What is scan compression?

Scan compression is the most commonly used design-for-test (DFT) architecture for reducing ATPG test application time and test data volume. A traditional compression structure is made up of three distinct blocks: a decompressor, a compressor, and an X-tolerance or X-mask.

What is scan insertion in DFT?

Scan Insertion: Tool Objective. SCAN is a DFT design technique used in IC Design to increase the overall testability of a circuit. SCAN insertion architecture helps to test each of the logic elements in the IC irrespective of its position by inserting test vectors to device pins.

What is DFT codec?

Both CPU and non-CPU logic encapsulate DFTMAX compressor-decompressors (CODECs) to reduce test application time and test data volume[2] for low-cost manufacturing test. The compression ratios implemented for the CPU and non-CPU CODECs are chosen to ensure a uniform scan chain length across all logic in the design.

What is DFTmax?

DFTMAX Ultra uses a new compression architecture to reduce total scan test data and test time by 2-3X over existing compression technologies. DFTMAX Ultra also achieves higher compression when fewer chip pins or tester channels are available for manufacturing test.

What does high compression mean when scanning?

High Compression is an advanced multi-layer compression technology available in PDF or XPS file types for color or grayscale settings. Select the Black setting. note: Images scanned in Black color compress the file to a small size, especially when the background is black and the text is in white color.

What is the difference between high compression and low compression engines?

Compression ratios usually range from 8:1 to 10:1. A higher compression ratio — say, from 12:1 to 14:1 — means higher combustion efficiency. Higher compression ratios and combustion efficiency mean more power with less fuel, and fewer exhaust gases.

What is Synopsys DFT Compiler?

DFT Compiler writes. detailed scan chain information to the Synopsys design database. which IC Compiler then reads to perform further optimizations to. reduce area impact and decrease overall routing congestion.

What is scan shift and scan capture?

Scan chain operation involves three stages: Scan-in, Scan-capture and Scan-out. Scan-in involves shifting in and loading all the flip-flops with an input vector. During scan-in, the data flows from the output of one flop to the scan-input of the next flop not unlike a shift register.

What is chain test in DFT?

A chain test simply shifts a sequence, typically ‘00110011’, through the entire scan chain without exercising the functional circuitry. The pattern that appears on the device output pins is expected to be exactly the same sequence that’s shifted in, assuming there are no inverters along the chain.

Should compression level be high or low?

Think of it as quality of compression or level of compression. With lower compression, you get a bigger file, but it takes less time to produce, whereas with higher compression, you get a smaller file that takes longer to produce.

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