The STMicroelectronics TDA7293 is a high-power Class-AB audio amplifier IC designed for Hi-Fi and other demanding audio applications. It combines a DMOS power stage with a wide supply-voltage range, mute and standby functions, thermal shutdown, short-circuit protection, clip detection, and support for parallel operation.
ST currently lists the TDA7293 as an active, volume-production device. The device is available in the Multiwatt15 package and is specified for applications including home stereo systems, self-powered loudspeakers, and high-power TV audio.
One point is important from the beginning: the often-quoted 100 W rating should not be interpreted as “100 W under every condition.” ST specifies 100 W into an 8 Ω load at 10% THD with a ±40 V supply. The actual usable output power depends on supply voltage, speaker impedance, distortion, thermal conditions, and the complete amplifier design.
What Is the TDA7293?
The TDA7293 is a monolithic Class-AB audio power amplifier using ST's Multipower BCD technology and a DMOS output stage. Its relatively wide supply-voltage capability makes it attractive when more voltage swing or output power is needed than many lower-voltage audio amplifier ICs can provide.
Its main features include:
- Class-AB operation
- DMOS power output stage
- ±50 V operating-voltage capability
- 100 W output rating under specified conditions
- Mute and standby functions
- Turn-on muting to reduce switching noise
- Thermal shutdown
- Short-circuit protection under specified conditions
- Clip detector
- Parallel operation using multiple devices
- Multiwatt15V and Multiwatt15H package options
For an engineer designing a discrete amplifier from scratch, these integrated protection and control functions can save considerable board space and development work.
TDA7293 Key Specifications
| Parameter | TDA7293 |
|---|---|
| Manufacturer | STMicroelectronics |
| Amplifier class | Class AB |
| Technology | Multipower BCD / DMOS |
| Package | Multiwatt15 |
| Operating supply range | Up to ±50 V |
| Rated output power | 100 W into 8 Ω under specified conditions |
| Input resistance | About 100 kΩ minimum |
| Slew rate | About 10 V/µs typical |
| Closed-loop gain | About 30 dB typical |
| Functions | Mute, standby, clip detection |
| Protection | Thermal shutdown, short-circuit protection |
| Parallel operation | Yes |
The datasheet is the right source to use when selecting operating conditions because several of these specifications depend strongly on load resistance, supply voltage, frequency, and THD.
Do not confuse ±50 V with the 120 V name
The product is often described as a “120 V / 100 W” amplifier. This does not mean that ±60 V should be applied to the IC. ST specifies a very high operating-voltage range of up to ±50 V. The “120 V” description refers to the device's high-voltage capability rather than a recommendation to operate it continuously at ±60 V.
This distinction matters when designing the power supply. The rectified no-load voltage of a transformer supply can be considerably higher than its nominal loaded voltage, so the worst-case supply voltage should always be checked.
TDA7293 Pinout and Pin Functions
The TDA7293 uses a 15-pin Multiwatt package. The main pins are:
| Pin | Function |
|---|---|
| 1 | STBY-GND |
| 2 | Inverting input |
| 3 | Non-inverting input |
| 4 | Mute |
| 5 | Clip detector |
| 6 | Bootstrap |
| 7 | +VS |
| 8 | Signal ground |
| 9 | Standby |
| 10 | Mute control |
| 11 | Buffer driver / parallel operation |
| 12 | Bootstrap loader |
| 13 | +Power VS |
| 14 | Output |
| 15 | −Power VS |
The exact pin functions and recommended connections should be taken from the ST datasheet when laying out a PCB. The device also uses separate signal and power supply connections, which is useful when managing high-current output paths and sensitive input circuitry.
Pins 6, 11, and 12 deserve particular attention in advanced designs. Pin 11 is especially important because it allows multiple TDA7293 devices to be configured for parallel operation.
How Does the TDA7293 Work?
At a basic level, the TDA7293 takes a relatively small audio signal at its input and drives a much larger voltage and current into the loudspeaker.
The signal passes through the input and voltage-gain stages before reaching the DMOS output stage. Negative feedback sets the closed-loop gain and helps control distortion and frequency response.
The output stage operates in Class AB. This means the two halves of the output stage share the job of reproducing the waveform while maintaining much better efficiency than a pure Class-A amplifier.
The DMOS output stage is one of the main reasons the TDA7293 is attractive for high-power audio. It also allows the device to operate from relatively high supply voltages.
However, high voltage and high output current also mean significant heat. A TDA7293 design should therefore be treated as a complete power system, not simply as an IC connected to a speaker.
TDA7293 Typical Application Circuit
A standard TDA7293 circuit contains the amplifier IC together with input, feedback, bootstrap, mute/standby, supply-decoupling, and output components.
The feedback network determines the closed-loop gain. In a conventional non-inverting configuration, the gain can be estimated from the feedback resistor network, but the practical circuit should follow the values and topology recommended by ST rather than treating the IC as an ideal operational amplifier.
The datasheet's typical application circuit includes local supply bypass capacitors and larger reservoir capacitors on the positive and negative rails. These capacitors are not optional decoration. They provide a low-impedance local supply path when the output stage demands current.
For a new PCB, I would pay particular attention to three areas:
- Keep the high-current power and speaker paths short.
- Keep sensitive input traces away from the output trace.
- Place the small supply bypass capacitors close to the IC.
Many audio amplifier problems that appear to be “IC problems” are actually grounding, decoupling, layout, or thermal-design problems.
TDA7293 Power Supply Design
The power supply is one of the most important parts of a TDA7293 amplifier.
A typical high-power design uses a split supply with positive and negative rails. The exact transformer voltage must be selected according to the target speaker impedance and output power rather than simply choosing the highest voltage that the IC can tolerate.
For example, ST specifies the 100 W figure at ±40 V, 8 Ω, and 10% THD. That is a specific test condition, not a universal design target.
When designing the supply, check:
- Transformer secondary voltage
- Rectified peak voltage
- Mains-voltage tolerance
- Transformer regulation
- Reservoir capacitor voltage rating
- Speaker impedance
- Maximum output power
- IC power dissipation
- Heatsink temperature
A common design mistake is to calculate the supply using only the transformer's nominal AC voltage. The no-load DC voltage after rectification can be substantially higher.
TDA7293 Thermal Design
The TDA7293 can deliver high output power, but it cannot escape the laws of thermodynamics.
The speaker may receive 100 W while the amplifier IC itself dissipates a different amount of power as heat. That heat must be transferred from the silicon to the package, heatsink, and finally the surrounding air.
For this reason, heatsink selection should be based on the expected IC power dissipation and thermal resistance, not simply on the advertised speaker output power.
At high output levels, especially with low-impedance speakers, monitor:
- Heatsink temperature
- Case temperature
- Supply voltage
- Output current
- Continuous versus music-program power
The built-in thermal shutdown is valuable protection, but it should not be treated as part of the normal thermal-management strategy. If the amplifier repeatedly reaches thermal shutdown, the design needs more cooling or lower operating stress. ST includes thermal shutdown as one of the device's protection features.
TDA7293 Parallel Operation
One of the most useful features of the TDA7293 is its ability to operate several devices in parallel.
ST specifically supports parallel operation through pin 11. This allows the amplifier to deliver high output power to very low-impedance loads while distributing the thermal and current burden among multiple devices.
In a parallel configuration, one device acts as the master and the other devices operate as slaves. The bootstrap and control connections must follow the ST application circuit. This is not a case where several output pins can simply be connected together on an arbitrary PCB.
When using parallel TDA7293 devices, pay extra attention to:
- Equal current paths
- Short output connections
- Grounding
- Bootstrap connections
- Supply decoupling
- Thermal coupling
- PCB symmetry
If you need to drive a very low-impedance load, parallel operation can be more practical than forcing a single amplifier IC to provide all of the required current.
Can TDA7293 Be Used in Bridge Mode?
Bridge-tied-load, or BTL, operation can be used to obtain a larger voltage swing across a speaker. However, bridge operation changes the electrical stress on the amplifier devices and speaker.
The load seen by each amplifier channel is effectively different from the load connected between the two outputs. Therefore, supply voltage, speaker impedance, output current, and thermal dissipation must all be checked again.
Do not assume that two 100 W amplifiers automatically produce a safe 200 W bridge amplifier. The actual result depends on the supply rails, load, distortion limit, current capability, and thermal conditions.
TDA7293 PCB Layout Tips
A good schematic can still produce a poor amplifier if the PCB layout is wrong.
For a practical TDA7293 board:
Keep high-current loops small. The output and power-supply currents should not share long, thin traces with sensitive input signals.
Use a sensible grounding strategy. Keep high-current return currents away from the small-signal input ground as much as practical.
Place bypass capacitors close to the IC. Long traces add inductance and reduce the effectiveness of local decoupling.
Separate input and output routing. The output signal has a much larger amplitude than the input, so unwanted coupling can cause noise or even oscillation.
Give the heatsink and mounting arrangement proper attention. The package and mechanical design are part of the thermal path.
These details become even more important in parallel configurations.
TDA7293 Protection Features
The TDA7293 integrates several useful protection and control functions:
Short-Circuit Protection
The device includes short-circuit protection under the conditions specified by ST. This provides an important safety layer, but external wiring and repeated fault conditions should still be designed carefully.
Thermal Shutdown
If the junction temperature becomes excessive, the protection system can shut down the amplifier.
Mute
Mute allows the audio output to be controlled without removing the main power supply.
Standby
Standby provides a lower-power operating state and is useful in system power-management designs.
Clip Detection
The clip detector can be used by the surrounding system to monitor when the amplifier is approaching output clipping.
The built-in turn-on muting is also useful because it helps reduce the annoying switching noise that can otherwise occur when an amplifier powers up.
TDA7293 vs TDA7294
The TDA7294 is one of the most obvious related parts when evaluating the TDA7293.
Both belong to ST's popular high-power Class-AB audio amplifier family and use a DMOS output stage. However, the TDA7293 offers a wider supply-voltage capability and specifically supports modular parallel operation.
The important lesson is that similar part numbers do not automatically mean drop-in compatibility.
Before replacing a TDA7293 with a TDA7294, verify:
- Pinout
- Supply voltage
- Output power
- Speaker impedance
- Protection behavior
- Package variant
- PCB footprint
- Thermal requirements
For another popular Class-AB alternative, engineers often compare the TDA7293 with the LM3886. Community discussions frequently compare these devices, but subjective claims about which one “sounds better” are not a reliable engineering specification.
For component selection, measurable parameters and the actual application should take priority over subjective audio descriptions.
Other related audio amplifier ICs worth researching include TDA7295, TDA7296, TDA2030A, and LM1875T, although these should be treated as functional alternatives rather than assumed direct replacements.
Common TDA7293 Problems
Why does my TDA7293 overheat?
Usually check supply voltage, speaker impedance, output level, heatsink size, airflow, and PCB thermal design first.
Why does the amplifier distort at high volume?
The amplifier may be reaching its voltage or current limit, the power supply may be sagging, or the device may be entering thermal protection.
Can TDA7293 drive a 4 Ω speaker?
Yes. ST specifically states that the device can supply high power into both 4 Ω and 8 Ω loads. The actual safe output level depends on supply voltage, cooling, and operating conditions.
Can I use ±50 V directly?
±50 V is within the stated operating-voltage capability, but that does not mean ±50 V is appropriate for every load or output-power target. Check the complete operating conditions and worst-case supply voltage before choosing the rail voltage.
Can several TDA7293 ICs be connected together?
Yes. Parallel operation is a supported feature, using the appropriate pin-11 master/slave configuration and the circuit recommended by ST.
Final Thoughts
The TDA7293 remains an interesting choice when a design needs a relatively high-power, integrated Class-AB audio amplifier with a wide supply range and useful system-level features.
Its biggest strengths are not simply the headline 100 W number. The combination of a DMOS output stage, high-voltage capability, mute and standby control, protection functions, clip detection, and parallel operation gives engineers considerable flexibility.
At the same time, the TDA7293 should not be treated as a “100 W amplifier in a box.” The power supply, speaker impedance, PCB layout, grounding, bootstrap network, and heatsink all have a direct effect on real-world performance.
For a reliable design, start with the STMicroelectronics TDA7293 datasheet, select the supply and load conditions first, calculate the expected thermal stress, and then build the PCB around those requirements. Related devices such as TDA7294, TDA7295, TDA7296, LM3886, TDA2030, and LM1875 can also be useful when comparing architectures or looking for alternatives, but their electrical and mechanical specifications must be checked individually before substitution.
That engineering approach is much more reliable than choosing an amplifier IC based only on its advertised wattage.
TDA7293 Quick Reference
- Manufacturer: STMicroelectronics
- Type: Class-AB audio power amplifier
- Technology: DMOS / Multipower BCD
- Package: Multiwatt15
- Operating voltage: Up to ±50 V
- Rated output: 100 W into 8 Ω under ST's specified test conditions
- Control: Mute and standby
- Protection: Thermal shutdown and short-circuit protection
- Monitoring: Clip detector
- Advanced feature: Parallel operation
- Typical applications: Home stereo, powered speakers, TV audio, and other high-power audio systems
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