Contents

Warning: These chips has been discontinued and are susceptible to fakes. If you're buying, make sure it is from a good supplier to get a genuine chip otherwise performance will be bad, the chip may be easily damaged and create a hazard, or hum/buzz/hiss may be worse than the official chip, or it may just not work at all.

Note: This article is largely a copy of my updated TDA7052 article, however, there are just enough differences that merging the two could became unclear, so I've separated them. This article includes build pictures and information specific to the TDA7053A, and also information on the TDA7053 (though I've not been able to get it for testing).

The original TDA7053 chip is very hard to find and expensive if you do. The TDA7053A chip is easier to find but not a drop in replacement (despite commonly advertised without the A suffix by some sellers). The 'A' variant is still cheap, and the circuit is still very simple hence my update to add these details. All chips should be made by Philips (now NXP) or UTC Unisonic Technologies Co.

If you can't get the TDA7053 or TDA7053A variants mentioned here, alternative include:

• PAM8403 (stereo) for 5V USB or 4.5V battery operated use - this is a Class D amplifier, but is surface mount and you would buy a pre-built module rather than solder yourself
• TDA7266 supports the same 3V to 18V voltage output, is stereo, is also bridged, and gives much more power, however it needs more components. TDA7297 (stereo) and STA540 / TDA7375 are other alternatives, but 8V upwards only
• TDA2822M or KA2209 are similar DIP style chips, but more components are needed. You would need to use the bridge circuit to get similar power output. It is also discontinued, but still quite easy to find online.
• TDA7052 / TDA7052A are the mono versions of the stereo chips featured here. You would need two for stereo though.

Recommended Experience : beginner

Above: My implementation of the TDA7053A

TDA7053 application

Quick facts TDA7053

• Power output: 2x 1.2W into 8 ohms at 10% 1kHz distortion with power supply 6V
• Gain: 39dB (fixed)
• Power supply: 3V to 15V single supply
• Datasheet available here

Guide

All those years ago, the TDA7053 was not available at the retailers I used to use, so I was unaware of it and hence have never used it. For stereo applications I just went with two TDA7052 chips.

The TDA7053 chip is an alternative that would allow you to make a smaller PCB with two amplifiers on it. Unfortunately like the original TDA7052, it's very hard to find and I've never built it, only the TDA7053A variant (see below).

The specifications are basically the same, except now there are two amplifiers on one chip. If pushing it hard, heat might be slightly worse than two separate chips. A benefit is the chip shares the same power supply (VDD) pin and so it can share the same bypass capacitors C1 and C2, but otherwise the rest is the same.

The chip is built by Philips Semiconductors and a data sheet is available here. The chip itself has four amplifiers inside it - two in bridge configuration for each channel to give a good power output for its size. The circuit shown in this data sheet is very simple indeed, requiring only four other components at its bare minimum.

#	Type	Quantity
U1	TDA7052	1
U1	(optional) 16 pin DIL DIP socket	1
R1,R2	4k7 ohm Resistor, ¼W Metal Film, 1%	2
C1	100nF Capacitor, 50V+ Ceramic X7R or MLCC	1
C2	220µF Capacitor, 16V+ Electrolytic	1
VR1	100k ohm Dual Lin Potentiometer	1
C5,C6	(optional) 10µF Capacitor, 16V+ Electrolytic	1
In L/R,Vdd,SPK L/R	2.54mm header 9-pin (cut as needed)	1
	cable, connectors	~

Here is a schematic of a stereo audio amplifier using the TDA7053 which will work effectively. Like the TDA7052 (its mono brother), it's very simple and quick to build, only two capacitors and two resistors are needed beyond the chip for a simple stereo amplifier, plus a dual gang potentiometer (VR1) and two DC protection capacitors (C5 and C6) if you want a volume control.

The capacitors C1 and C2 are for power supply decoupling and are considered necessary. C1 should be a 100nF (0.1µF) ceramic capacitor and located closest to the TDA7053 pins. C2 should be an electrolytic capacitor of 220µF or higher with a voltage rating of a few volts higher than your supply voltage (i.e. 10V for 6V supply, 16V for 12V supply, 25V for 15V supply).

Resistors R1 and R2 can be any 4k7 resistor which is 5% tolerance or better. Metal film resistors are best, however since the resistor is not directly in the signal path a cheap carbon resistor will also be fine.

The volume control is made up of VR1 which is a variable resistor or potentiometer. It should be 47k dual gang linear, as the linear potentiometer loaded with R1 will give a good logarithmic response. In order to stop it becoming noisy after time, DC blocking capacitor C5 and C6 should be 10µF electrolytic capacitors rated for 16V or better in case your source has a DC offset. The positive lead should be facing away from the potentiometer.

Below is a layout for the TDA7053 amp for beginners using Veroboard or 'stripboard'. The layout is simple, but you will need to use a few wires / jumpers and a track cutter to cut 7 traces where the amplifier chip is soldered onto the board. The orange squares are where the traces must be cut. When cutting, remember to leave the trace between pin 7 and 10 alone as this trace connects the power and signal grounds.

Two jumpers are also required in order to connect all the ground pins of both amplifier halves. I suggest to keep a couple of offcuts from the resistors or capacitors after soldering them and trimming the excess lead lengths. These can then be used as jumpers. Alternatively single core wire is easy to use too. Multi-core wire might be more of a challenge to ensure you thread all of the wire cores through the PCB hole, but it's still possible if you've already discarded the lead offcuts.

The layout does not include a volume control (or C5 and C6 before it) or any LED power indicator. If you have some understanding of electronic circuit design, then you can easily incorporate these onto the board. This will require additional wiring and/or track cutting for the preferred layout.

Construction

The orange squares show where the tracks MUST be cut. If this is not done sufficiently, the amp will not work. You can do this with a proper track-cutting tool available at some retailers (this is recommended) but if you cannot get one, it is possible to cut the tracks by carefully using a drill bit or cutting the copper tracks with a knife.

Use a multimeter (or if you do not have one, a battery and led/bulb/buzzer circuit) to make sure there is no short between the cut tracks to ensure that they are cut fully.

Soldering is required to fix the components to the board. If you're a beginner and have not done this before, by all means practice. Soldering on stripboard can be a little challenging at first as it is easy to short the adjacent tracks if too much solder is used. Once this is done, it is difficult to correct without desoldering braid or pump, so avoid using too much solder and touching the other tracks with the iron. I suggest having desolder braid handy as it really saves time to use it to mop up solder when you do make a mistake.

The TDA7053 chip will NOT tolerate lots of solder heat. My recommendation is a buy 16 pin DIL socket and solder that instead because it will forgive you more easily if you apply too much heat.

After soldering, use your continuity tester to ensure that adjacent tracks are not accidentally touching. You can also check the leads of most components to see if they are electrically connected to the stripboard tracks.

The 0.1µF (or 100nF) C1 is a ceramic capacitor. These will allow the leads to bend to fit the 5mm gap on the layout above. The 220µF capacitor C2 is an electrolytic capacitor, and it may need some lead bending to fit the 5mm spacing. Don't worry if it does not fit flush to the board. THE CAPACITOR MUST BE CONNECTED THE RIGHT WAY ROUND, otherwise it's bubble, burst, or launch itself off the board, especially with higher voltages (i.e. 9-12V). On both the schematic and stripboard layout the positive side is shown. On the capacitor itself the negative lead is usually clearly labelled on the capacitor can, or if it's a new capacitor the positive lead is usually the longest lead.

The 4k7 resistors R1 and R2 are mounted vertically to avoid the need for an extra jumper if they were mounted horizontally. To mount them vertically, simply bend one end 180 degrees back on itself. The two lead ends should now easily fit in adjacent holes in the board. Vertically mounting resistors like this is often fine and I've seen it done in equipment too.

This amplifier is intended to power two 8 ohm speakers from a 6V power supply. You can push it with a higher voltage for a bit more power, but the datasheet contains no output information for such and giving the TDA7053 is a DIP chip with no heatsink, I would not go beyond 9V. The maximum voltage of 15V is intended for higher impedance speakers such as 16 ohm and 32 ohm.

Driving 4 ohm speakers with it is a risk you'll take. If you do, then keep the supply at 3V, or 5V at the most otherwise the chip will likely overheat.

When wiring the loudspeaker, do not ground it. The TDA7053 uses BTL (Bridge Tied Load) which gives you up to 4 times the power into the same impedance speaker with two amps (which are integrated in each TDA7053 half) in to the same load impedance. If you short the loudspeaker to ground, do not expect it to work. It may not even protect itself from a repeated loudspeaker short condition.

As a last note, make sure you put the TDA7053 in the right way before you solder it. The diagram shows an asterisk on the chip. This asterisk indicates pin 1 and the chip itself should have a small dot, line or semicircle indent on the side where pin 1 is. Pin 1 will be in the top left. Insert the chip the wrong way and it will not forgive you and you will have to get a new one, trust me, I've (foolishly) done it!

The TDA7053, whilst great, is not bullet proof, so avoid mistakes such as connecting the power supply the wrong way round, soldering or inserting the DIP chip the wrong way round or shorting out the loudspeaker connections. To avoid this for loudspeaker connections, do not use 3.5mm style connections to the loudspeaker because they may briefly short it whilst inserting/removing whilst the amp is powered on. Use spring clips, banana plugs, DIN sockets or (since it's low power) phono and mini DIN sockets are also fine.

Power

The datasheet is brief on power details. It states 1.2W output for a 6V power supply into 8 ohms. This is at a 10% THD (distortion) though, which will sound terrible, so expect less in reality. This figure though is only quoted at 6V. By increasing the power supply to 9V, you'll get more power - perhaps 2W, however you should install a stick on DIP heatsink to avoid it overheating. It certainly capable for portable applications, and you'll find 1W of power can be quite loud.

Given this is a single supply chip (positive and ground), there are many options for powering it.

Consider up to 6 1.5V AA cells (or UM-3, M, RX6), giving 9V. As the TDA7053 can operate on as little as 3V, you can use less cells, but bear in mind the maximum power will be less. For longer life, but more size/weight feel free to use larger cells such as C or D size. These days though, lithium ion rechargeable batteries will give more power in a smaller space and add that rechargeable flexibility. A 7.4V lithium battery will work well. Whilst a 9V PP3 battery will also work, they are intended for low current applications and they will not last as long and end up a costly way to power the amp.

Power through USB is also an option. USB gives 5V and most PC USB ports now are capable of supplying more than 1A of current. At 5V though you can only expect 1W of power at best and at this power, the TDA7053 will draw up to 1A, so be vary of running it off USB ports that can only supply 500mA.

The best power is available from a dedicated power supply. Wall/brick power supplies are easy to find though, and you may even have some unused ones laying around! Aim for 9V for the best power into 8 ohms, 12V in to 16 ohms. These should have a rated output of 1A or better for a single TDA7053. Double that for a stereo pair (or the TDA7053). I recommend increasing C2 to 1000µF to bypass and smooth the voltage further.

Gain

The gain is fixed and cannot be changed by changing/adding like many other amplifiers. The fixed gain of 39dB is rather high, representing a voltage gain of nearly 90 times! This is calculated as 10^(dB/20) = 10^(39/20) = 89.1.

Because of the high gain, noise performance won't be fantastic, and you may find that the volume control is rather sensitive if you use a potentiometer that has a too low or too high value.

Despite the troubles with the high gain though, in reality for use as a portable amplifier, it works quite well as you might be using a phone or portable mp3, CD player or whatever as the source which is designed to drive headphones and you won't have to turn the volume all the way up on the portable device in order to get good volume output on your TDA7053 driven speakers.

Because it's so hard to find now, I've never been able to build it. It should work just as well as the TDA7052 mono version though.

TDA7053A application

Quick facts TDA7053A

• Power output: 2x 1W into 8 ohms at 10% 1kHz distortion with power supply 6V
• Gain: 40.5dB (variable via DC control) - max gain of 31dB in my application
• Power supply: 4.5V to 15V single supply
• Datasheet available here

Much easier to find than the TDA7053 (but still a discontinued chip) is the TDA7053A. Like the mono TDA7052A vs TDA7052, some additional components are needed in the schematic, and it will not work in the same TDA7053 circuit. The TDA7053A is very similar in terms of performance.

It's still a beginner friendly amplifier to make though, and cheap. The extra cost you'll incur with the three additional 1µF capacitors required will be saved by the cost of the DC volume control as only a single gang linear potentiometer is needed which will be cheaper than the dual pot log potentiometer needed for a volume control of the TDA7053 + DC blocking capacitors to stop it going noisy anyway.

There is also a surface mount variant of this chip - TDA7053AT which is smaller but can only output around half the power as its DIP brother (2x 0.55W for both the TDA7053AT). The circuit is for this is similar, but I won't cover it specifically.

Comparing the circuit to the TDA7053, the TDA7053A needs four additional components at minimum. This is because there is a DC volume control input, which needs to be connected to ground via a 1µF capacitor. The input pin for the TDA7053A (unlike the TDA7053) has a DC offset at its input pin too, meaning that a 470nF capacitor is also needed in series with the input and the input pin.

The extra components and therefore the larger board needed are the disadvantages. The advantage is the DC volume control pin 4 provides us some flexibility over the basic TDA7053 above:

• The volume control potentiometer can now go directly to this dedicated pin
• The volume control input is logarithmic, and more accurate than a log potentiometer. This allows use of common linear potentiometers for volume control
• A single gang potentiometer can be used to control both TDA7053A stereo channels

Here's the adjusted schematic for a simple amplifier, with a sensible maximum gain of around 27dB:

Here is a schematic of a stereo audio amplifier using the TDA7053A which will work effectively. Like the TDA7053, it's very simple and quick to build, only five capacitors and two resistors are needed beyond the chip for a simple stereo amplifier, plus a single gang potentiometer and additional series resistor if you want a good volume control.

#	Type	Quantity
U1	TDA7053A	1
U1	(optional) 8 pin DIL DIP socket	1
R1,R2	4k7 ohm Resistor, ¼W Metal Film, 1%	2
R3	6.8k or 5.6k ohm Resistor, ¼W Metal Film, 1%	1
C1	100nF Capacitor, 50V+ Ceramic X7R or MLCC	1
C2	220µF Capacitor, 16V+ Electrolytic	1
C3,C4,C5	1µF Capacitor, 16V+ Electrolytic	3
VR1	220k Lin Potentiometer	1
In,Vdd,SPK	2.54mm header 10-pin (cut as needed)	1
	Heatsink, cable, connectors	~

Like the TDA7053, there are power supply bypass capacitors needed - C1 and C2. C1 should be a 100nF ceramic and as close to the TDA7053A pins as possible. C2 is an electrolytic capacitors of 220µF or higher. Electrolytic capacitors are polarised so the positive lead in must go in the positive voltage supply. This is the longest lead if the capacitor is new but check the casing anyway as the negative lead is usually clearly marked.

C4 and C5 are input capacitors. 470nF is suggested in the datasheet and combined with the 20k input impedance this will give a high pass cut-off frequency of 16.93Hz (that's calculated by 1/(2πRC) - 1/(2 × 3.14159 × 20000 × 0.00000047).

C4/C5 should be a polyester or electrolytic capacitors. Polyester is known to have the best audio quality but on an amplifier of this size you're unlikely to notice the difference and an electrolytic will be fine. Avoid a ceramic for this capacitor. If you have 1µF electrolytics, feel free to use those instead (that's what I did on my board). The positive lead must face the chip.

R1 and R2 provide a DC path to ground for the audio signal for each channel, and also gives the amplifier a predictable input impedance for whatever source you connect. The resistors suggested are 5k in the datasheet but 4.7k is a more commonly available value that will work just as well.

Below is a layout for the amp for beginners using Veroboard or 'stripboard'. The layout is simple, but you will need to use a track cutter to cut seven traces where the amplifier chip is soldered onto the board but be careful to leave the trace between pin 7 and pin 10 connected as this is where the signal and power grounds meet. If your power and signal ground meet elsewhere in your system, you can also cut this trace in order to avoid ground loops.

Note that resistors R2 and R3 are mounted vertically in order to keep the layout small and simple. Simply bend one of the leads almost 180 degrees back and feed both leads through the holes on the board and carefully solder, ensuring you leave a small gap between the board and the body of the resistor to avoid overheating when soldering.

There are two jumper wires required. The smaller one on the right hand side is from pin 10 to pin 14 to connect the power grounds of each stereo amplifier half on the chip. This can be easily made with an offcut from the legs of resistors or capacitors once you've soldered in one or two of those.

The other jumper is to connect the volume control pin 8 to the volume control pin of the other amplifier half at pin 2. This allows you to control both amplifiers on the chip with a single volume control.

The volume control potentiometer itself I have not included on the board as the size/shape will vary. See below for more details on the volume control, but series resistance R3 is included (see below).

DC volume control

The DC volume control is at pin 4. The TDA7053A produces a voltage of around +1.105V at this pin, as well using the current at this pin as a volume reference.

Note: It is not possible to control multiple TDA7053A chips with a single volume control by connecting all the VC pins together. If you really need a quad channel amplifier with two TDA7053A chips, you could still use a dual gang potentiometer to control the volume of all channels.

Capacitor C4 is a 1µF electrolytic that is used for power on muting. How this works is the capacitor initially looks like a short circuit, keeping the TDA7053A muted. The capacitor will then slowly charge by the 1.105 volts on pin 4, leaving the only path to ground via the resistor R3 and potentiometer VR1.

The datasheet shows a 1M ohm potentiometer to allow control of the volume of up to 34dB. 34dB is a high gain, at over 50 times voltage gain, calculated as 10^(34/20). I actually measured nearly 57x (35dB) when I tried. A 220k potentiometer instead will give a gain of around 31dB (36x), which I found more suitable for plugging into laptops, phones, MP3 players etc.

If a gain of 31dB is too low (unlikely), with 500k I measured the gain to 51x (34dB) and that will give better control compared to the 1M potentiometer.

In order to mute the amplifier, the resistor from the VC pin to ground needs to be around 6.8k ohms, so that's why my circuits include a series resistor otherwise there is a 'dead' point from the minimum setting until the potentiometer is turned enough to exceed just over 7k ohms of resistance. Feel free to leave this resistor out though if you wish.

If some signal is still coming through in your source though when the volume control is set to its minimum, reduce the value from 6k8 to 5k6 or maybe lower still.

For reference, the voltage at the VC pin with the 6k8 resistor is 255mV with VR1 set to its minimum (0 ohms, almost). Turning the 220k to its maximum of 220k, plus the 6k8 resistor gives a voltage of 976mV. At around half volume (110k + 6k8) it's 913mV. With a 500k pot (plus 6k8 resistor), it's 255mV min, 979mV half and 1.014V full. Figure 8 in the datasheet gives the relationship between volume control voltage and the gain.

The potentiometer is not shown on my layout, but it should be wired like this so that turning it clockwise turns the volume up. This is the front view:

The ground lead (first pin from the left) should be connected to input ground - either back to the board or your input socket. The other two pins connect together and lead to your amplifiers VC pins, or the series resistor R3 (Vol pot pin on the stripboard layout).

To avoid noise when touching the potentiometer, consider grounding the metal casing of the pot too. This will not be needed if the potentiometer is mounted on a grounded metal case though, and you'll probably get away with not needing to ground the case either if you have a plastic knob on the potentiometer.

With no volume control connected to the VC pin (only the capacitor), the TDA7053A will still work with a gain of about 65x (36.2dB) from what I measured.

That's somewhat off the maximum possible gain quoted of 40.5dB 105x (typical). To get this gain maximum gain, you actually need to apply a voltage of 1.4V or higher to the VC pin 4. You could do this by connecting a resistor to the positive input, as suggested in the TDA7053A datasheet below. I suggest though that you don't wire the volume in this way unless you really need the maximum gain as the resistor needed will depend on your supply voltage and I prefer the flexibility of being able to plug the amplifier into whatever power supply is available.

Power and performance

Below is my actual build. It only took less than 30 minutes to solder up. It's small, convenient, and works well.

On the underside you can see how my TDA7053A layout above looks in real lift (and also mirrored). Soldered stripboard never looks particularly neat, but all joints are held well, and not shorting with each other. You can also see the seven cuts to the strip I made down the left side which is where the TDA7053A chip is.

The power is pretty good. It's enough to get a couple of small 3 inch speakers moving and creating a decent volume. Certainly, it will meet the needs for most portable speakers, 'ghetto blasters' and similar toys!

Like it's mono cousin, the TDA7053A is a great little amp. Very easy to build, very cheap to obtain (including components) and the sound quality is decent for such a small amp.

Considering that, I think the TDA7053A still makes a great beginner project for building your own stereo set of speakers. There's plenty of competitors nowadays of course, but if you have it or want to build a chip amp from scratch this is my recommendation.