zoulzubazz
Member level 5
Hey guys,
Attached is the figure of a instumentation amplifier which I am trying to get to work. I am trying to amplify a 10MHz signal received by a 2uH center-tapped aircoil. Its running off a 9V battery and a reference voltage of 2.5 V (Vref) is generated by a general purpose op amp. Also an LDO provides a regulated 5V supply to the opamps (LMH6629, 900MHz GBW). Now I am seeing spurious voltages reaching the 5V supply when nothing is connected to the input and also when the coil is connected to the input. Am i missing something here, what extra care should i take to ensure that the circuit does not oscillate. Any ideas thoughts will be very helpful. Thanks.
![IMG_20150819_224423.jpg IMG_20150819_224423.jpg](https://www.edaboard.com/data/attachments/55/55463-e044a29f364e4f69d5e579f8cd213723.jpg)
Attached is the figure of a instumentation amplifier which I am trying to get to work. I am trying to amplify a 10MHz signal received by a 2uH center-tapped aircoil. Its running off a 9V battery and a reference voltage of 2.5 V (Vref) is generated by a general purpose op amp. Also an LDO provides a regulated 5V supply to the opamps (LMH6629, 900MHz GBW). Now I am seeing spurious voltages reaching the 5V supply when nothing is connected to the input and also when the coil is connected to the input. Am i missing something here, what extra care should i take to ensure that the circuit does not oscillate. Any ideas thoughts will be very helpful. Thanks.
![IMG_20150819_224423.jpg IMG_20150819_224423.jpg](https://www.edaboard.com/data/attachments/55/55463-e044a29f364e4f69d5e579f8cd213723.jpg)