Power Supplies. Messungen an der Stromversorgung. Thomas Giehm/ datatec

Transcription

1 Power Supplies Messungen an der Stromversorgung Thomas Giehm/ datatec

2 Agenda Grundlagen Bauarten und Eigenschaften von Power Supplies DC Power Analyser N6705B Module Beispiele Portfolie Überblick High Performance Power Supplies (APS) Source Measure Unit (SMU) 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

3 Power Supply Categories Basic Supplies Manual or Programmable Used for setting bias, powering circuits, etc. Performance Supplies Faster, more accurate, higher power Typically used in system applications Modular Supplies Compact, flexible, mix-and-match Easily interconnected Specialty Supplies Battery Simulation Solar Array Simulation 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte Page 3

4 DC Power Supply Topologies Linear or series-pass Advantages Low output ripple & noise Fast programming speed Fast transient recovery Disadvantages Low efficiency High weight/watt Physically large Applications Bench & laboratory Automated test Low power: < 500 W Note: Agilent's linear Power Supplies classically have fast programming speed which make them a good fit in test systems datatec Ihr Spezialist für Mess- und Prüfgeräte Page 4

5 DC Power Supply Topologies Switched mode (SMPS) Advantages High power in small package High efficiency Disadvantages Moderate to high** ripple & noise Moderate programming speed Moderate transient recovery Applications Subassembly test Burn-in Bench & laboratory Electromechanical test **Note: Agilent's newest Switching Power Supplies have noise, slew rate, programming speed and transient performance nearly that of linear supplies 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte Page 5

6 Key Power Supply Specs: Comparing Noise Typical PC Power Supply (not an instrument) Typical Switching (SMPS) Supply High Noise 100 mvpp 20 mvpp Hint Noise is very dependent on output voltage, so a 5V output will have much less noise than a 100 V output Agilent Switching Supply Typical Linear Supply Low Noise 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte 10 mvpp 1 mvpp Agilent Low Noise Switching Supply Agilent Linear Supply Page 6

7 Output Measurements built-in voltmeter and/or ampermeter - read back own output displayed on front panel or queried by remote interface accuracy is specified as a % of full scale plus an offset 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte Page 7

8 Remote Sense (150 mv drop) Lead resistance can contribute a significant voltage drop between the output of the supply and the actual voltage presented at the load I =10 Amps (150 mv drop) The sense leads measure the voltage present at the load itself, and adjusts the output of the supply to compensate for the voltage drops in the leads 5.3 V High Z Input I =Zero 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte Page 8

9 N6705A Remote sense: called 4 Wire Sense Access from Source Settings screen Illuminates a green 4 wire LED on front panel for each output with 4 Wire Sense turned on Setting is stored in non-volatile memory CAUTION: If you do not have sense wires connected, turn 4 Wire Sense off. Otherwise, output will regulate slightly higher than setting (a few %) datatec Ihr Spezialist für Mess- und Prüfgeräte

10 DC Power Supply Capabilities Constant voltage (CV) mode Output sensing V Set CV I Constant current (CC) mode V CC I Set 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte Page 10

11 Output Characteristics Rectangular V max P max V max P max Dual-range P max I max I max Autoranging V max Maximum power range I max 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

12 Special Capabilities Protecting the Device Under Test Over Voltage Protection (OVP) Over Current Protection (OCP) Discrete Fault Indicator (DFI) / Remote Inhibit (RI) Protecting the Power Supply Over Temperature Protection (OTP) Output Disconnect Relay Output Polarity Reversal 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte Page 12

13 Unique Feature: Down Programming Capacitors discharge slowly under light loads Static voltage source: no problem Varying voltage levels: slow tests Down programming Rapidly decrease the output voltage Reducing discharge times by hundreds of ms 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte Page 13

14 Parallel and Series Safety Precautions SERIES CONNECTION Never exceed the floating voltage rating of any of the supplies. Never subject any of the power supplies to negative voltages. Program each power supply independently. If two supplies are used, program each one for 50% of the total output voltage. If three supplies are used, program each supply for about 33% of the total output voltage. Set the current limit of each supply to the maximum that the load can safely handle. PARALLEL CONNECTION One unit must operate in constant voltage (CV) mode and the other(s) in constant current (CC) mode. The output load must draw enough current to keep the CC unit(s) in CC mode. Program the current limit of each unit to its maximum value and program the output voltage of the CV unit to a value slightly lower than the CC unit(s). The CC units supply the maximum output current that they have been set to and drop their output voltage until it matches the voltage of the CV unit, which supplies only enough current to fulfill the total load demand datatec Ihr Spezialist für Mess- und Prüfgeräte

15 DC Power Analyzer N6705B has sourcing and measurement capability Sourcing functions Simple DC bias Arbitrary waveform generator-like functions Sequencing outputs Measurement functions DC measurements Oscilloscope-like functions Datalogger function 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

16 Agilent N6705 Sourcing Capabilities Output sequencing Output waveforms V V DC bias V pulse t Module 1 Module 2 Module 3 Module 4 t V V OUTPUT ON t Step turnon Trapezoid Delay 2 Delay 3 Delay 4 t V t Ramp turnon V t V dropout V V t Staircase turn-on t AC + DC offset V1 V2 V3 V t Exponential turn-on V User defined t V datatec Ihr Spezialist für Mess- und Prüfgeräte

17 N6705A Rear View Trigger In/Out Digital port USB, LAN, GPIB (LXI Class C) 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

18 Flexible: Mix and Match Power Modules N6705A DC Power Analyzer, 600W Holds up to 4 modules, below, in any combination 50 W DC Power Modules (6 models up to 100 V or 10 A) 100 W DC Power Modules (6 models up to 100 V or 20 A) 300 W DC Power Modules (4 models up to 100 V or 15 A) For basic DUT or fixture power 50 W High-Performance, Autoranging DC Power Module 100 W High-Performance, Autoranging DC Power Module 300 W High-Performance, Autoranging DC Power Module For applications where power supply plays key role as source and measurement instrument 50 W Precision DC Power Module 100 W Precision DC Power Module For semiconductor testing and applications requiring precision in the milli- and microampere region 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

19 7 New High Power Modules, 300 & 500 Watts Brings the N6700 family total to 33 modules N6755A N6756A N675x N6751A 50V, 5A 50W Max N6752A 50V, 10A 100W Max N6753A 20V, 50A 300W Max N6754A 60V, 20A 300W Max 20V, 50A 500W Max $2800 REF 60V, 17A 500W Max $2800 REF High Performance Series N6763A N6764A N6765A N6766A N676x N6761A 50V, 1.5A 50W Max N6762A 50V, 3A 100W Max 20V, 50A 300W Max $3500 REF 60V, 20A 300W Max $3500 REF 20V, 50A 500W Max $3900 REF 60V, 17A 500W Max $3900 REF Precision Series N6777A N677x N6773A 20V, 15A 300W N6774A 35V, 8.5A 300W N6775A 60V, 5A 300W N6776A 100V, 3A 300W 150V, 2A 300W $1350 REF Basic Series 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

20 New N6700 Series SMU Products - Applications 2-Quadrant SMU for Battery Drain Analysis 20W 20V +1A / 6V +3A 2-Quadrant SMU for Functional Test 20W 20V +1A / 6V +3A 4-Quadrant SMU for General Purpose 20W +20V +1A / +6V +3A Application N6781A N6782A N6784A Battery drain logging and analysis Battery run-down logging & analysis Chip set test PMU test Active device test Semiconductor test Discrete device test Passive device test 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

21 N6781A 2-Quadrant Source/Measure Unit for Battery Drain Analysis Voltage Source Current Source Electronic Load Glitch free sourcing and measurement Multiple measurement ranges Excellent transient response to GSM pulse Stable with capacitive loads up to 150 µf Programmable output resistance: -40mΩ to +1Ω Auxiliary voltage measurement input for battery rundown test Measurement Built-in digitizer of 200,000 samples/second +6V -3A -1A +20V +1A +6V +3A Introduced in A Software 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

22 Making Measurements Battery Rundown Test N6781A only Battery Rundown Test (Single reading, Scope or Data log) Zero-burden ammeter mode --plus-- Aux input voltage measurement to measure battery voltage Gives most realistic assessment of DUT operation under battery power Your power source _ Battery Current Drain 0 Volts Ammeter + DUT Aux In Voltage Measurement on N6781A Up to datatec Ihr Spezialist für Mess- und Prüfgeräte

23 Example Application: Helping to solve an ABS module manufacturing problem Problem: At automotive body & assembly plant, during final assembly, as battery connector was slid onto battery post, intermittent power was briefly applied to ABS module causing ABS light to erroneously come on Testing requirement: Quality Engineers needed a way to simulate intermittent power to the ABS module to test it on the bench 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

24 Example Application: Helping to solve an ABS module manufacturing problem (continued) Solution: N6705A arbitrary waveform generator was used to create a variety of power drop-outs to look for problems and evaluate margin after design changes were made Arb definition: User defined voltage Only part of arb shown above Voltage bouncing between 0V & 14.4V Experiment with time settings & number of dropouts to try to create problem Scope view 200ms/div Shows simulated intermittent battery connection 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

25 Effect of Output Capacitor on Current Measurements Ic = C x dv/dt Each module measures its output current here Ic = cap current User s current Note: Ic flows only when Vout is changing 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

26 5000V/s slew rate Compensate current measurements during voltage transients setting 25V step N6762A, no load The only difference 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

27 14585A Control and Analysis Software for the DC Power Analyzer Works with N6705A/B, N6715A/B mainframes only Simultaneously control up to 4 mainframes; Up to 16 power supplies Advanced features made easy, such as record & playback Works with all N6700 modules $1,240 per mainframe license (after 30 day free trial) 2014 datatec Ihr Spezialist für Mess- und Prüfgeräte

28 Dynamic Battery Test Examples Examples of dynamic battery drain: GSM phone current during a phone call Digital camera current during a picture Google G1 phone current during boot process (turn on) Dynamic battery drain reproduced using N6781A as an electronic load: All screenshots are of 14585A Control & Analysis Software for the DC Power Analyzer datatec Ihr Spezialist für Mess- und Prüfgeräte

29 Agilent Basic DC Power Supplies Non-programmable (for Labs and Low-cost Manufacturing) U8000A 90 W, 150 W Being discontinued E3610A-17A 30 W - 60 W E3620A 50 W E3630A 35 W $290 Single output 11 models Multiple Output $700 Programmable (All have GPIB -- some include RS-232 or USB + LAN/LXI) E3640A-45A Single Output 30 W - 80 W E3646A-49A Dual Output 60 W W E3631A Triple Output 80 W E3632A-34A Single Output 120 W W N5700 Single Output 750 W, 1500 W N8700 Single Output 3200 W, 5100 W N8900 Single Output 5 kw, 10 kw, 15 kw $ models $12,000

30 Agilent Performance DC Power Supplies $8,000 $20,000 $4,000 $15,000 N6700 Low-Profile Modular Power System $6,000 $20, Modular Power System 8 x 150 W, for legacy systems N6705 DC Power Analyzer Single Output DC, GPIB, Ideal for ATE, Accurate, Low Noise W W, 2Q W W W N6900 Advanced Power System 1000 W, 2000 W W $2, models $8, W

31 Agilent Precision DC Power Supplies U2722/3A USB Modular Source Measure Unit B2900A Precision SMU B2960A 6.5 Digit Low Noise Power Source E5260A series High Speed Measurement E5270A series High Precision Measurement B1500A Semiconductor Device Analyzer B1505A Power Device Analyzer / Curve Tracer $2,300-$4,000 $6, models $13,000 $20,000-$110,000 $50,000-$150,000 $70,000-$250,000 $2,000 5 modules $5,000 $2,000 5 modules $5,000 $9, models $12,900 N676xA Series Precision DC Power Modules 50 W, 100 W, 300 W, 500 W N678xA Series SMU and Application Specific Modules N7900 Series Dynamic DC Power Supplies Advanced Power System 1000 W, 2000 W

32 The APS: A high performance ATE system dc power supply Small, fast and accurate Advanced triggering Advanced measurements Low output noise Optional: 2-quadrant source/sink operation Optional: strip-chart recorder for forensic troubleshooting The APS has 2 series, each optimized to meet your test needs N6900 Series DC Power Supply N7900 Series Dynamic DC Power Supply Designed for ATE applications where high performance is critical Designed for ATE applications where high-speed dynamic sourcing and measurement is needed

33 DC to DC Converter Test with the APS Test setup with the APS APS, Dynamic DC Power Supply Target power range ~500 W to 5 kw Load DC to DC Converter The APS will make your DC to DC converter customer s life easier by: Providing an integrated one box solution APS provides an integrated solution Providing throughput, performance, and test integrity never before seen in a power product

34 Bidirectional DC to DC Converter Test with the APS Bidirectional DC to DC Converter Can allow current to flow in both directions. Used widely in energy storage applications Today most customers use a power supply, electronic load, and a switch This method is not a continuous 2 quadrant solution APS Power Supply APS Power Dissipater Test setup with the APS APS power supply combined with the APS Power Dissipater Unit solves bidirectional DC to DC converter test challenge Provides a continuous 2-quadrant solution

35 Why Buy the APS for DC to DC Converter Customer test challenges APS solves them Increasing test throughput Output speed, List mode, advanced triggering Generating power transients AWG capabilities, fast output, high output bandwidth Characterizing dynamic currents I and V digitizers, seamless ranging, high resolution

36 Why Buy the APS for DC to DC Converter Customer test challenges APS solves them Efficiency measurements I V measurements, datalogging, high accuracy Characterizing inrush current I V digitizers, advanced triggering, slew rate control +V Continues current source and sink -A E-Load Quadrant II DC Source Quadrant I +A Provides continuous two quadrant operation

37 The Agilent Advanced Power System 1000 W in 1U 2000 W in 2U Agilent N6900 Series DC Power Supplies 1000 W and 2000 W Agilent N7900 Series Dynamic DC Power Supplies 1000 W and 2000 W Accessories N6950A 9V, 100A N6951A 20V, 50A N6952A 40V, 25A N6963A 60V, 16.7A N6954A 80V, 12.5A N7950A 9V, 100A N7951A 20V, 50A N7952A 40V, 25A N7963A 60V, 16.7A N7954A 80V, 12.5A N7907A Rack Mount Kit N7908A Black Box Recorder N7909A 1000 W Power Dissipater Unit N6970A 9V, 200A N6971A 20V, 100A N6972A 40V, 50A N6973A 60V, 33A N6974A 80V, 25A N6976A 120V, 16.7A N6977A 160V, 12.5A N7970A 9V, 200A N7971A 20V, 100A N7972A 40V, 50A N7973A 60V, 33A N7974A 80V, 25A N7976A 120V, 16.7A N7977A 160V, 12.5A High performance ATE system dc power supplies (400 V and 600 V models under investigation)

38 APS rear panel and connections LAN, USB, GPIB All 3 computer interfaces are standard Earth ground point DC output bus bars Universal AC in Trigger in/out and digital I/O connector Parallel control connector Remote sense connector Dissipater connectors

39 APS N6900 and N7900 series 2-quadrant operation +V E-Load DC Source N7909A 1000 W in 1U Full Rack -A Quadrant II Quadrant I +A 100% Add an N7909A Power Dissipater Unit to any APS power supply to provide continuous sink current at up to 100% with no limits on duty cycle Provides seamless transition between source and sink. All control comes from the DC Source. No extra programming or interfacing required. Add one dissipater for each 1 KW unit; add two dissipaters for each 2 KW unit Gives you a DC Source and E-load in one setup with measurement and control of current flow in either direction (source or sink) Ideal for testing batteries and other bi-directional power sources, or for emulating dynamic braking of motors

40 1000 W, 1U power supply power and sense connections Output power bus bars Remote sense Plastic safety cover with knock-outs for bus bars or wires of various sizes

41 APS seamless current measurement ranging Go faster with no time wasted during ranging Range Measurement Accuracy Example using APS N7974A 80V, 25A, 2000W = Seamless range change High range 25 A (100% of FS) ±(0.04% ma) Activity Amperes Low range 2.5 A (10% of FS) ±(0.05% µa) Idle Time (ms)

42 APS N7900 series built-in data logger Operates in continuously sampled mode Sample Interval n Min = 100 µs Max = 60 s Sample Interval n+1 Sample Interval n+2 Avg Min Max Avg Min Max Sampled every 5 µs Select what measurements to log: V average, V min, V max, I average, I min, I max Readings stored in circular buffer of 200K readings (= 20 s at max speed). User written app needs to unload before buffer over-writes. Longer interval gives data reduction but still fast measurement BW No gaps in data; never misses a sample

43 1000 W, 1U APS power supply with dissipater unit CAT-6A, 1 m max Signals are not Ethernet High current twisted wire, 1 m max

44 APS N7908A Black Box Recorder Unique and innovative feature for high value DUTs Concept: Flight Data Recorder on an airplane Continuously records everything that is happening No configuration needed; always running from moment AC switch is turned on Completely independent from all sourcing and measurement functions Circular recording size of 24 hours at 100 readings/second (=8.6M readings) or 10 days at 10 readings/second. Non-volatile and user installable An airplane s flight data recorder Each reading captures: Min, max, average V out, I out, P out, all status, events (front panel or commands received, trigger occurred, user generated tags) You can read out a snapshot of the recording whenever you want. Recording continues while you are extracting the data. Includes a Windows software utility to decode the recording and see the traces on a timeline Capture critical data with no effort. Eliminates need for external strip chart recorders.

45 Measurement Challenge: Dynamic Current Devices with dynamic current, such as battery operated mobile devices, transition between sleep current, idle current pulses and active current pulses when in full transmit mode Measuring low current, pulsing current, current with fast rise/fall times over a wide dynamic range is difficult: Extremely wide dynamic range Current signal rapidly changing (wake up, transmit, go back to sleep) Current varies (random in nature) depending on what tasks the device/subcircuit is doing Cannot make these difficult measurements using today s test tools A µa na Active current pulses Idle current pulses Sleep current and, customers also worry about: Does the DC source impact my current measurement accuracy? How do I make long term (data logging) measurements?

46 Test Challenge: Unable to Measure Dynamic Current Accurately Using Today s Methods Scope DMM V meas shunt shunt V burden V bat V shunt V DUT I bat DUT V bat I bat V DUT DUT Scopes V DUT = V bat V shunt Sufficient bandwidth for dynamic current Insufficient accuracy Selecting proper shunt is nearly impossible to get good low current measurement and tolerable burden voltage at high current Current probe compensation and drift DMMs/Ammeters: V DUT = V bat V burden Sufficient accuracy Insufficient bandwidth for dynamic current Imposes an unacceptable burden voltage Range changing is slow Range changing turns off output and in some cases causes DUT to shut off

47 Dual Channel Current Probes with Sense Resistors Agilent N2820A current probe example Vcc DUT Zoom-out view Low gain amp R s High gain amp Zoom-in view

48 Test Challenge: Unable to Measure Dynamic Current Accurately Using Today s Methods SMU shunt PC Data Acq equipment V shunt I bat V DUT DUT shunt V bat V DUT = V bat V shunt V bat V shunt V DUT I bat DUT Traditional SMUs Easy to connect, provides DC voltage, sufficient bandwidth, built-in measurement Measurement system unable to handle dynamic pulsing currents when spanning multiple ranges Autoranging measurement system causes DC output instability issues Burden voltage issues, multiple internal shunts V DUT = V bat V shunt Custom Digitizing System: Offers high sampling rates, data logging Requires multiple instruments, multiple shunts, complex configurations Requires programming Measurement accuracy suffers at very low levels Offset, drift, and noise issues

49 Patented Seamless Current Measurement Included in N6781A and N6782A SMU s Range Measurement Accuracy = Seamless range change Seamless Range Changes 3 A ±(0.03% µa) TRANSMIT MODE Current 100 ma ±(0.025% + 10 µa) STANDBY MODE 1 ma ±(0.025% na) SLEEP MODE 10 µa ±(0.025% + 8 na) FIXED RANGE See the complete current waveform you ve never seen before from sub µa to A in one pass and one picture Time

50 What Is an SMU? = Source/Measure Unit SMU = Precision PS + DMM SMU is a single or combination of voltage/current sources and voltage/current measurements. Like power supply Voltage source, current source Like multi-meter Voltage meter, current meter As an SMU I-V measurement Voltage source - Current measurement Current source - Voltage measurement Diode I-V curve 4 functions in 1 frame

51 B2900A Line Up B2900A Source Measure Unit : Good Source and Measure Capability B2960A Low noise Power Source : Low Noise & Excellent Sourcing capability Source Function Measure Function Source Function Measure Function 5.5 digit source (*1) (1 µv/1 pa) 6.5 digit measure 6.5 digit source (100 nv/10 fa) 4.5 digit measure Sweep waveform generation function I/V-t plotting Sweep waveform generation function I/V-t plotting 2,500 points Introduced May, 2011 Sweep measurement & I-V plotting Measurement auto-range 10 µvrms output noise Performance (*2) Built-in waveform generation function 100,000 points Introduced Nov I/V characteristic *1) 6.5 digit for B2911A/12A *2) with noise filter option emulation function

52 B2960A with low noise filter option offers World s Lowest Noise Source What is Great? Achieve ultra low noise which is required for recent sensitive devices. >x 100 less noise than other competitor s product! > 3mVrms (conventional switching power supply) Conventional Switching DC Source Much smaller than scope s resolution! 10µVrms / 350µVrms B2961A/62A +ULNF LNF:N1294A-021 Low Noise Filter (210V/3A) ULNF:N1294A-022 Ultra Low Noise Filter (42V/105mA)

53 Application Example for B2960A: Bias Source with Network/Spectrum Analyzer S21 S12 S22 S11 S parameter measurements using voltage source mode Issues: The conventional power supplies require a bias resistor to source current in order to bias circuits Solved: The B2961A s current source mode makes it easy to provide a more precise and repeatable current bias. 55 ma 40 ma 30 ma 25 ma Forward gain (S21) measurements with various current using current source mode

54 B2900A: Front View Trigger key generates a single trigger Auto key turns the automatic trigger on/off Vertical Softkeys (Asist keys) set the measurement condition On/Off switch enables/disables the output Rotate knob assists moving among input fields (click to set) Horizontal Softkeys (Function keys) set the instrument condition View key changes view mode Cancel/Local key cancels the current operation or return the control mode to local SMU Channel 1 Output

55 B2900A: Rear View SMU Channel 2 Output (2-channel models) Digital I/O for triggering and interlock functions GPIB, USB, and LAN ports for instrument remote control.

56 B2900A Related Accessories Model Description Note 1 N1294A-001 Banana - Triax Adapter for 2-wire (non recommend typ. < 1nA Kelvin) connection 2 N1294A-002 Banana - Triax Adapter for 4-wire recommend typ. < 1nA (Kelvin) connection 3 N1294A-021 Ultra Low Noise Filter (42V/105mA, 50Ohm) for B2961/62A only for B2961/62A 4 N1294A-022 Low Noise Filter (210V/3A) for B2961/62A only for B2961/62A 5 N1294A-031 GPIO - BNC Trigger Adapter 6 N1295A Device/Component Test Fixture with 4 Triax Connectors for Agilent B2900A Series <= 42V, 1A DC A Triaxial Cable (Not Disty Preferred) L GND Cable (Not Disty Preferred) B COAXIAL CABLE (Not Disty Preferred) , 8 5

57 What is a Source/Measure Unit (SMU)? Simplified equivalent circuit (2-wire measurements): Voltage Source Ammeter A + - V High Force Low Force Chassis Ground Current Source Voltmeter Note: The tight integration of these measurement resources yields better accuracy and faster measurement than would an equivalent collection of separate instruments.

58 Why Are Triaxial Cables Needed for Low-Current? BNC (Coaxial) Cable: Triaxial Cable: Leakage Current: Leakage Current: Triaxial cable reduces leakage current by a factor of 100,000,000.

59 Triaxial SMU Outputs Simplified Diagram Buffer x1 The guard voltage tracks the force voltage exactly. Cable charging current and noise are eliminated. Do not ever short the guard to the force line or ground line! Guard V Rs Simplified SMU Schematic Ground Force

60 What is a 4-Wire (Kelvin) Measurement? I Force Force Line 2 R cable R cable Force Line 1 R DUT - + Sense Line 2 R cable V Sense R cable Sense Line 1 I=0 I=0 Eliminate cable resistance from the measurement

61 SMU Sense, Force & Guard Connections Simplified Diagram Buffer x1 Guard Sense Relay Force V Shield

62 Quick I/V Software Provides Convenient PC-Based Instrument Control

63 VIELEN DANK FÜR IHRE AUFMERKSAMKEIT.