Transmitter-Only IC Chip External Loopback Test Using Pad Reconfiguration

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Solution Overview

Problem

Conventional methods for performing an external loopback test on transmitter-only IC chips require additional receive pins, separate RX units, or expensive high-speed test equipment, increasing IC size, manufacturing cost, and test complexity.

Innovation Solution

A transmitter-only IC chip with a loopback test circuit that uses one of the transmit pads as a receive pad for external loopback data, enabling data comparison without additional receive pins or high-speed test equipment, utilizing a receive buffer, monitoring unit, and deskewer to generate and compare test results.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional receive pins and separate RX units are designed and mounted in the chip to perform external loopback test, then external loopback testing capability is achieved, but IC size and manufacturing cost increase

Engineering Contradiction:

Improveexternal loopback test capabilityVSAvoidIC size

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The transmit pad is designed to serve dual purposes: normal data transmission function and receive pad function for loopback testing. By enabling the transmit pad to be configured as a receive pad through control signals, the chip eliminates the need for separate receive pins and RX units, thereby reducing IC size while maintaining external loopback test capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The transmit and receive functions are merged into a single pad structure. The pad can be dynamically switched between transmit mode and receive mode through control signals, combining what would traditionally require separate physical components into one multi-functional element, thus reducing overall device complexity

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

Engineering Contradiction:

Improveexternal loopback test capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If expensive high-speed test equipment is used to perform external loopback test on transmitter-only IC chip, then accurate transmission testing is achieved, but test cost increases

Engineering Contradiction:

Improvetransmission test accuracyVSAvoidtest cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The transmitter-only IC chip performs its own transmission testing by using its internal resources. The chip configures one transmit pad as a receive pad and uses its own drivers and loopback test circuit to generate, transmit, receive, and compare test signals, eliminating the need for expensive external high-speed test equipment while maintaining test accuracy

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The chip creates an internal feedback loop where transmitted signals are routed back to the input through the configured receive pad. The loopback test circuit compares the received signal with the original transmit data and generates test result signals, providing self-validation without requiring external test equipment

Inventive Principle:

Principle #23Feedback

4Productivity

If internal loopback is performed in transmitter-only IC chip without transmitting signal to exterior, then testing is completed at pre-driver stage, but AC attribute test for final stage drivers connected to transmit pad is not performed

Engineering Contradiction:

Improvetest completion speedVSAvoiddriver performance verification

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Instead of keeping the traditional internal loopback approach where signals stay within the chip, the invention inverts the approach by routing signals outside the chip through the transmit pad and back through the same pad configured as receive pad. This ensures that the final stage drivers connected to the transmit pad are actually exercised and tested for their AC attributes

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS8559492B2Transmitter-only IC chip having external loopback test function and external loopback test method using the same

Publication Date: 2013.10.15 SAMSUNG ELECTRONICS CO LTD

AI summary

A transmitter-only integrated circuit (IC) chip for performing an external loopback test without an additional receive pin in a chip and an external loopback test method include drivers, mounted on the transmitter-only IC chip, for transmitting data through transmit pads that are installed in correspondence to a plurality of channels; and a loopback test circuit for receiving data as external loopback data through one of the transmit pads set as a receive pad for a test, the data being transmitted through one of the remaining transmit pads, and then comparing the received external loopback data with original transmit data.