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At page 2 on top left there is written "Supply Voltage, V+ to V- ......... 7,5 V"

Low-Power, Single-Supply, CMOS INSTRUMENTATION AMPLIFIERS

Is that the supply range? Or is it meant like maximum V+ = 7,5 V and V- = 7,5 V (range would be 15 V)?

I can't figure it out with the data sheet. Will be grateful for any help!

Greets, keep

Mahendra Gunawardena
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keep it simple
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  • The voltage drop from V+ to V- can be no more than 7.5V, that means you could have [V+ at 7.5V and V- at 0V ] OR [ V+ at 3.5V and V- at -4V ] OR [ V+ at 0V and V- at -7.5V ] and still be in the limit of the absolute maximum ratings. – Voltage Spike Jun 27 '16 at 22:10

3 Answers3

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enter image description here

Figure 1. Page 3 of datasheet.

The big clue for intended use is on the top of page 3. As others have said, this can be a split-rail power supply provided \$ V_+ - V_- < 7.5~V \$.

If running on split supplies you need to take particular care (just because it would be easy to make a mistake) not to exceed the limits on the inputs. The rule applies on single voltage supplies too but usually you will be running from a supply common to all the other chips so out-of-range signals would be more difficult to generate.

enter image description here

Figure 2. Note that the maximum signal input is \$ V_+ + 0.5V \$ and minimum is \$ V_- - 0.5V \$.

Transistor
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It simply means that the (algebraic) difference between V+ and V- has to be 7.5 V. It doesn't matter, in principle, what is the value of V+ and V- with respect to ground.

Electrical Architect
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As this is a single supply part, it means that (V+ - V-) <= 7.5V If you would use dual supplies, it would translate to +-3.75V.

However, this Instrumentation Amp is designed for single supply, which you can also see by the specified supply range (page 3): Specified Voltage Range (min..max) +2.7 .. +5.5 V. You can use it with dual supply but would have a very limited +-1.35..+-2.25V supply voltage to stay within device specs.

The absolute maximum ratings just ensure the part is not damaged permanently, they do not ensure that the part stays within specifications.

cx05
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