Texas Instruments OPA227P

Overview

OPA227P from Texas Instruments is a single-channel, high-precision, low-noise operational amplifier in an 8-pin PDIP package. It delivers 8 MHz unity-gain bandwidth, 2.3 V/µs slew rate, 3 nV/√Hz input voltage noise, 138 dB CMRR, and ±75 µV max input offset voltage across –40°C to +85°C. It serves as a direct pin-for-pin upgrade to OP27 in precision data acquisition and professional audio signal conditioning.

For engineers reviewing the OPA227P datasheet, OPA227P pinout, OPA227P application, or OPA227P equivalent, key selection considerations include its unity-gain stability, low 10 nA max input bias current, wide ±2.5 V to ±18 V dual-supply operation, and validated performance in sensor front-ends requiring sub-100 µV dc accuracy and <5 µs settling to 0.1%.

Technical Context

The OPA227P implements a fully compensated, bipolar-input op amp architecture optimized for unity-gain stability without external compensation. Its internal offset trim terminals (Pins 1 and 8) enable manual calibration to reduce initial V_OS below 5 µV, and its high open-loop gain (160 dB typ.) supports precision closed-loop configurations with minimal error contribution.

It operates over ±2.5 V to ±18 V supplies with rail-to-rail output swing limited to within 2 V of each rail at 10 kΩ load. Input common-mode range extends from (V–) + 2 V to (V+) – 2 V, and its 1 GΩ || 3 pF common-mode input impedance ensures minimal loading in high-Z transducer interfaces.

Key Specifications

Pinout & Package

OPA227P is housed in an 8-pin Plastic Dual In-line Package (PDIP), with 0.3-inch body width and standard through-hole mounting. Thermal resistance R_θJA is 48.9°C/W, supporting reliable operation up to +85°C ambient under typical PCB layout conditions.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-precision op amp applications.

Compared with OPA227UA, the OPA227P offers accessible offset trim and superior thermal dissipation in through-hole layouts; compared with OP27GP, it delivers measurable improvements in noise, CMRR, and dc precision - justifying upgrade in new designs targeting 16-bit+ system accuracy.

Availability

OPA227P is available at Aetrix Electronics and suitable for data acquisition systems, professional audio equipment, spectrum analyzer front-ends, and condition monitoring sensor interfaces requiring stable component supply and long-term obsolescence management.

Supply support for OPA227P includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision op amp design and manufacturing.

The OPAx227 series was developed to replace legacy OP27/OP37 devices with improved noise, CMRR, and dc accuracy while maintaining pin compatibility - targeting high-fidelity test equipment and industrial measurement systems.

FAQ

What is the maximum operating temperature range for the OPA227P?

The OPA227P is specified for operation from –40°C to +85°C ambient temperature. Its absolute maximum junction temperature is 150°C, and thermal resistance R_θJA is 48.9°C/W in the PDIP-8 package. Derating is required above +85°C ambient unless heatsinking or forced airflow is applied. The OPA227P maintains full electrical performance across this industrial temperature range.

Does the OPA227P require external compensation for unity-gain stability?

No, the OPA227P is internally compensated for unity-gain stability. It does not require external capacitors or resistors to remain stable at G = 1. This is confirmed in the datasheet Section 7.1 and Figure 6-1 (open-loop gain/phase plot), which shows >60° phase margin at unity gain. External compensation is unnecessary and would degrade bandwidth and slew rate.

Can the OPA227P drive capacitive loads, and what is the recommended limit?

Yes, the OPA227P can drive capacitive loads up to 100 pF while maintaining stability and ≤10% overshoot, as shown in Figure 6-26. For loads >100 pF, isolation resistance (e.g., 10–100 Ω in series with the output) is recommended. The device's robust output stage supports ±45 mA short-circuit current, enabling direct interface to moderate-capacitance cables or ADC input filters without buffering.

How do the offset trim pins (1 and 8) function on the OPA227P?

Pins 1 and 8 on the OPA227P connect to an internal resistor network that adjusts input stage bias currents to null V_OS. A 10-kΩ potentiometer is wired between these pins, with its wiper grounded. Adjusting the wiper changes the current balance, reducing V_OS to <5 µV. Leaving both pins unconnected defaults to factory-trimmed performance (±75 µV max). No external voltage sources are applied.

Is the OPA227P pin-compatible with the OP27, and what are the key functional upgrades?

Yes, the OPA227P is a direct pin-for-pin replacement for the OP27 in PDIP-8 sockets. Key upgrades include 3 nV/√Hz vs 3.8 nV/√Hz input noise, 138 dB vs 110 dB CMRR, ±75 µV vs ±100 µV max V_OS, and inclusion of offset trim pins. It also features improved PSRR and wider supply range (±2.5 V to ±18 V), making it a drop-in enhancement for existing OP27-based designs requiring higher precision.