Stereo audio amplifier with TDA2003

 Author:   Posted on:   Updated on:  2019-01-12T17:55:49Z

Build a stereo audio amplifier with TDA2003. Find the PCB design here.

TDA2003 is an integrated audio amplifier circuit capable of providing up to 10 W into 2 ohms load and 6 W into 4 ohms load when powered at 14.4 V. It is very easy to build a reliable circuit with it because it has short circuit protection. It will withstand a permanent short circuit on the output as long as supply voltage doesn't exceed 16 V. The maximum operating DC voltage is 18 V, however TDA2003 will not get damaged as long as supply voltage is less than 28 V. It comes with integrated thermal limiting circuit.

Having these features, the TDA2003 proves to be a good option for small power amplifiers. It was designed for car audio, that's why it is powered from single supply of about 12 V. Although nowadays it is considered obsolete, there are plenty of electronic parts suppliers which have TDA2003 in stock. At very low prices, by the way. Using the datasheet as source of inspiration, I designed my own PCB for two TDA2003 circuits, to make a stereo amplifier.

Stereo audio amplifier with TDA2003

The TDA2003 amplifier on homemade PCB without heatsink

The schematic is the recommended one from datasheet, drawn twice for two channels.

TDA2003 stereo amplifier schematic

TDA2003 stereo amplifier schematic

I designed the PCB in KiCad as a single board of 35 by 85 millimeters that holds both channels. A three pin header is used as audio input and screw terminals are present at supply voltage port and audio output ports.

TDA2003 stereo amplifier PCB outline

TDA2003 stereo amplifier PCB outline

With the screw terminals facing towards you, the speaker outputs have ground on the left and signal output on the right. The power input has VCC at left and ground at right. These polarities are not marked on silkscreen, but are easy to spot if you look at the tracks.

Recommended parts values

Recommended parts values

Component values are not critical as you can see in the above table adapted from datasheet (Gv is voltage gain and B is frequency). I used 25 V capacitors for power supply filtering and output coupling (the 100 uF and 1000 uF ones). It's okay to use 16 V capacitors if you'll be powering this circuit from a stabilized 12 V supply. For the non polarized, small capacitors, I prefer to use film type instead of ceramic type. The latter have some disadvantages in audio circuits.

To get a decent ouput, TDA2003 must be mounted on a heatsink. It can be a common one and there is no need to isolate IC packages electrically. Spacing between ICs is 49.5 millimeters.

When building this PCB, don't forget the wire that brings supply voltage to the TDA2003 of right channel. The wire connection points are actually vias in KiCad. That's no problem if you build the PCB at home, but if you send the files to get it manufactured, you might want to change those vias for regular pads that are not covered by solder mask.

The input audio signal should be maximum 0.85 Vp-p (0.3 Vrms). You can connect standard line out by using a resistor and a potentiometer as voltage divider. Or you can add an input preamplifier or tone correction circuit. If using such additional devices, avoid ground loops (in audio circuits, grounds from all modules connect to a single point and there's a single ground wire for each module).

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