Open drain buffer output pull-up on warm reset circuit?

[cospan]

Hi,

I love the OSD3358-512M-BSM, I’m planning on making a small board with it. I’ve been going through your site’s very useful design tutorial. Currently, I’m working on the reset circuit, specifically the warm reset. I’ve used this page as a reference:

OSD335x Reset Circuitry

There is something that I’m not clear about. The output if the SN74LVC1G07  is attached to the APX811’s MR# pin. I don’t see a pull up for the output of the open drain buffer. It doesn’t look like it’s being pulled up anywhere. I looked through both of the datasheets for the parts and I don’t see any declared internal current pullup. Perhaps I missed it. I’d like to know if I’ve missed something.

I’m planning on adding a 10K pull up to SYS_VDD1_3P3.

 

Thanks again for the part and the documentation.

 

Dave

[Neeraj Dantu]

Dave,

The reset supervisor APX811 is a clone of MAX811 which has an internal pull-up resistance of 10K. We have measured the presence of this internal pull up on APX811. The datasheet of APX811 just doesn’t specify the pull-up but it is present.

Hope that helps,

Neeraj

[cospan]

Makes sense, thanks for the clarification!

[Author]

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