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:
Dec. 30, 2008
Filed:
Feb. 28, 2006
Cheng-hsiung Huang, Cupertino, CA (US);
Chih-ching Shih, Pleasanton, CA (US);
Hugh Sung-ki O, Fremont, CA (US);
Yowjuang (Bill) Liu, San Jose, CA (US);
Cheng-Hsiung Huang, Cupertino, CA (US);
Chih-Ching Shih, Pleasanton, CA (US);
Hugh Sung-Ki O, Fremont, CA (US);
Yowjuang (Bill) Liu, San Jose, CA (US);
Altera Corporation, San Jose, CA (US);
Abstract
A pair of SCR devices connected in antiparallel between first and second nodes. Each SCR device comprises an NPN and a PNP bipolar transistor. Reverse-biased Zener diodes are used for triggering the NPN bipolar transistor in each SCR device when it breaks down in an ESD event. Advantageously, additional Zener diodes are provided for pre-charging the PNP transistor of each SCR device at the same time, thereby reducing the delay time for turning on the PNP bipolar transistor. In addition, the breakdown current of the Zener diodes is preferably maximized by reducing the P-well and N-well resistance of the SCRs. This is achieved by connecting external resistances between the base of each bipolar transistor and the node to which the emitter of the transistor is connected.