AD515AH Sourcing Guide: Obsolete IC Availability & Replacements

The AD515AH is a monolithic FET-input electrometer operational amplifier Analog. It is primarily used in high-precision circuits requiring extremely low input bias currents, such as pH electrodes, photocurrent detection, and vacuum ion-gage measurements Analog.

Key Technical Specifications

Input Bias Current: Guaranteed maximum of 75 fA for the L variant Analog.
High Impedance: Common-mode input impedance of $10^{15} \Omega$ Analog.
Packaging: Hermetically sealed TO-99 metal can package with a guarding pin to minimize leakage Analog.

Market Trends & Status

Official Lifecycle: The AD515A family is currently Obsolete by Analog Devices Analog. The recommended official replacement is the AD549 Analog.
Availability: Despite its obsolete status, the AD515AH (and the military-grade AD515AH/883) remains available through third-party platforms as New Old Stock (NOS) or refurbished units Alibaba Alibaba.
Pricing: Current market listings on B2B platforms range from $0.77 to $1.99 per unit, with some military-grade variants listed at significantly higher prices due to their specialized screening Alibaba.