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Digital
Functional Test System
Digital Functional Test System
Vektrex designed, built, and integrated a general-purpose digital test platform to
functionally test multiple types of large (9U x 400mm) digital circuit
boards. The test requirements were demanding: a board test speed of 50 MHz;
an interchangeable test fixture with vacuum hold-down for each board type;
and finally, a VME communications interface to the board under test.
Vacuum test fixture
To
meet this challenge Vektrex designed a sophisticated Digital Functional
Tester (DFT). The DFT has a number of innovative features:
A custom
test-sequencing engine enables test development using interactive front
panels. These front panels present the test assets in a straightforward
manner, allowing test engineers to quickly develop tests.
Interactive front panel
"Wireless" connections to the UUT are implemented using a custom PCB in the
fixture and double-ended precision pogo pins. Logic translators on the
custom PCB assure signal integrity at the UUT pin.
"Wireless" fixture
RF
analog amplifiers buffer key-clock signals to provide a true representation
of the clock waveform at the VXI instrument.
Programmable power
supplies with remote voltage sensing supply up to 40 amps to the UUT, to
support voltage margin testing. Specialized clamping crowbar circuitry on
the custom PCB prevents UUT damage in the event of a programming error.
Clamping Crowbars
To
supply the required VME communications interface, the custom PCB integrates
a VME backplane and a three-slot card cage. This arrangement allows a
National Instruments MXI to VME board to act as a VME controller. Precision
double-ended pogo pins convey the VME bus to the UUT.
Expertise
Used
National Instruments LabVIEW
software, VXI, Custom
Analog, Custom RF, Test Fixturing, Custom PCB Development, Systems Design,
Test Specification Development, Boundary Scan, Digital Design.
Additional Information
Prior to the DFT, the
manufacturer tested and debugged these boards, at the system level, in a
clean room. The DFT eliminates this expensive practice. The DFT also tests
the boards more thoroughly, reducing a large "bone pile" of faulty boards.
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