I am working with LTC6253-7 op amp which should have a bandwidth of 2 GHz but when I simulate the output for a follower and the output is being severely attenuated. Is there a technique that must be used to achieve unity gain? My signal is 500 MHz I am using to test this op amp. enter image description here

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    \$\begingroup\$ The LT part numbers ending with dashed numbers means the minimum gain for stability. If you need unity gain stable, I would try the AD8000 recommended to you in your previous question: analog.com/en/products/ad8000.html \$\endgroup\$
    – Ste Kulov
    Commented Jun 25 at 20:15
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    \$\begingroup\$ Also, I noticed you post many questions and never accept any answers. See this for more info: meta.stackexchange.com/a/5235 \$\endgroup\$
    – Ste Kulov
    Commented Jun 25 at 20:16
  • \$\begingroup\$ I should also note that most GHz range unity gain opamps will be "current feedback" instead of "voltage feedback". \$\endgroup\$
    – Ste Kulov
    Commented Jun 25 at 20:22
  • \$\begingroup\$ but you can use them the same way right? so i think its ok. \$\endgroup\$ Commented Jun 25 at 22:03
  • \$\begingroup\$ Ehhhh...mostly, but there are some differences. One important thing is that CFB opamps usually have a very limited input and output range, so you don't have much headroom operating from a single supply. Additionally, I think for your application (unity gain buffer) you need to be careful of the feedback resistor. See Figure 4 and the text above it in the following application note: ti.com/lit/pdf/sboa081 \$\endgroup\$
    – Ste Kulov
    Commented Jun 26 at 6:47

1 Answer 1


It's quite simple. You are using the device outside it's prescribed limits as stated in the data sheet: -

The device is stable for closed loop noise gains of 7 or higher

In other words, the minimum gain is not unity but 7. More info from the data sheet: -

Gain Bandwidth Product: 2 GHz
–3dB Frequency (AV = 7): 160 MHz

I am working with LTC6253-7 op amp which should have a bandwidth of 2 GHz

No, it has a gain-bandwidth-product of 2 GHz


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