On chip I/sub DDX/ sensor

The aim is the design of an I/sub DDX/ sensor integrated within the Circuit Under Test (CUT). Its function is transparent because its power consumption does not affect the behaviour of the CUT. This transducer is fast, accurate, linear and small for its possible duplication in the CUT. It does not need a specific power supply, and this power supply should be cut to inhibit the I/sub DD/ function whenever the CUT is in normal use. In response to a Heaveside signal, a rise time lower than 1 ns was chosen. The desired I/sub DD/ range is 0 to 10 mA. This work is not a new approach of fault detection but shows the application of new means for static and dynamic measurements of I/sub DD/.