OPA2836-Q1: Output current pulse close to max output current rating

Conor Rochford

Part Number: OPA2836-Q1
Other Parts Discussed in Thread: OPA2837, OPA2836

Hi,

The output current rating of the OPA2836-Q1 is 50mA and the absolute max is 60mA.

In my circuit, the op amp output is saturated low for about 0.4% of an 85kHz periodic signal.

While the op amp output is saturated low (0.4% of the time), the current the op amp is sinking reaches ~40mA. The RMS current is 6.9847mA and the average power dissipation is 5.2482mW. The temperature I observe on the bench is 28C.

I am curious about whether or not this operation is going to compromise reliability of the part.

Is the output current of the op amp not internally limited? (my guess is no)

Is the continuous absolute max current of 60mA the RMS value or the peak value if the current is periodic?

Thanks,

Conor

over 3 years ago

0 Michael Steffes over 3 years ago

Guru 47635 points

There is no current limit in the OPA2836. The iimproved OPA2837 has slightly more output current, might not be a Q1 version though,

The output current in the AbsMax table is a continuous DC current that is set by a metalization migration concern. This is a program run at the very end of layout to make sure the output traces are wide enough.

0 Conor Rochford over 3 years ago in reply to Michael Steffes

Prodigy 40 points

We require a AEC-Q1 component.

So if the output current is AC, do I use the RMS or peak value of the periodic waveform to compare against the AbsMax spec?

0 Hasan Babiker31 over 3 years ago in reply to Conor Rochford

TI__Genius 15555 points

Hello Conor,

It doesn't sound like you are achieving the abs max current even at the peak current of your signal, so reliability shouldn't be an issue here. Note that at these high load currents the output swing is reduced and signal becomes more distorted as can be seen in figures 8 & 11.

Best,

Hasan Babiker

0 Conor Rochford over 3 years ago in reply to Hasan Babiker31

Prodigy 40 points

Hi Hasan,

Thanks for your response. I am still curious about whether the abs max current for an AC signal should still be interpreted as RMS or peak value. If it is RMS, then there is tons of margin (RMS of the signal is 7mA). If it is peak, then I would need to verify the simulation on the bench by measuring the output current.

Thanks,

Conor

0 kai klaas69 over 3 years ago in reply to Conor Rochford

Guru 140200 points

Hi Conor,

how is the output sink current controlled to 40mA?

Cab you show a schematic?

Kai

0 Michael Steffes over 3 years ago in reply to Conor Rochford

Guru 47635 points

Since the absmax is set by a metal electromigration concern by either long term DC or RMS current, you can use the latter.

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OPA2836-Q1: Output current pulse close to max output current rating