- The IC TDA2003 contains pre-amplifier, driver amplifier and output amplifier internally.Basically, TDA2003 is an improved version of TDA2002 with various features like very low harmonic distortion and high output current capability. Circuit Description of 20-Watt Audio Amplifier using TDA2003.
- C1 + Rx C2 + Cx R1 C3 R3 C5 C4 + GND R2 Vi RL +Vs GND TDA2003 C6 A.G A.G PCB-Layout in 1:1 scale Components placement / Components-side view TDA2003A 1 1 10W Audio Amplifier - TDA2003.
Jun 27, 2020 The TDA2050 is a great sounding chip amplifier with lots of power. In this tutorial, I’ll walk you through the amplifier design process as I build a 25 Watt stereo amplifier with the TDA2050.First, I’ll show you how to calculate the voltage and current requirements of your power supply, and show you how find a properly sized heat sink.
Recommended Experience : lower intermediate, knowledge of amplifiers, PCB etching, heatsink attaching, and (optional) mains qualification
TDA2003 application
Quick facts TDA2003 / TDA2003A
- Power output: 6W into 4 ohms at 10% 1kHz distortion with power supply 14.4V
- Power output: 10W into 2 ohms at 10% 1kHz distortion with power supply 14.4V
- Power output: 4.5W into 4 ohms at 0.15% 1kHz distortion with power supply 14.4V
- Power output: 7.5W into 2 ohms at 0.15% 1kHz distortion with power supply 14.4V
- Gain: 40dB, adjustable, but with consequences
- Power supply: 8V to 18V single supply
Guide
Warning: These chips have been discontinued and are susceptible to fakes. If you're buying, make sure it is from a good supplier (i.e. not auction sites) to get the genuine chip otherwise performance will be bad, the chip may be easily damaged and create a hazard, or hum/buzz may be worse than the official chip.
The TDA2003 is a cheap amplifier that is designed to run on single rail power supplies. It has many applications (including in car systems if you do not need to show off down the high street with your high power subwoofers!) and is protected against short circuits in almost every way you would think them possible.
It is a mono amplifier, but the TDA2009 is a stereo version alternative (not covered here).
Here are some applications it would be happy to work as:
- A pair can form a capable amp for a stereo system (i.e. a homemade or upgraded midi system or 'ghetto-Blaster', although battery operation may not be the best).
- This amplifier can be used to complete small surround sound systems (i.e. centre and rear channel amps).
- A pair can be used to improve the sound from a TV.
- Beefing up those 400W+ amps in PC speakers (seriously)!
- Tweeter or mid-range amplifiers in bi-amp or tri-amp systems.
- Bluetooth speakers.
- Music instruments i.e. Keyboard, Theremin.
This amplifier is based on the typical application in the ST Microelectronics datasheet. The performance from this circuit is satisfactory. The sheet contains data for typical noise and distortion statistics, I cannot confirm these statistics because I don't have the equipment, but my ears tell me that the sound is good and with sensitive speakers, this amp will show some power, but its power output isn't amazing. Output power into 8 ohms isn't shown anywhere, but expect it to be small!
For best power, I suggest the bridge circuit is used. This needs two TDA2003 chips and more components, but doesn't need that 1000uF (or higher) output capacitor which is costly and reduces bass.
The circuit is very simple, as can be seen, however you will have problems with Veroboard / Stripboard mounting due to its pin layout. It is possible, but you will find this amp A LOT easier to build on a PCB. The PCB layout suggestion in the original datasheet is a mistake copy of the bridge version, so don't use that, however a more up to date TDA2003A datasheet does have the correct layout, but note that C3 (the 100uF) bypass capacitor is not included. I suggest extending the board further right and locating C3 to the right of C5. It needs to go from +Vs to ground.
Note: The above image is copied directly from the datasheet and is not mine, nor is it likely to be 1:1 scale. To achieve this scale, the best idea is to print to PDF file to A4 paper. Please use the datasheet to view the schematic and the component values.
If you must use stripboard however, this is how I would mount them. First straighten all the pins, then cut them to the length of the shortest two. Now you need to spread them out so they will fit into the stripboard. Do not spread them too much or they will break and your TDA2003 chip becomes useless.
Resistor are recommended as 1% metal film, but as the picture of my prototype shows below, 5% resistors are capable, except for the critical Rx resistor, which should be 1%. R2 and R3 are low value resistors and you should try and get close tolerance resistors for these. Capacitors should be electrolytic above 1uF and rated at 25V minimum. They must all be connected the right way round or failure and possibly injury will follow when the amp is powered up.
The gain is set by R1 and R2, which is 1+(R1/R2) in gain voltage. Using the default values in the datasheet that is 1+(220/2.2) giving a gain voltage of 101. In decibels, that is 20*log(101) coming to 40dB. That's a very high gain! At this gain, a 50mV RMS signal will output 6W into 4 ohms, which is pretty much its maximum power. It means this chip is unlikely to need a preamp and is probably intended to be hooked directly to an FM output or tape output.
Reducing R1 will reduce the gain. To get it to a more standard 30dB, R1 needs to be reduced to 68 ohms. That's a really low value for a feedback resistor though and drain current will be increased. Alternately we can raise the value of R2 above 2.2 ohm, however this degrades supply voltage rejection (SVR).
A reasonable compromise would be to reduce/increase both to say 150 ohm for R1 and 4.7 ohm for R2. This gives a gain 30.3dB.
Rx and Cx are needed for stability and must be worked out using the data sheets mathematical calculations. Calculate Rx first which is 20 times R2, giving 44 ohms (39 ohms is the closest). Cx is 1 / (2 * π * B * R1) where B is the frequency cut off and R1 is 220 ohm by default. Using 20Hz; 1 / (2 * π * 20000 * 220) gives 0.000000033 - that's 33 nano farads (nF).
If you went with less gain and picked 150 ohm for R1, 4.7 ohm for R2, then Rx/Cx will be different. Rx would be 20 * 4.7 = 94 ohm (pick 100 ohm) and Cx would be 1 / (2 * π * 20000 * 150) = 49nF (pick 47nF).
Other non-electrolytic capacitors can be any type available. I used polyester layer capacitors because they have a closer tolerance (i.e. 5%) than most other capacitors.
For C3 (bypass capacitor) and C5 (Zobel capacitor) - these should be ceramic or multi-layer ceramic (MLCC) capacitors
A heatsink is important. The one shown in my prototype is actually too small and you should obtain something bigger for improved operation.
Power Supply
12V single supply power supplies are plentiful, and 16V can also be found which will give more power. I don't recommend going higher than this. You can purchase a great deal of 12V to 16V external power supplies that will happily provide the TDA2003 what it needs. Make sure they are rated for audio or video, otherwise noise and ringing will be heard through the amplifier. Laptop PSUs work well, but unsure their voltage isn't too high. The output should be at least 30W, meaning a 2A output minimum would be fine. Double this for a stereo amplifier, or bridged amplifier. Quadruple it for a stereo bridged amplifier (i.e. 4x TDA2003s)!
Alternative, you can build your own PSU, but before wiring a power supply, take note of this:
THE POWER SUPPLY REQUIRES MAINS VOLTAGE WIRING. DO NOT WIRE IT UNLESS YOU ARE SUITABLE QUALIFIED, DEATH OR SERIOUS INJURY MAY RESULT.
If in doubt, do not wire your own transformer and get a pre-built one. The power supply is simple to wire and my prototype board already has it wired in. You cannot see the bridge rectifier because it is hidden behind the huge 4700uF 35V capacitor. You can see that I added an LED though, this is easy to do and needs 1.2k resistor, 5% tolerance is fine.
The transformer should not be rated above 12V AC. This will give a 17V DC output (give or take) unregulated.
You could get away with a small transformer such as around 30VA with 2-wire AC outputs, for one amplifier. Double that for a stereo pair, or mono bridged amplifier, and so on.
The components on the earth and ground connections form a loop breaker. This is recommended construction because it can eliminate those evil earth loops. R1 is a 5W or better wire-wound resistor. The 100nF capacitor must be rated for 250V AC, you cannot use a 250V DC cap as it would fail if there ever was a fault causing mains to flow to earth. Check your country's rules and regulations before constructing this as it may be illegal. If so, omit all these components and connect the earth to ground but never disconnect the earth lead.. it could save your life or somebody elses!
Bridge Versions
There are two bridge versions available in the ST data sheet. A 20W version is below and performance from this circuit should be good.
The benefit of the bridge version is you'll get double the output for not much extra space and cost. The large capacitor on the single chip version (C4), required to block the DC current flowing through the speaker is no longer needed (as both sides of the speaker now have the same DC voltage, hence no current flows). Baroness discography torrent.
The circuit is a bit more complex, but should not pose any great layouts challenges. Again, PCBs are recommended as there are now two TDA2003 chips.
An alternative is the low-cost bridge amplifier which has a smaller component count and an output power of 18W. All you need is several 0.1uF caps, plus a 1nF and a 10uF electrolytic. Put in one resistor, and there you have it. I must add though that a did try wiring this circuit years ago on stripboard and the amp refused to work. You may have more luck than me but it would be more comforting if you used PCB instead, especially as the ST Microelectronics datasheet does contain a very nice stereo layout for it as shown below:
Note: The above image is copied directly from the datasheet and is not mine, nor is it likely to be 1:1 scale. To achieve this scale, the best idea is to print to PDF file to A4 paper. Please use the datasheet to view the schematic and the component values.
For the bridged version, do not go for loads lower than 4 ohms (this includes two 8 ohm loads in parallel) and do not short the loudspeaker to ground.
Performance and Prototype Photo:
My prototype works well. This board not only includes the amp, but its power supply and a very simple passive crossover (that's the axial electrolytic you can see bottom left). This allows a woofer and tweeter to be added with ease in the proposed system. You may notice the pins on the TDA2003 chip. They are spread out like they have to be when stripboard mounting. This is because this chip was used on my stripboard bridge version that failed.
Inputs are also on the left and the AC is the green and white wires appearing at the back. You can also see an LED at the front, this was to ensure me that everything in the supply was fine. The large 4700uF and 1000uF capacitors hide a few of the components.
The sound is quite impressive, with response across the audio spectrum. This amp will not go very loud though, turn it up and it will clip. I would expect better performance from the bridge versions, I am proposing to build one and will update this page with its performance. The bridge version (especially the low cost one) may actually beat the TDA2040 on price, but that depends on your supplier.
See, this is a TDA2003 amplifier circuit, popular IC from SGS Thomson.
Why we should use this? It is the normal operation of the integrated circuit, the music amplifier for car audio radio sound.
Which uses a supply voltage from a 12V car battery. But this circuit is adapted for use in a home. With changing the power supply voltage to 18V.
So, this IC can easily deliver 10W to a 4Ω load speaker.
Read also: TDA2004 – TDA2005 subwoofer Bridge Amplifier circuit diagram
Datasheet in short
Look at TDA2003 looks like TDA2030.
Cre photo: Exiron
TDA2003 Pinout and symbol
Then, see its Circuit connection or symbol below.
We will see that it looks like TDA2030.
The maximum output power and relationship
Do you want to know the output power of this chip? If, Yes look at the graph below.
It shows the relationship between power out and applied voltage.
We will notice how the 8 watts only applies to a 4 ohms speaker. And, results when the applied voltage (VS) is about 18V.
We can use load is 1.6 ohms to 4 ohms speaker impedances.
Then, if we change load is an 8 ohms speaker, the power is practically halved.
This feature is a good side, right? It means that you can parallel:
- Two 8-ohm speakers
- Four 8-ohm speakers
- Two 4 ohms speaker.
They still get the same power. Or loudness emerging from each speaker.
We may place four 8 ohm speakers in parallel to output.
The volume is quite sufficient for the people in the assembly room and the volume control was only about half.
The clarity and bass response was exceptional. The figure distortion up to 5 watts is 0.2%.
In the datasheet, If you use 14.4V of VS.
In fact, the amplifier has very good figures up to 8 watts with a 2 ohms speaker and 6 watts with a 4-ohm speaker.
Once these limits are reached, the distortion level increases rapidly to 10%.
And at this level, the average person can noticeably hear that something is wrong.
How TDA2003 circuit works
See in the circuit below we will learn how it works. The output power is more than about 10 watts RMS.
And the TDA2003 can protect from damage and short circuits. When the load over.
Tda2003 Pcb Board
And, Maximum Voltage of 28 volts. At the frequency response 40 Hz to 15 kHz.
The external components required for the power amplifier are either for feedback, decoupling or high-frequency suppression.
The amplifier itself is of a highly stable design with an enormous open-loop gain.
What is more? Let’s learn.
Here is step by step a process in each component.
Tda2003 Pinout
Input capacitor
C1: The 4.7 uF electrolytic at the input. It is designed to AC couple the amplifier to a source such as a tuner or any audio signal.
The C1- 4.7 mfd input capacitor allows the circuit to operate without and DC shift occurring.
We may add the volume control to the input. And must be placed before the capacitor.
The power filter capacitor
See at the power rail has a C7: 1,000uF electrolytic and C6: 0.1uF capacitor across it.
The C7 is a storage capacitor for supplying high currents during peak passages. And, it also reduces the power supply ripple.
The C6 capacitor is quite important. It can prevent a form of oscillation from occurring at risky power supply impedance levels.
Frequency Cut-off
The C3: 0.039uF and R1: 39 ohms resistor form the negative feedback network.
The value of C is designed to set the upper-frequency cut-off.
And a larger value of C3 will reduce the maximum frequency.
The R1 also sets the high frequency cut off point and if reduced in value, oscillation may occur.
The gain setting
Pcb Tda 2003 Bridge
The actual gain of the amplifier is set by the ratio of the 220-ohm resistor and 2.2-ohm resistor.
If you like the TDA2003. And want to try it. See:
Read next: TDA2009 Amplifier stereo 10W | High Bridge 28 watts
Parts you will need
- IC1: TDA2003, 10-watt audio amplifier IC
Electrolytic Capacitor - C1: 4.7uF 25V
- C2: 470uF 25V
- C4,C7: 1,000uF 25V
Ceramic Capacitor - C3: 0.039uF 50V
- C5, C6: 0.1uF 50V
0.5W Resistors, tolerance: 5% - 39 ohms
- 220 ohms
- 2.2 ohms
- 1 ohm
- SP1: 2 ohms to 8 ohms Speaker
When entering the power supply 15 volts to the circuit. The C1 coupling audio signal through the VR1 to adjust the volume. Then sent to the C2 anti-noise DC input signal to pin 1 of IC. The non-inverting amplifier circuit is a non-return phase. This is the signal output pin 4, by a C5 enhances the stability of low-frequency response the better. And the noise will be dropped down to the ground by R4 and C6 before outputting to speakers. Another part of the output signal, which is fed back through C3, and R1, to enter the pin 2 inverting. To maintain a constant frequency response at-3dB. And if you want to add. The frequency response is to reduce the C3. The C8 is a filter file before the operation.C7 cut out noise from the supply. If you want a stereo amplifier,Is to create an additional set.
Read others: Thanks Credit: 8-watt amplifier using TDA2002 on Talking Electronics No.9
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