The OPA27 and OPA37 are ultra-low noise, high-precision monolithic operational amplifiers. Laser-trimmed thin-film resistors provide excellent long-term voltage offset stability and allow superior voltage offset compared to common zener-zap techniques. A unique bias current cancellation circuit allows bias and offset current specifications to be met over the full –40°C to +85°C temperature range. The OPA27 is internally compensated for unity-gain stability. The decompensated OPA37 requires a closed-loop gain 5. The Texas Instruments’ OPA27 and OPA37 are improved replacements for the industry-standard OP-27 and OP-37.