Page 1 Component Industry Trends Driven by New End-User Equipment VHS * #
Page 2 Agenda Impedance Measurement Basics Measurement Discrepancies Measurement Techniques Error Compensation
Page 3 Impedance Definition Impedance is the total opposition a device or circuit offers to the flow of a periodic current AC test signal (amplitude and frequency) Includes real and imaginary elements Z = R + j X Z = R + j B B G RX
Page 4 Impedance Measurement Plane O - Z = R + jX = |Z| = ARCTAN X R |Z| Resistive Real Axis Imaginary Axis Capacitive Inductive +j -j |Z| = R + X 2 2 D U T ( ) O - - O
Page 5 Admittance Measurement Plane O - Y = G + jB = |Y| = ARCTAN B G |Y| Conductive Real Axis Imaginary Axis Inductive Capacitive +j -j |Y| = G + B 2 2 D U T ( ) O - - O Y=1/Z
Page 6 Agenda Impedance Measurement Basics Measurement Discrepancies Measurement Techniques Error Compensation
Page 7 Which Value is Correct? Z Analyzer Q : 165 Q = 120 LCR meter L : uH ? ? Q : 120 LCR meter D U T L : uH uH uH
Page 8 Measurement Discrepancy Reasons Component Dependency Factors Measurement Errors True, Effective, and Indicated Values Circuit Mode (Translation Equations)
Page 9 Kobe Instrument Division Back to Basics - LCRZ Module Measurement Discrepancy Reasons Component Dependency Factors Test signal level Test signal frequency DC bias, voltage and current Environment (temperature, humidity, etc.)
Page 10 Component Parasitics Complicate the Measurements
Page 11 Real World Capacitor Model Includes Parasitics
Page 12 Quality and Dissipation Factors Q = R Energy lost Energy stored = X R 0 Q O s s O Different from the Q associated with resonators and filters The better the component, then D = 1 Q, mainly used for capacitors
Page 13 Capacitor Reactance vs. Frequency Capacitor Model |X| Frequency X = wL X = 1 wC L C
Page 14 Example Capacitor Resonance Impedance vs. Frequency A: |Z| A MAX B MAX deg B: MKR Hz MAG PHASE mdeg A MIN START Hz STOP Hz 0 B MIN deg m m
Page 15 Kobe Instrument Division Back to Basics - LCRZ Module C Variations with Test Signal Level SMD Capacitors, Various dielectric constants K Vac C Low K Mid K High K C vs DC Voltage Bias Type I and II SMD Capacitors Vdc Type I Type II C / % NPO (low K) X7R (high K) C vs AC Test Signal Level
Page 16 Kobe Instrument Division Back to Basics - LCRZ Module C vs. Temperature Type I and II SMD Capacitors T / C Type I Type II C / % NPO (low K) X7R (high K)
Page 17 L vs. DC Current Bias Level Power Inductors Idc L / %
Page 18 Component Dependency Factors Test signal frequency Test signal level DC bias, voltage and current Environment ( temperature, humidity, etc.) Aging Component's current state
Page 19 Which Value Do We Measure? TRUE EFFECTIVE INDICATED +/- Instrument Test fixture Real world device %
Page 20 Measurement Set-Up DUT R + jXx x Test Fixture Instrument Port Extension
Page 21 Sources of Measurement Errors Measurement technique inaccuracies Fixture residuals RFI and other noise DUT stray and lead parasitics Port Extension complex residuals
Page 22 Sources of Measurement Errors DUT R + jX x x Test Fixture Instrument Port Extension Technique Inaccuracies Residuals Noise Parasitics Complex Residuals
Page 23 Actions for Limiting Measurement Errors DUT R + jXx x Test Fixture Instrument Port Extension Calibration Compensation Guarding LOAD Compensation EShielding
Page 24 What Do Instruments... I-V Method Reflection Coefficient Method Measured Direct I, V Z = Ls, Lp, Cs, Cp, Rs or ESR, Rp, D, Q Calculations Model based Approximations C R C R p p s s D U T ? x,y Z = Z o I V Measure ? Calculate ? Approximate ?
Page 25 Circuit Mode Requires Simplified Models No L Capacitor Model Complete Capacitor Model Rs,Ls,Rp,Cp ? TOO COMPLEX
Page 26 Circuit Mode Large C Small C No L Capacitor Model Series model Parallel model Rs Rp C Rs Cs Rp Cp Small L Large L Rs vs Rp, who wins ? SMD
Page 27 Which Model is Correct ? Both are correct One is a better approximation For high Q or low D components, C s C p C R C R C = C (1 + D ) p p s s sp 2
Page 28 Agenda Impedance Measurement Basics Measurement Discrepancies Measurement Techniques Error Compensation
Page 29 Measurement Techniques Auto Balancing Bridge Resonant (Q-adapter / Q-Meter) RF I-V Network Analysis (Reflection Coefficient) TDR (Time Domain Reflectometry) I-V (Probe)
Page 30 Measurement Technique Topics Technique Selection Criteria Theory of Operation Advantages and Disadvantages of each technique Expanded connection information and theory for auto balancing bridge (r4 terminal pair) instruments Error Compensation to minimize measurement error
Page 31 Measurement Technique Selection Criteria Frequency DUT Impedance Required measurement accuracy Electrical test conditions Measurement parameters Physical characteristics of the DUT
Page 32 Frequency vs. Measurement Techniques Network Analysis 100KHz K 10K100K 1M 10M 100M 1G 10G Frequency (Hz) Auto Balancing Bridge 5HZ 40MHz 22KHz 70MHz Resonant I-V 10KHz110MHz 30MHz RF I-V 1 MHz1.8 GHz
Page 33 Z and C vs. Frequency K 10K100K 1M 10M 100M 1G 10M 1M 100K 10K 1K m 1mF 10mF 100mF 100uF 10uF 1uF 100nF 10nF 1nF 10pF 100fF 1fF Frequency (Hz) Impedance (Ohms) pF 1pF 10fF
Page 34 Reactance Chart K 10K100K 1M 10M 100M 1G 10M 1M 100K 10K 1K m 10nH 1nH 100pH 100nH 1uH 10uH 100uH 1mH 10mH 100mH 10H 1KH 100KH 1mF 10mF 100mF 100uF 10uF 1uF 100nF 10nF 1nF 10pF 100fF 1fF Frequency (Hz) Impedance (Ohms)
Page 35 Solution by Frequency Comparison Frequency 10M 1M 100K 10K 1K m Impedance (Ohms) 10m 1m 100M 100K 1M 10M 100M 1G Hz 10G Network Analysis RF I-V K 10K I-V (Probe) Auto Balancing Bridge
Page 36 Which is the Best ? All are good Each has advantages and disadvantages Multiple techniques may be required
Page 37 Auto Balancing Bridge Theory of Operation V V 1 DUT V = I R Z = V I 1 2 = V R V H L R 2 I 2 Virtual ground I I = I 2
Page 38 Auto Balancing Bridge Most accurate, basic accuracy 0.05% Widest measurement range Widest range of electrical test conditions Simple-to-use Advantages and Disadvantages Low frequency, f < 40MHz C,L,D,Q,R,X,G,B,Z,Y,O,...
Page 39 Performing High Q / Low D Measurement is Difficult Q = X R l -jX +jX R Impedance of very high Q device Very small R, difficult to measure R1 X1
Page 40 Resonance (Q - Meter) Technique Theory of Operation Tune C so the circuit resonates At resonance X = -X, only R remains DC D V ~ OSC Tuning C (X c) V L (X ), R D D DUT e I= e Z X = = (at resonance) C V I R V e D Q = = = |V| e |X | R D D R D C
Page 41 Resonant Method Advantages and Disadvantages requires experienced user VectorScalar automatic and fast manual and slow easy to use No compensation limited compensation 75kHz - 30MHz 22kHz - 70MHz Very good for high Q - low D measurements Requires reference coil for capacitors Limited L,C values accuracy
Page 42 I - V Probe Technique Theory of Operation V 2 V 1 DUT V = I R Z = V I 1 2 = V R V I 2 R 2
Page 43 I-V (Probe) Medium frequency, 10kHz < f < 110MHz Moderate accuracy and measurement range Advantages and Disadvantages Grounded and in-circuit measurements Simple-to-use
Page 44 RF I-V Theory of Operation Vi Vv Ro Vi Vv Ro DUT Voltage Current Voltage Detection Current Detection High Impedance Test Head Low Impedance Test Head
Page 45 RF I-V High frequency, 1MHz < f < 1.8GHz Most accurate method at > 100 MHz Grounded device measurement Advantages and Disadvantages
Page 46 Network Analysis (Reflection) Technique Theory of Operation DUT V V INC R V V R Z - Z L O Z + Z L O = =
Page 47 Network Analysis High frequency - Suitable, f > 100 kHz Moderate accuracy Limited impedance measurement range (DUT should be around 50 ohms) Advantages and Disadvantages - Best, f > 1.8 GHz
Page 48 H TDR Theory of Operation V V INC R Z - Z L O Z + Z L O = = Z L DUT Oscilloscope Step Generator V V INC R Series R & L Parallel R & C 0 t
Page 49 TDNA (TDR) Reflection and transmission measurements Single and multiple discontinuities or impedance Advantages and Disadvantages DUT impedance should be around 50 ohms mismatches ("Inside" look at devices) Good for test fixture design, transmission lines, high frequency evaluations Not accurate for m or M DUTs or with multiple reflections
Page 50 Simple Selection Rules Summary Auto balancing bridge, I-V, in-circuit and grounded measurements, medium frequency, 10KHz < f < 110MHz low frequency, f < 40MHz Network analysis, Resonant, high Q and low D TDNA, discontinuities and distributed characteristics high frequency, f > 1.8 GHz RF I-V, high frequency impedance measurement, 1MHz < f < 1.8GHz
Page 51 Measurement Methods and HP products Auto Balancing Bridge (Four-Terminal Pair) Resonant (Q-Meter) RF I-V Measurement MethodHP ProductsFrequency range HP 41941A Impedance Probe (with HP 4194A) HP 4193A Vector Impedance Meter HP 42851A Q Adapter ( with HP 4285A) 10KHz to 100MHz 400KHz to 110MHz 10Hz to 40MHz 5Hz to 13MHz 20Hz to 1MHz spot 100Hz to 10MHz spot 75KHz to 30MHz HP 4263A LCR Meter HP 4284A Precision LCR Meter HP 4192A LF Impedance Analyzer HP 4194A Impedance/Gain-Phase Analyzer HP 4285A Precision LCR Meter HP 427xA LCR Meters HP 4286A RF LCR Meter HP 4291A Impedance/Material Analyzer 100Hz to 100 kHz spot 1 MHz to 1 GHz 1 MHz to 1.8 GHz I-V (Probe)
Page 52 Measurement Methods and HP products (cont.) Network Analysis (Reflection Coefficient) TDNA (TDR) Measurement Method HP Products Frequency range 300KHz to 1.3GHz/6GHz 130MHz to 13.5GHz/20GHz 45 MHz to 100GHz 5Hz to 500MHz 100 kHz to 500MHz 100 kHz to 1.8 GHz HP 8751A Network Analyzer HP 8752C/8753D RF Network Analyzers HP 8510B Network Analyzer HP 54121T Digitizing Oscilloscope and TDR HP 4195A Network/Spectrum Analyzer with HP 41951A Impedance Test Set HP 8752C/8753D RF Network Analyzers HP 8719C/8720C Network Analyzers HP 8510B Network Analyzer HP 8719C/8720C Network Analyzers HP 4396A Network/Spectrum Analyzer with HP 43961A Impedance Test Kit
Page 53 Selecting a Test Frequency Ideal case is at operating conditions Reality, must make trade-offs Too high a frequency adds measurement, test fixture and instrument errors m and M DUTs more diffucult to measure
Page 54 Measurement Tradeoff Example K 10K100K 1M 10M 100M 1G 10M 1M 100K 10K 1K m 1mF 10mF 100mF 100uF 10uF 1uF 100nF 10nF 1nF 10pF 100fF 1fF F (Hz) 100pF 1pF 10fF Z ( ) 1MHz (1600 ) : 0.05% 4284A4194A A Want to measure 100 pF ideal 200 MHz 10MHz (160 ) : 1.3 % 40MHz ( 40 ) : 5.2 % 40MHz ( 40 ) : 3.6 % 100MHz ( 16 ) : 6.2 % 200MHz ( 8 ) : 1.9 % Accuracy comparison
Page 55 Auto Balancing Bridge A: Cp A MAX pF B MAX m B: D MKR Hz Cp pF A/DIV fF START Hz STOP Hz B\DIV m D
Page 56 I - V A: Cp A MAX pF B MAX B: D MKR Hz Cp pF A/DIV fF START Hz STOP Hz B MIN D
Page 57 Network Analysis A: REF 13.00p [ F ] B: REF MKR Hz Cp p F DIV START Hz STOP Hz 500.0f D IMPEDANCE [ F ] RBW: 3 KHZ ST: 6.15 sec RANGE: A= 0, T= 0dBm DIV
Page 58 Agenda Impedance Measurement Basics Measurement Discrepancies Measurement Techniques Error Compensation
Page 59 Error Compensation to Minimize Measurement Errors Compensation and Calibration (Compensation = Calibration) – Definition of Compensation and Calibration – Cable correction OPEN/SHORT Compensation – Basic Theory – Problems which can not be eliminated by OPEN/SHORT compensation OPEN/SHORT/LOAD Compensation – Basic Theory – Load device selection Practical Examples Summary
Page 60 To define the "Calibration Plane" at which measurement accuracy is specified Definition of Calibration Z Analyzer LCR Meter Standard Device 100 Calibration Plane (Measurement accuracy is specified.) ! 100
Page 61 Cable Correction Definition : Calibration Plane extension using specified HP cables (HP 16048A/B/D/E) LCR Meter LCR Meter HP Measurement Cable Calibration Plane
Page 62 Definition of Compensation To reduce the effects of error sources existing between the DUT and the instrument's "Calibration Plane". Z Analyzer LCR Meter Fixture Cables Scanner, etc Z Z DUT types of compensation - OPEN/SHORT compensation - OPEN/SHORT/LOAD compensation Calibration Plane
Page 63 OPEN/SHORT Compensation - Basic Theory - Zdut Rs Ls CoGo Hc Hp Lp Lc Zm Stray Residual Test Fixture Residuals Admittance ( Yo ) Impedance ( Zs ) Zs = Rs + j Ls Yo = Go + j Co Zdut = 1 - (Zm - Zs)Yo Zm - Zs
Page 64 OPEN/SHORT Compensation Issues Problem 1 SCANNER Complicated Residuals Stray capacitance Residual inductance Residual resistance DUT Difficulty to eliminate complicated residuals LCR Meter
Page 65 OPEN/SHORT Compensation Issue Problem 2 Difficulty to eliminate Phase Shift Error LCR Meter DUT Test Fixture Not a standard length cable* * Or not an HP cable
Page 66 OPEN/SHORT Compensation Issue Problem 3 Difficulty to have correlation among instruments. Discrepancy in Measurement Value 100 pF 99.7pF 101 pF 102 pF Ideal CaseReal World Instrument #1 Instrument #2 Instrument #3
Page 67 OPEN/SHORT/LOAD Compensation - Basic Theory - Zdut A B C D DUT V 2 V 1 Unknown 2-terminal Impedance Instrument I 1 I 2 pair circuit
Page 68 OPEN/SHORT/LOAD Compensation - Basic Theory - Zstd (Zo - Zsm) (Zxm - Zs) * Zxm - Zs) (Zo - Zxm) Zdut = Zo : OPEN measurement value Zs : SHORT measurement vaue Zsm : Measurement value of LOAD device Zstd : True value of LOAD device Zxm : Measurement value of DUT Zdut : Corrected value of DUT * These are complex vectors. Conversions to real and imaginary components are necessary
Page 69 OPEN/SHORT/LOAD Compensation Eliminates phase shift error Maximizes correlation between instruments Eliminates complicated residuals
Page 70 OPEN/SHORT/LOAD Compensation Effects ) ( 1 2 C-measurement error [%] Frequency [kHz] OPEN/SHORT compensation OPEN/SHORT/LOAD compensation ) ( 3
Page 71 Procedure of OPEN/SHORT/LOAD Compensation 1. Measure LOAD device 2. Input LOAD measurement value as a reference value. Direct-connected test fixture as accurately as possible.
Page 72 Procedure of OPEN/SHORT/LOAD Compensation 3. Perform OPEN/SHORT/LOAD compensation at the test terminal. 4. Measure DUT at the test terminal. Test Terminal Test Fixture with complicated residuals
Page 73 LOAD Device Selection - Consideration 1 - When you measure DUTs which have various impedance values, Select a LOAD device whose impedance value is 100 ~ 1k . When you measure a DUT which has only one impedance value, Select a LOAD device whose impedance value is close to that of the DUT to be measured.
Page 74 LOAD Device Selection - Consideration 2 - Select pure and stable capacitance or resistance LOAD value must be accurately known. loads (low D capacitors - i.e. mica)
Page 75 Practical Examples 4284A 16047C DUT 4285A 16048D 16047A (A)(B) (1) (2)
Page 76 Practical Examples 4285A DUT 4285A 16048A (C) (D) DUT 16047A Non-HP Cable SCANNER (1) (2)
Page 77 Practical Example (E) 4195A 16092A 41951A (2) (1)
Page 78 Summary Calibration and Compensation Comparison Theory Calibration Cable correction Compensation OPEN/SHORT Compensation OPEN/SHORT/LOAD Compensation Eliminate instrument system errors Define the "Calibration Plane using a CAL standard Eliminate the effects of cable error Extend "Calibration Plane" to the end of the cable Eliminate the effects of error sources existing between "Calibration Plane" and DUT Eliminate the effects of simple fixture residuals Eliminate the effects of complex fixture residuals
Page 79 Summary Which compensation technique should you select? - Selection Guideline - Instruments Fixture Connection Primary Fixture Secondary Fixture Residual Compensation OPEN/SHORT only Cable correction + OPEN/SHORT OPEN/SHORT/LOAD OPEN/SHORT or OPEN/SHORT/LOAD Direct Test Fixture Complicated Fixture Scanner, etc. Direct Test Fixture Other Fixtures Direct Test Fixture Specified HP Cable Non-specified HP cable Non-HP cable Self-made Test Fixture (4284A, 4285A etc.) Z Analyzer LCR Meter Cable correction + OPEN/SHORT/LOAD