OPA651U - 470MHz Wideband Low-Power Op Amp | Texas Instruments
Teilenummer: OPA651U ✗ Abgekündigt| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $1.43 | $1,43 |
| 10 | $1.36 | $13,60 |
| 100 | $1.21 | $121,00 |
| 500 | $1.05 | $525,00 |
| 1.000 | $0.92 | $920,00 |
OPA651U Übersicht
What is a voltage-feedback op amp? A voltage-feedback operational amplifier (VFA) is a class of analog amplifier whose differential input pair senses a voltage difference and whose output drives a load through a high-gain internal stage. VFAs sit in the hierarchy: op amp -> amplifier IC -> analog signal chain -> semiconductor. Unlike current-feedback amplifiers (CFAs), VFAs can typically be used in any closed-loop gain configuration, with bandwidth that scales inversely with the closed-loop gain. The OPA651 belongs to the classic wideband VFA family designed for video, ADC driver, and high-speed signal-conditioning roles.
Architecturally, the OPA651 uses a complementary bipolar input stage feeding a high-slew-rate gain block, which is why it achieves both low input bias current and a fast 340 V/µs slew rate simultaneously. The voltage-feedback topology gives the designer freedom to set gain with two external resistors while the internal compensation keeps the part stable from a gain of 2 V/V upward. A disable pin (pin 8) on selected grades allows power saving in multi-channel systems.
Typical applications include video line drivers, RGB routing, ADC input buffers for 12-bit pipelined converters, ultrasound pre-amplifier stages, active filters, and IF/RF signal-chain blocks where 50 mW dissipation and SO-8 footprint are acceptable. The low input bias current of 4 µA also makes it usable in photodiode transimpedance front-ends when bandwidth and noise trade-offs are managed.
When laying out the OPA651, place the feedback and gain-setting resistors as close as possible to the inverting input pin, use a solid low-impedance ground plane, and bypass both supply pins with 0.1 µF ceramics in parallel with 4.7 µF tantalums. For lowest distortion, terminate the input with 50 Ω and keep the output load capacitance below 20 pF.
This page synthesizes distributor pricing, drop-in alternative MPNs, and practical PCB design notes that the original 1998-era datasheet does not consolidate in a single place, giving the working engineer a faster path to a vetted BOM entry.
Drop-in-Alternativen für OPA651U – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Varianten dieser Serie
Modelle derselben Serie, die drop-in-kompatibel sind mit OPA651U (gleiche Bauform und Footprint) – abweichend in Amplifier Type, Package, Slew Rate, Operating Temperature Range.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
OPA651U/2K5
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
OPA651UB
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
OPA651N
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
NE5532D
✅ Drop-In✓ Auf Lager
Preis auf Anfrage
Datenblatt ansehen →LM358D
✅ Drop-In✓ Auf Lager
$0.0514 / Stück
Datenblatt ansehen →OPA651U Grenzwerte & elektrische Eigenschaften
| Amplifier Type | Voltage Feedback Operational Amplifier |
| Number of Channels | 1 |
| Slew Rate | 340 V/µs |
| Small-Signal Bandwidth (G = +2) | 470 MHz |
| Settling Time to 0.01% | 16 ns |
| Quiescent Power | 50 mW (typ) |
| Supply Voltage Range | ±4.5 V to ±5.5 V (single 9 V to 11 V) |
| Input Bias Current | 4 µA |
| Stable Gain | ≥ 2 V/V |
| Differential Gain / Phase | 0.05% / 0.1° |
| Low-Distortion Bandwidth | 5 MHz |
| Betriebstemperaturbereich | -40 °C to +85 °C |
| Gehäuse | 8-SOIC (D, 0.154" / 3.90 mm width) |
| Montageart | Surface Mount |
| Pinout | Standard SOIC-8 single op-amp (OUT, IN-, IN+, V-, DIS*, V+, NC, V+) |
OPA651U Pin-Konfiguration
| Pin 1 | Offset Null / NC — Offset trimming pin or no-connect depending on datasheet revision |
| Pin 2 | IN- — Inverting input |
| Pin 3 | IN+ — Non-inverting input |
| Pin 4 | V- — Negative supply voltage |
| Pin 5 | Offset Null / NC — Offset trimming pin or no-connect depending on datasheet revision |
| Pin 6 | OUT — Amplifier output |
| Pin 7 | V+ — Positive supply voltage |
| Pin 8 | DIS (NC on some grades) — Disable pin on selected grades; NC on standard OPA651U |
Typische Anwendungen
OPA651U ist geeignet für 6 Anwendungs: Video Line Driver and RGB Routing, 12-Bit ADC Input Buffer, Active Filter Building Block, Ultrasound Pre-Amplifier Stage, IF / RF Signal-Chain Block, Photodiode Transimpedance Front-End.
Video Line Driver and RGB Routing
The OPA651U is well suited to drive 75 Ω video loads in broadcast and professional video routing equipment. Its 470 MHz small-signal bandwidth at a gain of +2 easily exceeds the 30 MHz required for HD-SDI, while the 0.05% / 0.1° differential gain and phase errors preserve color accuracy across the full NTSC/PAL bandwidth. The 340 V/µs slew rate keeps large-signal transitions sharp on 2 Vpp composite video outputs. Compared to a CFA-based line driver, the OPA651's voltage-feedback topology allows the designer to change gain by swapping one resistor pair, which simplifies gain-matched multi-output routing matrices.
Empfohlen
12-Bit ADC Input Buffer
Used as an input buffer in front of 12-bit pipelined ADCs such as the ADS808 or ADS5231, the OPA651U's 470 MHz bandwidth and 16 ns 0.01% settling time directly support 10 to 40 MSPS conversion rates. Its 4 µA input bias current and low distortion allow accurate sampling of single-ended or differential signals without an additional driver. The 50 mW power budget is well matched to portable data-acquisition designs. To minimize settling degradation, the feedback resistor should be chosen so the closed-loop gain matches the ADC input range, and the ADC input capacitance should be isolated by a small series resistor.
Empfohlen
Active Filter Building Block
The OPA651U is a strong choice for wideband active low-pass, high-pass, and band-pass filter stages in the 1 to 50 MHz range. Its 470 MHz gain-bandwidth product allows 5th-order filter designs at 10 MHz with over 40 dB of stop-band rejection, while the voltage-feedback topology keeps component selection straightforward. Compared to a current-feedback amplifier, the OPA651 preserves symmetric filter response at any gain setting. Place the filter capacitors as close to the inverting node as possible and use 1% metal-film resistors to maintain Q accuracy across production lots.
Empfohlen
Ultrasound Pre-Amplifier Stage
In medical and industrial ultrasound receivers, the OPA651U serves as a low-power pre-amplifier following the transducer and time-gain-compensation (TGC) stage. Its 4 µA input bias current keeps the DC error low for time-gain-controlled signals, while the 470 MHz bandwidth supports imaging frequencies up to 20 MHz with harmonics for harmonic-imaging modes. The 50 mW dissipation is a strong fit for portable cart-based systems. For best noise performance, terminate the input with 50 Ω and place a 1 nF to 10 nF AC-coupling capacitor immediately at the inverting input.
Empfohlen
IF / RF Signal-Chain Block
The OPA651U functions as a low-power IF amplifier or AGC driver in radio receivers and software-defined radio front-ends. Its 470 MHz bandwidth covers IF frequencies up to 200 MHz comfortably, while the 50 mW dissipation makes it suitable for handheld and battery-powered radios. The voltage-feedback architecture allows mixer-to-IF gain changes without re-compensation. To preserve linearity, keep the output stage inside its linear region by sizing the load resistor so the peak output voltage stays below the supply rails by at least 1.5 V.
Empfohlen
Photodiode Transimpedance Front-End
With a 4 µA input bias current and 470 MHz bandwidth, the OPA651U is usable in moderate-speed photodiode transimpedance amplifiers (TIAs) for optical encoders, bar-code scanners, and pulsed-laser rangefinders. The 4 µA bias is the limiting factor for low-light applications, but at higher optical power it allows bandwidths up to 50 MHz with a 10 kΩ transimpedance gain. For sub-nanoampere precision, migrate to a FET-input part such as the OPA656 or OPA657. Place the feedback resistor directly at the inverting input and add a small feedback capacitor to control peaking.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für OPA651U – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | OPA651U/2K5 | OPA651UB | OPA651N | NE5532D | LM358D |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments (Burr-Brown) | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments (Signetics heritage) | Texas Instruments |
| Package | 8-SOIC (D) | 8-SOIC (D) - same | 8-SOIC (D) - same | 8-SOIC (D) - same | 8-SOIC (D) - same | 8-SOIC (D) - same |
| Bandwidth (G=+2) | 470 MHz | 470 MHz | 470 MHz | 470 MHz | 10 MHz | 1 MHz |
| Slew Rate | 340 V/µs | 340 V/µs | 340 V/µs | 340 V/µs | 9 V/µs | 0.3 V/µs |
| Quiescent Power | 50 mW | 50 mW | 50 mW | 50 mW | 70 mW/channel | 15 mW/channel |
| Channels | 1 | 1 | 1 | 1 | 2 | 2 |
| Input Bias Current | 4 µA | 4 µA | 4 µA | 4 µA | 200 nA | 45 nA |
| Lifecycle Status | Obsolete | Obsolete (via Rochester) | Obsolete (via Rochester) | Obsolete | Active | Active |
Wichtigste Unterscheidungsmerkmale
- 470 MHz bandwidth at 50 mW dissipation (vs. NE5532D)
- Voltage-feedback topology allows any gain setting (vs. OPA659 (current-feedback))
- 340 V/µs slew rate enables 5 MHz low-distortion operation (vs. LM358D)
Designhinweise
Place the gain-setting feedback resistor within 5 mm of the inverting input pin (pin 2) and the ground-referenced resistor within 5 mm of the non-inverting input (pin 3). Use a continuous ground plane on the layer directly beneath the SO-8 footprint, and route the output (pin 6) directly over the ground plane to keep parasitic inductance below 2 nH. Bypass V+ (pin 7) and V- (pin 4) with a 0.1 µF X7R ceramic in parallel with a 4.7 µF tantalum, both within 3 mm of the supply pins. This layout keeps the 470 MHz bandwidth stable and prevents oscillation in high-gain configurations.
Estimated: at ±5 V supplies and 50 mW quiescent dissipation in an 8-SOIC (theta-JA ≈ 150 °C/W), junction-to-ambient temperature rise is roughly 7.5 °C, so the part will not require a heatsink in normal operation. However, if the output drives a heavy load (e.g. 50 Ω to ground) at full bandwidth, additional dissipation of 30 to 100 mW is possible and the junction temperature can rise an additional 5 to 15 °C. Always derate to keep Tj below 150 °C and ensure the PCB copper pour around pins 4 and 7 is maximized for heat spreading.
Capacitive loading on the OPA651U output above 20 pF can cause peaking and even oscillation. If the load capacitance cannot be kept below 20 pF, insert a 20 to 50 Ω series resistor between the output pin and the load to isolate the amplifier from the capacitance. For driving long PCB traces or cables, also place a 50 Ω source-termination resistor close to the output pin. These measures preserve the 470 MHz bandwidth while preventing the 340 V/µs slew rate from being wasted on overshoot.
Do not operate the OPA651U below a closed-loop gain of +2 V/V - the part is only stable in gains of 2 or higher, and using it at unity gain will cause oscillation. Avoid exceeding the absolute maximum supply voltage of ±6.5 V, and ensure the input common-mode voltage stays within 1.5 V of either supply rail. When migrating to a different op amp, never assume pin compatibility even within the same 8-SOIC package - the OPA656 (FET-input) and OPA659 (current-feedback) have different pin assignments.
Compliance-Informationen
RoHS, REACH, lead-free, and halogen-free status for the original OPA651U production lots are not explicitly stated in the verified web data; consult Rochester Electronics lot documentation for compliance certificates. AEC-Q100 is not applicable to this commercial/industrial op amp.
