The OPA381AIDGKT is a precision low power transimpedance amplifier in 8 pin VSSOP package. This high speed single transimpedance amplifier provides 18MHz of gain bandwidth (GBW) with extremely high precision, excellent long term stability and very low 1/f noise. The OPA381 far exceeds offset, drift and noise performance that conventional JFET op-amps provide. The signal bandwidth of transimpedance amplifier depends largely on GBW of amplifier and parasitic capacitance of photodiode as well as feedback resistor. The 18MHz GBW of OPA381 enables a transimpedance bandwidth of greater than 250KHz in most configurations. The device is ideally suited for fast control loops for power level measurement on an optical fibre. In contrast to logarithmic amplifiers, the OPA381 provides very wide bandwidth throughout over full dynamic range. By using an external pull down resistor to -5V, the output voltage range can be extended to include 0V.