240W Class-D surface-mount amp IC

[audioguru2]

Hi Guys,
They take a 4-channel class-D amp that operates its PWM at 385kHz, run the channels bridged to get a high-power stereo amp, then parallel those two bridged amps to get 240W output. Fairly difficult.

Then they integrate the whole thingy into a tiny surface-mount package!
The package does have a metal top for a heatsink, and they claim 85% efficiency. Very amazing. ;D
http://focus.ti.com/docs/prod/folders/print/tas5152.html

View attachment 36962

 

[audioguru2]

Read the fine print: it's rated in Whats, not Watts.
They even invented a special clipped input signal when it's pumping-out the square-wave Whats.
At reduced output where it and the source aren't clipping, it would make a nice small amp to be hid inside a sub-woofer or something. You could make a small sub with 4 small 8 ohm woofers on each of its sides, all in parallel.;D

 

[Miles Prower]

125 W at 10% THD+N Into 4- BTL
98 W at 10% THD+N Into 6- BTL
76 W at 10% THD+N Into 8- BTL
45 W at 10% THD+N Into 3- SE
35 W at 10% THD+N Into 4- SE
192 W at 10% THD+N Into 3- PBTL
240 W at 10% THD+N Into 2- PBTL

Take a LQQK at those specs. 10% THD?! It takes some set of brass cojones to call this "high fidelity". That thing might be good for a PA system or, perhaps, an AM modulator for a ham rig (for those who still haven't made the move to SSB -- how many of those are left anyway?) where fidelity isn't a consideration. Other than that: FUGGEDABOUDIT!.

A simple single-ended VT design sounds better.

 

[Alun]

I'm sure the local rude boy crew won't mind - you don't need a good quality amplfier to play hip-hop at full blast in your car with the windows down. ;D Often these idiots have the volume way too high and you can hear the speakers clipping as they strain to produce the booming bass. ;D

 

[audioguru2]

Hi Miles,
All car amplifiers are rated in Whats where the amp is clipping badly to make the numbers much higher. After all, a square-wave that has the same p-p voltage as a sine-wave produces double the amount of power. Their parts are also spec'd with a rediculously low impedance load of 2 ohms and some at 1.6 ohms.

Our 22W + 22W amp project is the same or worse. http://www.electronics-lab.com/projects/audio/006/index.html
The curves in Philips' datasheet shows very low distortion up to clipping. They show it clipping at 8.5W/ch into the 4 ohm loads and 12V supply as per our project's text. They don't even talk about the low power it would produce into 8 ohm speakers with a 12V supply but I figure it to be only 5W/ch at clipping.

Our 10W mini-amp project is much worse. http://www.electronics-lab.com/projects/audio/016/index.html
The project's text says to use a 9V battery and does't mention a recommended load. The IC's datasheet shows it producing 1.4W into a 4 ohm load at clipping and I figure a whopping 0.8W into an 8 ohm speaker.
The project's TDA2003 IC is labeled as a 10W amp. At clipping with a very high supply voltage and with a 1.6 ohm load, its datasheet shows it producing 10W.

 

[Miles Prower]

All car amplifiers are rated in Whats where the amp is clipping badly to make the numbers much higher.

I caught that in the original post, and figured the whole thing was a joke site. I went through all 26 pages on that, looking for the punch line before realizing that it wasn't a satire. Although it is still a joke, but not that way.

Our 10W mini-amp project is much worse. [...]
The project's text says to use a 9V battery and does't mention a recommended load.

I saw that too, and wondered just what kind of battery that could possibly be.  ;D

That's mainly why I avoid ICs for audio projects: can't trust the specs.  :

I'm sure the local rude boy crew won't mind - you don't need a good quality amplfier to play hip-hop at full blast in your car with the windows down. Grin Often these idiots have the volume way too high and you can hear the speakers clipping as they strain to produce the booming bass.

I did say that it would be good for applications not requiring fidelity  ;D  ;D

Where does Texas Instruments get their supply of chutzpah anyway?  :

 

[audioguru2]

Hi Miles,
Modern audio amp IC's perform extremely well. At diyaudio.com guys are copying commercial IC amps that have very good sound.
One commercial amp uses an excellent IC from National Semi. The IC costs only a few dollars but the amp is selling by the thousands for a few thousand dollars each. The 1st one that the site tested nearly caught fire. The amp's designer personally brought over a replacement which also nearly caught fire. He left with a red face and returned with a new power supply unit that performed flawlessly. ;D

BTW, a brand new little 9V alkaline battery can supply about 450mA into a dead short for a few minutes. The resulting 4.05W isn't 10W like our project but is enough to be dangerous.
At a conference a woman gave a presentation and used a wireless mike. Suddenly she started jumping around like she had ants in her pants. It was her spare 9V battery touching her keys in her pocket and burning her! Yeah, her hair is blond.  ;D ;D 

 

[Miles Prower]

diyaudio.com

There's a site that'll keep me busy for awhile.

 

[audioguru2]

They have so many members on-line that a topic that you are looking at changes quicker than you can read it. ;D