1. Analog Dialogue Technical Journal
    2. RAQs

    Rarely Asked Questions

    RAQ Issue: 169
    Issue 169, September 2019

    A Simple Way to Measure Temperature Using One GPIO Digital Interface

    Question: How can I make an analog measurement if I only have a single GPIO left on the FPGA/microprocesser for my system?

    VIEW THE ANSWER
    RAQ Issue: 168
    Issue 168, August 2019

    Bootstrapping a Low Voltage Op Amp to Operate with High Voltage Signals and Supplies

    Question: Can I bootstrap a low voltage amplifier to get a high voltage buffer?

    VIEW THE ANSWER
    RAQ Issue: 167
    Issue 167, July 2019

    When Smaller Is Better

    Question: How does a μModule® regulator fit into such a small space?

    VIEW THE ANSWER
    • RAQ Issue: 166

      How to Convert Light Intensity Into an Electrical Quantity

      Issue 166, June 2019
    • RAQ Issue: 165

      Discrete Difference Amplifier vs. an Integrated Solution

      Issue 165, May 2019
    • RAQ Issue: 164

      Guidelines for Placing the Inductor on a Switch Mode Power Supply Printed Circuit Board

      Issue 164, April 2019
    • RAQ Issue: 163

      SAR Converter with PGA Achieves Dynamic Range of 125 dB

      Issue 163, March 2019
    • RAQ Issue: 162

      Enablement of Batteryless Applications with Wireless Power

      Issue 162, February 2019
    • RAQ Issue: 161

      A New Spin on a Classic Architecture: Achieving a Fully Differential Output Using Single-Ended Instrumentation Amplifiers

      Issue 161, January 2019
    • RAQ Issue: 160

      Simple Circuit Measures Relative Intensity of Two Light Sources

      Issue 160, December 2018
    • RAQ Issue: 159

      When Grounds Are Separated

      Issue 159, November 2018
    • RAQ Issue: 158

      Driving a Unipolar Gate Driver in a Bipolar Way

      Issue 158, October 2018
    • RAQ Issue: 157

      Overvoltage Protection for RTD-Based Measurement Systems

      Issue 157, September 2018
    • RAQ Issue: 156

      Optimized Power Supply Measurement Setup

      Issue 156, August 2018
    • RAQ Issue: 155

      Home on the Range: Getting Multiple Gain Ranges With Instrumentation Amplifiers

      Issue 155, July 2018
    • RAQ Issue: 154

      Pocket-Size White Noise Generator for Quickly Testing Circuit Signal Response

      Issue 154, June 2018
    • RAQ Issue: 153

      High Speed ADC Power Supply Domains

      Issue 153, May 2018
    • RAQ Issue: 152

      Problem Solver: Multiplying Digital-to-Analog Converter

      Issue 152, April 2018
    • RAQ Issue: 151

      High-Side Current Sensing

      Issue 151, March 2018
    • RAQ: Issue 150

      Dynamic Use of the Disable Pin on an Amplifier

      Issue 150, February 2018
    • RAQ: Issue 149

      Intermediate Voltage to Increase Power Conversion Efficiency

      Issue 149, January 2018
    • RAQ: Issue 148

      Unique Gate Drive Applications Enable Rapidly Switching On/Off for Your High Power Amplifier

      Issue 148, December 2017
    • RAQ: Issue 147

      Synchronous Rectification on the Secondary Side

      Issue 147, November 2017
    • raq-issue-146

      Why Is My Processor Leaking Power? That Sounds Like an Open-Ended Question

      Issue 146, October 2017
    • RAQ:  Issue 145

      A Low Power, Low Cost, Differential Input to a Single-Ended Output Amplifier

      Issue 145, September 2017
    • RAQ:  Issue 144

      Accelerometer Tilt Measure Over Temperature and in the Presence of Vibration

      Issue 144, August 2017
    • RAQ: Issue 143

      Burned by Low Power? When Lower Current Consumption Can Get You Into Trouble

      Issue 143, July 2017
    • RAQ: Issue 142

      Orthogonal Perspectives

      Issue 142, June 2017
    • RAQ: Issue 141

      Sometimes, a Signal Needs to Ride the Rails

      Issue 141, May 2017
    • RAQ: Issue 139

      Presto! Multiply Your ADC’s Virtual Channel Count with DDC Magic

      Issue 140, April 2017
    • RAQ:Issue 139

      The Case of the Misguided Gyro

      Issue 139, March 2017
    • RAQ: Issue 138

      This Noise Will Keep You Up at Night

      Issue 138, February 2017
    • RAQ: 137

      Psychotic ADC?

      Issue 137, January 2017
    • RAQ: Issue 136

      Precision Current Outputs Are Easy to Make

      Issue 136, December 2016
    • RAQ: Issue 135

      Amplifier RF: Think Before you Choose!

      Issue 135, November 2016
    • RAQ: Issue 134

      Because Mr. Ohm Said So …

      Issue 134, October 2016
    • RAQ: Issue 133

      Common Sense for Current Sensing

      Issue 133, September 2016
    • RAQ:  Issue 132

      Choosing a Precision Op Amp? Trust Goldilocks.

      Issue 132, August 2016
    • RAQ:  Issue 131

      Going Full Tilt

      Issue 131, July 2016
    • RAQ:  Issue 130

      Who Killed the Component?

      Issue 130, June 2016
    • RAQ:  Issue 129

      Who Ate My dBs?

      Issue 129, May 2016
    • RAQ:  Issue 128

      Citius, Altius, Fortius

      Issue 128, April 2016
    • RAQ:  Issue 127

      Kalman or FIR Filter for My IMU?

      Issue 127, March 2016
    • RAQ:  Issue 126

      When Second Sources Aren't

      Issue 126, February 2016
    • RAQ:  Issue 125

      O CMRR, CMRR! Wherefore Art Thou CMRR?

      Issue 125, January 2016
    • RAQ:  Issue 124

      Missing Half the Signal

      Issue 124, December 2015
    • RAQ:  Issue 123

      Unused Pins

      Issue 123, November 2015
    • RAQ:  Issue 122

      The Truth About Voltage Feedback Resistors

      Issue 122, October 2015
    • RAQ:  Issue 121

      Unfiltered Analog

      Issue 121, September 2015
    • RAQ:  Issue 120

      Voltage References Can Bite You, Too

      Issue 120, August 2015
    • RAQ:  Issue 119

      The Ingenious Gentleman and the Mysterious Paddle

      Issue 119, July 2015
    • RAQ:  Issue 118

      Mystery Spur Explained: Don't Blame the DDC!

      Issue 118, June 2015
    • RAQ:  Issue 117

      Murphy Rules!

      Issue 117, May 2015
    • RAQ:  Issue 116

      Muntzing can save cost, components, and even your sanity

      Issue 116, April 2015
    • RAQ:  Issue 115

      Isn’t that gain specification a bit lopsided?

      Issue 115, March 2015
    • RAQ:  Issue 114

      Choosing Voltage References

      Issue 114, February 2015
    • RAQ:  Issue 113

      Don’t Get Caught Speeding

      Issue 113, January 2015
    • RAQ:  Issue 112

      Exposed Paddles and Downbonds Improve Performance and Reduce Pin Count

      Issue 112, December 2014
    • RAQ:  Issue 111

      Choosing Analog ICs

      Issue 111, November 2014
    • RAQ:  Issue 110

      I Grew Up in the 80s and Survived!

      Issue 110, October 2014
    • RAQ:  Issue 109

      ADCs for High Dynamic Range – Successive-Approximation or Sigma-Delta?

      Issue 109, September 2014
    • RAQ:  Issue 108

      LEDs are Photodiodes Too

      Issue 108, August 2014
    • RAQ:  Issue 107

      The Diamond Plot

      Issue 107, July 2014
    • RAQ:  Issue 106

      Overranged Converter Recovers Quickly

      Issue 106, June 2014
    • RAQ:  Issue 105

      Discretion is the better part…

      Issue 105, May 2014
    • RAQ:  Issue 104

      Looking for Trouble in All the Wrong Places

      Issue 104, April 2014
    • RAQ:  Issue 103

      Programmable ADC Input Range Provides System Benefits

      Issue 103, March 2014
    • RAQ:  Issue 102

      Defying Scrooge

      Issue 102, February 2014
    • RAQ:  Issue 101

      Bits Per Second Make My Head Hertz

      Issue 101, January 2014
    • RAQ:  Issue 100

      RAQs: 100 Issues and Counting

      Issue 100, December 2013
    • RAQ:  Issue 99

      Overrange Flag Indicates Data Validity

      Issue 99, November 2013
    • RAQ:  Issue 98

      Design Tools and Support Communities Make Analog Fun, not Fearful

      Issue 98, October 2013
    • RAQ:  Issue 97

      EngineerZone Makes Getting Answers a Breeze

      Issue 97, September 2013
    • RAQ:  Issue 96

      Soft Clipping vs. Hard Clipping

      Issue 96, August 2013
    • RAQ:  Issue 95

      Do-it-Yourself ASICs

      Issue 95, July 2013
    • RAQ:  Issue 94

      Crystal Radio Sets and Op Amps—Both Can Detect RF Signals

      Issue 94, June 2013
    • RAQ: Issue 93

      Input Magic—Differential Signals Allow Input Swing to Exceed Supply Voltage

      Issue 93, May 2013
    • RAQ:  Issue 92

      Multipliers and Modulators

      Issue 92, April 2013
    • RAQ:  Issue 91

      Noise Gain vs. Signal Gain

      Issue 91, March 2013
    • RAQ:  Issue 90

      Resolution vs. ENOB – Still Hazy After All These Years

      Issue 90, February 2013
    • RAQ:  Issue 89

      Electronics is Fun

      Issue 89, January 2013
    • RAQ:  Issue 88

      The Decline of Rounding—or How Significant is Significance?

      Issue 88, December 2012
    • raq-issue-87

      Apples and Oranges—Correlating Specifications Requires Common Test Conditions

      Issue 87, November 2012
    • raq-issue-86

      Current Transformers—and Vacuum Cleaners

      Issue 86, October 2012
    • raq-issue-85

      Great Expectations Come From Basic Understandings

      Issue 85, September 2012
    • raq-issue-84

      Driving Miss ADC

      Issue 84, August 2012
    • raq-issue-83

      Dual Op Amps and Double Agents

      Issue 83, July 2012
    • raq-issue-82

      Transformers: They’re Not All Boat Anchors

      Issue 82, June 2012
    • raq-issue-81

      Switching Bits

      Issue 81, May 2012
    • raq-issue-80

      The Electromotive Force and Op Amps

      Issue 80, April 2012
    • RAQ:  Issue 79

      Nobody is Perfect – Not Even an Engineer!

      Issue 79, March 2012
    • RAQ:  Issue 78

      Considerations on High-Speed Converter PCB Design, Part 4: Plane Coupling

      Issue 78, February 2012
    • RAQ:  Issue 77

      Beware of big claims and large numbers.

      Issue 77, January 2012
    • RAQ:  Issue 76

      In and Out – or – Why Have a Capacitor?

      Issue 76, December 2011
    • RAQ:  Issue 75

      Crosstalkin’ Converters

      Issue 75, November 2011
    • RAQ:  Issue 74

      Rotary Potentiometers: There Must Be a Better Option

      Issue 74, October 2011
    • RAQ:  Issue 73

      The Benefits of Ancient Logic

      Issue 73, September 2011
    • RAQ:  Issue 72

      Balancing Phase in High-Speed Converters

      Issue 72, August 2011
    • RAQ:  Issue 71

      Looking for savings in all the wrong places

      Issue 71, July 2011
    • RAQ:  Issue 70

      Do Something with that Unused Pin!

      Issue 70, June 2011
    • RAQ:  Issue 69

      Considerations on High-Speed Converter PCB Design, Part 3: The E-Pad Low Down

      Issue 69, May 2011
    • RAQ:  Issue 68

      A Foolish Question about Op Amps and Capacitors

      Issue 68, April 2011
    • RAQ:  Issue 67

      Measuring the DC Parameters of Op Amps

      Issue 67, March 2011
    • RAQ:  Issue 66

      Considerations on High-Speed Converter PCB Design, Part 2: Power and Ground Planes.

      Issue 66, February 2011
    • RAQ:  Issue 65

      Op Amp Dedicated Feedback Pin Helps Achieve New Levels of Performance.

      Issue 65, January 2011
    • RAQ:  Issue 64

      Oversampling and Undersampling

      Issue 64, December 2010
    • RAQ:  Issue 63

      Considerations on High-Speed Converter PCB Design, Part 1: Power and Ground Planes.

      Issue 63, November 2010
    • RAQ:  Issue 62

      Is amplifier headroom cramping your style?

      Issue 62, October 2010
    • RAQ:  Issue 61

      Make do!

      Issue 61, September 2010
    • RAQ:  Issue 60

      Watch for Those Multiple Clocking Edges!

      Issue 60, August 2010
    • RAQ:  Issue 59

      Is Your Amplifier Disabled, or is it Merely Sleeping?

      Issue 59, July 2010
    • RAQ:  Issue 58

      How to Avoid Burning Cakes

      Issue 58, June 2010
    • RAQ:  Issue 57

      Keeping Your A/D Converter Clocks Jitter Free

      Issue 57, May 2010
    • RAQ:  Issue 56

      Amplifier, attenuator or both?

      Issue 56, April 2010
    • RAQ:  Issue 55

      Taming A/D Converter Power Supplies

      Issue 55, March 2010
    • RAQ:  Issue 54

      Don’t be Mean - be Root Mean Square!

      Issue 54, February 2010
    • RAQ:  Issue 53

      VFB or CFB that is the question!

      Issue 53, January 2010
    • RAQ:  Issue 52

      Bring on the Converter Noise! – Part 2

      Issue 52, December 2009
    • RAQ:  Issue 51

      Bring on the Converter Noise! – Part 1

      Issue 51, November 2009
    • RAQ:  Issue 50

      What’s the big deal about ABSOLUTE MAXIMUM RATINGS?

      Issue 50, October 2009
    • RAQ:  Issue 49

      What’s the (Converter) Frequency Kenneth?

      Issue 49, September 2009
    • RAQ:  Issue 48

      Some Chips Have Moving Parts!

      Issue 48, August 2009
    • RAQ:  Issue 47

      Which carries more weight, a datasheet or SPICE macromodel?

      Issue 47, July 2009
    • RAQ:  Issue 46

      What shall we do with an unused op-amp?

      Issue 46, June 2009
    • RAQ:  Issue 45

      Glass Diodes May See the Light — and Hum

      Issue 45, May 2009
    • RAQ:  Issue 44

      Keeping Common Modes Common

      Issue 44, April 2009
    • RAQ:  Issue 43

      Impedance Measuring Chip Offers Little Resistance to Applications

      Issue 43, March 2009
    • RAQ:  Issue 42

      Are Your Filters Filtering?

      Issue 42, February 2009
    • RAQ:  Issue 41

      What’s in Your Toolbox?

      Issue 41, January 2009
    • RAQ:  Issue 40

      How Big Is It?

      Issue 40, December 2008
    • RAQ:  Issue 39

      What The Heck Are Off-Amps?

      Issue 39, November 2008
    • RAQ:  Issue 38

      Single Supply Amplifiers—They Sound Simple…are they?

      Issue 38, October 2008
    • RAQ:  Issue 37

      Lock Down That Noise — Don’t Let It Escape

      Issue 37, September 2008
    • RAQ:  Issue 36

      The Difference Between Different Differential Amplifiers

      Issue 36, August 2008
    • RAQ:  Issue 35

      Stress Is Bad For You — and For Analog ICs

      Issue 35, July 2008
    • RAQ:  Issue 34

      A Capaciticectomy? Sounds Awfully Painful!

      Issue 34, June 2008
    • RAQ:  Issue 33

      Hysteresis Blocks Magic

      Issue 33, May 2008
    • RAQ:  Issue 32

      Political Correctness and Datasheets

      Issue 32, April 2008
    • RAQ:  Issue 31

      Too Hot or Too Cold May Be Just Right*

      Issue 31, March 2008
    • RAQ:  Issue 30

      Capacitive Sensors: Rugged Enough for the Real World?

      Issue 30, February 2008
    • RAQ:  Issue 29

      Half Full or Half Empty? Thoughts on Capacity.

      Issue 29, January 2008
    • RAQ:  Issue 28

      What's Your Amplifier's Febricity Due to Electricity?

      Issue 28, December 2007
    • RAQ:  Issue 27

      Resistors Have Hidden Depths

      Issue 27, November 2007
    • RAQ:  Issue 26

      Op-Amp Noise can be Deafening Too

      Issue 26, October 2007
    • RAQ:  Issue 25

      Resistor Noise can be Deafening, and Hard to Reduce

      Issue 25, September 2007
    • RAQ:  Issue 24

      Are leaky amps sinking your design?

      Issue 24, August 2007
    • RAQ:  Issue 23

      Should you butcher your circuit or your test gear?

      Issue 23, June 2007
    • RAQ:  Issue 22

      Things (animals and ADCs) are not always what they seem

      Issue 22, May 2007
    • RAQ:  Issue 21

      Breadboarding With Surface Mount ICs

      Issue 21, April 2007
    • RAQ:  Issue 20

      Igor, pass me some supply sequencers!

      Issue 20, March 2007
    • RAQ:  Issue 19

      Observing Maximum Ratings or How to Avoid Forecasts of Doom

      Issue 19, February 2007
    • RAQ:  Issue 18

      Just How Accurate was William Tell, Anyway?

      Issue 18, January 2007
    • RAQ:  Issue 17

      More Chips are Better than One (or the Benefits of Belgian Food)

      Issue 17, December 2006
    • RAQ:  Issue 16

      Replacing Optocouplers with Digital Isolators

      Issue 16, November 2006
    • RAQ:  Issue 15

      How to Age Gracefully and Avoid Sudden Death

      Issue 15, October 2006
    • RAQ:  Issue 14

      Why Good Engineers Use the Best Components

      Issue 14, September 2006
    • RAQ:  Issue 13

      Sigma Delta Converters are Not Really Hard to Understand

      Issue 13, July 2006
    • RAQ:  Issue 12

      How Not to Design Active Filters

      Issue 12, June 2006
    • RAQ:  Issue 11

      Comparators & Op Amps—May They Never Meet

      Issue 11, May 2006
    • RAQ:  Issue 10

      Digital Processing Does Not Always Rule

      Issue 10, April 2006
    • RAQ:  Issue 9

      Grounding Converters

      Issue 9, March 2006
    • RAQ:  Issue 8

      Happy Groundhog Day!

      Issue 8, February 2006
    • RAQ:  Issue 7

      It’s easy to drive an EE to drink—but what drives one to poetry?

      Issue 7, January 2006
    • RAQ:  Issue 6

      Tick-Tock, Tick-Tock

      Issue 6, December 2005
    • RAQ:  Issue 5

      Check the Bias Current

      Issue 5, November 2005
    • RAQ:  Issue 4

      Caveat Emptor!

      Issue 4, October 2005
    • RAQ:  Issue 3

      Isolating the Key Detail

      Issue 3, September 2005
    • RAQ:  Issue 2

      Slow “starting” ADCs

      Issue 2, July 2005
    • RAQ:  Issue 1

      Radio Frequency Interference (or how to get a free lunch at a very good restaurant)

      Issue 1, June 2005
      天天日天天操