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QSD2 V1.0 Regulator Circuit Change

This note covers a recommended change to the QSD2EZ V1.0 circuit. The board will probably work well without this change, however, in some boards the 2.5 volt regulators may not properly regulate. This is due to the very light load on the regulators. Also, I recommend removing one of the regulators, and installing an option “DNP” (Do Not Place) so that the circuit works with a single regulator.

Here is a list of the changes:

  1. Solder a 2.2kohm resistor on top of the 1uF capacitor C23. This is shown in the image below:

    2.2kohm resistor on top of C23
    2.2kohm resistor on top of C23

  2. Remove regulator device U8 as shown in the image below:

    Remove SOT-23 regulator U8
    Remove SOT-23 regulator U8

  3. Add 0ohm resistor R16 on the back side of the board:

    Add 0ohm resistor R16
    Add 0ohm resistor R16

Verify the regulator’s 2.5 volt output when the board is powered up. That is all!

73 Greg KF5N