Test system and test method for accurately testing IC reference voltage

Abstract

The invention relates to a test system and a test method for accurately testing the IC reference voltage. The test system comprises an IC device, a structurally-symmetrical signal processing circuit, and a V / I test source. The signal input end of the signal processing circuit is connected with the reference voltage test terminal of the IC device, and the signal output end of the signal processing circuit is connected with the V / I test source. According to the test method, the signal processing circuit buffers and amplifies an input voltage Vin and the voltage Vz of a Zener diode, compares Vin with Vz, and outputs a voltage Vout to the V / I test source after differential amplification of a signal after comparison. The common-mode interference of a test equipment ground line and space noise can be eliminated, the influence of test error on the test system can be reduced, and a higher-accuracy test result can be obtained.

Description

technical field [0001] The invention relates to a test system and a test method for accurately testing an IC reference voltage, belonging to the field of integrated circuit testing. Background technique [0002] In integrated circuits, a constant reference voltage is generated inside the chip to provide accurate and stable reference voltage values ​​for internal digital circuits and analog circuits, that is, voltage references are an integral part of analog circuits and digital circuits. In the production process, usually due to uncertain factors such as reference voltage offset, temperature drift, process deviation, etc., the accuracy of the chip's reference voltage often deviates from the preset value, and the reference voltage needs to be trimmed through voltage trimming technology. For example, the current fuse repair technology is used to correct the IC reference voltage. [0003] Before the IC reference voltage is trimmed, it is necessary to accurately test the IC ref...

AI Technical Summary

Problems solved by technology

Due to the wide variety of integrated circuits involved in reference voltage trimming, and the variety of ATE test systems, the accuracy of the test system will also decrease with the increase in the use time of the test system. Happening

The existing test method for IC reference voltage depends entirely on the accuracy of the test system, which makes it difficult to guarantee the consistency of IC reference voltage and the overall cost is high

Due to the certain distance between the test system and the IC, spatial noise will also interfere with the test results, resulting in instability of the test value of the IC reference voltage

[0004] Although in order to reduce the test error caused by the test system as much as possible, the existing practice is to verify the test system with a 6.5-digit voltmeter before the test, and use the same test system for each product variety, but this practice is always Symptoms, not root cause

Images