The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 23, 1991
Filed:
Dec. 01, 1989
Douglas W Babcock, Londonderry, NH (US);
Analog Devices, Incorporated, Norwood, MA (US);
Abstract
Automatic test equipment (ATE) for post-production testing of multi-pin integrated circuits (ICs). Each pin is assigned to a pin card having a pin driver and an active load with the latter including both a current source and a current sink. The pin driver and active load are connectable alternatively to the IC pin in response to complementary inhibit signals. Within the active load, the source and sink and connected/disconnected by respective pairs of matched transistor switch circuits the individual switches of which are alternatively activatable by differential control means. Both switch circuits of each pair are supplied from a single current source. One switch circuit of each pair, when activated, directs the current from the single current source to (from) the IC pin, while the other switch circuit, when activated, directs the current to (from) a return line. All of the switch circuits include Darligton-connected transistors and an additional transistor to draw base charge from the principal Darlington transistor when the switch is turned off.