ZQ Calibration Code Conversion for Memory Driver Impedance

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Solution Overview

Problem

Existing ZQ calibration devices have long calibration times, which can lead to increased signal loss and noise interference in high-speed interface operations of semiconductor devices.

Innovation Solution

The implementation of a memory device with a driver unit, a ZQ calibration unit, and a code conversion unit that generates ZQ codes corresponding to various voltage levels, thereby shortening the calibration time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional ZQ calibration is performed for each voltage level separately, then calibration accuracy is improved, but calibration time increases

Engineering Contradiction:

Improvecalibration accuracyVSAvoidcalibration time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs ZQ calibration at a first voltage level (e.g., 1.2V) beforehand to obtain a first ZQ code. This preliminary calibration result is then reused when the voltage level changes to a second voltage level (e.g., 0.6V), avoiding the need to perform calibration again at each voltage transition. The code conversion unit converts the first ZQ code to a second ZQ code based on the voltage level change, thereby reducing calibration time while maintaining sufficient accuracy.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If calibration is performed frequently to adapt to voltage changes, then interface stability is improved, but power consumption and time loss increase

Engineering Contradiction:

Improveinterface stabilityVSAvoidcalibration time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent detects voltage level changes (e.g., from 1.2V to 0.6V) and performs calibration only when necessary. The code conversion unit adjusts the ZQ code based on the detected voltage level change, maintaining interface stability without requiring full recalibration. This selective approach based on parameter changes reduces unnecessary calibration operations.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If separate calibration is performed for each voltage level, then impedance matching precision is improved, but device complexity increases

Engineering Contradiction:

Improveimpedance matching precisionVSAvoidcalibration system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses a single ZQ calibration unit that can operate at different voltage levels (e.g., 1.2V and 0.6V) without requiring separate calibration circuits for each voltage. The code conversion unit converts calibration results between voltage levels, allowing one calibration system to serve multiple voltage conditions, thereby reducing device complexity while maintaining impedance matching precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250166677A1Calibration devices and operating methods thereof

Publication Date: 2025.05.22 SAMSUNG ELECTRONICS CO LTD

AI summary

Disclosed is a memory device which includes a driver unit that includes a pull-up driver and a pull-down driver, a ZQ calibration unit that performs ZQ calibration with respect to the driver unit based on an external resistor and a first reference voltage and generates a first ZQ code corresponding to the first reference voltage, and a code conversion unit that generates a second ZQ code corresponding to a second reference voltage different from the first reference voltage, based on the first ZQ code.