OPA2604 Dual FET-Input Operational Amplifier

Overview

The OPA2604 is a high-performance, dual-channel operational amplifier featuring FET-input architecture. Designed for precision audio and signal processing applications, this component delivers exceptional noise performance, low distortion, and high slew rate. Its wide supply voltage range and ability to drive low-impedance loads make it suitable for professional audio equipment, active filters, and data acquisition systems.

Features

• Ultra-Low Distortion: 0.0003% at 1kHz ensures pristine signal integrity
• Low Noise Performance: 10nV/√Hz noise density for high-fidelity applications
• High Slew Rate: 25V/µs enables fast signal response
• Wide Gain-Bandwidth Product: 20MHz for broad frequency response
• Unity-Gain Stable: Operates reliably at any gain configuration
• Versatile Power Supply: ±4.5V to ±24V operating range
• Strong Output Drive: Capable of driving 600Ω loads
• Dual-Channel Design: Two matched amplifiers in single package
• FET-Input Architecture: High input impedance and low bias currents

Applications

Audio Processing

• Professional audio mixing consoles
• High-end preamplifiers and equalizers
• Digital-to-analog converter interfaces
• Headphone amplifiers

Instrumentation and Measurement

• Spectral analysis equipment
• Medical instrumentation
• Transducer signal conditioning
• Precision current-to-voltage converters

Signal Processing

• Active filters (low-pass, high-pass, band-pass)
• Analog computing circuits
• Data acquisition front-ends
• PCM DAC I/V conversion

Electrical Characteristics

(Typical values at VS = ±15V, TA = 25°C unless otherwise noted)

DC Characteristics

• Input Offset Voltage: 1mV (max)
• Input Bias Current: 50pA (typ)
• Input Offset Current: 10pA (typ)
• Common-Mode Rejection Ratio: 90dB (min)
• Power Supply Rejection Ratio: 90dB (min)
• Open-Loop Gain: 100dB (min)

AC Characteristics

• Gain Bandwidth Product: 20MHz (typ)
• Slew Rate: 25V/µs (typ)
• Settling Time (0.1%): 1µs (typ)
• THD+N: 0.0003% at 1kHz (typ)
• Input Voltage Noise: 10nV/√Hz at 1kHz (typ)
• Input Current Noise: 1fA/√Hz at 1kHz (typ)

Power Characteristics

• Supply Voltage Range: ±4.5V to ±24V
• Quiescent Current (per channel): 5mA (typ)
• Output Current: ±30mA (min)
• Operating Temperature Range: -40°C to +85°C

Package Information

Standard Package Options

• 8-Pin SOIC (D):
  • Dimensions: 4.90mm × 3.91mm
  • Height: 1.58mm
  • Lead Pitch: 1.27mm
• 8-Pin PDIP (P):
  • Dimensions: 9.81mm × 6.35mm
  • Height: 3.30mm
  • Lead Pitch: 2.54mm

Thermal Characteristics

• SOIC Package:
  • θJA (Thermal Resistance): 160°C/W
  • θJC (Thermal Resistance): 45°C/W
• PDIP Package:
  • θJA (Thermal Resistance): 100°C/W
  • θJC (Thermal Resistance): 35°C/W

Design Considerations

PCB Layout Guidelines

For optimal performance with the OPA2604:

• Use a low-impedance ground plane
• Keep input traces short and away from output traces
• Place decoupling capacitors (0.1µF ceramic) close to power pins
• Use surface-mount components for high-frequency applications
• Consider guard rings for sensitive high-impedance inputs

Thermal Management

While the OPA2604 has modest power dissipation, thermal considerations become important at high supply voltages or when driving heavy loads:

• For continuous operation at maximum ratings, consider heat sinking
• Use thermal vias when implementing in SOIC package
• Monitor junction temperature in high ambient temperature environments

Conclusion

The OPA2604 represents a premium choice for applications demanding the combination of FET-input advantages with high-speed performance. Its exceptional audio characteristics make it particularly valuable in professional audio equipment, while its precision DC performance suits demanding instrumentation applications. The dual-amplifier configuration provides design flexibility while maintaining space efficiency. Engineers can leverage its wide supply range and robust output drive capability across diverse analog signal processing challenges.