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Blown (socketed) TDA2822?
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William Cullison
While attempting to get digital working on my ?Bitx, I had the plugs from the Easy Digi mislabeled. The line from the computer audio out was plugged into my speaker jack. I discovered my error and swapped the cables fixing one problem and probably causing another. Transmission was encoding the data but the receive seemed to be dead. Before retiring for the night, 3:30 am Hi Hi, I turned the rig on and had no audio output. How do I test the TDA2822.?
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¿ªÔÆÌåÓýI received my uBitx in February but did not put it together until early May. ?As soon as I plugged in a mono headphone I blew out the TDA2822. ?It did have the WX on it. ?I removed the chip and installed a socket and replaced it with a pin compatible NJM2037D. ?It has worked fine since and even sounds better than the 2822. ?I am very satisfied with this NJM2037D amplifier chip.73, Al KB4RA On Jun 21, 2018, at 11:23 AM, William Cullison <wa8vih@...> wrote:
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The WX branded TDA2822 simply does not meet spec.??
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We have no idea what spec it meets, as WX does not have a datasheet for it. In addition to an apparent absolute max supply voltage of around 6 or 8v, it quite likely suffers in the audio quality department. The NJM2073D (not NJM2037D) is a compliant TDA2822, built by a respected manufacturer. Easily available, in stock at Mouser (513-NJM2073D) and Digikey (NJM2073D-ND), both distributors have thousands in stock. Good choice. Those wishing greater speaker volume on a v4 board could do well to dead bug a NJM2073D to the back of the uBitx board, replacing everything between the volume control and the speaker as per the v3 schematic.? Or do the same with an ebay LM386 audio amp module (a fully assembled board) as per the Bitx40 schematic, cost of about $1.? Plus shipping. Jerry On Thu, Jun 21, 2018 at 09:47 am, allen west wrote: I received my uBitx in February but did not put it together until early May. ?As soon as I plugged in a mono headphone I blew out the TDA2822. ?It did have the WX on it. ?I removed the chip and installed a socket and replaced it with a pin compatible NJM2037D. ?It has worked fine since and even sounds better than the 2822. ?I am very satisfied with this NJM2037D amplifier chip. |
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On Jun 21, 2018, at 1:08 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
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Jerry,
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I think its the TDA2822D that has been repackaged. See the specs attached! Raj At 21/06/2018, you wrote:
The WX branded TDA2822 simply does not meet spec. |
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Thanks RAJ? sir. The datasheets? whther suffix D or normal(dip) show test results all defined around 6 or 9V supply. and definitely not not at 12 or 13.8. Regards MVS Sarma ? On Fri, Jun 22, 2018 at 7:40 AM, Raj vu2zap <rajendrakumargg@...> wrote: Jerry, |
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Summary:? All is well, unless you have a WX branded TDA2822.
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Here's an old post regarding the TDA2822, many other posts in that thread worth browsing: ? ??/g/BITX20/message/43342 Yes, the TDA2822D is still available from ST, would be a good choice if you don't mind?the 50 mil pin spacing.? ?I'd stick with the NJM2073. There was a lot of guessing in the forum when the WX clone chips first started blowing. Many of the WX chips blew when somebody first plugged something into the headphone jack, that seemed to put them over the edge. And some blew when first powered up. But I don't think anything other than a WX chip ever blew. Most of the TDA2822 datasheets spec a max operating voltage of 15v. The UTC clone (never used by hfsignals) gives a max operating voltage of 12v, but does say it will survive 15v. The WX clone does not have a datasheet, reports show it?can blow if they see more than 6 or 8 volts. A power up event or plugging in headphones can be what puts them over the edge and causes them to smoke. If you still have a WX chip, I suggest you either swap it out or add a voltage regulator to it as per? ? ?? That page suggests brands other than WX can blow when the output is shorted. I don't recall any such reports in the forum, let me know if anybody can find such a report. All of the datasheets specify distortion levels and power out as a function of supply voltage, these tables typically top out at 9v or so.? ?So we don't know what the harmonic distortion is at 12v, but that is well under the 15v maximum operating voltage. All except the WX operate fine at 12v, my only concern would be that the chip might overheat when driving a low impedance load (such as a short or a 4 ohm speaker) with?the volume turned up high.? If the chip is not too hot to hold our finger on it, all is well.? A momentary short would not give it enough time to overheat.? ? Jerry, KE7ER On Fri, Jun 22, 2018 at 12:59 am, Mvs Sarma wrote:
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You missed my point Jerry. I am not suggesting 2822D. Please see
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the spec sheet I attached. It is a lower power version of tda2822. I think that die is being repackaged as TDA2822 in 8 pin DIP. It cannot take the load and blows up. Raj At 22/06/2018, you wrote: Summary:? All is well, unless you have a WX branded TDA2822. |
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You think the WX might be a repackaged TA2822D meant for the SOIC8?
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I doubt it. I think the WX is a cheap copy that simply doesn't meet the 15v absolute max spec We had reports that there are clones of the TDA2822 (not necessarily the WX)? that blow when given a supply over 7 or 8 volts.? (Some club project in England) Didn't have to be putting out significant power to blow. As I recall, some of the WX failures happened instantly, and all struck me as consistent with too much voltage for it to handle. The SOIC datasheet you point to has the same 15v absolute max spec that the DIP part does. The primary differences I see between the SOIC and DIP datasheets from ST have to do with power dissipation, possible that ST was using the same die in both but the SOIC simply can't deal with the heat. Failure mode on the SOIC would be due to?overheating under load and take a bit of time. I don't think that is what we were seeing with the WX. ? But I'm just guessing. Could be proven wrong. Jerry On Fri, Jun 22, 2018 at 09:59 pm, Raj vu2zap wrote:
You missed my point Jerry. I am not suggesting 2822D. Please see |
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Would be interesting to pop the lids off the various TDA2822 parts,
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examine the die under a microscope. I'm betting the WX looks significantly different than an ST. On Fri, Jun 22, 2018 at 10:30 pm, Jerry Gaffke wrote: But I'm just guessing. |
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It appears that there are multiple versions of the TA2822 audio amplifier, by several different manufacturers.?? Some are rated 3V to 15 or 16V and others are 1.8V to 12V.? But that doesn't explain why some apparently have no safety voltage range above the rated voltage.? Maybe when they say Maximum Voltage = 12V they really mean 12V. Arv _._ On Fri, Jun 22, 2018 at 11:30 PM Jerry Gaffke via Groups.Io <jgaffke=[email protected]> wrote: You think the WX might be a repackaged TA2822D meant for the SOIC8? |
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Some of the clones are going for the lowest possible price, and fab/qc is as cheap as possible.
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They work well enough for some applications when powered from 5 or 6v. But depending on where that die was cut from in the wafer, may blow at 8v. They simply don't meet the ST spec. Most of them that do have a datasheet claim a max working voltage of 15v as per the original ST part. There are exceptions, claiming a max working voltage of 12v, absolute max of 15v. The WX does not have a datasheet.?? It does not have a spec and might be doing anything it darn pleases. That's my take. Jerry, KE7ER On Sat, Jun 23, 2018 at 08:18 am, Arv Evans wrote:
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Raj vu2zap
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