JAJSC60F April 2016 – June 2024 THS6212
PRODUCTION DATA
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The THS6212 is designed to be used as a differential driver in high-performance applications. Therefore, analyzing the noise in such a configuration is important. Figure 6-3 shows the op amp noise model for the differential configuration.
As a reminder, the differential gain is expressed in Equation 1:
The output noise can be expressed as shown in Equation 2:
Dividing this expression by the differential noise gain [GD = (1 + 2RF / RG)] gives the equivalent input-referred spot noise voltage at the noninverting input, as shown in Equation 3.
Evaluating these equations for the THS6212 circuit and component values of Figure 7-1 with RS = 50 Ω, gives a total output spot noise voltage of 53.3 nV/√Hz and a total equivalent input spot noise voltage of 6.5 nV/√Hz.
To minimize the output noise as a result of the noninverting input bias current noise, keep the noninverting source impedance as low as possible.