Op-Amp Bandwidth / Gain-Bandwidth Product Checker

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Electrical & Electronics Engineering — Circuits, Power Systems, Electronics Lab

Tranche

tranche-4

Evidence ID

t4-257

Ledger rows

1

No ledger note is attached.

Review findings

The arithmetic formula is acceptable as a first-order estimate only after the gain definition, units, and op-amp model are made explicit. The empty honest_label is a concern: the interface should state that this is an approximate GBW-based estimate, not a guaranteed usable bandwidth.

Formula and scope findings

• BW=GBW/Av is a standard first-order approximation for a voltage-feedback op-amp with a single dominant pole, where Av is the positive closed-loop noise gain magnitude, not necessarily the signal gain magnitude.
• For an inverting amplifier, the relevant gain for bandwidth is the noise gain 1+Rf/Rin, not the magnitude of the signal gain Rf/Rin.
• The label 'maximum usable closed-loop bandwidth' is too strong: actual bandwidth also depends on compensation, additional poles, feedback network loading, capacitive loading, stability margin, slew rate, output amplitude, and the required accuracy.
• The requested 'feasibility warning' has no defined input target bandwidth or warning threshold, so the instrument cannot determine feasibility from the supplied inputs alone.
• The specification does not define valid gain constraints; zero gain causes division by zero, and negative or nonnumeric gain values are ambiguous.

Unit assumptions

• GBW and the resulting bandwidth must use the same frequency unit; the test outputs below normalize bandwidth to Hz.
• Av must be a dimensionless voltage gain magnitude expressed as V/V, not dB.
• The formula assumes a voltage-feedback op-amp with approximately constant gain-bandwidth product and a dominant-pole response.
• For an inverting configuration, Av must be interpreted as noise gain rather than signal gain.
• The formula estimates the approximate closed-loop -3 dB bandwidth, not a guaranteed usable bandwidth under all load, amplitude, accuracy, or stability conditions.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The formula is undefined when desired gain is zero, so the instrument must reject Av = 0 or explicitly report an undefined result. The specification also does not define a formula branch, a feasibility-warning threshold, or whether gain should be signed or treated by magnitude.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "gbw": 1,
    "gbw_unit": "MHz",
    "desired_gain": 10
  },
  "expected_outputs": {
    "achievable_bandwidth": 100000,
    "bandwidth_unit": "Hz",
    "feasibility_warning": "Cannot be determined: no target bandwidth or feasibility criteria were supplied."
  },
  "working": "1 MHz = 1,000,000 Hz. BW = GBW / Av = 1,000,000 Hz / 10 = 100,000 Hz."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json