Patent ID: 7336088

Claim:
A test apparatus for testing a quiescent current of a circuit under test, the test apparatus comprising a power supply voltage source for supplying a power supply voltage, a switch being coupled to a terminal of the circuit under test, a driver for controlling the switch to remove the power supply voltage from the terminal at a start of a testing cycle, a comparator for comparing a voltage at the terminal with a reference value, a clock generator for supplying clock pulses, a counter for counting the clock pulses during a count period to obtain a count number, wherein the count period has a start determined by the start of the testing cycle and an end determined by an instant the voltage at the terminal crosses the reference value, a threshold circuit for comparing the count number with a reference number to supply a pass/fail signal, and a control circuit for controlling the value of the reference number and/or a clock frequency of the clock pulses in dependence on process parameters of the circuit under test.