OPA637BP - 80MHz Precision Difet Op Amp DIP-8 | Texas Instruments
MPN: OPA637BP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $14.1 | $14.10 |
| 10 | $13.5 | $135.00 |
| 100 | $12.9 | $1,290.00 |
| 500 | $12.35 | $6,175.00 |
| 1,000 | $11.8 | $11,800.00 |
OPA637BP Overview
An operational amplifier (op amp) is a high-gain voltage amplifier with differential inputs and a single-ended output that, with external feedback networks, forms the basis of amplifiers, filters, integrators, buffers, and precision signal-conditioning stages within the broader hierarchy of analog signal-chain ICs. JFET-input and Difet-process op amps combine the low input bias current of field-effect inputs with the speed of dielectrically isolated bipolar processes, occupying a niche between general-purpose CMOS and fully bipolar high-speed amplifiers.
Key features of the OPA637BP include very low input offset voltage of 100 uV maximum, offset drift of 0.8 uV/C maximum, and input bias current of 5 pA maximum - values enabled by the JFET input stage. Compared to the popular OPA111, the OPA6x7 family offers lower noise, lower offset, and higher speed. The B-grade OPA637BP provides tighter precision than the A-grade OPA637AP.
Technically, the OPA637 is fabricated on a high-speed dielectrically isolated complementary NPN/PNP (Difet) process. Critically, it is decompensated: unlike the unity-gain-stable OPA627, the OPA637 is stable only at closed-loop gains of 5 or greater, which permits its higher bandwidth and slew rate. Designs using the OPA637 in gain below 5 will oscillate.
Typical applications include precision ADC/DAC buffering and I/V conversion, photodiode transimpedance amplifiers, high-speed data-acquisition front ends, and professional audio and test instrumentation stages where gain is configured at 5 or higher.
Design consideration: verify the noise-gain of your topology is at least 5 V/V; for unity-gain buffering use the OPA627 instead. Also respect the 135 V/us slew rate when driving large signals to avoid distortion from slew limiting.
This page adds distributor pricing tiers, pin-compatible alternatives, comparison tables, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for OPA637BP — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with OPA637BP (same form factor and footprint) — differing in Package, Supply Voltage Range, Amplifier Type, Slew Rate, Gain Bandwidth Product.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
OPA637AP
✅ Drop-In✓ In Stock
$1 / Unit
View Datasheet →OPA637BPG4
✅ Drop-In📋 Reference alternative (not in catalog)
OPA627BP
✅ Drop-In✓ In Stock
$21.3 / Unit
View Datasheet →OPA627AP
✅ Drop-In📋 Reference alternative (not in catalog)
OPA2107AP
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$5.45 / Unit
View Datasheet →OPA637BP Maximum Ratings & Electrical Characteristics
| Amplifier Type | Precision High-Speed Difet Operational Amplifier |
| Number of Channels | 1 |
| Bandwidth (Unity-Gain Crossover) | 80 MHz |
| Slew Rate | 135 V/us |
| Supply Voltage Range | +/-4.5 V to +/-18 V |
| Input Offset Voltage (Max) | 100 uV |
| Offset Voltage Drift (Max) | 0.8 uV/C |
| Input Bias Current (Max) | 5 pA |
| Stability | Stable in closed-loop gain >= 5 (decompensated) |
| Input Type | JFET (Difet process) |
| Package | 8-PDIP (DIP-8) |
| Mounting Type | Through Hole |
| Grade | B (precision grade) |
| RoHS Status | unknown |
| Manufacturer | Texas Instruments |
OPA637BP Pin Configuration
| Pin 1 | OFFSET TRIM — Offset null trim (connect to trim potentiometer) |
| 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 | OFFSET TRIM — Offset null trim (connect to trim potentiometer) |
Typical Applications
OPA637BP is suitable for 6 applications: Photodiode Transimpedance Amplifier, Precision ADC/DAC Signal Conditioning, Professional Audio High-Gain Stages, Test and Measurement Instrumentation, High-Speed Data Acquisition Front Ends, Active Filters and Precision Integrators.
Photodiode Transimpedance Amplifier
The OPA637BP's 5 pA maximum input bias current and JFET input make it an excellent front end for photodiode transimpedance stages, where input-current error directly appears as dark-current offset in the measurement. Its 80 MHz bandwidth supports wideband optical receivers used in instrumentation and communications test equipment. In a TIA configuration the feedback resistor and photodiode capacitance set the noise-gain curve, so the OPA637BP's gain-5 stability requirement is naturally satisfied at moderate to high transimpedance values; for low-gain circuits, a feedback capacitor shapes the response for stable operation. Unlike FET-input general-purpose amplifiers, the Difet process keeps broadband noise low while preserving picoamp-level bias, yielding both precision DC accuracy and fast pulse response in a single DIP-8 device.
Recommended
Precision ADC/DAC Signal Conditioning
High-resolution data converters demand drivers with low DC error and enough bandwidth to settle within the converter's acquisition window. The OPA637BP's 100 uV maximum offset voltage and 0.8 uV/C maximum drift preserve accuracy at the converter input, while the 80 MHz bandwidth and 135 V/us slew rate allow fast settling to 0.01% for sampling ADCs. It is typically configured at gains of 5 or more as an input scaler or I/V converter following a DAC current output, where the decompensated design's speed advantage is fully realized. Placing the OPA637BP close to the converter with a short, low-capacitance feedback path minimizes parasitic poles. Compared with general-purpose amplifiers, the Difet bias current of 5 pA avoids loading high-impedance reference and sensor nodes ahead of the converter.
Recommended
Professional Audio High-Gain Stages
In professional audio equipment, the OPA637BP suits high-gain microphone preamps, summing amplifiers, and equalizer stages where closed-loop gain is 5 or higher. Its very low noise and 100 uV offset keep the signal path quiet and DC-safe for direct coupling, while the 135 V/us slew rate provides generous headroom against slew-induced distortion on full-scale 20 kHz program material. Audio designers should note the well-documented family distinction: for unity-gain buffers and low-gain line stages, the unity-gain-stable OPA627BP is the appropriate choice, and the OPA637 should not be dropped into those sockets blindly. In its proper high-gain role, the OPA637BP delivers a wide open-loop bandwidth that keeps distortion low across the audio band even with demanding feedback networks.
Recommended
Test and Measurement Instrumentation
Bench instruments - oscilloscope vertical channels, function generator outputs, and precision measurement front ends - require amplifiers that combine wide bandwidth with DC precision. The OPA637BP's 80 MHz crossover supports instrument-grade small-signal bandwidth at gains of 5 and above, while 5 pA bias current and 100 uV offset preserve measurement integrity on high-impedance probes and sensor outputs. The 135 V/us slew rate prevents slewing artifacts on fast edges and large-amplitude sweeps. Its DIP-8 through-hole package also simplifies socketed calibration and upgrade paths common in serviceable laboratory equipment. When paired with a high-speed buffer such as the BUF634, the OPA637BP can drive 50-ohm loads and cables while retaining its precision front-end characteristics, a classic two-chip instrumentation topology.
Recommended
High-Speed Data Acquisition Front Ends
Industrial and scientific data-acquisition systems benefit from the OPA637BP as a programmable-gain or fixed-gain front-end amplifier. Its 80 MHz bandwidth accommodates multi-megahertz signal capture, and fast 0.01% settling allows multiplexed input channels to switch and settle within the sampling budget. The JFET input's 5 pA bias current prevents error accumulation across high-impedance sensor channels, and the 0.8 uV/C drift keeps calibration stable over temperature in rack-mounted equipment. Because the part is stable at gains of 5 or higher, it fits naturally in PGA stages whose minimum gain is set above that threshold; anti-aliasing filter networks placed after the amplifier further shape the noise gain for robust stability. Supply operation at +/-15 V provides wide common-mode and output swing for industrial signal ranges.
Recommended
Active Filters and Precision Integrators
The OPA637BP performs well in high-frequency active filter topologies (multiple-feedback, Sallen-Key at moderate Q) and precision integrators used in control loops and function generation. Its 80 MHz open-loop bandwidth keeps the amplifier's own pole far above the filter corner, preserving the designed transfer function, while the 100 uV offset minimizes integrator output drift and the need for frequent resets. In integrator service, the JFET input's 5 pA bias current is critical - bipolar-input amplifiers would charge the integration capacitor and cause output ramping. Designers should configure filter gain so the noise gain at the amplifier crossover stays at or above 5, adding a small parallel feedback capacitor where necessary. The DIP-8 package eases prototyping and empirical tuning of compensation networks on breadboards.
Recommended
Recommended Products Summary
Engineering reference data for OPA637BP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | OPA637AP | OPA637BPG4 | OPA627BP | OPA627AP |
|---|---|---|---|---|---|
| Package | 8-PDIP (DIP-8) | 8-PDIP (DIP-8) - same | 8-PDIP (DIP-8) - same | 8-PDIP (DIP-8) - same | 8-PDIP (DIP-8) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Input Bias Current (Max) | 5 pA | 5 pA | 5 pA | 5 pA | 5 pA |
| Stability | Stable in gain >= 5 (decompensated) | Stable in gain >= 5 | Stable in gain >= 5 | Unity-gain stable | Unity-gain stable |
| Precision Grade | B (precision) | A (standard) | B (precision) | B (precision) | A (standard) |
Key Differentiators
- Higher speed via decompensated design (vs OPA627BP)
- B-grade precision limits (vs OPA637AP)
- Picoamp input bias for high-impedance nodes (vs OPA627BP)
Design Notes
The single most common failure mode with the OPA637 is operating it below its minimum stable gain. This decompensated amplifier is stable only at closed-loop (noise) gains of 5 V/V or greater; placed in a unity-gain or follower configuration it will oscillate. If your application needs gain below 5, use the pin-compatible unity-gain-stable OPA627 instead. In inverting and transimpedance topologies, the noise gain at the amplifier's crossover frequency is set by feedback and input capacitance - verify it stays above 5 across frequency, adding a feedback capacitor to shape the noise-gain curve where needed.
Use short, direct feedback paths and keep the summing-junction node compact to limit stray capacitance, which interacts with the decompensated response. Provide 100 nF ceramic decoupling capacitors directly at pins 4 and 7 to a solid ground plane, plus 10 uF bulk capacitance per supply rail. Offset trim (pins 1 and 8) uses a potentiometer to the trim supply per the datasheet typical connection; keep trim traces away from the inputs to prevent leakage. For DIP-8 through-hole layouts, minimize loop area between decoupling caps and supply pins for best high-frequency behavior.
To exploit the full 135 V/us slew rate and 80 MHz bandwidth, match source impedances at the two inputs and use a small resistor (typically hundreds of ohms) in series with the non-inverting input when source impedance is low, which also limits current into the protection structure. In transimpedance designs, calculate the feedback capacitor from the photodiode capacitance and desired bandwidth rather than omitting it - an uncompensated TIA with a large photodiode can violate the gain-5 stability floor. Estimated: with a 1 M-ohm feedback resistor, keep total input capacitance compensation such that the noise gain crossover remains safely above the stability boundary.
Compliance Information
Compliance status not stated in the provided web data; verify on the TI product page for OPA637 before design-in.
