AD7656A/7A/8A and A-1's Absolute maximum ratings say “Vdd to AVcc is AVcc+0.7 to +16.5V”
I would like to know what mean about this spec.
I moved this post to the precision converter space, someone here should be able to help.
This just means that the potential difference between VDD and AVCC should not go below AVCC+0.7V nor should it go over 16.5V.
Thank you very much for your reply.
You mean VDD= AVCC= 0V is exceed this spec?
AD7656, not A, spec say
Vdd to Avcc AVcc-0.3V to 16.5V.
Is AD7656A different from AD7656?
Let me retract my previous answer and echo the answer in this thread, that is, that the VDD to AVCC is AVCC + 0.7 V to 16.5 V in the abs max table means that the voltage for VDD should not go below AVCC+0.7V and never greater than 16.5V. This is particularly important in your power up sequence. Please also note that the figures in the abs max table are stress ratings only and that for normal operation, the figures in the specs table should be followed.
The thread also discusses the difference of the AD7656A from the AD7656.
Thank you very much for your support.
The thread that you introduced say
>The AD7656A and AD7656A-1 have incorporated the external schottky diodes required on the AD7656 and AD7656-1 when application of VDD and VSS before analog inputs cannot be guaranteed.
This mean AD7656A and AD7656A-1 has the external Schottky inside.
(I saw AD7656A D/S Figure20 and D7656 D/S Figure 24)
> In other words bring VDD up before AVCC or ensure that VDD is never less than AVCC - 0.3V and never greater than 16.5V
I got "VDD should supply before AVcc", by the spec of VDD to AVcc.
I ask again
Regarding about Abso max spec,“VDD to AVcc ; AVcc+0.7V to 16.5V”
Does this spec allow VDD=0V AVcc=0 conditions?
Thank you for your cooperation.
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