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Which equipment is used to generate test vectors shifted into the scan chain?

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akrlot

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hi;
my question is: which equipment is used to generate test vectors shifted into
the scan chain?
thx
 

JesseKing

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ATPG question

snps teramax
 

    akrlot

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roger

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Re: ATPG question

akrlot said:
hi;
my question is: which equipment is used to generate test vectors shifted into
the scan chain?
thx

It's tools, tools generate ATPG pattern => test machinie => fed into chips => get the shift-out series.

Tools includes
1. Teramax
2. Syntest
3. Mentor fastscan

ATPG pattern by different ventor varies in the length.
 

    akrlot

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akrlot

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Re: ATPG question

im talking about equipment thats implemented on the chip.
thx
 

jackson_peng

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Re: ATPG question

Scan Chain are often multiplex with other function PAD for test.

Besides, JTAG protocol is also often used. but can not perform a parallel test and the speed is limited
 

    akrlot

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dddain_bramage

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Re: ATPG question

> im talking about equipment thats implemented on the chip.

Your question isn't very clear.

In traditional SCAN/ATPG methodology, the test-patterns come from an external device (test-console.) The on-chip hardware is very limited -- 1) some I/O drivers to receive the incoming pattern, and transmit the observed response. 2) SCAN registers to allow the external-console "set" the state of the entire chip (usually by means of serial scan-chains.) The SCAN registers can either be multiplexed D-flipflops, or level-sensitive latches, the foundry tells you which they support.

More recently, ASICs have gotten larger and larger (millions of gates), so test patterns have grown correspondingly. At some point, the time it takes to sweep a full ATPG-pattern through the device-under-test becomes uneconomical. So EDA-companies have come up with an alternative approach -- logic BIST (built-in-self-test.) In this methdology, the DFT-tool inserts an intelligent state-machine + control-logic into your design-netlist. The embedded state-machine generates the test-pattern, exercises the logic, then measures the logic's response to determine PASS/FAIL. This approach has the advantage of using very little data transmission over the I/O, and this also reduces test time. But of course, the logic-BIST controller adds a lot gates by itself (area overhead.) There are other variations on logic-BIST, but they all try to accomplish the same thing -- minimize the amount of external pattern-data needed to test a chip. (Basically, logic-BIST puts 'intelligence' in the chip. Traditional BIST keeps intelligence out of the chip, in the external tester-console.)
 

    akrlot

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nittinsharma80

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Re: ATPG question

ATPG Generater generates the test vectors
but BIST approach seems to answer you better.
IST aproach uses LFSRs etc to generate the test patterns in the chip itsef.
 

    akrlot

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ken_ooi

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Re: ATPG question

The scan vector is generated by ATPG tool (like tetramax).
The vector (in STIL format) then can be used by the IC tester, to test the chip.
 

    akrlot

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extraord

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ATPG question

yeah, most test are based on ATPG pattern, function patterns are develop for testing the uncovered aspects
 

    akrlot

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