Stupid question about opamp's quiescent supply current

[ricothetroll]

Hi,

I'd like to know how much current will an opamp "eat" without any signal, with a dual power supply. TL07x for example, the datasheet says between 1.4 and 2.5mA, but is it for EACH supply pin of for both (between 0.7 and 1.25mA for each pin) ?

Best regards.

Eric

[amptramp]

I'm old enough to have the printed data book and it states Supply Current (each amplifier) 1.4 typical 2.5 maximum mA so that would be 2.8 to 5.0 for the TL072 and 5.6 to 10.0 for the TL074.

[PRR]

> is it for EACH supply pin of for both

It goes in one pin and out the other.

[ricothetroll]

Thanx for your answers !

I'm old enough to have the printed data book and it states Supply Current (each amplifier) 1.4 typical 2.5 maximum mA so that would be 2.8 to 5.0 for the TL072 and 5.6 to 10.0 for the TL074.

I must admit my formulation was imprecise, I should have written "EACH pin of a TL071 (then x2 for TL072 and x4 for TL074".

My question's purpose was to choose the size of the charge pump converter I'll use in my circuit to convert 9V to +/- 12V (I'll have to use two). I'll use a TC962 (9 -> 18V) -> LM78L12 (18 -> 12Vreg) -> TC7662 (12V -> -12V). I have to choose between TC7662 A or B (40mA or 20mA).

It goes in one pin and out the other.

So that's 1.4 to 2.5mA for each "side" of the dual PSU.

By the way, 1.4->2.5mA is a variation between specimens, for a given supply voltage (+/- 15V), right ? Will my opamps need less supply current when working with lower supply voltage ?

Best regards.

Eric

[amptramp]

According to the data book, an amplifier drawing 1.3 mA (just under the typical value) at +/- 4 VDC would take 1.35 mA at +/- 15 VDC, so there is almost no variation with voltage.  The power drain has a negative temperature coefficient so that an amplifier taking 1.5 mA at -40C takes 1.0 mA at +100C and the variation is linear.

Note that when you are sizing a regulator, the currents above are quiescent currents where no load is drawn from the output.  You have to calculate this load and add it to the current to be supplied and regulated.  If you drive 8 volts into a 2K output load, add 4 mA to the supply current.  I would always use the higher output devices where available just to allow some design margin.  For example, if you bring the unit in from a cold van in the middle of winter, you may find higher power consumption until it warms up.

[ricothetroll]

Hi,

I think I'll go with the A model (tested good up to 40mA) for margin, or maybe with a second TC962 (80mA), as the price difference between TC7662A and TC962 is so small.

Thanx a lot !

Best regards.

Eric