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# Differential Mode Output

155 Threads found on edaboard.com: Differential Mode Output

## Help for opamp design

Hello, i am usign THS4503 fully differential OPAMP in my design. I am using it in single supply mode. +Vs= 5V and -Vs=GND and Common mode Voltage Vocm = 2.5V. Now how to decide input voltage and output voltage swing? How to take care so that my output will not clip. OPAMP designed with unity gain. I (...)

## Input bias of transconductor

Perhaps the grounded input is an ac ground..? I think that fully-differential gm-C would use a common mode feedback loop to determine dc bias. Probably, the input and output of the stage have the same dc point and the stages are dc-coupled after that...( not sure about that )

## Does common-mode voltage depend on the AC amplitude of the input at the gate?

hi, i have a very simple question. does the output common-mode voltage of a simple differential amplifier depend on the input AC amplitude at the gate? why or why not? thanks Voc = Ac Vc, so it depends on the amplitude of Vc and the common mode gain

## Fully differential output stage with low impedance

Common-mode voltage of the input differential signal is 1V. Vdd is 1.8V. What kind of output stage could a use to get several tens or hundreds KOhms? CM voltage of output diff signal approximatly 1V.

## How to do stability analysis of a common mode feedback loop?

Hi, 1) First, what is the intent of your main circuit? You have the input at gate of NMOS differential pair tied to gate of an NMOS load (positive feedback?) 2) You have shorted the output with a resistor (Why?). 3) For stability analysis, you have to keep Rc in place - the second picture shows that one of the Rc is missing. 4) In your

## Differential Amplifier with a BJT input stage gain

I have a simple Bipolar differential Amplifier with a BJT input stage. The equivalent circuit I have drawn and attached. When I do an AC simulation of the diff amp, giving a 500m and -500m signals at the inputs, I get the output which looks like the one I have attached. The differential gain of the output looks around (...)

## How to improve CMRR(common mode rejection ratio)?

In OPA(operational Amplifier) circuit design, the input is differential, the output is single ended. How to improve CMRR(common mode rejection ratio)? Thank U!

## fully differential amp without cmfb

Fully differential amplifier without feedback have very high differential gain and very high common mode gain. differential feedback provides certain differential gain and common mode feedback provides small common mode gain.

## differential mode output from opamp with current mirror load

Current mirror load convert differential currents of input pair into single ended output , If I am not wrong?but I was curious if we can still take differential output from such a structure ?? anybody can throw some light on this ?.

## how to simulate psrr in hspice?

As in any other simulator: add an AC component to you supply voltage; tie you inputs to signal ground by properly setting the DC voltage. Perform Monte Carlo AC simulation and look at you output node. If your system is an amplifier, then instantiate your main cell and make it to work in differential mode by using a copy of the AC (...)

## Opamp design for Pipeline ADC

I am designing a Pipeline ADC (VDD=1v, Resolution 8 bit, F=15MHz) . The Opamp which i intend to use is a two stage differential Opamp. The input stage is a folded cascode and the second is a simple source follower which offers rail to rail output. My questions are the following: What is the necessary input Common mode Range of the (...)

## About opamp's SR and CMRR

It is not different from what you do for single ended amplifiers. Just measure your output signal in differential way. Also, remember to test your common mode feedback. Have a look at

## Pls help for an OTA design method with CMFB

Hi Everybody, I would like to know, in term of the practical design issue, how should I deal with common-mode output values between open loop OTA with CMFB and open loop OTA without CMFB. This is a one stage differential fold-cascode opamp design with CMFB. Say, Case 1, if the VDD is 5 v, the common-mode (...)

## Output swing & ICMR

For output swing, you need to sweep the inputs differentially. For ICMR, you need to sweep both inputs at the same time.

## Matching of a dual mode speaker

Dear all, I have a 2-wire dual mode speaker with the differential impeance 32 ohm, and it will driving by a audio amplifier with the output differential impedance 8 ohm. My question is that how can i do matching between them to maximize the efficiency. Thx a lot, Best rgds.

## PSS and large transient plot for SC-CMFB OTA

Hello Everybody, For my fully differential fold-cascode OTA with SC-CMFB, according to the Ken's paper "Simulating Switched-Capacitor Filters with SpectreRF", I use PSS and can achieve good common mode output voltage results when I let two input signals are disabled. I have used two "vsource" as my two differential (...)

## Fully differential OTA simulation

one thumb of rule maybe help you: the GBP of CMFB should be larger than ur differential GBP that's equivalent to that common mode feedback should be established faster than the operation of ur differential amp.

## Unity gain amplifier for switched capacitor circuits

If you are connecting the differential in/differential out as a buffer, you must be careful that there is not a contention with the common mode at the output. You could SIGNIFICANTLY load the previous section by your amplifier trying to set the common mode output voltage. Because of this, (...)

## Why tail transistor need to be in saturation region?

no the reason for the tail transistor to be in saturation is that,u are not going to allow the common mode signal to affect the output of the op amp,since when u are maintaining this transistor in saturation u are not going to allow the currents of the of the transistors in the differential arm of the differential (...)