The XTR1xx use an advanced zero-drift architecture to achieve ultra-low offset and offset drift for OPA-A and OPA-B. This architecture uses a clock and switches internally to create a dc error-correction path. The clocking is filtered internally, and typically not observable for most configurations. Take the following precautions to minimize clock noise in the signal chain when using OPA-B. The clocking creates a small charge-injection pulse at the input of the amplifier; therefore, do not use high-value resistors (> 100kΩ) in series with the inputs to avoid higher clock voltage noise at the output.