Op Amp Current Supply - Is 3 Amps Too Much?

In summary, the user is experiencing problems with their circuit, which includes an OP-27 dual supply connected to 2 9V batteries. They believe there may be an issue with the opamps and plan to replace them. They also mention connecting the batteries to the circuit in a specific order and ask if this could be damaging the opamps. Another user suggests using a DPDT switch to properly connect both power rails at the same time. They also mention the possibility of high currents being drawn through the device's substrate if the power supply connections are reversed.
  • #1
m718
88
0
Do opamps have current limit, I have an OP-27 dual supply connected to 2 9V batters the battery measures 3 Amps and 16 volts is this too much current?
 
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  • #2
m718 said:
Do opamps have current limit, I have an OP-27 dual supply connected to 2 9V batters the battery measures 3 Amps and 16 volts is this too much current?

There is some circuit problem. The OP27 is a standard opamp, so it will not draw or drive currents much over a few 10's of milliamps.

http://www.analog.com/en/other/militaryaerospace/op27/products/product.html

Check the power connections (maybe the +/- supplie connections are reversed?). Also, be careful to take usual ESD/handling precautions, as touching a powered-up exposed circuit can cause latchup.

When you power up your circuit (assuming the 9V batteries aren't dead by now), what gets hot?
 
  • #3
berkeman said:
There is some circuit problem. The OP27 is a standard opamp, so it will not draw or drive currents much over a few 10's of milliamps.

http://www.analog.com/en/other/militaryaerospace/op27/products/product.html

Check the power connections (maybe the +/- supplie connections are reversed?). Also, be careful to take usual ESD/handling precautions, as touching a powered-up exposed circuit can cause latchup.

When you power up your circuit (assuming the 9V batteries aren't dead by now), what gets hot?

resistors I put on the + supply got hot anything less than 10k just burned
 
  • #4
Can you post your schematic? Something in the middle must be hooked up wrong. If you do not load the opamp, are the currents small?
 
  • #5
berkeman said:
Can you post your schematic? Something in the middle must be hooked up wrong. If you do not load the opamp, are the currents small?

Its a very simple 2 opamp circuit so it must be the op amps I will replace them.
 
  • #6
But my opamps were brand new, when I connect the batteries to the opamp circuit I connect the ground first then + then -, is this ok or is it damaging the amps?
 
  • #7
m718 said:
But my opamps were brand new, when I connect the batteries to the opamp circuit I connect the ground first then + then -, is this ok or is it damaging the amps?

Not sure without a schematic. Generally you should use a DPDT switch to connect both of the rails at the same time.
 
Last edited:
  • #8
Sounds like it's mis-wired. It's easy to run high currents through the device's substrate. For example, just reversing the power supply connections will draw a huge current, while only dropping about .6-1 volt.

-Mike
 

1. Is 3 amps too much for an op amp current supply?

It depends on the specific op amp and its maximum current rating. Some op amps can handle up to 3 amps, while others may have a lower maximum current rating. It is important to consult the datasheet for the op amp to determine its maximum current rating and ensure that it is not exceeded.

2. What happens if I exceed the maximum current rating for an op amp?

Exceeding the maximum current rating for an op amp can result in damage to the op amp and potentially other components in the circuit. It can also cause the op amp to malfunction or fail, leading to inaccurate or unreliable results.

3. Can I use a current limiting resistor to prevent the op amp from exceeding 3 amps?

Yes, a current limiting resistor can be used to limit the amount of current flowing through the op amp. However, it is important to select a resistor with the appropriate resistance value to ensure that the current remains below the maximum rating for the op amp.

4. How do I determine the maximum current rating for an op amp?

The maximum current rating for an op amp can be found in its datasheet. It is typically listed as the maximum output current or the maximum supply current. It is important to carefully review the datasheet and ensure that the op amp can handle the desired current before using it in a circuit.

5. Can I use a heat sink to increase the maximum current rating for an op amp?

No, a heat sink cannot increase the maximum current rating for an op amp. The maximum current rating is determined by the internal design and structure of the op amp, and cannot be changed by using a heat sink. Using a heat sink can help dissipate heat and prevent the op amp from overheating, but it will not increase its maximum current rating.

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