Input and Output Circuit Block Delay Measurements
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
This measurement technique uses recirculating loops to measure block delays of an input or output (receiver or driver). A problem is encountered in using recirculating loops for I/O block delay measurements because a threshold delta exists between most receiver inputs and driver inputs. However, if a fast-changing voltage signal is used as an input to both receiver and driver, this delta can be made small enough to be ignored. This fast-changing signal is achieved by correctly choosing the value of R. The equations for the recirculating loop are as follows, where Ton is "turn-on delay" and Toff is "turn-off delay" of the circuit in parentheses.