Two-Port Analyzers Book

0 Preface

1 TPA Concepts

What Are TPAs? 1

Ports 3

Bipolar Junction Transistors 5

Incremental and Static Resistance 7

BJT T Model 9

BJT Configurations 10

Common-Emitter (CE) Amplifier 11

Transistor Parameters 14

Parameter Measurements 15

   BJT α 15

   BJT and FET Transconductance, r_m 15

   BJT Emitter Incremental Resistance, r_e 16

   BJT and FET Early Voltage, V_A, and r_o 16 

   FET μ 18

Transistor Failures 19

Tek 575 Transistor Curve Tracer 20

   Electron-Tubes 21

   Tek 575 Step-Generator Circuit 22

Measuring FETs and IGBTs 25

Transistor Parameter Analyzers 25

The Two-Port Analyzer (TPA) 26

Port Current Interaction 27

SMU Input Interface 29

Number of Supplies 30

A/D and D/A Converters in Circuits 31

2 Source-Measure Unit Sensing

Voltage- and Current-Sense Interaction 34

Voltage-Current Sense Interaction 36

   Sense Compensation: Grounded COM 37

   Sense Compensation: Floating COM 43

   Active Compensated Divider Circuits 46

TPA SMU Configurations 50

High-Side Current-Sense Circuits 53

   Wilson Current Mirror 54

One-Op-Amp Diff-Amp 57

The Effect of Resistor Tolerances 60

Diff-Amp Common-Mode rejection 64

Statistical Error Analysis 67

SMU Calibration 76

   Two-Point Calibration 77

   Diff-Amp Characterization 79

   Diff-Amp Measurement 80

Software VSN Compensation 83  

Software ISN Compensation 84

High-Side One-Op-Amp Diff-Amp ISN 85

Gain-Switched One-Op-Amp Diff-Amp 89

Trimmed Resistance Design 92

μC-Based Σ-Δ ADCs 94

   The Σ-Δ ADC 95

   Simple mC-Based S-D ADCs 96

   Σ-Δ ADCs with Op-Amp Integrator 101

   Σ-Δ ADC Dynamics 102

ADC Input Ranging 104

   Two-Resistor Bipolar-to-Unipolar Conversion 104

   General Bipolar-to-Unipolar Conversion 105

   ADC Input Divider Design Procedure 107  

3 Source-Measure Unit Driving

Amplifier Types by Output Polarities 110

Switched Differential-Output Driver 114

Driver Operational Envelope 115

Amplifier Supply Margins 116

High-Efficiency Analog Amplifiers 119

   Series and Parallel Segmented Amplifiers 123

   Optimal Segmented Supply Voltages 129

Polarity-Switched Driver Input Range 134

Error from Driver Input Current 134

Ground Current from Floating ISN 134

TPA Input-Current Error 136

LLF High-Voltage Driver Feedback Loop 139

Optimal Optocoupler Placement 144

Bipolar Op-Amp Current Source 147

Feedback Amplifier Port Impedances 148

   Feedback Amplifier Example 152

   Transistor High-Frequency Port Impedances 154

Driver Output Stability 157

Guard Stabilization 162

HP 4145A Guard Circuit 168

4 Simple μC TPAs: TPA240 and TPA242

Specification 170

TPA240 INP and OUT SMUs 173

TPA242 INP and OUT SMUs 174

TPA242 Diff-Amp Error 176

TPA242 Power Supply 180

TPA42x Software 181

5 TPA201

Specification 182

TPA201 Input SMU 183

TPA201 Output SMU 186

TPA201 Power Supply 188

6 TPA202

Description and Specifications 191

TPA202 Input-Port SMU 194

TPA202 Output-Port SMU 196

TPA202 DVM 201

TPA202 Power Supply 205

TPA202 Adjustment and Calibration 206

7 TPA203 

Specification 208

TPA203 Input-Port SMU 208

TPA203 Output-Port SMU 210

TPA203 Power Supply 214

8 The Floating Differential Source

FDS Functions 218

FDS Specifications and Capabilities 220

Circuit Description 223

FDS Floating Differential-Mode Source 223

FDS Current Source 227

FDS Common-Mode Source 227

FDS Digital Voltmeter 230

FDS Front-Panel & Serial Port 234

FDS Power Supply 237

FDS Calibration 240

Output Attenuator Increases Resolution 241

   High-Side Current-Sense CM Gain 242

Diff-Amp Resistance Measurement 244

9 TPA204

TPA204 SMUs 247

TPA204 OUT SMU 249

μC, DVM, and Front-Panel 251

TPA204 Power Supply 253

TPA204 Sense Circuits Error Estimation 256

10 TPA Software

TPA Family Functions 259

TPA Software Model 260

Command-Line Structure 262

TPA Command Set 264

Switch Mouse 266

Numeric Display 267

Graphic DSO and LCD Displays 268