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How Much is Quiescent Current Iq of OP27 OP AMP?

01/25/2025 3:05 AM

How much is quiescent current Iq of OP27 OP AMP? Has anyone measured it? Datasheet has no listing of Iq.

Shyam

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Guru

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#1

Re: How much is quiescent current Iq of OP27 OP AMP?

01/25/2025 6:07 AM
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Guru

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#2

Re: How Much is Quiescent Current Iq of OP27 OP AMP?

01/25/2025 5:33 PM

Iq guiescent current is the supply current with no output current (e.g. output disconnected)

https://www.ti.com/lit/an/slyt412/slyt412.pdf

Iq per channel (typ) (mA)2.8

(OP27 is single channel)

https://www.ti.com/product/OP27

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#3
In reply to #2

Re: How Much is Quiescent Current Iq of OP27 OP AMP?

01/25/2025 7:02 PM

I believe this would be the circuit operating current...but I could be wrong...

How to calculate power consumption of opamp?

For OP Amp itself, the power consumption is quiescent current * power supply voltage. Consider of the load, the power consumption is (Vsupply-Vout) * Iload. The total power consumption is the combination of above.

https://www.analog.com/en/products/op27.html

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#4
In reply to #3

Re: How Much is Quiescent Current Iq of OP27 OP AMP?

01/26/2025 11:37 AM

Here's my understanding...

There's a load (not shown) between Vo and ground, a voltage source between Vs+ and ground, and a voltage source between Vs- and ground.

If the output is driven positive (v1<v2), current flows into the op amp Vs+ and out Vo, through the load to ground and back to the positive power supply. Likewise, if (v1>v2) current flows the other way from ground, through the load, into Vo, and back through Vs- to the negative supply.

If (v1==v2), Vo is at ground potential, no current is flowing in or out of Vo. There is a small amount of current flowing into the op amp at Vs+ and out through Vs-, the quiescent current, Iq.

Low quiescent current, Iq, is important in applications where the input signal is intermittent with a low-duty cycle and long battery life is important.

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#5
In reply to #4

Re: How Much is Quiescent Current Iq of OP27 OP AMP?

01/26/2025 12:18 PM

I would agree this all sounds correct...I look at it as the op amp chip takes some small amount of current to operate, minimal losses characterized by the lq designation...this I think would vary according to testing conditions and operating environment, lab vs field...the lab testing under ideal conditions and the field operating within the parameters of design...so we would have a typical or ideal measurement, and a max field operating reading...I would also note that the version of chip may vary...

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#6

Re: How Much is Quiescent Current Iq of OP27 OP AMP?

01/27/2025 5:46 AM

From memory, long time ago, the answer would depend on your intended operating condition.

If using the OP AMP as a two state device On/Off, the result would be different to that if using it within the linear range as an amplifier.

As an amplifier, it would depend on the specifics of the signal at that particular point of time.

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