OPA454: E/D pin setting

Hi Mia,

Section 9.3.6 of the OPA454, ENABLE and E/D Com, discusses the options you have for setting the E/D pin and E/D Com pin levels. As mentioned you could float the E/D pin for minimal components and it will be self enabled. However, it does mention may be sensitive to transients capacitively coupled into the pin. There is possibility of inadvertent disable occurring. Adding just a small capacitor 33 to 47 pF to the pin should solve a transient coupling to the pin issue. If that isn't an issue at all, then no additional components are required minimizing the circuit space required.

Another option is to use a simple two resistor, resistive voltage divider from V+ to the E/D Com voltage being applied. Just satisfy the requirement that the E/D voltage is between E/D Com + 2.5, and E/D Com + 5 V as required by the Electrical Characteristic's table. The resistors can be high value and very small such as 0402 size if the power dissipation is kept low and they can withstand the high voltage that may be across them.

Regards, Thomas

Precision Amplifiers Applications Engineering

Hi Kuehl

Clear and many thanks.

Best regards

Mia Ma