JQs in practice
JQ tests are carried out on a customer’s system. But both the customer and the silicon vendor can each carry out the qualification work in parallel, so that it may be completed faster.
Cypress starts its testing on a customer-supplied system after adding debug capabilities to it. Next, it characterises the memory devices before and after exercising them using automated test equipment (ATE), to detect any effects attributable to the customer’s application or to mechanical, electrical or thermal stress in the customer’s assembly process. Feedback from these tests helps Cypress’s engineering group to refine the product’s design, so that it can release the best possible product in the future.
While checking and testing Cypress devices in the customer’s system, it is crucial to exercise them in a way that is as similar as possible to real-world usage. Comparisons between the real customer system and Cypress’s own worst-case parameters are particularly revealing. Real customer production methods are also often different from those anticipated, and can have unexpected effects on a device’s behaviour.
This information about a device’s behaviour in the real world would not be acquired without JQ, and it allows Cypress to recommend to its customers best practices to maximise the robustness of their systems. It also allows customers to determine the best settings to optimise system performance. JQ also enables Cypress to find mismatches between the customer’s system, and the test system used by Cypress to determine the specifications of important electrical parameters. This helps the customer’s engineers to pinpoint those aspects of their system’s operation in which behaviour might be imperfectly represented by the IC’s datasheet.