OPA643P - Wideband Low-Distortion Op Amp | Texas Instruments
N.º de pieza: OPA643P ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $6.95 | $6,95 |
| 10 | $6.2 | $62,00 |
| 100 | $5.1 | $510,00 |
| 500 | $4.3 | $2.150,00 |
| 1.000 | $3.75 | $3.750,00 |
OPA643P Descripción general
A voltage-feedback operational amplifier is an analog active device that amplifies the difference between two input voltages while presenting a high input impedance and a low output impedance. The "voltage-feedback" architecture (as opposed to current-feedback) is characterized by a constant gain-bandwidth product, meaning that as closed-loop gain increases, usable bandwidth decreases proportionally. This topology sits within the broader hierarchy: operational amplifier -> analog amplifier -> amplifier IC -> integrated circuit -> semiconductor. The "P" suffix in the OPA643P designation specifically identifies the PDIP-8 plastic through-hole package, distinguishing it from surface-mount variants such as the OPA643N (SOIC-8) and OPA643U (SOT-23-5).
Key features include low distortion specified at 5 MHz, 2.3 nV/√Hz input voltage noise density, 800 MHz gain-bandwidth product, 1000 V/µs slew rate, and stability for gains of 3 or higher. The wide supply range of ±5.5 V (11 V total) makes the device compatible with typical ±5 V analog rails. Its high open-loop gain and excellent DC precision support demanding instrumentation applications that require both wideband AC performance and accurate low-frequency operation.
The OPA643P is built on a high-speed complementary bipolar process, which is the underlying technology enabling the combination of high slew rate, low noise, and low distortion. The internal topology is fully compensated for unity-gain stability, and external feedback components set the closed-loop response. Designers can exploit the high gain-bandwidth product for wideband transimpedance and ADC-driver applications, while the low-distortion characteristic suits communications IF stages, video buffers, and high-fidelity audio line drivers.
Typical applications include wideband instrumentation amplifiers, low-distortion ADC input buffers, high-speed line drivers, video amplifier stages, communications IF amplifier blocks, and active filters. The device is also frequently deployed in test and measurement front-ends, medical imaging analog front-ends, and high-speed transimpedance amplifiers for photodiode interfaces.
When designing with the OPA643P, attention to PCB layout is critical because the 800 MHz gain-bandwidth product makes the circuit susceptible to parasitic capacitance, ground bounce, and supply-rail ringing. Use a solid ground plane, short input traces, and well-bypassed supply pins (typically 0.1 µF ceramic in parallel with 6.8 µF tantalum) to preserve the datasheet's distortion and noise performance in practice.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes not found in the manufacturer datasheet alone.
Alternativas directas para OPA643P — 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 OPA643P (mismo factor de forma y huella) — difiere en Mounting Type, Slew Rate, Supply Voltage Range.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
OPA642P
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
OPA637P
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
OPA604P
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
NE5532P
✅ Sustitución directa✓ En stock
Consulte el precio
Ver hoja de datos →LM358P
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
OPA643P Valores máximos y características eléctricas
| Manufacturer | Texas Instruments (Burr-Brown) |
| Amplifier Type | Voltage Feedback |
| Number of Channels | 1 |
| Gain-Bandwidth Product (GBP) | 800 MHz |
| Slew Rate | 1000 V/µs |
| Input Voltage Noise Density | 2.3 nV/√Hz |
| Low Distortion (specified at) | 5 MHz |
| Stable for Closed-Loop Gains | ≥ 3 |
| Supply Voltage Range | ±5.5 V (max); ±5 V typical |
| Rango de temperatura de funcionamiento | -40 °C to +85 °C |
| Encapsulado | 8-pin PDIP (P) |
| Tipo de montaje | Through-Hole |
| Estado RoHS | Compliant (Pb-free variants available) |
| Datasheet Publication | 1998-04-27 (Burr-Brown original) |
Configuración de pines de OPA643P
| Pin 1 | NC — No connection |
| Pin 2 | IN- — Inverting input |
| Pin 3 | IN+ — Non-inverting input |
| Pin 4 | V- — Negative supply |
| Pin 5 | NC — No connection |
| Pin 6 | OUT — Amplifier output |
| Pin 7 | V+ — Positive supply |
| Pin 8 | NC — No connection |
Aplicaciones típicas
OPA643P es adecuado para 6 aplicacións: Wideband Instrumentation Front-End, High-Speed ADC Input Buffer, Video Line Driver / Buffer, Communications IF Amplifier, Transimpedance Amplifier for Photodiodes, Test and Measurement Front-End.
Wideband Instrumentation Front-End
The OPA643P's 800 MHz gain-bandwidth product and 1000 V/µs slew rate make it a strong choice as the first-stage amplifier in wideband instrumentation channels where signals of interest span from DC to tens of MHz. With 2.3 nV/√Hz input voltage noise, the amplifier preserves signal-to-noise ratio at low input levels. In a typical front-end it is configured as a non-inverting gain-of-2 to gain-of-5 stage, followed by an anti-alias filter and ADC. Trade-off: at high closed-loop gains the GBP rolls off linearly, so designs that need 100+ MHz of usable bandwidth must keep the gain low and cascade stages.
Recomendado
High-Speed ADC Input Buffer
The OPA643P is well-suited as a buffer between sensor signal conditioning and a high-speed ADC. Its 1000 V/µs slew rate handles fast transient edges at 12-14 bit resolution, and its low 2.3 nV/√Hz noise floor supports SNR preservation. Place a 10-50 Ω series isolation resistor between the OPA643P output and the ADC input to damp sampling-glitch kickback. Unlike a discrete transistor buffer, the OPA643P adds negligible distortion (specified at 5 MHz) and maintains DC accuracy, which is critical for calibration. Trade-off: the device draws moderate quiescent current, so it is not ideal for always-on battery-powered channels.
Recomendado
Video Line Driver / Buffer
The OPA643P's 800 MHz GBP easily covers standard-definition, enhanced-definition, and high-definition video bandwidths with substantial headroom. Its 1000 V/µs slew rate prevents edge-rate limiting of fast video transitions, and its low differential gain/phase error preserves color accuracy in composite video paths. The amp is commonly configured as a gain-of-2 driver capable of swinging 2 Vpp into 75 Ω back-terminated video loads. Trade-off: the 8-pin PDIP package is large for modern compact video modules - consider the SOIC-8 OPA643N variant for space-constrained designs.
Recomendado
Communications IF Amplifier
In communications intermediate-frequency (IF) stages operating from 10 MHz to 100+ MHz, the OPA643P delivers the gain, bandwidth, and distortion performance required. Its 5 MHz low-distortion specification extends to usable performance at IF frequencies when operated at moderate closed-loop gain. The amplifier is often deployed in cellular base-station IF chains, software-defined radio (SDR) front-ends, and spectrum analyzer input stages. Trade-off: the 2.3 nV/√Hz noise floor is good but not class-leading for ultra-low-noise IF use; pair with a narrowband SAW or crystal filter ahead of the OPA643P for best selectivity.
Recomendado
Transimpedance Amplifier for Photodiodes
The OPA643P's combination of 800 MHz GBP, 2.3 nV/√Hz input noise, and voltage-feedback topology makes it a viable transimpedance amplifier (TIA) for high-speed photodiodes in optical receivers, LIDAR front-ends, and medical imaging detectors. The voltage-feedback architecture yields low input bias current, which minimizes DC error in continuous-wave optical power measurements. Use a feedback resistor in the 1 kΩ to 100 kΩ range with a small feedback capacitor for stability. Trade-off: voltage-feedback TIAs have lower gain-bandwidth product at high transimpedance than current-feedback TIAs, so for very high gain (1 MΩ+) consider a dedicated current-feedback op amp.
Recomendado
Test and Measurement Front-End
The OPA643P fits naturally into oscilloscope input buffers, spectrum analyzer front-ends, and arbitrary waveform generator output stages. Its 1000 V/µs slew rate and 800 MHz GBP preserve the integrity of fast arbitrary waveforms and high-frequency spectral content. In a 50 Ω output buffer, the OPA643P can deliver several mA of output current with low distortion. Trade-off: the PDIP-8 package has higher parasitic inductance than an SOIC-8, which may show up as ringing above 200 MHz; for highest-frequency test equipment the OPA643N (SOIC-8) is preferred.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para OPA643P — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | OPA642P | OPA637P | NE5532P | LM358P |
|---|---|---|---|---|---|
| Package | 8-pin PDIP (P) | 8-pin PDIP (P) - same | 8-pin PDIP (P) - same | 8-pin PDIP (P) - same | 8-pin PDIP (P) - same |
| Brand | Texas Instruments (Burr-Brown) | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Gain-Bandwidth Product | 800 MHz | ~200 MHz | ~80 MHz | ~10 MHz | ~1 MHz |
| Slew Rate | 1000 V/µs | ~250 V/µs | ~100 V/µs | ~9 V/µs | ~0.3 V/µs |
| Input Voltage Noise | 2.3 nV/√Hz | ~3.5 nV/√Hz | ~4.5 nV/√Hz | ~5 nV/√Hz | ~40 nV/√Hz |
| Topology | Voltage Feedback | Voltage Feedback | Voltage Feedback | Voltage Feedback | Voltage Feedback |
| Channels | 1 (Single) | 1 (Single) | 1 (Single) | 2 (Dual) | 2 (Dual) |
| Supply Voltage (max) | ±5.5 V | ±5.5 V | ±15 V | ±15 V | +32 V single-supply |
Diferenciadores clave
- Highest GBP and slew rate in the listed same-package alternatives (frente a OPA642P)
- True single-channel wideband vs dual-channel general-purpose (frente a NE5532P)
- Through-hole PDIP package for legacy and prototype builds (frente a OPA643N (SOIC-8))
Notas de diseño
At 800 MHz GBP, the OPA643P is highly sensitive to parasitic capacitance on the inverting input node. Keep the inverting-input trace to the feedback network as short as possible, and use a ground plane on the layer directly beneath the op amp. Place the feedback resistor (Rf) within 5 mm of the inverting-input pin to minimize stray capacitance, which otherwise reduces phase margin and can cause peaking or oscillation. Estimated: stray capacitance of 1 pF at 800 MHz contributes approximately 25 Ω of impedance, which is significant relative to typical Rf values of 1-5 kΩ.
Bypass the supply pins with a 0.1 µF ceramic capacitor placed within 3 mm of each supply pin, in parallel with a 6.8 µF to 10 µF tantalum or low-ESR electrolytic capacitor. Star-ground the analog ground to the op-amp load ground to prevent ground-loop noise from coupling into the signal path. For dual-supply operation, ensure that the V+ and V- rails come up simultaneously to avoid reverse-biasing the input stage during power sequencing.
The OPA643P's 1000 V/µs slew rate demands a wideband output connection. Use a 50 Ω characteristic-impedance trace for output runs longer than approximately 10 mm, and terminate appropriately to avoid reflections. For ADC-driver applications, place a 10-50 Ω series resistor between the OPA643P output and the ADC input pin; this resistor isolates the capacitive ADC input from the op-amp output and prevents the sampling glitch from feeding back into the amplifier's output stage.
Do not operate the OPA643P at closed-loop gains below 3 - it is not unity-gain stable and may oscillate at lower gains. Do not exceed the ±5.5 V maximum supply; the absolute-maximum rating is 11 V total across V+ and V-. Do not use the OPA643P in low-gain precision-instrumentation paths where DC accuracy is paramount - consider the precision-optimized OPA627 or OPA637 family instead. Estimated: with ±5.5 V supplies, maximum output swing is approximately ±4.5 V into 1 kΩ load.
Información de cumplimiento
RoHS-compliant Pb-free variants of the OPA643P are available. Original 1998 Burr-Brown datasheet pre-dates RoHS; the current TI datasheet and product page reflect RoHS/REACH compliance. Not AEC-Q100 qualified - the OPA643P is intended for industrial, instrumentation, communications, and test & measurement, not automotive.