OPA462: E/D pin open

Hello David,

Section 7.3.4 in the OPA462 datasheet, "Enable and Disable" provides information for applying the E/D pin. It indicates that you can leave the E/D pin and the output will be enabled. But because the E/D pin is a very high impedance pin it suggests that a small capacitor such as 30 pF be added from the pin to ground. That helps keep the pin from changing state should a fast impulse on an adjacent trace be coupled to it. Section 7.3.4 and Figure 60 provide you with alternative connection information for the E/D pin.

Be sure you solder the PowerPAD, underneath the OPA462 package, to a PC board pad that is connected to the V- (-75 V) supply potential. The datasheet discusses the connection on Page 28, in Section 10.1.2, PowerPAD™ Integrated Circuit Package Layout Guidelines. That is sometimes overlooked and can result in unexpected issues.

Regards, Thomas

Precision Amplifiers Applications Engineering 

Hi Thomas,

When E/D com is connected to -75V, what connection do you recommend?

30pF@E/D to GND or 30pF@E/D to -75V?

Thanks.

Hi David,

Section 7.3.4 states "a conservative approach is to connect E/D through a 30-pF capacitor to a low impedance source." The Figure 60 schematic shows the capacitor connected directly to ground. The V- supply should work as well because the supply bypass capacitors connected back to ground. However, for simplicity's sake I would connect it to ground.

Regards, Thomas

Precision Amplifiers Applications Engineering