Difference among Transconductor, Gm, and OTA?

[DoctorX]

I have been seeing people use transconductor, gm, and operational-transconductance amplifier (OTA) interchangeably, but I am not convinced that they are the same. May I get an opionion on them in terms of:

(1) What are the types of input/outputs (voltage, current, etc)?
(2) What are the impedance of input/outputs (high, low, resistive, capacitive, etc)?
(3) What are the voltage swing at input/output (virtual ground, low, high, etc)?
(4) What is the difference between Gm-C, OTA-C filters?
(5) Yes, if OTA is also high-gain V-in V-out amplifier, what is its difference from an Opamp?

Just some questions to provoke your thoughts.
Cheers

 

[analoger]

OPAMP is equal to OTA+Buffer, OTAs always have high output resistance.

 

[DoctorX]

OPAMP is equal to OTA+Buffer, OTAs always have high output resistance.

Did you mean that OTA is a high-gain voltage-input voltage-output high-output-impedance opamp that is able to drive capacitive load only? Its name suggests some kinship with Gm, but it is really meant to be a voltage amplifier?

 

[nandu_r]

1) if you talk about trance conductance then output definately will be a current
2) In case of trance conductance input is a voltage and output is a current so both output and input impedance will be high
3)Voltage swing at the output will be depend opon the load

The ota output will be G*i
if you connect a capacitor load practicaly output will swing till the one side of the output get saturated

 

[zenisle]

he says is good