Op amp power question

speakerguy79 · 11th February 2007, 09:48 PM

OK, say I have a power supply. +/-15V, 500ma per rail.

I have a dual opamp, listed at 5ma current consumption per device (10ma total).

When they say 5ma consumption per device, is that 2.5ma from the + rail and 2.5ma from the - rail? How do I calculate power consumption of the op amp and which rail the current is being drawn from? Thanks!

paulb · 11th February 2007, 10:04 PM

The 5 mA flows "into" the V+ terminal and "out of" the V- terminal. You'll notice there is no power supply ground terminal on the device. Kirchoff's Current Law.
Until you start driving a load with the opamp, all the current that flows into V+ will come out of V-.

11th February 2007, 09:48 PM	#1
speakerguy79 diyAudio Member Join Date: May 2006	Op amp power question OK, say I have a power supply. +/-15V, 500ma per rail. I have a dual opamp, listed at 5ma current consumption per device (10ma total). When they say 5ma consumption per device, is that 2.5ma from the + rail and 2.5ma from the - rail? How do I calculate power consumption of the op amp and which rail the current is being drawn from? Thanks!

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11th February 2007, 10:04 PM	#2
paulb diyAudio Member Join Date: Jun 2001 Location: Calgary	The 5 mA flows "into" the V+ terminal and "out of" the V- terminal. You'll notice there is no power supply ground terminal on the device. Kirchoff's Current Law. Until you start driving a load with the opamp, all the current that flows into V+ will come out of V-.

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