Testing the configurable analog blocks of field programmable analog arrays

The problem of testing the configurable analog blocks (CABs) of field programmable analog arrays (FPAAs) is addressed in This work. The considered fault model comprises deviations in the nominal values of CAB programmable capacitors, deviations in the programmable gains of CAB input amplifiers and stuck-on/stuck-open faults in CAB switches. The problem of test stimuli generation is solved, in a first approach, by using the oscillation test strategy (OTS), which is associated to a test response analysis external to the device under test. In a second approach, a built-in self-test (BIST) scheme is proposed by associating to the OTS an output response analyzer (ORA) built using the internal FPAA resources. Both approaches are validated using the ispPAC10 FPAA from the Lattice Semiconductor Corporation. In the paper, the approaches are compared in terms of fault coverage, test application time and required external hardware resources for testing. Experimental results show that a good compromise of these aspects can be found by taking the best of each approach.