Hi,
How to make/simulate a simple operational amplifier, transconductance amplifier, and comparator in QSPICE?
Assume you are looking for textbook type of simulation
In this Github : KSKelvin-Github/Qspice: Qspice technique, symbols and examples
- Folder : Symbol - Ideal Opamp and Ideal Comparator symbol and pdf explanation
- Folder : Guideline -
Qspice - Device Reference Guide by KSKelvin.pdf
Goto section Ã-Device, explain detail about Multiplying Gm AmplifierMULTGMAMP
1 Like
Hi Kelvin, I am wondering if this ideal operational amplifier can be transformed into an ideal transconductance amplifier in order to be used as transconductance amplifier:
Is it possible this?
Qspice has operational transconductance amplifier (OTA), which is Ã-Device <MULTGMAMP>. Both Qspice and LTspice have OTA, but they are defined differently in how output current is drawn. Qspice OTA current return to Vdd/Vss, LTspice OTA current return to REF.
Get my latest Device Reference Guide or goto Qspice HELP for more information.
(I made an update for OTA last week, but I am uncertain something about Rout and may be information in that section may change in future)
2 Likes
But how to spot the differences between them (op-amp vs transconductance amplifier) in terms of transient and ac analysis? A comparison between them…this is the idea
KSKelvin, do you have any examples on how to hook up the “GmAmp++ – Multiplying Gm Amplifier” that appears in the Symbols & IP Behavioral Analog selection? The two - and two + inputs might be what I need, but my attempts at guessing connections have failed. I didn’t see anything about this device in your Device Reference Guide.
Thanks,
Carl