OPA128

® OPA128 Difet ® Electrometer-Grade OPERATIONAL AMPLIFIER FEATURES q ULTRA-LOW BIAS CURRENT: 75fA max q q q q LOW OFFSET: 500µV max LOW DRIFT: 5µV/°C max HIGH OPEN-LOOP GAIN: 110dB min HIGH COMMON-MODE REJECTION: 90dB min APPLICATIONS q ELECTROMETER q q q q q MASS SPECTROMETER CHROMATOGRAPH ION GAUGE PHOTODETECTOR RADIATION-HARD EQUIPMENT q IMPROVED REPLACEMENT FOR AD515 AND AD549 DESCRIPTION The OPA128 is an ultra-low bias current monolithic operational amplifier. Using advanced geometry dielectrically-isolated FET (Difet®) inputs, this monolithic amplifier achieves a performance level exceeding even the best hybrid electrometer amplifiers. Laser-trimmed thin-film resistors give outstanding voltage offset and drift performance. A noise-free cascode and low-noise processing give the OPA128 excellent low-level signal handling capabilities. Flicker noise is very low. The OPA128 is an improved pin-for-pin replacement for the AD515. Difet® Burr-Brown Corp. 5 Trim 1k Ω 2k Ω 2k Ω 4 –VCC OPA128 Simplified Circuit Case (Guard) 8 7 +VCC –In 2 3 +In Noise-Free Cascode 6 Output Trim 1 1k Ω 28k Ω 28k Ω International Airport Industrial Park Mailing Address: PO Box 11400 Tel: (520) 746-1111 Twx: 910-952-1111 Cable: BBRCORP © Tucson, AZ 85734 Street Address: 6730 S. Tucson Blvd. Tucson, AZ 85706 Telex: 066-6491 FAX: (520) 889-1510 Immediate Product Info: (800) 548-6132 1986 Burr-Brown Corporation PDS-653E Printed in U.S.A. May, 1995 SPECIFICATIONS ELECTRICAL At...