Overview
The OPA1678, produced by Texas Instruments, is a dual-channel, low-distortion audio operational amplifier. It is part of the OPA167x series, which includes single-channel (OPA1677), dual-channel (OPA1678), and quad-channel (OPA1679) versions. These amplifiers are designed to offer higher system-level performance compared to legacy op amps commonly used in audio circuitry. The OPA1678 stands out with its low noise density of 4.5 nV/√Hz and low distortion of 0.0001% at 1 kHz, ensuring exceptional audio signal fidelity. It features rail-to-rail output swing, which provides ample headroom and maximizes dynamic range for superior audio reproduction.
Key Specifications
| Parameter | Typical Value | Unit |
|---|---|---|
| Number of Channels | 2 | |
| Total Supply Voltage (Min) | 4.5 | V |
| Total Supply Voltage (Max) | 36 | V |
| Gain Bandwidth (Typ) | 16 | MHz |
| Slew Rate (Typ) | 9 | V/µs |
| Rail-to-Rail Output | Yes | |
| Offset Voltage at 25°C (Max) | 2 | mV |
| Quiescent Current per Channel (Typ) | 2 | mA |
| Noise Density at 1 kHz (Typ) | 4.5 | nV/√Hz |
| Total Harmonic Distortion + Noise at 1 kHz (Typ) | 0.0001% | |
| Common-Mode Rejection Ratio (Typ) | 110 | dB |
| Operating Temperature Range | -40 to 85 | °C |
| Output Current (Typ) | 50 | mA |
Key Features
- Low Noise: 4.5 nV/√Hz at 1 kHz, ensuring high audio signal fidelity.
- Low Distortion: 0.0001% at 1 kHz, contributing to superior audio quality.
- High Open-Loop Gain: 114 dB, providing excellent amplification capabilities.
- High Common-Mode Rejection Ratio: 110 dB, minimizing common-mode noise.
- Low Quiescent Current: 2 mA per channel, efficient power consumption.
- Low Input Bias Current: 10 pA (typical), reducing input offset errors.
- Unity-Gain Stable: Stable operation without additional compensation.
- Rail-to-Rail Output: Output swing within 800 mV of the supply rails with a 2-kΩ load.
- Wide Supply Range: ±2.25 V to ±18 V or 4.5 V to 36 V, accommodating various power supply constraints.
- Independent Internal Circuitry: Minimizes crosstalk and interactions between channels.
Applications
The OPA1678 is suitable for a wide range of audio circuitry applications, including:
- Audio preamplifiers and line drivers
- Active filters and equalizers
- Audio mixing consoles and sound cards
- Professional and consumer audio equipment
- High-fidelity audio systems
Q & A
- What is the noise density of the OPA1678 at 1 kHz?
4.5 nV/√Hz at 1 kHz.
- What is the distortion level of the OPA1678 at 1 kHz?
0.0001% at 1 kHz.
- What is the typical quiescent current per channel for the OPA1678?
2 mA per channel.
- What is the slew rate of the OPA1678?
9 V/µs.
- Is the OPA1678 unity-gain stable?
Yes, it is unity-gain stable.
- What is the operating temperature range of the OPA1678?
-40°C to +85°C.
- What are the available package types for the OPA1678?
SOIC-8, small SON-8, VSSOP-8.
- What is the common-mode rejection ratio (CMRR) of the OPA1678?
110 dB (typical).
- Can the OPA1678 operate on a single supply voltage?
Yes, it can operate from single supply voltages ranging from 4.5 V to 36 V.
- What is the gain bandwidth of the OPA1678?
16 MHz (G = 1).
