TDA1905 Introduction
The TDA1905 is a monolithic audio power amplifier IC housed in a POWERDIP package. Designed for low-frequency applications, it is commonly used in radios, TVs, and other consumer audio systems. This package offers the compactness and easy assembly of a standard DIP while supporting power dissipation up to 6W and a low thermal resistance of 15°C/W (junction to pins).
TDA1905 Working Principle
The main function of the TDA1905 amplifier is to amplify weak audio signals to a level sufficient to drive the speaker. It usually adopts a class AB amplifier structure. In the internal circuit, the input signal is amplified in voltage and current through the cascade and feedback control of multiple transistors (such as Q1 to Q14), and a built-in bias circuit and overheat protection mechanism are built in to ensure the operation of the chip.
In addition, the TDA1905 also integrates a muting control function to suppress noise when the system is in standby or switching state; its output part drives the load through a push-pull output stage (Q12 and Q13), effectively increasing the output power and reducing crossover distortion.
TDA1905 Pin Connection
OUTPUT – Audio signal output pin; connects to the speaker or load.
VS+ – Positive power supply input.
BOOTSTRAP – Boosts the output stage drive.
THRESHOLD – Sets the mute control threshold level.
MUTING – Mute control pin; toggles audio output on/off based on logic level.
INVERT.IN – Inverting input for differential amplification or gain control.
SVR (Supply Voltage Rejection) – Connects to a capacitor to filter power supply noise.
NON INVERT.IN – Non-inverting input; receives the main audio input signal.
GND – Ground pins; ensure stable operation and help with thermal dissipation.
TDA1905 Symbol
TDA1905 Footprint
TDA1905 3D Model
TDA1905 Specification
| Parameter |
Value |
| Package Type |
16-PowerDIP |
| Supply Voltage (VS) |
4V ~ 30V |
| Output Power |
6W |
| Output Type |
1-Channel (Mono) |
| Total Harmonic Distortion |
≤ 0.5% (at Pout = 1W, f = 1kHz) |
| Quiescent Current |
40 mA |
| Input Impedance |
100 kΩ |
| Voltage Gain |
40 dB |
| Max Output Power x Channels @ Load |
5.5W x 1 @ 8Ohm |
| Thermal Resistance (Junction to Pin) |
15°C/W |
| Operating Temperature Range |
-40°C ~ 150°C |
TDA1905 Features
Muting facility
Protection against chips over temperature
Very low noise
High supply voltage rejection
Low "switch-on" noise
Voltage range 4V to 30V
TDA1905 Applications
Audio power amplifier for radios and televisions
Small speaker amplifiers in portable systems
Built-in amplifier circuits in CRT or LCD TVs
Public announcement systems (low-power use)
DIY audio amplifier modules
Intercom or sound reinforcement systems
Embedded audio systems in appliances
Educational audio projects and electronics kits
TDA1905 Schematic Diagram
The diagram shows the internal schematic of the TDA1905 audio power amplifier. The circuit can be divided into three main functional blocks from left to right:
Input Stage and Muting Control: Transistors Q1 to Q3 and diode D7 form the input amplifier stage and the muting control. The MUTING pin controls transistor Q2, which determines whether the input signal is amplified or suppressed. When muting is active, Q2 conducts and pulls the input low, muting the audio output.
Voltage Amplification and Driver Stage: Transistors Q4 to Q9, along with associated resistors and capacitor C1, make up the differential amplifier and voltage gain section. Capacitor C1 provides frequency compensation for stability. Q6 and diode D2 act as a current source, improving linearity. The output from Q7 is the amplified signal that drives the final output stage.
Power Output and Protection: Q12 and Q13 form a complementary push-pull output stage, delivering high-current audio output. Transistors Q10, Q11, Q14 and diodes D3–D6 implement thermal and short-circuit protection, shutting down the output in fault conditions to prevent chip damage.
TDA1905 Amplifier Circuit
This diagram shows a typical audio amplifier application circuit using the TDA1905 chip. On the left, the audio input signal passes through resistor R1 and coupling capacitor C1. The signal is then adjusted by the 20kΩ potentiometer (P1) for volume control, and enters the amplifier through capacitor C3. The VT pin is the muting control input, allowing the audio to be muted via an external control voltage.
TDA1905 supports single-supply operation and integrates all amplification stages. On the output side, capacitors C7 and C9 act as DC-blocking capacitors to ensure clean AC audio output. R2 and C8 form a Zobel network to stabilize high-frequency response and prevent oscillation. Capacitor C6 and resistor R3 are part of the gain and compensation network. The output directly drives a 4-ohm speaker load.
TDA1905 Package
TDA1905 Datasheet
Datasheet PDF(https://dir.heisener.com/DatasheetDownload/TDA1905.pdf)
FAQs
What is the TDA1905 used for?
The TDA1905 is a low-frequency audio power amplifier typically used in TVs, radios, and small audio systems to drive speakers with up to 5W output power.
What type of package does the TDA1905 come in?
It comes in a 16-pin POWERDIP package, which allows efficient heat dissipation and easy PCB integration.
Does the TDA1905 require external components?
Yes, it typically requires a few external components such as capacitors and resistors for filtering, gain control, bootstrap, and muting functions.
0
Login/Register
BOM
Cart
