Lesson 1Working out bandwidth and stability: closed-loop bandwidth from op-amp GBW, phase margin factors, and compensation methodsWe work out closed-loop bandwidth using op-amp gain-bandwidth product and feedback factor, linking phase margin to stability and response. We cover compensation 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 comparing op-amp datasheets (examples with sensor-grade amps)This part teaches you how to go through op-amp datasheets for sensor work. You'll check noise, offset, input range, supply options, and packaging, learning to quickly filter parts for your system's 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 sim plan for amplifier section: input signals (diff sine, common-mode, noise), AC analysis, transient, noise checks, and offset/error testsThis part builds a clear SPICE plan for the amp block, setting stimuli, analyses, and measurements. You'll verify 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 diff and common-mode input impedanceWe look at achieving high input impedance for diff and common-mode signals with op-amp inputs, buffers, and resistor picks, 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 docs checklist: listing calcs, assumptions, part numbers, and margin checks for PCB handoverThis part sets a solid docs package for amp and sensor front-ends, noting calcs, assumptions, parts, 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 main specs and picking process: input noise density, bias current, offset, GBW, slew rate, CMRR, PSRR, supply rangeWe go over key op-amp specs for small-signal sensors and set a reliable pick process. Focus on noise density, bias current, GBW, slew rate, CMRR, PSRR, and supply matching app 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 calcs for diff amps and in-amps: gain equations and loading effectsWe derive gain equations for standard diff and in-amp setups, including resistor rules and loading. Stress on matching, CMRR, and sensor/ADC impedance effects on 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 amp target specs: gain, bandwidth, input impedance, offset, drift, noise allowanceThis part shows turning system sensor needs into amp targets for gain, bandwidth, input Z, offset, drift, noise. You'll make a clear spec table to guide topology and parts.
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 9Grasping differential sensor signals: source Z, common-mode, diff-mode ideasThis part explains diff sensor action, covering source Z, common-mode level, diff signal range. You'll see how these impact noise, loading, amp topology, and reference setup.
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 10Topology picks for small diff signals: in-amp, diff amp, diff stage with front buffer — trade-offs and casesThis part compares in-amps, standard diff amps, buffered diff stages for small signals. You'll learn CMRR, noise, input range, cost, layout trade-offs per topology.
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 budgeting: calcing expected DC error from offset, bias currents, resistor tolerances, thermal shiftsWe build a DC error budget mixing op-amp offset, bias currents, resistor mismatch, temp drift. You'll allocate error limits, calc worst-case and RSS, 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, outside interferenceWe spot and measure noise in low sensor signals: resistor thermal, amp input noise, interference. Ways to model, budget, 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 sim plots and measures: gain vs freq, phase, input-referred noise, output noise spectrum, transient to 1 kHz sine, worst offset casesThis part sets key plots and measures from sim and bench. You'll tie Bode plots, noise spectra, transients, offset sweeps to original specs and error budgets.
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
