OPA134 Ultra-Low Distortion, Low-Noise Operational Amplifier

Overview

The OPA134 series represents a family of ultra-low distortion, low-noise operational amplifiers designed for high-performance audio and precision analog applications. These devices combine excellent audio quality with precision DC performance, making them ideal for demanding professional audio equipment, medical instrumentation, and high-end consumer audio products.

Built using Burr-Brown's proprietary dielectric-isolation (DI) process technology, the OPA134 achieves unprecedented levels of audio performance while maintaining excellent DC precision. The series is available in single (OPA134), dual (OPA2134), and quad (OPA4134) configurations to suit various application requirements.

Key Features

• Ultra-low distortion: 0.00008% at 1kHz
• Low noise: 8nV/√Hz at 1kHz
• High slew rate: 20V/µs
• Wide bandwidth: 8MHz
• Low input bias current: ±10pA max
• Wide supply range: ±2.5V to ±18V
• Excellent DC precision: 1mV max offset voltage
• Available in single, dual, and quad versions
• Industry-standard pinouts

Applications

The OPA134's exceptional performance characteristics make it suitable for a wide range of professional and high-end applications:

Professional Audio Equipment

• Microphone preamplifiers
• Mixing consoles
• Equalizers and tone controls
• Analog effects processors
• High-end AD/DA converters

Consumer Audio

• High-fidelity preamplifiers
• Phono stages
• Headphone amplifiers
• Active crossover networks
• Premium audio components

Medical and Instrumentation

• ECG amplifiers
• Medical imaging equipment
• Precision strain gauge amplifiers
• Laboratory instrumentation
• Sensor signal conditioning

Electrical Characteristics

The following table summarizes the key electrical specifications at V_S = ±15V, T_A = 25°C unless otherwise noted:

DC Characteristics

• Input Offset Voltage: 0.5mV (typ), 1mV (max)
• Input Offset Voltage Drift: 2µV/°C (typ)
• Input Bias Current: ±2pA (typ), ±10pA (max)
• Input Noise Voltage: 8nV/√Hz at 1kHz
• Input Noise Current: 0.6fA/√Hz at 1kHz
• Common Mode Rejection Ratio: 100dB (typ)
• Power Supply Rejection Ratio: 100dB (typ)

AC Characteristics

• Gain Bandwidth Product: 8MHz (typ)
• Slew Rate: 20V/µs (typ)
• THD+N: 0.00008% at 1kHz, G=1
• Settling Time to 0.01%: 1µs for 10V step
• Output Current: ±30mA (min)

Power Requirements

• Supply Voltage Range: ±2.5V to ±18V
• Quiescent Current: 4mA per amplifier (typ)
• Power Dissipation: 100mW (typ)

Package Information

The OPA134 series is available in multiple package options to accommodate different application requirements:

Single Version (OPA134)

• 8-pin DIP (Plastic)
• 8-pin SOIC (Surface Mount)
• TO-99 Metal Can (for highest performance)

Dual Version (OPA2134)

• 8-pin DIP (Plastic)
• 8-pin SOIC (Surface Mount)
• 8-pin MSOP (Mini Small Outline Package)

Quad Version (OPA4134)

• 14-pin DIP (Plastic)
• 14-pin SOIC (Surface Mount)
• 16-pin SSOP (Shrink Small Outline Package)

Design Considerations

To achieve optimal performance from the OPA134 series, consider the following design guidelines:

Power Supply Bypassing

Proper power supply bypassing is critical for achieving the lowest noise and distortion performance. Use 0.1µF ceramic capacitors located as close as possible to the amplifier power pins, with larger bulk capacitors (10µF tantalum or electrolytic) for each supply rail.

PCB Layout

Implement careful PCB layout practices including:

• Minimize trace lengths for critical signal paths
• Use ground planes for improved noise immunity
• Keep high-impedance nodes as small as possible
• Separate analog and digital grounds

Thermal Considerations

While the OPA134 has modest power requirements, thermal management becomes important in high-density designs or elevated ambient temperatures. Ensure adequate airflow and consider thermal relief patterns for surface mount packages.

Conclusion

The OPA134 series operational amplifiers set a new standard for audio performance in precision analog circuits. With their combination of ultra-low distortion, low noise, and excellent DC characteristics, these devices enable designers to achieve professional-grade audio quality in a wide range of applications. The availability in single, dual, and quad versions provides flexibility for system design while maintaining consistent performance across all configurations.

Whether used in professional recording equipment, high-end consumer audio, or precision instrumentation, the OPA134 delivers performance that meets the most demanding requirements while simplifying design implementation through its robust architecture and stable operation.