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Hammer How to Swtching 5V Regulator
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- This How To has sort of been OBE since the production Hammer_Carrier boards will no longer use an onboard 5V regulator, but use a 5V wall wart. Some may still find it useful.
The 5V linear regulator on the Hammer Carrier board is somewhat over stressed, just powering the Hammer, it can get to over 140 F. In order to be able to use USB peripherials, or add a Enc28j60, something must be done. The provided wall adapter puts out over 15Vdc no load and 13Vdc under load, this from a 9Vdc rated adapter.
I replaced the LM1117MPX-5.0 with a 78SR105VC. This provides up to 1A of power and runs cool to the touch.
First, unsolder U2.
Second, obtain a replacement, such as:
Third solder the repalcement to the Hammer carrier
Remove the Hammer module being sure not to crush any components.
Wire it up.
The 78SR105 that I used has built in bypasses so additional bypassing at the pins is unneccessary. We use the existing bulk bypasses of U2. Your replacement may require additional bypassing as neccessary.
Power up the board and verify that the 5V is present.
If it is ok, power off, then plug the Hammer module back in, being sure to have the JTAG connector on the same side as the serial connector of the Hammer_Carrier.
