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In datasheet they have provided two parameters named Quiescent Current and Operating current in which I am measuring quiescent current i.e, ground current flowing from the device VDD to GND , when device inputs (HI,LI) are grounded (test conditions as mentioned in datasheet.

Electrical Characteristics Table

I am measuring Quiescent current at 1 (VSS) for now from below figure, Or should I consider current at 2 (RT1 and RT2) so that it comes to Quiescent current= Current at 1 + Current at 2 ?

(RT bias voltage is 3V which is given internally)

Test Setup

Where should i measure operating current providing f=500KHz input?

This table gives operating current for 25 degree as 1.5mA

When I relate this to below plot which is w.r.t to temperature the operating current contradicts the table value.

Operating current vs temperature

Can anyone shed some light on these parameters measurements

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I am measuring Quiescent current at 1 (VSS) for now from below figure, Or should I consider current at 2 (RT1 and RT2) so that it comes to Quiescent current= Current at 1 + Current at 2 ?

Carefully look at the subscripts of the parameters (underlined in red):

enter image description here

The current \$ I_{DD}\$ is the current that enters the \$ V_{DD}\$ pin and is therefore called "\$ V_{DD}\$ Quiescent current". So, you should measure this current at the \$ V_{DD}\$ pin.

Where should i measure operating current providing f=500KHz input?

Same as above, at the \$ V_{DD}\$ pin

This table gives operating current for 25 degree as 1.5mA
When I relate this to below plot which is w.r.t to temperature the operating current contradicts the table value.

Note that the table specifies a typical value. I would also expect this typical value in Figure 2, but probably they used a different measurement setup, yielding a different operating current than the typical value. (Note the same applies to \$I_{HBO}\$.)
It is not uncommon to find such a (seemingly) "inconsistency" in datasheets.

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  • \$\begingroup\$ Here is what I understood Quiescent Current and Operating Current is measured at VDD. But, how Operating Current calculated is it average current at VDD? \$\endgroup\$ – Adithya Pai Aug 22 at 7:01

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