Summary: This paper proposes a new approach for analog portion testing, which can meet requirements for high-speed and high-accuracy testing simultaneously with reasonable cost. The key concept of the new method is cooperation of an LSI tester and some circuitry built in a target SoC device. We will explain the operation principle of the proposed method. The proposed method can be one of the methods to overcome today's expensive production test of analog portion on SoC (System on Chip) devices which heavily depends on LSI tester capability and will become harder in near future.