The OPA111BM is a low noise precision monolithic dielectrically isolated FET (Difet?) Operational Amplifier for use with optoelectronics. Outstanding performance characteristics allow its use in the most critical instrumentation applications. Noise, bias current, voltage offset, drift, open-loop gain, common-mode rejection and power supply rejection are superior to BIFET? amplifier. Very low bias current is obtained by dielectric isolation with on-chip guarding. Laser trimming of thin-film resistors gives very low offset and drift. Extremely low noise is achieved with patented circuit design techniques. A new cascade design allows high precision input specifications and reduced susceptibility to flicker noise. Standard 741 pin configuration allows upgrading of existing designs to higher performance levels.