Driving Down Test Cost, Agilent Technologies Schedule and ... · #1 - Automated test strategies Application emulation mode – Tests full operation- hardware & firmware –Slowest

Agilent Technologies ©

Webcast Series

Spring, 2012

Driving Down Test Cost,

Schedule and Risk

With a Smart Approach

to Switching

Agilent Technologies

Software and Modular Solutions

Division

Mark Bailey

Product Marketing Manager

May 30th, 2012


Webcast Series

Spring, 2012


Webcast Series

Spring, 2012

Driving Down Test Cost, Schedule & Risk

with a Smart Approach to Switching

#1: Automated test topologies – choosing the right one

#2: Switch types – choosing the right switches and protection

#3: Switch topologies – Getting the most from your switches

#4: Switching Power Supplies and Loads – what to watch for

#5: Grounding and noise in your switch systems – getting it right

#6: Switching Example: Testing Automotive Electronic Control Units (ECUs)

#7: Using a Web Interface to set up and monitor your switching system

- Equipment Cost

- Test Speed

- Development Time

- Measurement Integrity

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Spring, 2012

MUX

Switch

DMM

“Functional Test”

- Transactional

“Data Acquisition”

- Scanning

Two Basic Switch Applications

Matrix – can connect multiple DUT

points to various instruments

• Close relay

• Change instrument function

• Trigger measurement

• Return results

• Open relay

MUX – can connect one of many DUT

points to a single instrument • Close relay

• Take Measurement

• Close relay

• Take Measurement

• Close relay …etc.

PS

SA

Counter

Arb

DMM

Sig Gen Matrix

Switch DUT

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Functional test plans are switching intensive

Case study: Engine ECU testplan

Number of transactional communications

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#1 - Automated test strategies

Application emulation mode

– Tests full operation- hardware & firmware

– Slowest testing

– Difficult to leverage

– Emulation test methodology

DUT Assisted Test (DAT)

– Fastest method for high volume test

– Most Common & Most Reusable

– Embedded test code required

– Transactional test methodology

Application Emulation -

commonly used in

development or burn-in

testing

Design Assisted Test -

commonly used in

manufacturing test

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Spring, 2012

Automated test topologies for Speed of Test

Application test mode vs. DUT assisted test mode

Application Emulation Test

- Targeted for application DUT Assisted Test

- Optimizes flexibility

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Spring, 2012

Automated test topologies

• Measurement Matrix

Connect Instruments to DUT

1-, 2-, and 4-wire connections

• RF/µWave Switching

High frequency path

Multichannel

• Multi-channel Disconnect

Reduced loading

Consolidate measurements

• Load and Power

Simulate loading

Apply power to DUT

Automated systems are

constructed from

part or all of these

sections

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Webcast Series

Spring, 2012

Electromechanical Armature Relays

• Rugged, supports higher currents and voltages

• Low On-Resistance (< 1Ω)

• Slower switch speeds

Reed Relays

• High-speed switching

• Very low contact resistance

• Long mechanical life if not overstressed

FET Switches

• High-speed switching

• Higher “on resistance” (Typically 100 Ω)

• Low voltage/current handling capability

• Doesn’t provide “Voltaic Disconnect”

Armature

Reed

FET

# 2 - Switch Technology

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Spring, 2012

Relay Life Spans

Life span of relays affected by:

• Types of loads being switched

• High-power or high-voltage switching

• Resistance of relay contactss

Maximize relay lifetime:

• Always maintain signal within relay’s voltage/current ratings

• Avoid “hot switching”

• Use surge-suppression circuits

– Resistor in series with capacitive load

– Zener diode in parallel with inductive load

Load Type Derated

lifetime*

Resistive 75%

Inductive 40%

Capacitive 75%

Motor 20%

Incandescent 10%

* Of manufacturer specification

Slide 9


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Spring, 2012

TIP: Limit surge current for longer reed relay life

Load Life Operations

10 V / 4 mA 100 Million

7.5 V / 150 mA 20 Million






5 V / 500 mA 0.4 Million

Example reed relay data

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Webcast Series

Spring, 2012

#3 - Switching Topologies - General Purpose Switches

Simple Relay Configurations

• 3 common configurations

• Most often used for simple on/off

switching of power

• Can be linked together

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Spring, 2012

Switching Topologies - Multiplexers

Single-Wire Multiplexers

• Useful for common-low applications

Two-Wire Multiplexers

• Useful for floating measurements

Four-Wire Multiplexers

• Useful for four-wire

resistance measurements

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Spring, 2012

A Matrix is used to connect multiple points at

one time

• Widely used in functional test applications

• Can reconfigure on-the-fly

• Can connect power, stimulus and

measurement at one time

• Cautions

– Possible to accidentally connect sources

together

– More wires, more susceptible to noise and

crosstalk

In

stru

ments

DU

T p

oin

ts Switching Topologies - Matrix

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Examples of Switching Systems

Pro

duct F

lexib

ility

High

Low

Just Enough

Performance:

Up to 60 channels,

3 slots, 8 modules

Higher Level

Performance:

Up to 560 channels,

8 slots, 21 cards

Balanced Throughput &

Performance:

High Density,

High Speed,

Many modules

34980A Multifunction Switch

Measure Unit

34970A/72A Data Logger

Price Performance Decision Criteria

M9000-series

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Spring, 2012

RF / Microwave Switching Systems

1) Modules for 34980A:

For systems requiring both low and high frequency

switching, controlling multiple switch matrices

• 34941A/42A Quad 1x4 switch to 3GHz

• 34946A/47 2/3 SPDT switches to 26.5GHz

• 34945A/EXT uW switch driver

2) L4445A/EXT External Switch Driver:

For standalone switch driver to control

Switches, Couplers Attenuators, dividers

in the fixture

3) L4490A/91A RF Switch Platform:

2U or 4U high enclosure includes uW switch

driver, power, drivers and space to mount

switches

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True X-Y Matrix Configuration

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Matrix in X by Y by Z Configuration –

Reduces Cross Points & Saves Space and Money

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Example High Density Matrix Module

Best solution:

Protection resistors with bypass relays

• Limits surge currents

• Bypass relays used when providing light duty stimulus or for low level measurements

Row disconnect relays

• Reduces loading capacitance as matrix size increases

Agilent 34934A 512 Cross-Point Matrix with flexible configurations

Four 4x32 blocks

- 1-wire: 4x128, 8x64, 16x32

- 2-wire: 4x64, 8x32

Row

disconnect

Bypass

relays

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Webcast Series

Spring, 2012

Helpful hint: Matrix x structure

2 wire matrix structures provide good noise and bandwidth performance.

But in cases were two or more instruments need to be stacked, 2-Wire

matrix structures make that hard to do.

Problem:

Solution: Build a matrix X structure into your switching to allow

stacking of isolated instruments and signal inversion.

Stacked Inversion

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Cabling in Switching Systems

May need to run several meters to DUT

HINT: Twisted pair improves BW and reduces noise

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Two nodes are adjacent if there is only one switching

element connecting them. They are NOT adjacent if

more than one switching element connects them.

A is only adjacent to B

B is adjacent to A, C, and D

(etc.)

A

D

F

C

E

B

A is not adjacent to C, D, E or F

B is not adjacent to E or F

Switching Element

• A switching path is an ordered set of adjacent nodes

Possible switch paths are:

[A | B | C]

[A | B | D | F]

(etc.)

Switching Nodes and Paths

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Webcast Series

Spring, 2012

Watch for Resistance in Test System

• Cable & Matrix resistance can add to overall

measurement error

• Use 4 wire resistance measurement for

improved accuracy especially for measuring

low resistances.

• Minimum of 4 wire analog bus is required for

4 wire resistance measurements

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Webcast Series

Spring, 2012

How to select the right mux/matrix card(s)

1. How many signals need to be applied and/or measured with different instruments at the same time? (Calculate how many analog busses and/or banks will be needed)

2. How many total points are there that will ever need to be connected to any instrument? (Tells you how many channels you need; 20, 40, 70, etc.)

3. What kind of accuracy is required? (Tells you if you need 1-wire, 2-wire or 4-wire configuration)

4. What voltage and current rating is needed? (note that switch current is different from carry current)

5. Is current measurement needed?

6. How fast do the readings need to be?

7. Are non-DC signals being switched? If so, what is the highest frequency?

Application Note: Tips for Optimizing Your Switch Matrix Performance 5990- 4855EN

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Webcast Series

Spring, 2012

Switching Topology Summary

– Testing methodology: DUT Assisted Test vs. Full Functional Test

– Single vs. dual wire switching systems

– High Density Matrix with multiple analog bus lines allows flexible

interconnect from instruments to Device Under Test (DUT)

– Relay technologies - choose appropriate relays:

• Armature relays for robust switching of higher voltages and currents

• Reed relays for fast measurement switching

• FET relays for unlimited switching lifecycle

– Use current limit resistance to extend cycle-life

of reed relays. Use bypass relays when need

to source current through matrix

– Use twisted pair for best BW and

noise performance

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# 4 - Load and

Power Switching

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Load and Power Switching

• Required to properly stress

unit and simulate real life

• Multiple configurations

– High-side

– Low-side

– Multiplexed loads

– Bridge loads

• Use external load tray as

part of system or in fixture

• Switched loads allow

parametric measurements

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Load management methods

Use load tray for high powered loads

Power Bus 1 (PB1) GND

Power Bus 2 (PB2) Vbatt

Load tray structure located

either in test system or fixture

expand PBx

as needed

to DMM or digitizer

via meas matrix

Switching

measurement

matrix

To power supply(+)

(-)

Current shunt R

~0.05 ohm typically

current limiting resistors

180 180

180 180

180 180

over-current

protection if required

Device

Under Test

(DUT)

*

* special case; in event of very

high currents can use fixture

mounted disconnect.

Load tray example

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Power supply remote sense

Remote sense to remove V drop under load

Need to choose one location to sense

• at power bus in load tray -or-

• at DUT

Be careful about switching remote sense!

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Summary…

Power supplies and load trays:

• Use central load tray with power bus to manage high

power loads

• Resistive power shunts can be used to monitor currents

through loads – locate close to actual load

• Selectively place protection in-line to product tester in

event of defective DUT

• Power supply remote sensing, need to decide location

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(“STAR” Ground)

#5 - System Grounding Recommendations

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Source: "Noise Reduction Techniques in Electronic Systems“ by Henry W. Ott


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Spring, 2012

System Grounding Recommendations

Test System Ground Is Floating

Power Supply Grounds are Floating

UUT Ground Floats

Recommendation:

– At UUT, Tie System Ground and Power

Supply Grounds to UUT Ground

– Typically Reference these to Earth at UUT

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#6 - Automotive Applications

Testing of automobile electronics

Power Train (ECU, TCU)

Body Electronics (BCU, RKE)

Telematics / Infotainment

Automotive sensors

Safety:

• Air bags,

• ABS,

• Collision avoidance

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Testing Multiple ECUs simultaneously

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Spring, 2012

Agilent 34980A Switch/Measure Unit

- 8 slots, up to 560 channels

- 21 modules available

- Universal inputs with 300 V switching

- Easy front panel operation for setup and debug

- Built-in DMM with 1000 readings/second

- Can hot-swap modules

- LAN, GPIB and USB and LAN with Web interface

- Terminal blocks for easy connect/disconnect

- As much as 40% lower cost than PXI

Application Note 5989-5852EN: Comparing the Agilent 34980A and PXI

for Switch Measurement Applications

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Agilent 34980A Switch/Measure Unit Switch Cards

Slide 35


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Engine Control Unit Test Using

the 34980A Switch/Measure Unit

• Use the 34980A DACs to

source control pins, matrix

cards to route signals to

measurement equipment, GP

switches to switch supplies

and the internal DMM for

measurements

•34980A 4-wire Analog bus for

exceptional signal routing

Configuration:

34980A with 6 ½ digit DMM

34951A D/A Converter

34937A GP switch

34933A 1-wire matrix

34952A multifunction module

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#7 - 34980A Web Server - Multiplexer

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34980A Web Server - Matrix

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34980A Web Server - GP Switches

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Switching Solutions Available from Agilent

Bench and System Switching Products Catalog 5989-9872EN

Slide 40


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We’ve talked about the following:

Selecting the best test topology for your application

Switch types and configurations – Armature, Reed, Mux, Matrix, etc.

Considerations for switching power supplies and loads

Grounding concerns and recommendations

Benefits of an instrument’s built-in web server

Plan up front, and you will reduce risk

while saving time and money.

Driving Down Test Cost, Schedule & Risk

with a Smart Approach to Switching

41


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Spring, 2012


Webcast Series

Spring, 2012

Purchase a 34980A Multifunction Switch/Measure System

between May 1 and September 30, 2012 –

Get BenchLink Data Logger Pro Software FREE !!

(… A $1,000 USD Value…)

Here’s how:

1. Purchase a 34980A Switch/Measure system

2. Visit web site www.agilent.com/find/34980promo

3. Enter personal information & 34980A serial number

BenchLink Data Logger Pro software certificate and key will be emailed to the customer.

Customer uses the key to enable the BenchLink Data Logger Pro, shipped on a CD with the 34980A, to operate continuously with full capability.

Special Offer on BenchLink Data Logger Pro

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Webcast Series

Spring, 2012

1. Find out more: www.agilent.com/find/34980switch

2. Watch the 34980A in Action on YouTube

3. Get a Quick Quote

4. Contact a Distribution partner

Thank you for attending !! Questions??

Buy from an

Authorized Distributor

www.agilent.com/find/distributors

20 March 2012 Recorded Focus on Sensors: How to make fast, reliable

sensor measurements with your data logger system

30 May 2012 Recorded Focus on Switching: Multiplexers, Matrices and

System Performance

13 July 2012 11:00 AM MDT Focus on Control: Digital and Analog Control Tips

and Techniques

06 Sept 2012 11:00 AM MDT Focus on Data Acquisition: Setup, Programming,

Debugging and Maintaining a Reliable System

43

http://www.youtube.com/playlist?list=PL54201150017FE90D

http://www.home.agilent.com/agilent/product.jspx?pn=34980A

Documents

Driving Down Test Cost, Agilent Technologies Schedule and ... · #1 - Automated test strategies Application emulation mode – Tests full operation- hardware & firmware –Slowest