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-   -   NJM4558 and clones - what is minimum supply voltage ? (http://www.diyaudio.com/forums/solid-state/214719-njm4558-clones-what-minimum-supply-voltage.html)

nowhere 18th June 2012 09:32 PM

NJM4558 and clones - what is minimum supply voltage ?
 
I know, the thread name sounds utterly stupid in the age of web search engines and datasheets ;).

And I tried to play an intelligent person checked the datasheets.

For example, I tried this: http://www.cadeka.com/uploaded_files/NJM4558_DS.pdf , and in the very beginning I read: "Dual 4V to 36V Amplifier".

The "4V" part looks OK - I need something that would work from +5V.

However, in http://datasheetcatalog.org/datashee...io/ae04052.pdf I see "+/-4V", i.e. minimum 8V is necessary.

http://www.st.com/internet/com/TECHN...CD00005076.pdf doesn't directly mention minimum supply voltage, but on page 4 I see plots of positive and negative swing as a function of load resistance, and there I see minimum +/-3V supply voltage, i.e. 6V is needed.

So, what is the minimum tolerated supply voltage for, say, 2Vpp output ?

sofaspud 18th June 2012 10:24 PM

Since you want to operate near the design limits, you should check the datasheet for your exact part. Having said that, the first datasheet you linked states, "2V to 18V dual supply voltage range" right there on page one.

nowhere 18th June 2012 10:31 PM

Quote:

Originally Posted by sofaspud (Post 3064333)
Since you want to operate near the design limits, you should check the datasheet for your exact part. Having said that, the first datasheet you linked states, "2V to 18V dual supply voltage range" right there on page one.

The ST datasheet, as I wrote, doesn't explicitly say anything regarding minimum supply voltage.

sofaspud 18th June 2012 10:37 PM

Are you using the ST part, TJM4558?

nowhere 18th June 2012 10:42 PM

Quote:

Originally Posted by sofaspud (Post 3064344)
Are you using the ST part, TJM4558?

I am not using any part at all, I need to make a buying decision. And I want the parts to be no more than $5 for 10 parts including S&H.

Another problem is that I don't even know all possible clone names. For example, I came across TJM4558 incidentally.

sofaspud 18th June 2012 11:02 PM

I don't know what your project is. Maybe a quad device like the LM324 might help to meet your budget. You'd only need 5 instead of 10, and it's designed for +5V single supplies.

nowhere 18th June 2012 11:08 PM

Quote:

Originally Posted by sofaspud (Post 3064355)
I don't know what your project is. Maybe a quad device like the LM324 might help to meet your budget. You'd only need 5 instead of 10, and it's designed for +5V single supplies.

No, I need a dual and not quad device. And LM324 is not an audio amplifier.

Of course, *4558 is not of high quality audio, but suitable for my needs (it's frequency response measurements).

I also want a chip with pretty decent driving ability, so CMOS OpAmps may be a problem.

indianajo 19th June 2012 11:13 AM

The NJM4558 datasheet has a voltage swing versus power supply table that stops at +-6 power supply and +-4 voltage swing into 2 kohms load. Whereas the ST33078 datasheet shows a +-1 V output into 600 ohms with a power supply of +- 2v. I paid $.038 each for some ST33078's two years ago, on a distributor sale, and was very impressed with their lower hiss than the 4558's I took out. These are not the only part numbers in the world, you need to learn to download the datasheets for what is in stock at your local distributor and look up these tables yourself. As far as prefixes, you can end up with some weird widgit if you assume that some part is an op amp IC in a DIP package, but everybody in the world has made the 4558, probably there are 50 to 80 prefixes. Watch the suffix, there are 3 different packages, DIP, SIP, and SOIC.
I don't know about pricing in your part of the world, but in my country IC prices are trivial compared to the minimum $6 freight bill from some distributors and minimum $9 USPS postage from other distributors. The biggest part of economy here is getting everything you need from one distributor on one order, and not allowing back orders (two or more boxes shipped). I still have had a distributor (newark), despite my instruction for no backorders, to ship two boxes in one day for a $12 freight bill. I had another distributor (mouser) come up short in the warehouse for two $.008 resistors that had showed in stock, and disassemble the order one line at a time over a period of weeks to satisfy other customers.
Don't forget, if you are running an op amp with a single supply, you need to make a fake signal ground to simulate a dual supply with two resistors and two zener diodes, or two voltage regulator IC's, or two op amps hooked up as a voltage regulator. I detailed how to make the two zener version of a +- supply off a single voltage wall transformer (a slot car toy survivor) in this thread www.diyaudio.com/forums/analog-line-level/164102-improving-disco-mixer-mid-fi-performance.html I had to pay $1 a piece for the 8V 5 W zeners from a distributor that had attractive prices on fuse holders and solder type terminal strips. (latter as rare now as hen's teeth).

nowhere 19th June 2012 08:59 PM

Well, all I need is a microphone amplifier for electret capsule, and the amplifier should be able to drive 2 .. 3m of shielded cable.

And in the light of the above I more and more think of TDA2822M - I found them for $4.80 for 10pcs including S&H.

I'll most likely need half of it. Or I can even implement split phase driver using the second half - I intend to use differential receiver anyway.

The IC appears to be easy to deal with, I can even make its output stage work in class A by simply tying it through, say, 300 Ohm to ground.


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