Lesson 1Working out bandwidth and stability: closed-loop bandwidth from op-amp GBW, phase margin checks, and ways to compensateWe figure out closed-loop bandwidth from the op-amp's gain-bandwidth product and feedback factor, then link phase margin to stability and quick response. We cover fixes for capacitive loads and high gains with practical tips.
Relate GBW, feedback factor, and bandwidthInterpret Bode plots and phase margin targetsIdentify signs of marginal or unstable loopsDesign compensation for capacitive loadingCheck stability across process and temperatureLesson 2Picking components in practice: reading and understanding op-amp datasheets (examples with sensor-grade amplifiers)This part teaches you how to go through and compare op-amp datasheets for sensor work. You'll look at noise, offset, input range, power options, and packaging, and learn quick ways to pick parts that fit your system needs.
Identify sensor-grade amplifier familiesInterpret input offset and drift specificationsEvaluate noise, CMRR, and PSRR parametersCheck input and output voltage rangesAssess package, power, and cost constraintsLesson 3SPICE simulation setup for amplifier block: input signals (differential sine, common-mode, noise), AC checks, transient, noise analysis, and offset/error testsThis part builds a proper SPICE plan for the amplifier block, setting inputs, checks, and measurements. You'll learn to confirm gain, bandwidth, noise, offset, and common-mode action before PCB layout.
Define simulation objectives and key metricsSet up differential and common-mode sourcesPlan AC, transient, and noise analysesMeasure gain, offset, and linearity in SPICEOrganize testbenches for reuse and reviewLesson 4Designing for input impedance: ways to get high differential and common-mode input impedanceWe look at achieving high input impedance for differential and common-mode signals with op-amp inputs, buffer stages, and resistor picks, while managing bias currents, leaks, and bandwidth limits.
Define differential and common-mode impedanceUse buffer stages to isolate sensor loadingControl bias currents and leakage pathsGuarding and PCB techniques for high ZTrade-offs between impedance and bandwidthLesson 5Design notes checklist: listing calculations, assumptions, part numbers, and margin checks for PCB handoverThis part sets up a solid notes package for amplifier and sensor front-end designs, noting calculations, assumptions, part picks, and margins so PCB, layout, and test teams can build and check confidently.
List design assumptions and operating conditionsRecord key equations and intermediate calculationsDocument part numbers and critical parametersCapture margin analysis and derating choicesDefine required tests and acceptance criteriaLesson 6Op-amp key specs and picking process: input noise density, bias current, offset, GBW, slew rate, CMRR, PSRR, and power rangeWe go over main op-amp specs for small-signal sensor links and create a steady picking process. Focus is on noise density, bias current, GBW, slew rate, CMRR, PSRR, and power range against your needs.
Relate GBW and slew rate to signal bandwidthUnderstand input noise density and filtersBias current and source impedance interactionCMRR, PSRR, and supply rejection needsStep-by-step op-amp selection checklistLesson 7Resistor setups and gain working for differential amps and instrumentation amps: gain formulas and loading effectsWe work out gain formulas for standard differential and instrumentation amp setups, including resistor limits and loading. Focus on matching, CMRR, and how sensor and ADC loads change real gain.
Gain equations for basic differential stagesThree-op-amp instrumentation amp gain designImpact of resistor matching on CMRR and gainLoading from sensor and ADC input impedanceSelecting resistor values and power ratingsLesson 8Setting amplifier target specs: gain, bandwidth, input impedance, offset, drift, and noise allowanceThis part shows how to turn system sensor needs into amplifier targets for gain, bandwidth, input impedance, offset, drift, and noise. You'll make a short specs table to guide setup and part choices.
Translate sensor and ADC requirementsDefine gain, bandwidth, and headroom limitsSet input impedance and loading constraintsAllocate offset and drift performance goalsCreate a formal amplifier spec tableLesson 9Understanding differential sensor signals: source impedance, common-mode, and differential-mode ideasThis part explains differential sensor action, covering source impedance, common-mode level, and differential signal range. You'll see how these affect noise, loading, and amp setup and reference choices.
Define differential and common-mode componentsCharacterize sensor source impedance vs frequencyDetermine allowable common-mode voltage rangeRelate sensor specs to amplifier input limitsPlan cabling, shielding, and reference routingLesson 10Setup choices for small differential signals: instrumentation amp, differential amp, and difference stage with front buffer — trade-offs and usesThis part compares instrumentation amps, standard differential amps, and buffered difference stages for small signals. You'll learn trade-offs in CMRR, noise, input range, cost, and layout for each.
Review classic differential amplifier stageThree-op-amp instrumentation amplifier useBuffered difference stage with front-end gainCompare CMRR, noise, and input rangeGuidelines for topology selection by sensorLesson 11Offset and drift allowance: working out expected DC error from input offset, bias currents, resistor mismatches, and heat effectsHere we make a numbers-based DC error allowance, mixing op-amp offset, bias currents, resistor mismatches, and temp drift. You'll set error limits, compute worst-case and total stats, and link to sensor accuracy.
Define DC accuracy and allowable error budgetModel input offset and bias current effectsInclude resistor tolerance and mismatch termsAccount for temperature coefficients and driftCompare worst-case versus RSS error methodsLesson 12Noise sources in low signals: Johnson noise, amp input-referred noise, and outside interferenceWe spot and measure noise in low sensor signals, like resistor heat noise, amp input noise, and outside bother. Ways to model, allow, and cut total noise are covered.
Johnson noise of resistors and sensorsOp-amp voltage and current noise modelsInput-referred versus output noise conceptsEnvironmental and interference coupling pathsNoise budgeting and reduction strategiesLesson 13Expected simulation graphs and checks: gain vs frequency, phase, input-referred noise, output noise spectrum, response to 1 kHz sine, and worst offset casesThis part sets key graphs and checks from sims and bench work. You'll link Bode graphs, noise spectra, quick responses, and offset sweeps to original specs and error allowances.
Gain and phase versus frequency Bode plotsInput-referred and output noise spectraTransient response to sine and step inputsOffset versus common-mode and temperatureCompare simulated and measured performance
