An on-chip built-in self-test (BIST) circuit (10) uses a controller (16), analog-to-digital converter (ADC) (15), and digital-to-analog converter (DAC) (12) to sense voltage and/or temperature measures at predetermined circuit locations (19), to detect one or more idle states for an analog block during normal operation, to initiate a built-in self-test of the analog block during the idle state(s) by sending input test signals over a first bus (13) to the analog block, and to process analog test signals received over a second bus (14) from the analog block to generate digital built-in self-test results for the analog block so that the performance analyzer can analyze the digital built-in self-test results in combination with any voltage and/or temperature measurements to evaluate selected performance measures for the analog block against one or more performance criteria.