OPA627AP Operational Amplifier: Working Principle, Pinout and Features

OPA627AP Introduction

The OPA627AP is a high-performance precision FET-input operational amplifier. Compared to the widely-used OPA111, it offers lower input offset voltage, reduced noise, and significantly higher bandwidth.

Built using a high-speed, dielectrically-isolated complementary NPN/PNP process, the OPA627AP incorporates laser-trimmed input circuitry for tight offset control and a unique cascode structure that maintains ultra-low input bias current across a wide common-mode range. The device is available in compact SOIC-8 package.

OPA627AP Working Principle

The OPA627AP has high input impedance, low noise and high open-loop gain. In actual operation, when the input signal is input from the non-inverting terminal (IN+) or the inverting terminal (IN−), the OPA627 will amplify the voltage difference between the two input terminals and convert the difference into a stable output voltage signal through internal differential amplification, gain stage and output stage.

OPA627AP Pinout

NC (No Connect) – This pin is not internally connected and has no electrical function.

IN− (Inverting Input) – Receives the inverting input signal for differential amplification.

IN+ (Non-Inverting Input) – Receives the non-inverting input signal for amplification.

V− (Negative Supply) – Connects to the negative power supply.

NC (No Connect) – This pin is not used and can be left unconnected.

OUT (Output) – Outputs the amplified signal.

V+ (Positive Supply) – Connects to the positive power supply.

NC (No Connect) – This pin is not internally connected.

OPA627AP Symbol

OPA627AP Footprint

OPA627AP 3D Model

OPA627AP Specification

OPA627AP Features

Very low noise: 4.5nV/√Hz at 10kHz

Fast settling time: 550ns to 0.01% 

Low VOS: 100µV maximum

Low drift: 0.8µV/°C maximum

Low IB: 5pA maximum

 Gain options: Unity-gain stable 

OPA627AP Applications

Precision instrumentation

Fast data acquisition

DAC output amplifier

Optoelectronics

Sonar, ultrasound

High-impedance sensor amps

High-performance audio circuitry

Active filters

OPA627AP Test Circuit

This is a low-pass filter test circuit using the OPA627 op-amp. It helps pass signals in a certain frequency range while blocking unwanted low and high frequencies.

The input goes through R1 (590Ω) and C2 (39nF) to form a high-pass filter. Then, it passes through R3 (499Ω) into the non-inverting input. The op-amp’s feedback path includes R4 (2.94kΩ) and C5 (1nF), forming a low-pass filter. Together, the circuit selects and amplifies signals in a target frequency band with high accuracy.

OPA627AP Package

OPA627AP vs. OPA627BP vs. OPA627AU vs. OPA627SM

OPA627AP Manufacturer

Texas Instruments (TI) is a leading semiconductor company based in the United States, specializing in analog and embedded processing solutions. TI’s products are widely used in industrial automation, automotive electronics, consumer devices, and communication systems. Known for its robust performance, comprehensive technical support, and global supply capability, TI is a trusted partner for engineers and businesses around the world.

How to Use OPA627AP?

To use the OPA627AP, first connect it in a standard op-amp configuration, such as a voltage follower or non-inverting amplifier. Pin 3 is the non-inverting input, and Pin 2 is the inverting input. Apply your input signal to Pin 3 for non-inverting mode, and connect the feedback resistor from Pin 6 (output) back to Pin 2. Ground Pin 4 (V−) and connect Pin 7 (V+) to a positive supply voltage, typically ±15V or a single supply if suitable.

Next, ensure you have decoupling capacitors (like 0.1µF and 10µF) between the power pins and ground to stabilize operation and reduce noise. The output signal comes from Pin 6. Make sure your load impedance matches the op-amp’s drive capability, and avoid overloading it. 

FAQs

What is OPA627AP?

The OPA627AP is a high-precision, low-noise, high-speed operational amplifier from Texas Instruments.

Is OPA627AP unity-gain stable?

Yes, it is unity-gain stable and suitable for buffer configurations and other high-gain settings.

How does OPA627AP compare to OPA627BP or OPA627SM?

OPA627BP has tighter offset specs; OPA627SM is a hermetic version for military-grade applications, while OPA627AP balances precision and cost for general high-end use.