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Earphone audio level quiet and microphone not working

Do not connect the SPK- output to MIC ground. The speaker is driven by a H-bridge (maybe a D class amplifier) so both SPK+ and SPK- are active audio signal wires and neither of them is ground. The ...
Justme's user avatar
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3 votes

Designing a differential amplifier

Anya - you want to design a two-transistor differential amplifier. This means: It is the purpose of this amplifier to amplify only the voltage difference between both signal inputs. In the following, ...
LvW's user avatar
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1 vote

Designing a differential amplifier

Basic idea The differential pair (figuratively called "long-tailed pair" in the past) consists of two common-emitter stages with a common current source in the emitters. Depending on the ...
Circuit fantasist's user avatar
2 votes

How do I convert a differential RF signal to a single ended signal?

You use a balun this is a transformer which will convert the balanced differential pair output to the unbalanced SMA-coax. simulate this circuit – Schematic created using CircuitLab
RoyC's user avatar
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Confusion About Impedance Matching For Single-Ended and Differential Lines

Usually this means creating two 50Ω lines that form a differential pair. Because both pairs are also used differential they are coupled to each other so you need to calculate the impedance stackup and ...
Voltage Spike's user avatar
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Is a gap needed with LVDS with metal layer below it?

Does there have to be an air gap? You could put a thin thermal pad in there and vacuum bond the assemblies together. This should at least give you a more controlled height (H1) and dielectric ...
SteveSh's user avatar
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3 votes
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Is a gap needed with LVDS with metal layer below it?

The air gap/solder mask gap is currently a few thousands of an inch, maybe 1-3, but I could put some kapton tape underneath to ensure it's not a problem and widen that gap to whatever the thinkness of ...
Kuba hasn't forgotten Monica's user avatar
3 votes

Is a gap needed with LVDS with metal layer below it?

Yes. It will be a differential stripline geometry. Note that the dielectrics may differ as well. You show FR-4 in the calculation, but FFC is made of polyimide. It's not clear to me what your stackup ...
Tim Williams's user avatar
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Why is an offset voltage and an offset current sufficient to represent mismatches in a differential amplifier?

There's no proof. There's no need for a proof. It's a model that does a good job of representing nonidealities for the purpose of design (and op amp selection).
Fred's user avatar
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Why is an offset voltage and an offset current sufficient to represent mismatches in a differential amplifier?

If you accept that an amplifier will have offset (the DC bias at the input will have a difference WRT the output), then you know that this is only visible at the output. However, different amplifiers ...
Designalog's user avatar
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Proof of half-circuit analysis of perfectly-balanced differential amplifiers

I am not aware of any "proof" although I suppose one could choose a circuit, write equations relating output voltage to the input voltages, and perform some sort of matrix decomposition. I ...
Fred's user avatar
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Proof of half-circuit analysis of perfectly-balanced differential amplifiers

The slide deck in the link has a clear explanation of transforming two voltages into a combination of common-mode and differential-mode signals. I think your question is why that transformation at the ...
DavidG25's user avatar
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1 vote
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CM filter of differential input(AD7383-4)

I don't get why should we put common mode capacitor(C1). Does it work without CM capacitor? The data sheet is quite explicit about this: - So, if you want optimal performance, you fit the ...
Andy aka's user avatar
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Why is an offset voltage and an offset current sufficient to represent mismatches in a differential amplifier?

Circuit analysis of device mismatches with equivalent sources has strong parallels with the analysis of noise in circuits--- an often-referenced comparison is that offsets can be treated as "very ...
snEE's user avatar
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-1 votes

How does the current of RS485 signals return from the receiver to the sender?

https://www.renesas.com/us/en/document/oth/tb506-functional-principles-rs-485-drivers-and-receivers The output stage of an RS-485 driver is a H-bridge, where the upper transistor in one leg sources a ...
Thomas Kugelstadt's user avatar
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Proof of half-circuit analysis of perfectly-balanced differential amplifiers

A lot of claims in the linked PDF are about symmetry and addition/subtraction. This is mathematical stuff that is mostly based on axioms, which can not be proved but serve as basic building logic ...
Stefan Wyss's user avatar
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