semicon testing

7/29/2019 Semicon Testing

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Overview of mixed signal testing


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2006/9/15 Dept. of Electronic Engineering, National Yunlin Univ. of Science and Technology. ~ Weir Lin

Goals

n

Review of basics of digital devicesn Review of basics of analog devices

n Review of components in a typical digital test

system

n Review of components in a traditional analogtest system

n Thoroughly explain the components of a mixed

signal test system


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Digital signals

n

Two signal levels.n On/off, 1/0.

n Word = 2 bytes = 4 nibbles = 16 bits.

n Information storage with digital signals.

n Always valid no matter how much time passes.n Serial or parallel data.

n Sequence or group of levels.

n Uses for digital signals.

n Control signals.

n Number storage.

n Unsuitable for high speed transmission.


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Standard logic symbols

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46 ( 7

&/ 5

'

inverter buffer

NAND AND

NOR OR

XNOR XOR

D flip-flop


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Digital test systems


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Fundamental digital test items

n

Functional testingn Evaluation of device functionality verifies that a devices

transfer function matches the one which it was

designed.

n Test Vector : a parallel set of test patterns.

n May require millions of test vectors.

Vector 1

Vector 2

Output

Outputstrobe


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2006/9/15 Dept. of Electronic Engineering, National Yunlin Univ. of Science and Technology.

~ Weir Lin


n

Logic leveln Place input levels at worst case conditions and

monitor output levels to make sure that they are

within specification limits.

V I H=2v

V I L=0.8v

VOH=2.4v

VOL=0.4v


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2006/9/15 Dept. of Electronic Engineering, National Yunlin Univ. of Science and Technology.

~ Weir Lin


n

Parametric testingn Get precise data on a pins condition

n DC measurement

n

Use PMU (parametric measurement unit orprecision measurement unit)

n Voltage output low/high, power supply current

input leakage current.


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2006/9/15 Dept. of Electronic Engineering, National Yunlin Univ. of Science and Technology.~ Weir Lin


n

Absolute measurement

Outputedge

Phase 1Phase 2

Phase 3

Phase 4

Outputedge

strobeperiod

n Relative measurement

move

Setup time


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2006/9/15 Dept. of Electronic Engineering, National Yunlin Univ. of Science and Technology.~ Weir Lin

Analog signals

n

Continuously and infinite levelsn Contain a lot of information in a little bit of signal.

n Variation in frequency, amplitude, phase.

n Contain no information without time

n DC analog signal provides no information, only power.

Analog building blocks do mathematical operations

on signal. This is why they were names analog signals,

because they were used to mimic the behavior of physical

systems, thus the signals are analogous to real world.


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Analog test system

n

Rack and stack system.n Instrument.

n Oscilloscope, pattern generator, arbitrary waveform generator,

spectrum analyzer, network analyzer, LCR meter

n Mini-computer based.

n I/O interface.n IEEE-488(GPIB), RS-232, ethernet.

n Long test time.

n Precise reference trigger system.

n If device is unique, a new load board must be created.


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Mixed signal circuits

n

Mixed signal devices are those which mix analogand digital circuits

n ADC, DAC, sample-hold or track-hold, SC circuit.

n

Categories of specificationn Dynamic range

n Resolution

n Conversion accuracy

n

Conversion speedn Signal boundary

n Linearity


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Mixed signal tester

n

The use of DSP to analyze and generate analogsignal via digital signal.

n Reduce test time and enhance accuracy.

Clock, timing synchronization

Digital subsystem

Vectormemory

Control,stimulus

Conditioning,measurement

Device

Undertest

Waveformdigitizer

Waveformgenerator

Measurementunit

Storage

(capture)memory

Analog subsystem

DSP

processor

semicon testing

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