05457381 is referenced by 20 patents and cites 5 patents.

Test circuitry implemented in an integrated circuit having a plurality of I/O circuits for testing of the electrical parameters of the I/O circuits without probing the contact pads associated therewith. The test circuitry includes a test drive bus, a test drive pad connected to the test drive bus, a test observe bus, a test observe pad connected to said test observe bus. Associated with each I/O circuit are a test drive transmission gate connected between the associated I/O pad and the test drive bus, and a test observe transmission gate connected between the associated I/O pad and the test observe bus. The transmission gates for each pad are controlled in parallel via a scan control register, and are connected by separate conductive traces to the I/O pad. If an I/O includes an input buffer, the input to the input buffer is connected to the I/O pad via the separate conductive trace to the test drive transmission gate; and if an I/O has an output driver, the output to the output driver is connected to the I/O pad via the separate conductive trace for the test observe transmission gate.

Title
Method for testing the electrical parameters of inputs and outputs of integrated circuits without direct physical contact
Application Number
768796
Publication Number
5457381
Application Date
October 2, 1992
Publication Date
October 10, 1995
Inventor
William D Farwell
Thousand Oaks
CA, US
Agent
W K Denson Low
Leonard A Alkov
Assignee
Hughes Aircraft Company
CA, US
IPC
G01R 15/12
View Original Source