eventually the 2 AWG channel can output +/-5V 30mA 50R

[Clyde]

Then I do  not understand this part in the features section:

 

[attila]

Hi @Clyde

VIO = Digital Power Supply
2 pins on the DIO connector

[Clyde]

Ok, now I understand.  The description leads one to believe there is a more substantial connection, and perhaps an equal to a very light duty bench supply, or at least that is how I have interpreted it.

 

I am just trying to figure out if this is the instrument for me.

[JColvin]

Hi @Clyde,

I don't know what your specific needs are, but other devices, such as the Analog Discovery 3 or the Analog Discovery Pro 2230, have eFuses to limit the total power output (which you can set the value of) on their adjustable -0.5 V to -5 V and +0.5 V to +5 V supplies.

Thanks,
JColvin

[Clyde]

I have two pretty good bench supplies, so, I do have that covered.

What I am really after is a new scope to sort of replace my old Tek scope.  It has 100 MHz bandwidth and four channels.

I am spoiled at work with the newer digital scopes and would like those features.  From examining the specs, my take on the product offering highest analog bandwidth is 55 MHz.  This is probably more than adequate for what I do. Attached are couple of scope shots.  (This model scope was Tek's last glass CRT model they produced.)   One shows a SPI bus transaction and as you can see, this is a stretch for this instrument.  I would be curious to know how the Discovery 3 would do on these wavefomrs.

[JColvin]

Hi @Clyde,

The Analog Discovery 3 has 9 MHz bandwidth unless you're using the BNC Adapter which bumps the bandwidth up to 30 MHz: https://digilent.com/reference/test-and-measurement/analog-discovery-3/specifications#analog_input_channels, though the ADP3250/ADP3450 both have the 55 MHz analog input bandwidth like you indicated (ADP2230 has 50 MHz bandwidth for its two analog input channels).

Regarding a SPI bus transaction on the AD3 specifically, I would probably be using the Logic Analyzer instrument on the digital channels and have a result more like the splash screenshot I took for AD3 reference manual: https://digilent.com/reference/test-and-measurement/analog-discovery-3/reference-manual#logic_analyzer.

If you're instead looking for a more traditional MSO setup, you could use the Digital view inside the Scope instrument to view both the digital and analog input channels in a time correlated fashion (rather than having the logic analyzer and oscilloscope run simultaneously in two separate windows) along with the option to interpret one of the analog input signals as part of the digital bus directly, much like I've done here with the Scope Channel 1 being subbed in for the SPI peripheral out controller in line (MISO):

The catch with style is that the analog to digital interpretation is done in WaveForms, so you won't have the option to do any digital protocol triggering on a bus utilizing an analog input. If they are separated out, like how MISO is, you can still trigger off of the digital protocol values, like how I did above to trigger on the h40 value for MOSI.

If you're looking to analyze digital protocols directly within WaveForms though, I personally think you'll have an easier time with either the ADP3250/3450 or the ADP2230 since they both have on-board DDR memory. That'll let you get much longer captures relative to the Analog Discovery 3 which are more helpful for digital protocols where there can be a comparatively long amount of downtime between the fast bursts of communication.
The point is moot of course if you're only ever looking at a few frames at a time.

Let me know if you have any questions.

Thanks,
JColvin

P.S. The Analog Discovery Pro 5250 (a rebranded version of the NI VirtualBench 8012, now sold by Digilent) also has 100 MHz bandwidth for it's two analog input channels, but it lacks DDR memory and has a different price point than something like the Analog Discovery 3.