The Built-in Self-test For Embedded DLL

As the integrated circuit design has stepped into the deep ultra-submicron stage, the complexity of the circuit increases continually, chip test faces very huge challenge. The Built-in self-test technique can realize the test to integrated circuit by integrating a few logic circuits in a inner chip, which is considered as one of the effective method to solve the problems of long and complex development cycle and high costs.With the development of the SOC and IP core technology, the application of Phase locked technique is more widespread, both in Wireless communication and microprocessor electric circuit, its error will directly or indirectly affect the number of IC devices' performance, therefore, testing DLL is the important first step for testing the entire chip.In this paper, the traditional Built-in self-test (BIST) and the DLL are discussed seperatly, based on these study, a Delay-locked loop testing method is expounded, and a Built-in self-test (BIST) circuit for the test of the Delay-locked loop circuit (DLL) is proposed. The circuit is based on a simple XNOR logic gate and delay lines to sample the output of the XNOR gate, so very little area is introduced. In addition, no external stimulus is required for this BIST circuit, and fault simulation result shows high fault coverage of faults of Delay-locked loops, combined with some coverage of parametric variations.