Part Number: TLC2262
Tool/software: TINA-TI or Spice Models
I am now using TINA to simulate the behavior of an op amp TLC2262. But the result of AC analysis and transient analysis is different.
1, In the first case, it is ac analysis which operates between 1 to 500kHz and from the result below, the amplitude of the output waveform is increasing with the frequency.
2, But when it comes to transient analysis with a 1V input at 500kHz, the amplitude is about 200mV which is a conflict with the result of ac analysis who has 650mV at 500kHz.
Could anyone explain to me why the result behaves like this?
And here is the result of the second case:
My simulation circuit is also attached here.TLC2262.TSC
In reply to Haoyang Zhang42:
Gain is measured with virtually no signal amplitude, (small signal gain). Also the top scale is not dB it is (0.5 to 0.63) V/V result.
I tried a +/-1uV transient sine wave and I saw 1.26uV/2uV = gain = 0.63 V/V
So it works just fine. (other than saying "dB")
When I ran AC gain sweep, I got -6dB to -4dB (0.5V/V to 0.63V/V)
Regards,Ronald MichallickLinear Applications
TI assumes no liability for applications assistance or customer product design. Customer is fully responsible for all design decisions and engineering with regard to its products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning Customer's design. If Customer desires engineering services, the Customer should rely on its retained employees and consultants and/or procure engineering services from a licensed professional engineer (LPE).
Sorry for the delay. Many people on vacation because of weekend and New Year holiday.
First, please understand the TLC2262 is a 16V device. You cannot apply +/-15V (30V) to device.
When I change supply voltage to +/-8V, simulation has same behavior. When I replace TLC2262 device with ideal op amp, behavior is normal (gain is 0.5V/V and rolls off with open-loop gain).
Therefore I suspect an issue with the model. Please understand that the device and model are approximately 25 years old.
You should also be aware of slew rate. Given a signal that is 1Vp (2Vpp) at 500kHz the slew rate of the device should be at least 3.14V/us. I recommend at least doubling that and looking for devices with a SR of 6V/us or greater.
Therefore I suggest that you evaluate the OPA172. It is a wide-supply device with sufficient bandwidth and SR. Since it is a newer device the model is more robust. Please see attached.
Note that I removed some of the additional features you included in your design (cap load, for example). Of course you can add these in at your convenience.
Also, for more information on op amps including slew rate and op amp stability we have an excellent series of videos at http://www.ti.com/precisionlabs
General Purpose Amplifier Applications
In reply to Pete%20Semig:
Please refer to Figure 43 on page 23 (and the explanation at the top of page 24) in the data sheet. It shows the input capacitance as common-mode.
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.