OPA637AU/2K5 - 80MHz Precision Difet Op-Amp | TI
MPN: OPA637AU/2K5 ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $20.41 | $20.41 |
| 10 | $19.8 | $198.00 |
| 100 | $18.9 | $1,890.00 |
| 500 | $18.2 | $9,100.00 |
| 1,000 | $17.6 | $17,600.00 |
Drop-in alternatives for OPA637AU/2K5 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
OPA637AU
✅ Drop-In✓ In Stock
$35.86 / Unit
View Datasheet →OPA637AU/2K5E4
✅ Drop-In📋 Reference alternative (not in catalog)
OPA637AUE4
✅ Drop-In📋 Reference alternative (not in catalog)
OPA637AUG4
✅ Drop-In📋 Reference alternative (not in catalog)
OPA627AU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$12.1 / Unit
View Datasheet →OPA637AU/2K5 Maximum Ratings & Electrical Characteristics
| Amplifier Type | Precision High-Speed Difet Operational Amplifier |
| Number of Channels | 1 |
| Gain Bandwidth Product | 80 MHz |
| Slew Rate | 135 V/µs |
| Minimum Stable Gain | 5 V/V |
| Input Offset Voltage (max) | 100 µV |
| Offset Voltage Drift (max) | 0.8 µV/°C |
| Input Bias Current (max) | 5 pA |
| Input Voltage Noise | Low noise at 10 kHz (per datasheet) |
| Settling Time to 0.01% | Fast settling (per datasheet) |
| Supply Voltage Range | ±4.5 V to ±18 V |
| Supply Voltage Range (single) | 9 V to 36 V |
| Package | 8-SOIC (0.154", 3.90mm Width) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (2500 units) |
OPA637AU/2K5 Pin Configuration
| Pin 1 | TRIM — Offset voltage trim (connect trim potentiometer per datasheet) |
| Pin 2 | -IN — Inverting input |
| Pin 3 | +IN — Non-inverting input |
| Pin 4 | V- — Negative supply |
| Pin 5 | NC — Not connected (per datasheet) |
| Pin 6 | OUT — Amplifier output |
| Pin 7 | V+ — Positive supply |
| Pin 8 | TRIM — Offset voltage trim (connect trim potentiometer per datasheet) |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
OPA637AU/2K5 is suitable for 6 applications: Photodiode Transimpedance Amplification, Fast Data Acquisition Front Ends, DAC Output I/V Conversion, Video and Broadband Signal Conditioning, Precision Instrumentation Gain Stages, Active Filters and Wideband Precision Loops.
Photodiode Transimpedance Amplification
The OPA637AU/2K5 suits high-gain photodiode receivers because its 5 pA maximum input bias current converts a high-value feedback resistance into minimal output offset - with a 1 Mohm feedback resistor, 5 pA yields only 5 µV of error. The low noise at 10 kHz keeps the shot-noise floor dominant over amplifier noise, and the 80 MHz bandwidth supports fast photodiode signals. TIA topologies naturally operate at high closed-loop noise gain, satisfying the OPA637's gain-5 stability requirement. A small feedback capacitor (1-2 pF) compensates photodiode capacitance and tames noise-gain peaking near the 80 MHz rolloff, delivering stable, low-drift optical detection for instrumentation and communications receivers.
Recommended
Fast Data Acquisition Front Ends
In precision data-acquisition systems, the OPA637AU/2K5 amplifies low-level sensor signals before the ADC while preserving DC accuracy: 100 µV maximum offset and 0.8 µV/°C drift mean the amplifier contributes negligible error over temperature compared with a 16-bit converter's LSB size. The 135 V/µs slew rate lets the front end track fast input steps without slewing-induced distortion, and fast 0.01% settling ensures the signal is accurate at the ADC's sampling instant. Running at gain ≥5 from ±15 V rails with ±18 V maximum keeps headroom for industrial signal ranges. Pairing with a precision ADC such as the CS5532 family yields a complete low-drift, wideband measurement channel.
Recommended
DAC Output I/V Conversion
Current-output DACs require a transimpedance amplifier that settles rapidly to the converter's update rate while adding minimal DC error. The OPA637AU/2K5's 5 pA bias current avoids corrupting the DAC's current sources, its 100 µV offset keeps the virtual ground accurate, and 80 MHz bandwidth with fast 0.01% settling supports megasample-per-second update rates. Because the virtual-ground node runs at high noise gain, the OPA637's decompensated stability profile is well matched to this topology. Keeping feedback resistors low (hundreds of ohms to a few kilohms) preserves bandwidth, and a ground-plane-guarded layout minimizes digital feedthrough from the DAC's switching currents into the analog output.
Recommended
Video and Broadband Signal Conditioning
The 135 V/µs slew rate of the OPA637AU/2K5 allows full-swing signals at multi-megahertz frequencies without slew limiting, making it suitable for high-definition video gain stages and broadband IF amplification. With 80 MHz of bandwidth at gains of 5 or more, the part sustains flat gain across standard video bands while the Difet input's 5 pA bias current permits direct coupling to high-impedance sources through large-value bias networks. Supplying from ±15 V provides generous signal swing for standard video levels. Careful ground-plane design, series output isolation resistors, and short signal traces preserve the bandwidth advantage and prevent ringing in 75-ohm transmission environments.
Recommended
Precision Instrumentation Gain Stages
Laboratory instruments, curve tracers, and precision test fixtures benefit from the OPA637AU/2K5's combination of DC precision and speed. A gain-of-5 or gain-of-10 stage built around the part delivers sub-millivolt absolute accuracy thanks to 100 µV maximum offset and 0.8 µV/°C drift, while 80 MHz bandwidth captures fast transients that slower precision amplifiers would filter out. Using offset-trim circuitry on the trim pins nulls residual system error at a fixed temperature. The ±18 V maximum supply supports wide common-mode and output ranges for industrial signals, and pairing with instrumentation front ends like the INA101 or PGA207 extends the chain to programmable-gain measurement systems.
Recommended
Active Filters and Wideband Precision Loops
The OPA637AU/2K5 implements Sallen-Key and multiple-feedback active filters at cutoff frequencies in the megahertz range, something precision bipolar op-amps cannot achieve without excessive phase lag. The JFET input's 5 pA bias current permits megohm-level filter resistors for low-frequency high-impedance designs, while 80 MHz bandwidth supports megahertz corner frequencies with predictable response. In control loops (laser drivers, PLL loop filters), the part provides gain with minimal DC error at the summing node. Designers should verify each filter or loop operates at effective noise gain ≥5 per the stability requirement, and simulate phase margin including source impedance, since the decompensated compensation makes the part sensitive to capacitive loads.
Recommended
Recommended Products Summary
Engineering reference data for OPA637AU/2K5 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | OPA637AU | OPA637AUE4 | OPA637AUG4 | OPA627AU |
|---|---|---|---|---|---|
| Package | SOIC-8 (D) | SOIC-8 (D) - same | SOIC-8 (D) - same | SOIC-8 (D) - same | SOIC-8 (D) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Gain Bandwidth | 80 MHz | 80 MHz | 80 MHz | 80 MHz | 16 MHz |
| Slew Rate | 135 V/µs | 135 V/µs | 135 V/µs | 135 V/µs | [DATA_NEEDED] |
| Minimum Stable Gain | 5 V/V | 5 V/V | 5 V/V | 5 V/V | 1 V/V (unity-gain stable) |
| Input Offset Voltage (max) | 100 µV | 100 µV | 100 µV | 100 µV | 100 µV |
| Input Bias Current (max) | 5 pA | 5 pA | 5 pA | 5 pA | 5 pA |
| Packaging | Tape & Reel (2500) | Tube | Tube | Tube | Tube |
| Lifecycle Status | EOL (per Mouser) | Active at DigiKey | [DATA_NEEDED] | [DATA_NEEDED] | Active at DigiKey |
Key Differentiators
- 80 MHz bandwidth at gain ≥5 (vs OPA627AU)
- Same-die family variants enable guaranteed supply continuity (vs OPA637AUE4)
- Reel packaging for volume assembly (vs OPA637AU)
- Trade-off: decompensated stability (vs OPA627AU)
Design Notes
The single most common failure mode with the OPA637AU/2K5 is using it below the minimum stable gain of 5. Because the part shares a pinout and package with the unity-gain-stable OPA627, engineers frequently substitute it in buffer or gain-of-2 circuits, producing oscillation near the 80 MHz resonance. Audit every instance: any configuration with noise gain below 5 V/V must use the OPA627 instead. Also check AC feedback paths (e.g., integrators) that momentarily reduce effective gain at specific frequencies.
At 80 MHz, layout parasitics dominate stability. Place 0.1 µF ceramic decoupling capacitors within 2-3 mm of pins 4 (V-) and 7 (V+) with direct via connections to the ground plane, and add 4.7-10 µF bulk per rail. Keep the feedback resistor loop area minimal and never place sockets on high-speed precision paths. Guard-ring the +IN pin at the potential of the -IN node to cut leakage from the SOIC-8 surface into the 5 pA bias-current budget, especially in transimpedance designs.
The OPA637AU/2K5 drives capacitive loads poorly, as is typical for decompensated high-speed amplifiers; keep direct capacitive loading below roughly 10 pF or isolate with a small series resistor (20-50 ohm) at the output. In transimpedance applications, compute the feedback capacitor from photodiode capacitance and target bandwidth rather than copying values - excessive CF cripples the 80 MHz advantage while too little invites ringing. Verify phase margin in simulation including source impedance and PCB trace capacitance before release.
Compliance Information
RoHS and lead-free status not stated in the provided verified data; the E4/G4 suffix variants traditionally denote TI RoHS-compliant re-packaging but this must be confirmed on the TI product page for the specific ordering code. Not an automotive-qualified part per available data.
