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Attempting to power USB-6003 OEM with LT3582EUD

I am trying to power a USB-6003 OEM with an LT3582EUD DC/DC converter. This configuration requires me to use the terminal on top of the device. I have the converter providing a +5v signal to VBUS(pin 16) and the converter ground going to D GND(pin 32). I capped the +5v from the USB cable and connected D+, D- and USB ground. When I connect the USB to a computer though, I can hear the DAQ continuously connecting and disconnecting from the laptop and the blue LED indicator light will not illuminate. When I use this same configuration but use a bench top DC power supply or an AC/DC converter such as a Mean Well IRM-05-5 to provide +5v & ground, the DAQ works perfectly fine. I need to use the LT3582 though because my application requires the LT3582 to be powered by a 4.2v lithioum ion battery. The attached scope image shows the +5v signal (yellow) and VBUS current signal (purple) that the LT3582 is providing to the DAQ. 


Has anyone had a similar issue and do you have means to fixing this? I am trying not to use the +5v wire in the USB cable because I wish to power the DAQ from a single clean reliable source instead of from different laptop/computers which could have noisy supplies.

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Hi SGilis101,


Is the current draw the same when you use a power supply as you see when you are using the converter?



Claire C.
AppSW Staff Product Support Engineer
National Instruments
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