CDCE6214: OUT0 Shutting Down when OUT4 is Shut Down

Clayton Ferrazzo

Part Number: CDCE6214

When powering down OUT4, it appears that OUT0 also powers down. This is separate from the voltage enable setting in TICS Pro. When selecting OUT4 as powered down, TICS Pro does not indicate that OUT0 is also powered down. There appears to be a setting we are missing and during testing, we found that shutting down OUT4 also shut down the main 50MHz OUT0 we were using.

I need to document this to ensure that we do not run into this issue in the future as we plan to only use 2 or 3 of the outputs (in addition to OUT0). Can I get confirmation that this behavior is expected? There appears to be no documentation in the datasheet that indicates power to OUT4 is also tied to OUT0.

6 months ago

0 Clayton Ferrazzo 6 months ago

Prodigy 30 points

I should also add that the register map document does not explicitly call out an OUT0 LDO, but it does call out register settings for OUT1-4, so even in the register map, there is no indication that the behavior of shutting off OUT0 occurs when OUT4 is powered down.

+1 Kadeem Samuel 6 months ago in reply to Clayton Ferrazzo

TI__Genius 15030 points

Clayton,

The OUT0 channel is powered by the same LDO that drives the OUT4 channel. This behavior is expected. See below from the datasheet:

The Y0 text is outdated (Yx was later changed to OUTx), we will update this in the next revision of the datasheet.

Thanks,

Kadeem

0 Clayton Ferrazzo 6 months ago in reply to Kadeem Samuel

Prodigy 30 points

Hi Kadeem,

Does this mean that OUT3 powering down will also kill power to OUT0? Based on the first two snips, that's what I would assume. This is the "powerdown" action I'm referring to that tweaks bits in Register R4.

I think maybe I'm still a tad fuzzy on the ch4_pd/ch3_pd bits and what they have to do with VDDO_34. If I change 0x4 bit 7 CH3 or 4_PD to a "1" then I wouldn't expect this to have any effect on VDDO_34 aside from reducing the load on it.

0 Kadeem Samuel 6 months ago in reply to Clayton Ferrazzo

TI__Genius 15030 points

Clayton,

If VDDO_34 is not supplied, then OUT0 will not operate.

The software powerdown is controlled only by the CH4 powerdown bit, not the CH3 bit.

Thanks,

Kadeem

0 Clayton Ferrazzo 6 months ago in reply to Kadeem Samuel

Prodigy 30 points

Okay, thank you for the input, we will adjust our design to not powerdown OUT4 to keep OUT0 active. Thank you.

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CDCE6214: OUT0 Shutting Down when OUT4 is Shut Down