A Low-Power and Area-Efficient Design of a Weighted Pseudorandom Test-Pattern Generator for a Test-Per-Scan Built-in Self-Test Architecture

Abstract

A test pattern generator generates a pseudorandom test pattern that can be weighted to reduce the fault coverage in a built-in self-test. The objective of this paper is to propose a new weighted TPG for a scan-based BIST architecture. The motivation of this work is to generate efficient weighted patterns for enabling scan chains with reduced power consumption and area. Additionally, the pseudo-primary seed of TPG is maximized to obtain a considerable length in the weighted pseudorandom patterns. The maximum-length weighted patterns are executed by assigning separate weights to the specific scan chains using a weight-enabled clock. This approach reduces the hardware overhead and achieves a low power consumption of 26.7 nW. Moreover, the proposed weighted TPG is applied in two different test-per-scan BIST architectures and achieves accurate results. The weighted patterns are also generated with fewer switching transitions and higher fault coverages of 98.81% and 97.35% in two different BIST architectures. This process is observed with six other circuits under test as their scan chains. The simulation results are tested with a SilTerra $0.13~\mu \text{m}$ process on the Mentor Graphics IC design platform. Furthermore, the proposed weighted TPG is enlarged to a higher bit TPG, which is compared to accomplish the performance strategies. The experimental results of the proposed TPG design are compared and tabulated with existing potential TPG designs.