Overcurrent behavior of the Analog Deiscovery Pro analog-out channels

[Guest]

Hi all,

The datasheet of the Analog Discovery Pro says it can source 30 mA per channel on its analog-output terminals.

I am wondering what will happen if you put a static load with too low resistance on the channel. Will the voltage just collapse, or is there a danger of damaging the output driver?

In the extreme: what will happen if you short-circuit an analog output channel? Can this leas to permanent damage?

 

Best Sidney

 

 

 

[JColvin]

Hi @reddish,

I talked with the hardware design engineer for the ADP3450 and learned that the answer is yes, as long a low impedance external signal source is between -15 V and +15 V relative to ground, it can be connected to the AWG indefinitely without damaging the underlying circuitry even with the ~600 mW heat dissipation that arises out of some corner cases. This is achieved through multiple layers of protection including clamp diodes on the outputs and opamp supplies, a PTC resistor, and further overcurrent comparators with foldback mechanisms if the PTC is too slow to react; naturally, these are a lot more involved than just the bulleted list I presented.

Digilent verified the integrity of this setup outside of the listed maximum range of +/-15 V with both fast transients and bounces by mechanically shorting the AWG output with an external benchtop supply.

Thanks,
JColvin

[attila]

Hi @reddish

For ADP3X50 the AWG and DIOs are protected for shorts up to +/-15V. The Scope channels up to +/-50V. The AWG output impedance is 50R.
https://digilent.com/reference/test-and-measurement/analog-discovery-pro-3x50/specifications#arbitrary_waveform_generator_wavegen

[Guest]

I saw that spec but I didn't quite understand how to interpret it.

Is it saying that connecting any AC or DC voltage signal that stays between -15 to +15 V relative to GND to the analog signal output cannot, by design, damage the device?

[Guest]

Thanks @JColvin for checking!