Operational Amplifier Texas Instruments OPA134PA — Single Channel, 8 MHz Bandwidth, THD 0.00008%

Texas Instruments OPA134PA is a single-channel operational amplifier with 8 MHz bandwidth and exceptionally low total harmonic distortion (THD 0.00008%). Designed for high-fidelity audio and precision analog signal conditioning, this FET-input op amp offers wide output swing and strong output drive while remaining unity-gain stable. The device is suitable for PCB-mounted applications where compact package dimensions and reliable DC behaviour are required.

Advantages

OPA134PA combines ultra-low distortion and low noise performance with a true FET input stage that maintains low input bias current and excellent common-mode rejection. The amplifier delivers high open-loop gain and a wide supply range, permitting operation from ±2.5 V to ±18 V, and provides stable dynamic behaviour across a variety of loads, including capacitive loads. Its wide output swing to within approximately 1 V of the rails increases headroom for audio circuits and precision conditioning tasks.

Suitable for

• High-fidelity audio preamplifiers and headphone drivers
• Active filters and equalizers
• Precision measurement and sensor signal conditioning
• Low-noise instrumentation and buffer stages
• Space-constrained PCB designs requiring an 8-pin surface-mount package

Key specifications

• Topology: Single-channel operational amplifier with true FET input stage
• Bandwidth: 8 MHz (small-signal)
• Total harmonic distortion (THD): 0.00008%
• Noise density: 8 nV/√Hz
• Input bias current: typically in the picoampere range (FET input)
• Slew rate: 20 V/µs
• Open-loop gain: high (approx. 120 dB at 600 Ω load typical)
• Output swing: up to ~1 V from supply rails (increased headroom)
• Supply voltage range: ±2.5 V to ±18 V
• Operating temperature range: specified for –40°C to 85°C

How to use

Use OPA134PA in standard single-op-amp topologies such as non-inverting or inverting amplifiers, active filter stages, buffers and preamplifier circuits. Provide appropriate supply rails within the specified ±2.5 V to ±18 V range and observe correct decoupling close to the power pins to minimize supply noise. For audio and precision applications, configure feedback and input networks to achieve the desired gain while keeping the device within its linear output swing. The amplifier is unity-gain stable, so it can be used as a buffer without additional compensation. Grounding and layout practices that minimize input capacitance and maintain short input traces improve noise and stability performance.

Recommendations

For best audio fidelity and low distortion, use tight, low-noise passive components for feedback networks, place power decoupling capacitors close to the supply pins, and avoid driving heavy capacitive loads directly without a small series resistor at the output. When designing PCBs, keep input traces short and provide a solid ground plane to preserve the low-noise characteristics of the OPA134PA.