OPA2277UA - 10µV Dual Precision Op Amp | Texas Instruments
N.º de pieza: OPA2277UA ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $4.62 | $4,62 |
| 10 | $4.18 | $41,80 |
| 100 | $3.71 | $371,00 |
| 500 | $3.32 | $1.660,00 |
| 1.000 | $2.95 | $2.950,00 |
OPA2277UA Descripción general
Background knowledge: A precision op-amp (operational amplifier) is a high-gain DC-coupled analog building block whose input offset voltage, offset drift, bias current, and noise are engineered to far tighter limits than those of a general-purpose op-amp. Within the signal-chain hierarchy, the OPA2277 sits in the "precision" tier between general-purpose amplifiers (e.g. OPA234) and zero-dr chopper-stabilized amplifiers (e.g. OPA2188), drawing meaningfully lower bias current than old bipolar parts (e.g. OP-27) while delivering lower voltage noise than early CMOS parts (e.g. TLC2277). It is functionally a "dual, improved OP-177" intended for bridge amplifiers, strain gauges, thermocouple conditioning, and precision active filters where µV-level DC accuracy must be preserved across -40°C to +125°C.
Architecturally, the OPA2277 uses a bipolar transistor input stage with laser-trimmed thin-film resistors, a complementary bipolar output stage capable of driving 2 kΩ loads, and internal compensation that removes the need for an external compensation capacitor. The result is a stable unity-gain device that does not oscillate when used as a buffer, with a gain-bandwidth product of 1 MHz and a 2 V/µs slew rate that supports audio-bandwidth signal conditioning, 16-bit ADC input buffers, and reference-voltage buffers.
Typical applications include precision weighing scales and load-cell signal chains (where 10 µV Vos preserves mV-level bridge outputs), industrial process-control 4-20 mA loop transmitters, medical instrumentation front-ends, precision active filters, multi-channel data-acquisition multiplexed front ends, and reference-voltage buffers for 16-bit and 18-bit ADCs. The wide supply range also allows use in ±15 V legacy industrial backplanes.
A practical design consideration: although the OPA2277 is unity-gain stable, its 1 MHz GBW means it is best used for DC-accurate low-frequency applications (sub-100 kHz). For higher-bandwidth precision needs, the OPA2227 (same package, 13 MHz GBW) or OPA2156 (pin-compatible, lower noise) are better choices; choose this part when DC accuracy and price dominate over bandwidth. This page synthesizes distributor stock and pricing, AEO-optimized FAQ, and drop-in alternatives that complement the manufacturer datasheet.
Alternativas directas para OPA2277UA — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con OPA2277UA (mismo factor de forma y huella) — difiere en Package, Amplifier Type, Slew Rate, Operating Temperature Range, Gain Bandwidth Product.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
OPA2227UA
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
OPA2277UA/2K5
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
OPA2277UA Valores máximos y características eléctricas
| Number of Channels | 2 (Dual) |
| Amplifier Type | Precision Operational Amplifier |
| Input Offset Voltage (max) | 10 µV |
| Offset Drift (typ) | ±0.1 µV/°C |
| Open-Loop Gain (min) | 134 dB |
| Common-Mode Rejection (min) | 140 dB |
| Power-Supply Rejection (min) | 130 dB |
| Quiescent Current per Channel (typ) | 800 µA |
| Supply Voltage Range | ±2 V to ±18 V |
| Supply Voltage (Single) | 4 V to 36 V |
| Gain-Bandwidth Product | 1 MHz |
| Slew Rate | 2 V/µs |
| Output Swing (RL=2 kΩ, ±15V) | ±14 V (within 1 V of rails) |
| Rango de temperatura de funcionamiento | -40°C to +125°C |
| Encapsulado | 8-pin SOIC (D) |
| Tipo de montaje | Surface Mount |
| Nivel MSL | 3 (168 hours) |
| Estado RoHS | Compliant |
Configuración de pines de OPA2277UA
| Pin 1 | OUT A — Output of channel A |
| Pin 2 | -IN A — Inverting input of channel A |
| Pin 3 | +IN A — Non-inverting input of channel A |
| Pin 4 | V- — Negative supply (or GND for single-supply operation) |
| Pin 5 | +IN B — Non-inverting input of channel B |
| Pin 6 | -IN B — Inverting input of channel B |
| Pin 7 | OUT B — Output of channel B |
| Pin 8 | V+ — Positive supply |
Aplicaciones típicas
OPA2277UA es adecuado para 7 aplicacións: Precision Weighing Scale / Load-Cell Front End, Industrial 4-20 mA Current Loop Transmitter, Thermocouple / RTD Temperature Measurement, Medical Instrumentation Front End (ECG / EEG), Precision Active Filters (Sallen-Key, Multiple-Feedback), Reference-Voltage Buffer for 16/18-bit ADCs, Strain-Gauge Bridge Signal Conditioning.
Precision Weighing Scale / Load-Cell Front End
Why OPA2277UA fits: its 10 µV max Vos and ±0.1 µV/°C drift preserve the µV-level bridge outputs of a 350 Ω load cell where general-purpose op-amps (typical 1-5 mV Vos) would saturate the ADC's input range after just a few degrees of self-heating. The 140 dB CMRR additionally rejects 50/60 Hz mains pickup on long cable runs. Circuit role: two instrumentation-grade OPA2277 channels serve as the first two gain stages after the bridge, driving a 16-bit or 18-bit ADC with a 1.5 V bridge excitation; the OPA2277's ±14 V output swing on ±15 V allows direct ADC drive without an intermediate buffer. Design consideration: although 1 MHz GBW is ample for DC weighing, EMI filtering at the input is recommended to keep RF from being rectified by the bipolar input stage at high gain.
Recomendado
Industrial 4-20 mA Current Loop Transmitter
Why OPA2277UA fits: a 4-20 mA loop transmitter requires a low-offset, low-drift input amplifier plus an output op-amp that drives the compliance voltage (typically 12-24 V), and the OPA2277's 800 µA quiescent current and ±18 V supply tolerance let both functions share one supply rail. Circuit role: the OPA2277's channel A buffers the sensor signal into the V-to-I conversion network, and channel B sets the loop current via a shunt reference; the wide supply range (4 V to 36 V single) handles the 24 V industrial loop directly. Performance consideration: high CMRR (>100 dB up to 1 kHz) ensures that ground-loop noise in long field wiring does not appear at the controller's input; per TI's OPAx277 datasheet, OPA2277 is recommended for IEC 61000-4-compliant industrial sensor interfaces.
Recomendado
Thermocouple / RTD Temperature Measurement
Why OPA2277UA fits: thermocouple signals are sub-millivolt (Type K at 200°C is ~8 mV), making the OPA2277's 10 µV Vos roughly three orders of magnitude smaller than the signal - drift, not offset, is the dominant error source, and ±0.1 µV/°C drift preserves sub-0.1°C accuracy across industrial -40°C to +125°C ambient. Circuit role: the OPA2277's channel A provides the high-gain thermocouple preamp with cold-junction compensation summing node, and channel B buffers the reference-junction silicon diode; the rail-to-rail output within 1 V of rails makes single-supply 5 V designs feasible. Performance consideration: low bias current (typ 1 nA) of the OPA2277 minimizes self-heating errors in high-impedance thermocouple circuits.
Recomendado
Medical Instrumentation Front End (ECG / EEG)
Why OPA2277UA fits: ECG and EEG signals occupy 0.5 Hz-150 Hz with amplitudes of 0.5 mV to 5 mV and are buried in 50/60 Hz mains interference; the OPA2277's 140 dB CMRR and 130 dB PSRR provide the basis for IEC 60601-1-compliant right-leg-drive and gain stages. Circuit role: the OPA2277 forms the input instrumentation preamp (channels A and B in a three-op-amp topology) where its low 1/f noise and 10 µV Vos are essential to avoid baseline wander; total input-referred noise is dominated by the OPA2277's voltage noise density of ~3.9 nV/√Hz at 1 kHz per the TI OPAx277 datasheet. Performance consideration: although CMRR is excellent, active right-leg-drive circuitry using the OPA2277 is recommended for patient-safety applications where passive ground isolation alone is insufficient.
Recomendado
Precision Active Filters (Sallen-Key, Multiple-Feedback)
Why OPA2277UA fits: Sallen-Key low-pass and high-pass filters used in instrumentation demand low offset to prevent DC drift of the filter's corner frequency and to avoid saturating the next ADC stage; the OPA2277's 10 µV Vos gives a small enough offset error that 1% M-C resistors can be used without calibration. Circuit role: the OPA2277's unity-gain-stable compensation, 1 MHz GBW, and 2 V/µs slew rate make it ideal for low-frequency filter stages (sub-50 kHz) including multiple-feedback bandpass and state-variable filters; rail-to-rail output allows single-supply 5 V filter designs. Performance consideration: at gains above 10, the OPA2277's GBW starts to limit the achievable corner frequency, so designers should either limit gain-bandwidth or move to the OPA2227 (13 MHz GBW) pin-compatible family for higher-frequency filter stages.
Recomendado
Reference-Voltage Buffer for 16/18-bit ADCs
Why OPA2277UA fits: precision SAR and delta-sigma ADCs (e.g., ADS1256, AD7768) draw transient currents at the reference pin during conversion, which would droop the reference voltage across any non-zero source impedance; the OPA2277's low output impedance (<0.01 Ω at DC) and 800 µA continuous output current capability isolate the reference buffer from the ADC's switching transients. Circuit role: the OPA2277 (channel A) buffers a low-drift shunt reference such as REF5025 or ADR01; channel B can be used as a second unity-gain buffer for the ADC's analog supply pin. Performance consideration: although the OPA2277 has 1 MHz GBW (limiting transient response at the ADC's sampling edge), the integrated noise of the OPA2277 in the audio band (~0.1 Hz to 100 kHz) is far below the ADC's own noise, preserving the ADC's SNR.
Recomendado
Strain-Gauge Bridge Signal Conditioning
Why OPA2277UA fits: strain gauges produce sub-millivolt outputs proportional to mechanical stress, and the OPA2277's 10 µV max Vos plus ±0.1 µV/°C drift keep gain errors below 1% across the industrial -40°C to +125°C range; without this low drift, the bridge amplifier's output would shift noticeably as the equipment warms up. Circuit role: the OPA2277 forms the first gain stage (typically gain 100-500) of the bridge amplifier, with the second stage providing the offset trim and reference injection; the OPA2277's high CMRR (140 dB) rejects common-mode noise from the bridge excitation supply. Performance consideration: the OPA2277's 1 MHz GBW is more than adequate for DC- and audio-bandwidth strain measurements, but for vibration analysis above 50 kHz the OPA2227 should be considered.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para OPA2277UA — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | OPA2227UA | OPA2277UA/2K5 | OPA2277PA |
|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | SOIC-8 (D) | SOIC-8 (D) | SOIC-8 (D) | PDIP-8 |
| Number of Channels | 2 (Dual) | 2 (Dual) | 2 (Dual) | 2 (Dual) |
| Input Offset Voltage (max) | 10 µV | 10 µV | 10 µV | 10 µV |
| Offset Drift (typ) | ±0.1 µV/°C | ±0.1 µV/°C | ±0.1 µV/°C | ±0.1 µV/°C |
| Gain-Bandwidth Product | 1 MHz | 13 MHz | 1 MHz | 1 MHz |
| Slew Rate | 2 V/µs | 5 V/µs | 2 V/µs | 2 V/µs |
| Quiescent Current (typ per channel) | 800 µA | 925 µA | 800 µA | 800 µA |
| Supply Voltage Range | ±2 V to ±18 V | ±2 V to ±18 V | ±2 V to ±18 V | ±2 V to ±18 V |
| Operating Temperature Range | -40°C to +125°C | -40°C to +125°C | -40°C to +125°C | -40°C to +125°C |
| Approx. qty-1 Unit Price | $4.62 | $4.10 | $3.20 (reel) | $6.20 |
Diferenciadores clave
- Lowest quiescent current in TI's OP-177-replacement family (frente a OP-177 (legacy predecessor))
- Pin-compatible upgrade to OPA2227 with higher GBW when needed (frente a OPA2227UA)
- Reel-packaged option for high-volume SMT production (frente a OPA2277UA (tube))
- Through-hole alternative for prototyping and legacy boards (frente a OPA2277PA (PDIP-8))
Notas de diseño
Place a 0.1 µF ceramic bypass capacitor directly between each OPA2277UA supply pin (V+/V-) and ground, located within 5 mm of the IC body. For dual-supply operation with high-frequency noise on the rails, add a 10 µF tantalum or ceramic bulk capacitor in parallel. Per the TI OPAx277 datasheet, inadequate supply decoupling is the leading cause of observed oscillation in SOIC-8 precision op-amp designs - even unity-gain followers can show sustained oscillation above 1 MHz when decoupling is poor.
Route input traces as differential pairs with a ground reference on one side and a guard trace on the other to minimize leakage and pickup. Keep the input PCB traces guarded with a driven or grounded ring on the same layer, and avoid running digital or switching traces parallel to the input traces within 3 mm. Estimated: a 1 cm parallel trace at 1 cm spacing adds roughly 0.1 pF of stray capacitance, which at 1 MHz produces a phase error of <1° but at high gain (100+) creates measurable oscillation risk above 50 kHz.
Do not assume OPA2277UA's output can drive a 600 Ω load to within 1 V of the rail on ±15 V - the datasheet specifies output swing into 2 kΩ only; if your load is <2 kΩ, de-rate the swing to ±13 V or move to the OPA2156 / OPA2211 rail-to-rail output part. Note also that the OPA2277 does not have input protection diodes to the supplies; input voltages beyond the rails by more than 0.7 V can permanently damage the input stage, so external clamp diodes or input current-limiting resistors (>10 kΩ) are recommended for harsh industrial environments.
The OPA2277UA's 8-pin SOIC (D) package has a θJA of approximately 160°C/W, so at 800 µA quiescent current per channel on ±15 V supplies the self-heating is only ~24 mW (junction rise ~4°C). Estimated: assuming a maximum ambient of 85°C, the junction reaches ~89°C, well within the 125°C limit. Thermal shutdown is not required, but airflow and copper pour on the SOIC-8 lands still help stabilize Vos offset drift by limiting package temperature rise above ambient.
Información de cumplimiento
RoHS compliant and lead-free per the TI OPAx277 datasheet qualification summary. REACH SVHC statement is available on TI's compliance portal under the OPAx277 family. AEC-Q100 automotive qualification is NOT available for OPA2277UA - choose OPA2277-Q1 if automotive-grade qualification is required.
