An Auto-Zero-Stabilized Voltage Buffer With a Quiet Chopping Scheme and Constant Sub-pA Input Current

This article describes an auto-zero stabilized voltage buffer that achieves low offset and low noise with sub-pA input current. A high gain stabilization loop is used to periodically cancel the buffer’s offset. The loop itself is periodically disconnected from the buffer and auto-zeroed, during which its bandwidth is reduced to reduce the...