LT-RTPG: a new test-per-scan BIST TPG for low switching activity

A new built-in self-test (BIST) test pattern generator (TPG) design, called low-transition random TPG (LT-RTPG), is presented. An LT-RTPG is composed of a linear feedback shift register (LFSR), a κ-input AND gate, and a T flip-flop. When used to generate test patterns for test-per-scan BIST, it decreases the number of transitions that occur during scan shifting and, hence, decreases switching activity during testing. Various properties of LT-RTPGs are identified and a methodology for their design is presented. Experimental results demonstrate that LT-RTPGs designed using the proposed methodology decrease switching activity during BIST by significant amounts while providing high fault coverage.