Replacement for TDA2050v

[JonathanAnon]

Hi there,

I've just worked out the perfect design for my car kit... rang to order a few of these chips and they tell me that the chip has been discontinued... Contacted my supplier and they cant suggest a suitable replacement...

It's to work in my car, I need it to work with a 12v single source power supply and up to about the same wattage as the TDA2050, which is 32W... Anybody got any suggestions as to what I should use as a replacement...

thanks,
J

[stj]

Re: Replacement for TDA2050v

http://www.st.com/web/en/catalog/sen...5/CL1503/SC979

[mariushm]

Re: Replacement for TDA2050v

Jonathan, tda2050 can still be purchased and it's an easy to use chip, you can find it at online distributors like Digikey or Mouser but since you're in Ireland it's probably better for you to use Farnell or TME.eu

I would like to point out that TDA2050 *is* a 32w amplifier chip, but that's basically what the chip can do at almost the maximum input voltage it can tolerate and with some significant distortion. In real world, you don't want to push it that much because it would sound bad, a more realistic output would be about 25 watts but again, provided it gets enough input voltage.

Check the datasheet : https://cdn.badcaps-static.com/pdfs/...31cada06bb.pdf

On page 3, you can see it can do 32w with d=10% which is bad, and only at +/- 22v (or about 45v if you power it using single mode power supply).

With 12-14v available from a car's battery, you'll only get about 5 watts from a TDA2050, as you can see on page 8, figures 8 and 10.

The X axis on those graphs shows voltage in split mode power supply so your 12v is equivalent with +/- 6v on that x axis scale, and with that in mind you can look up on the y axis to see how much power you'd get from one.

The tda2050 is also fairly inefficient at around 60-70%, you'd waste your car's battery with it.

For a car amplifier working at 12v, you'd be better off with a Class D amplifier chip.

[ben7]

Re: Replacement for TDA2050v

Hah, mariush beat me to it. I was going to say, a class D amplifier needs either a very small, or no heatsink!
Only downside is it's likely going to be an SMD chip.

Hey, the LM1875 has the same pinout. Can't guarantee that it would be a drop-in replacement (looks like it would to me, with different feedback resistor values), you'll have to carefully check the specs to see if it would be ok.
https://cdn.badcaps-static.com/pdfs/...e9ec9f67d4.pdf

-Ben

[stj]

Re: Replacement for TDA2050v

class D - the D stands for Distortion!!

[ben7]

Re: Replacement for TDA2050v

Class D doesn't sound bad to me. There are some very good class D amplifiers out there. They are cheaper, lighter, and more efficient as well.

[tom66]

Re: Replacement for TDA2050v

class D - the D stands for Distortion!!

Good Class D amplifiers have better distortion figures than Class AB. And they are much more efficient and work with lower input voltages for a given power output.

[stj]

Re: Replacement for TDA2050v

well they arent the ones used on tv's then!

[Longbow]

Re: Replacement for TDA2050v

Good Class D amplifiers have better distortion figures than Class AB.

Untrue. This ethereal statement may appear in a text book somewhere. But as you would expect, there are always trade-offs. Class D was designed to offer efficiency and low cost which it does quite well. Class D amp modules are used almost exclusively to power the multiple channels in whole house area amplifiers, for example, which are designed for low volume audio at a reasonable price and with minimal heat. Class D is also great for car amplifiers, because the owners are not concerned with distortion levels.

For more critical listening, the residual switching carrier of class D raises the noise floor unacceptably. The output stage must essentially reconstruct a sine wave from square wave, which is a difficult task even at one particular frequency, let alone the whole audio spectrum. And, the overall result is also affected by the particular drivers connected to it.

Having said as much, class D audio modules do not differ much one from another. Have a look at the recommended switching frequency for a basis of comparison. If one particular type is NLA, it should not be a problem to install another (assuming the pinout is correct).

[JonathanAnon]

Re: Replacement for TDA2050v

Hi guys,

thanks for all the helpful responses.. Farnell and Radionics are the two suppliers that I use here in Ireland and both list the TDA2050 as gone.. Farnell says "No longer manufactured"...

http://ie.farnell.com/stmicroelectro...45?ost=tda2050

I actually have an LM1875T in my box here. I found a single supply circuit for it... I'll breadboard this and try it.. It is very very similar to the current single supply circuit that I am using with the TDA2050.


Here's a quick look at my handy work. I'm trying to use just a smaller package chip as it's only on a small piece of stripboard. There no max current specified on the stripboard, but I'm sure it's probably good for 2A. Here's how it's looking so far.... (edit: I havent done the mic part of the circuit yet).

[kaboom]

Re: Replacement for TDA2050v

If you are constrained by a single supply of 12-14V, why not go BTL?

Guaranteed output of 20-25W into 4 ohms, no DC-DC converter, and you'll save board space without the output coupling caps.

Try a TDA7370 (dual-btl) or TDA7240 (single-btl).

[redwire]

Re: Replacement for TDA2050v

I've used TDA2030, 40, 50's in BTL (with a single-supply) but the turn-on thumps were huge and almost killed small speakers.
I would use one of the cheap DC-DC converters on eBay or DX to get higher voltage.
You need a heatsink on the LM1875T in your pic's, and negative voltage transient protection on power coming in.
Cloth acoustic-damping material in the box would help a lot.

[tom66]

Re: Replacement for TDA2050v

From a measurement of THD+N perspective, you may have a point, the THD+N figure for class D is worse, but I would contend the overall audio performance as humans perceive, and in the measurable 0-20kHz range, is better in most respects.

Class D really only has one disadvantage, and that's the noise components at higher frequencies due to switching noise. Most class D amplifiers switch around 300~400kHz to minimise filter sizes. This is well beyond any human hearing range so I fail to see how this could be considered an issue. Bear in mind most audio is only sampled up to a maximum of 192kHz. There are few subharmonics created by a stable clock source (such as a crystal) so even those should not be of a concern.

The process of generating audio is much more linear. The ideal class D amplifier would be purely DSP driven and would achieve perfect linearity. Most class D amplifiers use analog electronics (comparators and voltage ramps) to generate the switching pulses which introduce linearity errors although good design can minimise these. The only nonlinearities introduced by the switching process would be from the power supply sag and inductor saturation... both of which can be minimised by using proper design techniques and air-core inductors.

Contrast that to class AB and similar amplifiers. There is crossover distortion, which to eliminate requires large bias currents. Most manufacturers try to minimise this because it causes high power dissipation when operational. Also, the transistors themselves are quite nonlinear devices, something the feedback loop must compensate for.

[stj]

Re: Replacement for TDA2050v

i just realised something.
the arcade stuff mostly used TDA2003 on a 12v supply.

it's almost a dropin for the TDA2050 with the same w/v curve.

[JonathanAnon]

Re: Replacement for TDA2050v

The datasheet for that 1875T says that it's input voltage is 16V-60V.. I tried swopping it in to the same circuit in place of the
TDA2050V, and changed the resistors to 200k and 10k in the feedback part of the circuit... But it sounds very low and completely distorted. I dont think it's gonna work without a DC-DC converter to boost the voltage >16V..

I didnt choose the TDA2003 initially cos it was only 10W, and I was planning on using the same circuit for a small guitar amp in the same plastic box / 4 ohm speaker combination. However, it may be a good option. There's a single supply circuit in the datasheet, and the chip operates with Vs of 8v-18v.



Of course I still have the option of just buying the TDA2050v on ebay or something... The chip has been around for years, and they only get rid of the thing when I decide to use it !!!

[stj]

Re: Replacement for TDA2050v

places like Dalbani probably have it, but those obsolete parts places charge a lot!

[budm]

Re: Replacement for TDA2050v

The datasheet for that 1875T says that it's input voltage is 16V-60V.. I tried swopping it in to the same circuit in place of the
TDA2050V, and changed the resistors to 200k and 10k in the feedback part of the circuit... But it sounds very low and completely distorted. I dont think it's gonna work without a DC-DC converter to boost the voltage >16V..

I didnt choose the TDA2003 initially cos it was only 10W, and I was planning on using the same circuit for a small guitar amp in the same plastic box / 4 ohm speaker combination. However, it may be a good option. There's a single supply circuit in the datasheet, and the chip operates with Vs of 8v-18v.



Of course I still have the option of just buying the TDA2050v on ebay or something... The chip has been around for years, and they only get rid of the thing when I decide to use it !!!

You need to Bias the LM1875 pin1 so the output will be at 1/2 VCC since you are not using Dual power supply (+/-), you are using single power supply, it is also picky about how the circuit ground traces are routed.
See app notes on how it is used, see Fig. 2.
https://cdn.badcaps-static.com/pdfs/...e9ec9f67d4.pdf

[JonathanAnon]

Re: Replacement for TDA2050v

You need to Bias the LM1875 pin1 so the output will be at 1/2 VCC since you are not using Dual power supply (+/-), you are using single power supply, it is also picky about how the circuit ground traces are routed. See app notes on how it is used, see Fig. 2.
https://cdn.badcaps-static.com/pdfs/...e9ec9f67d4.pdf

This is the single supply circuit that I'm working with.



From what I'm aware the two resistor R1 and R2 put the non-inverting input's biasing voltage at 1/2VCC. C1 and R3 form a high pass filter on the input. And I presume that the 1M ohm resistor is just to discharge any stray voltage when the chip is off. C4 and C7 are filtering caps on the input voltage. R7 and C5 is the Zobel network. R5, R6 and C3 set the gain and C6 blocks any DC from reaching the speaker. I'm open to correction but that's my reading of it.

I have the circuit built pretty much the same as it is above, but I'll take into account what you said about the chip being fussy, and I'll build it with the EXACT values (well, within 5%) on the datasheet...

[budm]

Re: Replacement for TDA2050v

OK, I thought you do the direct drop in with just the modification on the feedback, I did not know that you also added the biasing circuit.
So is the output pin sitting at 1/2VCC?

[redwire]

Re: Replacement for TDA2050v

I've never had a TDA circuit stable without adding a cap across the feedback resistor (R6) and an RF cap across the input (R4). The IC will oscillate or pick up AM radio, or both. It sounds like distortion but on an oscilloscope you can see HF oscillations. If you can't get things to make sense or sound decent:
In parallel with R6 add a 33pF cap (for 24kHz -3dB).
In parallel with R4 add a 220pF cap (for 70kHz -3dB).