TL5902 output timing

[bpiquette]

The OSD335x-SM Datasheet says:
7.2.2 SYS_VDD1_3P3V
The OSD335x-SMcontains a dedicated 3.4 VDC supply1to power external circuitry. This is supplied by the TL5209, powered by the TPS65217C SYS output, and enabled by the TPS65217C LDO4.

Does that mean that the Enable of the TL5209 is driven to ENABLE by the output of the LDO4 (SYS_VDD3_3P3V)?
So, when SYS_VDD3_3V3 goes high, then the TL5209 is enabled?

[bpiquette]

This is what I see on my PCBA.
It appears that the TL5209 output, SYS_VDD1_3P3V comes up before LDO4 (SYS_VDD3_3P3V)

Attachments:

1. 

   SYS_VDD1_3P3V_timing-scaled.jpg
   

[bpiquette]

The mid level voltage on SYS_VDD3_3P3V are puzzling.

[Eshtaartha Basu]

Hello bpiquette,

Yes, the enable pin of OSD335x-SM’s integrated TL5209 is driven by SYS_VDD3_3P3V. A minimum of 2V is sufficient to enable TL5209 (as indicated in its datasheet – https://www.ti.com/general/docs/suppproductinfo.tsp?distId=10&gotoUrl=https%3A%2F%2Fwww.ti.com%2Flit%2Fgpn%2Ftl5209).

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