Op-Amp Variants — Family Index

The operational amplifier ecosystem spans five orthogonal selection axes and dozens of subfamilies. A single application — say, a photodiode front-end at 100 MHz — narrows the choice to a handful of parts out of thousands. This index maps the variant landscape with real part numbers so you can match application to silicon without guesswork.

1. At a glance — the five-axis taxonomy

Every op-amp datasheet front page foregrounds a different metric. The five axes:

• Speed — gain-bandwidth product GBW (Hz) and slew rate SR (V/µs). General-purpose ~ 1 MHz, audio ~ 10–50 MHz, high-speed > 100 MHz, RF/optical > 1 GHz.
• Precision — input offset Vos (µV), Vos drift (µV/°C), common-mode rejection CMRR (dB), power-supply rejection PSRR (dB). Workhorse 1–10 mV, precision < 100 µV, chopper < 5 µV.
• Noise — input voltage noise density en (nV/√Hz) and current noise density in (pA/√Hz). Audio low-noise < 5 nV/√Hz, ultra-low-noise < 1 nV/√Hz, JFET trades high en for ultra-low in.
• Input / output stage — rail-to-rail input RRI, rail-to-rail output RRO, both RRIO; input topology bipolar / JFET / CMOS.
• Topology — voltage feedback VFB (the default), current feedback CFB (constant BW vs gain), fully-differential FDA (diff in + diff out).
• Special-function — instrumentation amp (3-op-amp in a package), chopper / auto-zero, transimpedance (TIA), isolation, programmable-gain (PGA), variable-gain (VGA).

2. General-purpose VFB

The 1970s workhorses. Internally compensated, unity-gain stable, single-supply capable, cheap (cents).

• LM358 / LM2904 — National Semiconductor / Texas Instruments 1976. Dual, single-supply (3–32 V), 1.1 MHz GBW, 0.3 V/µs slew. The most-shipped op-amp in history. Vos 2 mV typ.
• LM324 / LM2902 — quad equivalent of LM358.
• TL081 / TL082 / TL084 — Texas Instruments 1978 BiFET (JFET input, bipolar output). 3 MHz GBW, 13 V/µs slew, ~ 30 pA input bias. Single / dual / quad.
• LF356 / LF411 / LF412 — National JFET-input, 4 MHz / 15 V/µs.
• MC1458 — dual 741, bipolar. Vintage.

Use these when nothing critical is at stake — biasing, filter buffers, indicator drivers, slow servo loops.

3. Precision (low offset / low drift)

Sub-100 µV Vos and sub-1 µV/°C drift. Trimmed at wafer or auto-zeroed.

• OP07 — PMI (now ADI) 1970s bipolar precision classic. Vos ±75 µV max, drift 0.5 µV/°C.
• OPA277 — Texas Instruments / Burr-Brown. Vos 50 µV max, drift 0.5 µV/°C, low noise.
• OPA2188 — TI zero-drift, Vos 25 µV typ, drift 0.085 µV/°C. Effectively offsetless over temperature.
• OPA189 — TI 2nd-gen zero-drift, wider bandwidth (14 MHz).
• AD8628 — Analog Devices auto-zero, Vos 1 µV max, drift 0.002 µV/°C.
• ADA4522 — ADI zero-drift, 55 V rail.
• LTC2057 — Linear Technology / ADI zero-drift, low noise (11 nV/√Hz at chopper rate).
• MAX44248 — Maxim chopper, Vos 6 µV max.
• OPA391 — TI nanopower precision (15 nA Iq) for battery-powered sensor front-ends.

Use for bridge sensors, thermocouple cold-junction compensation, current-shunt amplification, integrating ADC front-ends.

4. Low-noise (audio + sensor)

Voltage-noise-optimized, typically bipolar input.

• NE5532 / NE5534 — Signetics 1979. The audio classic. 10 MHz GBW, 4 nV/√Hz, 9 V/µs slew. Single (5534, externally compensated for gain ≥ 3) or dual (5532).
• OPA1612 — TI audio, 1.1 nV/√Hz, 40 MHz GBW. ESS-grade DAC output.
• OPA1656 — TI 4 nV/√Hz CMOS-input audio (lower in than bipolar NE5532, useful for high-Z guitar pickups).
• LME49710 / LME49720 — TI / National audio singles / duals, 2.5 nV/√Hz.
• AD797 — Analog Devices ultra-low-noise bipolar, 0.9 nV/√Hz, 8 MHz. Hydrophone, seismometer, ultra-quiet preamps.
• OPA827 — JFET 4 nV/√Hz, 22 MHz, low bias for high-Z audio sources.
• AD8597 / AD8599 — ADI low-noise precision, 1.07 nV/√Hz, Vos 80 µV.

Note: en goes down with bipolar, but in goes up. For source impedance Rs greater than en/in (the optimum source resistance), JFET / CMOS beats bipolar even when datasheet en looks worse.

5. High-speed (wide GBW + high slew)

100 MHz to multi-GHz. Often CFB or decompensated VFB; rarely unity-gain stable below specified gain.

• OPA659 — TI 650 MHz GBW, JFET input, 2.5 nV/√Hz.
• OPA855 — TI 8 GHz gain-bandwidth-product (decompensated to gain ≥ 7), FET input, 0.8 pF Cin. Photodiode TIA for LIDAR and optical receivers.
• OPA858 — TI 5.5 GHz GBP, CMOS, 0.8 pF Cin.
• AD811 — Analog Devices CFB, 140 MHz, video distribution.
• AD8009 — ADI 1 GHz CFB, 5500 V/µs slew. Pulse / video.
• LMH6629 — TI 4 GHz GBP, 0.69 nV/√Hz — the lowest-noise high-speed amplifier.
• THS3491 — TI CFB, 900 MHz, 8000 V/µs, ±410 mA output drive.
• LT6200 — ADI 165 MHz, 0.95 nV/√Hz, rail-to-rail.
• OPA2674 — TI CFB dual, 250 MHz, current-drive for ADSL line.

CFB caveat: never put a capacitor in the feedback path (the inverting input is low-Z, so a feedback cap causes oscillation). Use VFB if you need a feedback integrator.

6. Rail-to-rail input / output (RRIO)

Single-supply portable + battery-operated. Output swings to within mV of rails; input can extend to or beyond rails.

• MCP6001 / MCP6002 / MCP6004 — Microchip CMOS, 1 MHz, single / dual / quad. Cheap (< $0.40).
• OPA340 / OPA341 — TI, 5.5 MHz, 6 V/µs.
• OPA365 — TI 50 MHz RRIO, no crossover distortion (single-stage input — see warning below).
• MAX9914 — Maxim, 1.5 MHz, 1 µA Iq for coin-cell load cells.
• AD8541 / AD8531 — ADI RRIO singles / duals.
• LMV358 / LMV324 — TI RRO only (input goes to V- only), low voltage.
• TLV2371 / TLV2372 / TLV2374 — TI RRIO, 3 MHz.

Input crossover-region warning: most RRI parts use two parallel input pairs (PMOS for low-side, NMOS for high-side) that hand off near mid-supply. The crossover introduces Vos shift (sometimes mV) and distortion. Single-stage rail-to-rail (charge-pump or zero-crossover) parts like OPA365 avoid this — check the datasheet.

7. JFET-input

Low input bias (pA range), good noise at high source impedance, no input protection diode current leakage at high temperature.

• TL081 / TL082 / TL084 — classic BiFET, 30 pA bias.
• OPA627 / OPA637 — premium audio JFET, 1 pA bias, 4.5 nV/√Hz. OPA637 is decompensated (gain ≥ 5).
• OPA827 — newer OPA627 alternative, 22 MHz, 4 nV/√Hz.
• ADA4625 — ADI, 0.1 pA bias, low-noise (3.3 nV/√Hz).
• OPA140 / OPA141 — TI JFET precision, 0.5 pA bias, 11 MHz.
• LF356 / LF411 / LF412 — National JFET legacy.
• AD745 — ADI ultra-low-noise JFET, 2.9 nV/√Hz, 250 fA bias.

Use for high-Z source: electret microphone, photodiode TIA, electrochemical electrode, pH probe, accelerometer charge-mode.

8. CMOS-input (electrometer / picoamp)

Sub-pA input bias — femtoamp territory. For charge amplifiers, electrometers, picoamp current measurement.

• LMP7721 — TI 3 fA bias max, the lowest commercial. PCB layout becomes the limit (guard rings + Teflon standoffs).
• MCP6V61 — Microchip zero-drift CMOS, < 100 fA bias.
• MAX44245 — Maxim, 1 pA bias.
• LMC6001 — National (legacy), 25 fA.
• OPA129 / OPA128 — TI Difet (dielectric-isolated JFET), 30 fA / 75 fA.

At fA levels: PCB leakage > op-amp bias. Guard the inverting node with a driven shield at Vin potential, use Teflon or polyimide standoffs, clean flux residue.

9. Single-supply (5V / 3.3V)

Almost everything in 2026 is single-supply capable. The classic list:

• LM358 / LM324 — bipolar single-supply legacy (output can’t quite reach negative rail without external pulldown).
• OPA340 / OPA365 / OPA391 — TI modern RRIO single-supply.
• MCP6001 / MCP6002 / MCP6004 — Microchip cheap CMOS.
• TLV271 / TLV2371 / TLV2462 — TI low-voltage RRIO down to 2.7 V.
• AD8541 / AD8542 — ADI RRIO 2.7–5.5 V.

If your design uses split supplies (±15 V), you have the full historic catalog. Single-supply 3.3 V narrows to RRIO + low-voltage subset.

10. Instrumentation amplifiers (in-amps)

Three op-amps + matched laser-trimmed resistor network on one die. Gain set by a single external resistor R_G. Differential input, single-ended output, CMRR > 100 dB.

• AD620 — ADI 1990s precision classic. Gain 1–10000 set by R_G (G = 1 + 49.4 kΩ / R_G), CMRR 100 dB at G = 10, Vos 50 µV max. The reference design.
• INA126 / INA128 / INA129 — TI / Burr-Brown. INA128/129 are AD620 alternatives.
• INA333 — TI precision zero-drift, Vos 25 µV, 75 µA Iq.
• INA188 — TI chopper, Vos 25 µV, 0.03 µV/°C drift, EMI filter.
• INA821 / INA826 — TI 35 V supply, Vos 35 µV, low noise.
• INA240 — TI 80 V bidirectional current-sense (specialized in-amp).
• AD8221 / AD8429 — ADI low-noise instrumentation, 1.0 nV/√Hz.
• AD8237 — ADI rail-to-rail micropower in-amp.

Use for bridge sensors (strain gauge, RTD, pressure), biomedical electrodes, isolated current shunts, thermocouple cold-junction.

11. Current-feedback (CFB)

Wide bandwidth that doesn’t shrink with gain (unlike VFB where BW = GBW / gain). Poor DC accuracy (mV Vos), used for video / RF / pulse.

• AD811 — ADI 140 MHz, video.
• AD844 — ADI 60 MHz CFB with current-output Tx pin (transimpedance topology).
• AD8009 — ADI 1 GHz, 5500 V/µs slew.
• THS3001 / THS3091 / THS3491 — TI CFB family.
• OPA695 — TI 1.4 GHz CFB.
• OPA683 — TI 200 MHz CFB.

Hard rule for CFB: never place a capacitor between the inverting input and output (no feedback integrator topology). The inverting input is the low-Z input of a current mirror; a feedback cap shorts the feedback path to ground at high frequency and triggers oscillation. If you need integration, use VFB.

12. Fully-differential amplifiers (FDA)

Differential-in + differential-out. Drives high-speed differential-input ADCs (every modern SAR + Σ-Δ ADC) without the common-mode shift problem that single-ended-to-differential conversion creates.

• LTC6403 / LTC6406 — ADI 200–3000 MHz, 1.5 nV/√Hz.
• ADA4938 / ADA4940-1 — ADI low-distortion ADC drivers.
• THS4521 / THS4541 — TI low-power, rail-to-rail.
• LMH6552 / LMH6553 — TI 1.5 GHz.
• ADA4930 — ADI ultra-low-distortion, –104 dBc at 70 MHz.

FDA also sets the output common-mode (V_OCM pin) — slave it to ADC reference midpoint, not generate a half-supply rail separately.

13. Transimpedance amplifiers (TIA)

Convert photodiode current to voltage with a single feedback resistor R_f. Bandwidth limited by stability — photodiode capacitance C_PD plus op-amp input C_in form a pole with R_f that creates phase shift; the feedback cap C_f shunts R_f to flatten the response. Stability rule of thumb: C_f = sqrt(C_PD + C_in) / (2π R_f f_GBW)^{1/2}.

• OPA855 — TI 8 GHz GBP, 0.8 pF Cin, the LIDAR TIA workhorse.
• OPA858 — TI 5.5 GHz GBP CMOS.
• OPA847 — TI 3.9 GHz, 0.85 nV/√Hz.
• ADA4807 — ADI 180 MHz, low-power TIA.
• MAX3658 / MAX3744 — Maxim integrated-Rf TIA for 1.25–10 Gb/s fiber receivers.
• LMH32401 — TI 240 MHz programmable-gain TIA for LIDAR.

Use for photodiode receivers, optical communication front-ends, LIDAR APD amplifiers, X-ray scintillator readout.

14. Chopper / auto-zero / zero-drift

Modulates the input to AC, amplifies, demodulates back to DC, cancelling Vos and 1/f noise. Bandwidth typically 1–10 MHz; sometimes a chopping artifact appears at the chop rate (filterable).

• OPA2188 / OPA189 — TI zero-drift, Vos 25 µV typ, drift 0.085 µV/°C.
• AD8628 / AD8629 / AD8630 — ADI auto-zero, Vos 1 µV max, drift 0.002 µV/°C.
• ADA4522 — ADI 55 V chopper.
• LTC2057 — ADI 4 MHz chopper, 11 nV/√Hz at chop rate (no 1/f corner).
• MAX44250 / MAX44248 — Maxim chopper, Vos 6 µV.
• MCP6V01 / MCP6V11 — Microchip zero-drift, cheap.

Use for strain-gauge front-ends, thermocouple cold-junction compensation, electrochemical sensors, DC-precision applications where Vos drift would dominate error budget.

15. Isolation amplifiers

Galvanically isolated input and output, typically capacitive or magnetic isolation across an integrated barrier. For high-side current sensing on EV motor drives, IGBT gate-driver feedback, medical patient isolation.

• AMC1100 / AMC1200 — TI ±250 mV input, capacitive isolation, ±50 V working voltage.
• AMC1300 / AMC1311 — TI precision iso-amp, AMC1311 ±2 V input for shunt-less sensing.
• AMC1306 — TI Σ-Δ modulator output (digital bitstream, decimate downstream).
• ACPL-790B / ACPL-C87B — Broadcom (Avago) optical isolation.
• ISO224 / ISO124 — TI bipolar isolated amp, ±10 V input.
• HCPL-7510 / HCPL-788J — Broadcom optical iso for current shunt.

Working voltage 5 kV typical, transient immunity > 15 kV/µs.

16. Special-function

Beyond the standard inverting / non-inverting topologies:

• Programmable-gain (PGA) — digitally selectable gain. LTC6915 (digital-bus gain 1–4096, ADI), PGA204 / PGA205 (TI), AD8231 / AD8253 (ADI).
• Variable-gain (VGA) — analog gain-control voltage (AGC loops). AD8331 (ADI ultrasonic + radar), AD8367, LMH6502 (TI).
• Logarithmic amps — output proportional to log of input. AD8307 / AD8310 (ADI RF log detector), LOG104 / LOG114 (TI photodiode log compression).
• Sample-and-hold — track-and-hold for ADC inputs. LF398 (National classic), AD783 / AD684 (ADI).
• Comparators — not strictly op-amps, but adjacent: LM393 / LM339 (open-collector slow), LMV7235 (10 ns), MAX9075 (push-pull, 7 ns), TLV3201 (40 ns, RRI).

Comparators differ from op-amps in: not unity-gain stable (intentionally), open-collector or push-pull output instead of class-AB linear, optimized for fast slewing into saturation, no input common-mode crossover handling for linear use.

17. Package families

• DIP-8 / SOIC-8 / SOIC-14 — through-hole and gull-wing SMD legacy. Single (8-pin), dual (8-pin), quad (14-pin).
• SOT-23-5 / SOT-23-6 / SOT-23-8 — modern single small-outline (1.6 × 2.9 mm).
• MSOP-8 / MSOP-10 / TSSOP-14 — mainstream low-profile SMD.
• DFN-8 / QFN-16 / QFN-20 — leadless, thermal pad on bottom for power op-amps.
• WCSP / DSBGA — Wafer chip-scale, 1.0 × 1.0 mm or smaller. Solder balls direct to PCB (no leads). For phone / wearable space-constrained designs.
• TO-99 metal can / TO-220 / TO-263 (DDPAK) — power op-amps (LM12, OPA541, OPA549, PA12) with > 1 A output.

Standard pinouts: single op-amp follows 741 standard 8-pin (offset null on 1+5, –in pin 2, +in pin 3, V- pin 4, V+ pin 7, output pin 6, NC pin 8). Dual op-amps drop offset null pins (out-A 1, –inA 2, +inA 3, V- 4, +inB 5, –inB 6, outB 7, V+ 8).

18. Selection table

Application	Critical parameter	Example parts
Audio preamp	Low en at moderate Rs	NE5532, OPA1612, LME49710
Audio MM phono cartridge	Low en, high-Z capable	OPA827, AD797
Hydrophone / seismometer	Ultra-low en	AD797, LMH6629
Photodiode TIA (slow)	Low Ib, low en at high Rf	OPA627, OPA140, ADA4625
Photodiode TIA (LIDAR)	Wide GBP, low Cin	OPA855, OPA858, OPA847
Fiber optic receiver	Integrated TIA, > 1 GHz	MAX3658, MAX3744, LMH32401
Strain gauge bridge	In-amp + chopper	AD8628 + INA826, INA188
RTD / thermocouple	Precision low-drift	OPA188, ADA4522, AD8628
Medical EEG / ECG	Low-noise in-amp	INA333, AD8221
High-side current sense	Isolation or in-amp	AMC1311, INA240
Low-side current sense	Zero-drift op-amp	OPA188, AD8628
Battery-monitor (BMS)	Iso + precision	AMC1311, AMC1306
High-speed ADC driver	FDA	ADA4938, THS4521
Precision voltage reference buffer	Low Vos, low Vos drift	OPA277, OPA188
DC servo loop	Low Vos	OP07, OPA277
RRIO portable battery	Single-supply RRIO	MCP6002, OPA340, TLV2462
Video distribution	CFB wide BW	AD811, AD844
Pulse / step recovery	High slew	AD8009, THS3491
Charge amplifier (piezo)	fA bias CMOS	LMP7721, MCP6V61
Electrometer / electrochemical	fA bias	LMP7721, OPA129
Industrial 4–20 mA loop	Single-supply precision	OPA188, AD8628

19. Selection heuristics

Decide in this order:

1. Bandwidth and gain — if BW × gain > 50 MHz at gain 1–10, you need CFB or high-speed VFB. Below 10 MHz, anything works.
2. DC accuracy — if total error budget < 100 µV across temperature, you need precision or chopper. If 1–10 mV is fine, general-purpose suffices.
3. Supply — single-rail 3.3 V or 5 V forces RRIO. Split ±15 V opens the legacy catalog.
4. Source impedance — if Rs > 100 kΩ, you need JFET or CMOS input. If Rs > 10 MΩ, CMOS. If Rs > 1 GΩ, electrometer-grade CMOS (LMP7721 class).
5. Load — driving 50 Ω cable or > 100 mA needs a high-output-drive part (THS3491, OPA541) and a back-termination resistor.
6. Differential-output ADC — use an FDA, not two single-ended op-amps. The FDA holds output common-mode to V_OCM and balances differential gain.
7. Isolation barrier — if input and output ground differ by > 5 V or > 100 V transient, use an iso-amp.

If two of these axes both push to “extreme” (e.g., precision + high-speed), expect to compromise — there is no part that delivers Vos < 10 µV and GBW > 1 GHz simultaneously. Split the function across two stages.

20. Cross-references

• op-amps — fundamentals: ideal-op-amp model, feedback theory, stability, compensation.
• semiconductor-packages — DIP / SOIC / QFN / WCSP package details.
• passive-components — feedback resistors, compensation caps, parasitic considerations.
• signal-processing-dsp — anti-alias filter design, ADC driver sizing.
• photonics — photodiode + TIA front-end design.

21. Citations

• Texas Instruments — op-amp application notes and selection guides (current: 2024–2026 editions at www.ti.com/amplifier-circuit/op-amps/overview).
• Analog Devices — op-amp portfolio and tech docs (current at www.analog.com/en/product-category/operational-amplifiers-op-amps).
• Walt Jung (editor) — “Op Amp Applications Handbook” (Analog Devices / Newnes, 2005). The canonical reference, free PDF from ADI.
• Bruce Carter, Ron Mancini — “Op Amps for Everyone” 5th ed (Texas Instruments / Newnes, 2018). Free PDF from TI.
• Sergio Franco — “Design with Operational Amplifiers and Analog Integrated Circuits” 4th ed (McGraw-Hill, 2014). University-level textbook covering noise, distortion, stability.
• Paul Horowitz, Winfield Hill — “The Art of Electronics” 3rd ed (Cambridge, 2015). Chapters 4–5 on op-amps and precision design.