Sharing is caring. That’s why as the nice person that I am, I want my neighbors to also hear the music that I am playing.
To do this, I need a loud enough audio amplifier with very low distortion as my neighbors should get the Hi-Fi sound they deserve. A good starting point is the LM386. It’s durable, small and compact, and has marginally okay sound quilty. Yet, it’s greatly underpowered. The datasheet specifies it can only push up to 700 mW! That’s way too small to make any substantial amount of sound.
That’s why, in today’s article I will show you how to use the TEA2025B, a 2W stereo audio amplifier that will shake your speakers until they pop.
With all jokes aside, there are many practical reasons for wanting a more powerful audio amplifier. For example, I have been working on a Bluetooth boombox conversion. I want the boombox to be as loud as possible while also having decent noise quality and good bass control. The TEA2025B satisfies all of those. Likewise, you could also implement the TEA2025B as a guitar amplifier. While it is nowhere loud enough for a gig, it would be perfectly usable for a practice amplifier.
What is it?
The TEA2025B is a 2 channel, 2-watt audio amplifier with built-in thermal protection and low switching noise.
So what does that all mean? Well for starters, the TEA2025B is stereo, so you only need one chip for two-channel music (instead of using two for an LM386). Likewise, as this chip is 3 times as loud as the LM386, it also gets 3 times as hot*. Thus, the TEA2025B packs in a thermal protection circuit that will turn on when things get hot and heavy.
- DIP 16 (12+2+2)
- SO 20 (12+4+4)
- 2W stereo
- Adjustable gain (up to 45dB)
- Soft clipping
- High channel separation
- Thermal protection
- Peak output current: 1.5A
- Supply voltage: 3V-15V
- Stereo or bridged mode (perfect for guitar amps)
You don’t really understand something until you can make it, that’s why I went ahead, bought a few TEA2025B chips from Amazon and made a PCB.
I based the PCB off of this circuit:
For the PCB’s, I also wanted a bit more piazzas compared to my other ones. I recently read an article on Instructables on how to add images to a PCB’s silkscreen so I thought this project might be a good place to try that out.
The process is quite simple, all you need to do is import a bitmap into Eagle, make sure it on the correct layer, and you’re done (this was an oversimplification so check out the article if you want to do it yourself).
Finished with the design, I ordered my PCBs from PCBWAY, a great place to get your designs manufactured from. I love how they give out coupons and how they host so many events for the makers. If your in the need for PCB’s you should definitely check out PCBWAY.
With the PCB ordered and shipped, all that’s left to do is solder them together.
Takeaways and Complaints
Designing the PCB has been really fun for me. I loved how they came out (shout out to PCBWAY) and how thick the solder mask is. Besides that, this PCB was made to test whether or not the TEA2025B’s I bought from Amazon were working or not (I got them from a 3rd party, not from STMicroelectronics directly).
At the end of the day, the TEA2025B is a powerful chip. With 2W, it can easily fill up an entire room with noise. However, there are a few things that I have learned from playing around with the amplifier chip.
Use the Right Capacitors!
I already explained this in the demo video but I did not have have any 470uF capacitors on hand, so I subsisted them out for 220uF capacitors. With a 150uF difference, I blame this as the main cause of having so much noise on the audio lines.
The TEA2025B can get HOT! And fast! If you are running it at even half its rated power, you will need to put a heatsink onto the TEA2025B
Keep the Audio Lines Short!
I accidentally blew a chip because my audio input lines were too long. It just went up in smoke. I don’t really understand how the audio lines can induce so much noise (like 8in long) but the TEA2025B is very sensitive. So keep them short!