ATE Pin Electronics Calibration via Dedicated Replica Circuits
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Solution Overview
Problem
Existing automatic test equipment (ATE) for integrated circuits requires lengthy recalibration times due to the need for central calibration resources, which necessitate disconnecting devices under test and are sensitive to temperature changes, leading to inefficiencies in the calibration process.
Innovation Solution
Each channel of the ATE includes a dedicated calibration circuit with a replica output, allowing for parallel calibration without disconnecting the device under test, using a state machine to control pin electronics and levels generators for precise calibration parameter determination and compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a central calibration resource is used to calibrate pin electronics one pin at a time, then calibration precision can be maintained, but recalibration time becomes excessively long (greater than an hour for a single ATE)
Solution Approach 1:
The patent divides the calibration system into multiple independent calibration circuits, each dedicated to a specific channel or group of channels. This segmentation allows parallel calibration operations across multiple channels simultaneously, dramatically reducing total recalibration time while maintaining calibration precision through dedicated resources for each segment.
Solution Approach 2:
The patent introduces a temporal dimension to the calibration process by implementing different operational modes (test mode and calibration mode) that can be switched rapidly. The calibration circuit can alternate between servicing multiple channels in test mode and performing calibration on individual channels, enabling time-multiplexed parallel calibration that reduces overall recalibration time.
2Reliability
If DUTs are disconnected during recalibration to access pin electronics, then calibration can be performed, but testing operations must be interrupted
Solution Approach 1:
The patent creates a replica output that duplicates the signal path of the pin electronics but remains independent of the DUT connection. This replica allows the calibration circuit to measure and adjust pin electronics parameters without requiring physical disconnection of the DUT, enabling calibration to proceed while testing continues uninterrupted.
Solution Approach 2:
The calibration circuit acts as an intermediary that can access pin electronics through the existing signal path without requiring DUT disconnection. The replica output serves as an intermediate measurement point that provides calibration access while maintaining the normal test connection, eliminating the need to interrupt testing operations.
3Measurement precision
If pin electronics are recalibrated frequently to account for temperature changes, then measurement accuracy is maintained, but system efficiency decreases due to lengthy calibration processes
Solution Approach 1:
The patent implements a dynamic calibration system that can rapidly switch between servicing multiple channels and performing calibration on individual channels. The calibration circuit responds to temperature change detections by dynamically allocating calibration resources to affected channels while maintaining testing on other channels, optimizing the balance between accuracy maintenance and system efficiency.
Solution Approach 2:
The patent implements periodic calibration cycles that are triggered by temperature change thresholds rather than continuous calibration. The calibration circuit monitors temperature and initiates calibration only when necessary, using the time-multiplexed parallel calibration capability to perform adjustments quickly during periodic intervals, thereby maintaining accuracy while minimizing interference with continuous testing operations.
Data Source
AI summary
An integrated circuit for automatic calibration control of pin electronics is disclosed. The integrated circuit includes a substrate, and both pin electronics and a calibration circuit integral with the substrate. The calibration circuit is dedicated to a single channel of automatic testing equipment for a single pin of a device under test. Each sub-circuit of the pin electronics may include a replica output. The replica output is electrically coupled to the calibration circuit. The calibration circuit may include a multiplexor for receiving each of the replica outputs from the sub-circuits, such as a comparator, load and a driver, and for selectively switching between the replica outputs to determine calibration parameters for one or more levels of the sub-circuit. The calibration circuit includes a state machine capable of determining calibration parameters including offset and gain. After determining the calibration parameters, the state machine can compensate the one or more levels for each sub-circuit of the pin electronics based upon the calibration parameters.