So I was handed a National Instruments USB-6009 and I had to tear it down.
It’s a fairly nice four layer design, with only a few major components. The board is marked USB-600X and there is an un-populated header – can a USB-6008 be easily upgraded to a USB-6009?
On the right, we see a USB B connector and a single indicator LED. There is a whole mess of unpopulated passives around the highspeed USB traces. They must have been concerned about signal integrity issues.
On the top and bottom of the image, there are two large screw terminal connectors. The top (in the image) port is designated “Digital” and the bottom port is designated “Analog”.
The “guts” of the 6009 are the following two parts
- SiLabs C8051F320 an 8051 core USB microcontroller with a whole ton of peripherals.
- TI ADS7871 a data acquisition system-on-a-chip.
On the top, “Digital” port, from the left to the right, are pins P0.0-P0.7, P1.0-P1-3, PFI0 (trigger interrupt), 2V5, 5V, and GND. The GPIO and trigger interrupt pins all have a similar analog front end which is connected directly to the 8051.
The engineers at NI did an excellent job on the silkscreen of the board, but looking at it, some of the markings leave me puzzled. Take a look at the analog input schematic. The passive in series with the input signal is marked RTx. Perhaps it’s an NTC thermistor? The SOT-23, three terminal part has CRx silkscreen markings. I’m thinking it might be a dual diode package. This part is also unpopulated on the USB traces.
Active components are marked Ux. U1 appears to be the 2V5 linear voltage regulator. U2 looks like a switching power supply controller for the 5V line.
On the bottom (in the picture) “Analog” port, the analog inputs are interspersed with ground pins. The analog inputs all also have a similar input structure (pictured above). They appear to be simple voltage dividers. Strangely the 150K pull-down resistor is 0402 while the others are 0603. The topcodes are strange for resistors also. Maybe a commenter can share some insight. The analog inputs (after their front-end) are all connected to the TI DAQ-on-a-chip part.
The NI USB-6009 also has two 12 bit 150S/s analog outputs on the lower right of the image. Around those two pins are grounds, and on the board there are a cluster of passive and active components. The signals presumably come from the TI part, but I’d have to get out a meter to check. U4 is a dual opamp and the other SOT-23-5 packages are presumably single opamps.
There is some other strangeness. What is part FL1 (on the far right opposite the USB connector)? What is R50? Why is it way over there? That’s a pretty serious trace-width for an un-populated part. Look at the traces near the letter “U” in USB-600x. Why do they go out of their way to put them adjacent to one another?
All told, it’s a pretty nice piece of hardware, I’ve had better luck with Labjack parts – much much better open source support, but the NI USB-6009 isn’t bad when you’ve gotta use Lab View.