ZHCSOR9A November 2021 – April 2022 OPA4H014-SEP
PRODUCTION DATA
The OPA4H014-SEP contributes both a voltage noise component and a current noise component. The voltage noise is commonly modeled as a time-varying component of the offset voltage. The current noise is modeled as the time-varying component of the input bias current and reacts with the source resistance to create a voltage component of noise. Therefore, the lowest noise op amp for a given application depends on the source impedance. For low source impedance, current noise is negligible, and voltage noise generally dominates. The OPA4H014-SEP has both low voltage noise and extremely low current noise because of the FET input of the op amp. As a result, the current noise contribution of the OPA4H014-SEP is negligible for any practical source impedance, which makes it the better choice for applications with high source impedance.
Equation 1 shows the calculation of the total circuit noise:
For more details on calculating noise, see Section 8.1.1.1.