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sinara-hw / Urukul

4 channel 1GS/s DDS (AD9910 or AD9912 variant)
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IC22 voltage #60

Closed gkasprow closed 3 years ago

gkasprow commented 3 years ago

I've just noticed that IC22 has a "0.8V" annotation close to the FB input. In fact, it should be 0.7V. The TPS62148 is able to deliver output from 0.8V but the nominal FB voltage is 0.7V With current resistors, it produces 6.5 instead of 7.5V which makes the 7V LDO out of regulation. Can somebody who has Urukul measure the voltage on C211? obraz

jordens commented 3 years ago

~Isn't this https://github.com/sinara-hw/Urukul/issues/20 ?~ Ah no. That was TPS62175DQC.

atcher0 commented 3 years ago

Voltage measured on C211: 6.58 V (I checked on two different Urukul AD9910 v1.5.1 boards). It produces about 6.33 V from the IC21 LDO.

gkasprow commented 3 years ago

R134=75k R136=7k5

gkasprow commented 3 years ago

fixed in v1.5.2

dnadlinger commented 3 years ago

What's the practical consequence of this being left unpatched? Worse output power stability (and more noise)?