OPA2381AIDGKT

The OPA381 series transimpedance amplifiers offer an 18MHz gain bandwidth product (GBW) with exceptional precision, excellent long-term stability, and very low 1/f noise. The OPA381 features a maximum offset voltage of 25µV, maximum offset drift of 0.1µV/°C, and bias current of 3pA. The offset, drift, and noise performance of the OPA381 far exceeds what conventional JFET op-amps can deliver. The signal bandwidth of a transimpedance amplifier depends largely on the amplifier's GBW, the photodiode's parasitic capacitance, and the feedback resistor. The OPA381's 18MHz GBW enables transimpedance bandwidth exceeding 250kHz in most configurations. The OPA381 is well suited for fast control loops in fiber optic power level measurement. With its high precision and low noise characteristics, the OPA381 achieves a dynamic range of 5 decades. This performance allows signal currents ranging from 10nA to 1mA to be measured within a single I/V conversion stage. Compared to logarithmic amplifiers, the OPA381 provides very wide bandwidth across the entire dynamic range. The output voltage range can be extended to include 0V by using an external pull-down resistor connected to -5V. Both the OPA381 and OPA2381 are available in MSOP-8 and DFN-8 (3mm x 3mm) packages, with an operating temperature range of -40°C to +125°C.

Applications

• Precision I/V conversion
• Photodiode monitoring
• Optical amplifier
• CAT scanner front-end
• Optical laboratory equipment

Key features

• Transimpedance bandwidth exceeding 250kHz
• Dynamic range: 5 decades
• Excellent long-term stability
• Low voltage noise: 10nV/√Hz
• Bias current: 3pA
• Offset voltage: 25µV max
• Offset drift: 0.1µV/°C max
• Gain bandwidth product: 18MHz
• Quiescent current: 800µA
• Fast overload recovery
• Supply range: 2.7V to 5.5V
• Single and dual channel versions available
• Available in compact packages: DFN-8, MSOP-8