Q&A AD5542A Power-on-Reset does not work

AD5542A Power-on-Reset does not work

yoichi_mac

on Jan 26, 2021

Hi Support team

I 'm evaluating the AD5542A, i rarely found the non-MID scale output when the power is turned on.

To ensure POR operation, are there any recommended conditions such as power supply slew rate or linear increase?

VDD and VLOGIC rising waveforms are attached for reference. Can you tell me if there is any problem?

Best regards,

Blue is VDD (5V) and light blue is VLOGIC (3.3V).

0 isantos

on Jan 26, 2021 7:14 AM
Hi yoichi_mac,

Do you have waveform showing the supplies and the output not going to mid-scale? Can you also share your schematic?

Typically, you should connect GND first followed by VDD, VSS then digital supply.

Have you tried ensuring VDD is at least 2.7V before supplying the digital supply ramps up?

Cheers,

Ivan
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0 yoichi_mac
on Jan 26, 2021 7:25 AM in reply to isantos
Thank you for your quick reply.

I don't have no-midscale waveform ,schematic is attached below.

AGND and DGND is tied at same PCB. those GND is first applied.

I'll try supplying VLOGIC after VDD reached at 2.7V.
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