ZHCSH86B December 2017 – February 2019 LMH5401-SP
PRODUCTION DATA.
The LMH5401-SP can set the output common-mode voltage to within a typical value of ±30 mV. If greater accuracy is desired, a simple circuit can improve this accuracy by an order of magnitude. A precision, low-power operational amplifier is used to sense the error in the output common-mode of the LMH5401-SP and corrects the error by adjusting the voltage at the CM pin. In Figure 71, the precision of the op amp replaces the less accurate precision of the LMH5401-SP common-mode control circuit while still using the LMH5401-SP common-mode control circuit speed. The op amp in this circuit must have better than a 1-mV input-referred offset voltage and low noise. Otherwise the specifications are not very critical because the LMH5401-SP is responsible for the entire differential signal path.