Overview
The LM4766T/NOPB is a dual 40W audio power amplifier produced by Texas Instruments. It is part of the Overture™ Audio Power Amplifier Series and is designed to deliver high-quality audio performance with advanced protection features. The amplifier is available in both non-isolated (NDL) and isolated (NDB) packages, making it versatile for various audio applications. It features a wide supply range of 20V to 60V and is optimized for high-end stereo systems, including TVs and minicomponent systems.
Key Specifications
| Parameter | Conditions | Typical Value | Limit | Units |
|---|---|---|---|---|
| Power Supply Voltage | VCC = +30V, VEE = −30V | 20 to 60 | 20 to 60 | V |
| Output Power (Continuous Average) | f = 1kHz, RL = 8Ω | 40W/ch (NDL), 30W/ch (NDB) | 40W/ch (NDL), 30W/ch (NDB) | W |
| THD+N at 1kHz | 2 x 30W Continuous Average Output Power Into 8Ω | 0.009% (Typ), 0.1% (Max) | 0.009% (Typ), 0.1% (Max) | % |
| Output Current | Internally Limited | - | - | A |
| Power Dissipation | - | 62.5W | 62.5W | W |
| Junction Temperature | - | 150°C | 150°C | °C |
| Thermal Resistance (θJC) | NDL Package | 1°C/W | 1°C/W | °C/W |
| Thermal Resistance (θJC) | NDB Package | 2°C/W | 2°C/W | °C/W |
Key Features
- SPiKe Protection: The LM4766 is safeguarded against overvoltage, undervoltage, overloads, and instantaneous temperature peaks.
- Quiet Fade-In/Out Mute Mode: Independent smooth transition fade-in/out mute for each amplifier, minimizing output pops.
- Minimal External Components: Requires a minimal amount of external components necessary for operation.
- Wide Supply Range: Operates over a wide supply range of 20V to 60V.
- Thermal Protection: Sophisticated thermal protection scheme to prevent long-term thermal stress, with shutdown at 165°C and restart at 155°C.
- Under-Voltage Protection: Prevents DC output spikes during power-up and transients during power-down.
- Over-Voltage Protection: Limits output current and provides voltage clamping without internal clamping diodes.
Applications
- High-End Stereo TVs: Ideal for high-quality audio in television systems.
- Component Stereo Systems: Suitable for component stereo systems requiring high-performance audio amplification.
- Compact Stereo Systems: Used in compact stereo systems where space and performance are critical.
- Bridged Amplifier Configurations: Can be configured in bridged mode to double the output swing and theoretically quadruple the output power.
Q & A
- What is the typical output power of the LM4766T/NOPB?
The LM4766T/NOPB can deliver typically 40W per channel with the non-isolated NDL package and 30W per channel with the isolated NDB package into an 8Ω load.
- What is the THD+N at 1kHz for the LM4766T/NOPB?
The THD+N at 1kHz is typically 0.009% and a maximum of 0.1% for continuous average output power into an 8Ω load.
- What is the power supply voltage range for the LM4766T/NOPB?
The power supply voltage range is from 20V to 60V.
- How does the mute function work on the LM4766T/NOPB?
The mute function is activated by drawing more than 0.5mA out of each mute pin. This can be achieved using a resistor and switch configuration as described in the datasheet.
- What kind of thermal protection does the LM4766T/NOPB have?
The LM4766T/NOPB has a sophisticated thermal protection scheme that shuts down the device at 165°C and restarts it when the temperature drops to 155°C.
- Can the LM4766T/NOPB be used in bridged amplifier configurations?
Yes, the LM4766T/NOPB can be configured in bridged mode to increase the output power, doubling the output swing for a specified supply voltage.
- What is the purpose of the under-voltage protection circuitry in the LM4766T/NOPB?
The under-voltage protection circuitry prevents DC output spikes during power-up and transients during power-down by allowing the power supplies to come up close to their full values before turning on the amplifier.
- How does the over-voltage protection work in the LM4766T/NOPB?
The over-voltage protection limits the output current to approximately 4.0A peak and provides voltage clamping without internal clamping diodes, using the output transistors to handle large current spikes.
- What is the significance of SPiKe Protection in the LM4766T/NOPB?
The SPiKe Protection safeguards the device against overvoltage, undervoltage, overloads, and instantaneous temperature peaks, ensuring safe operation.
- How can you minimize turn-on pops in the LM4766T/NOPB?
Turn-on pops can be minimized by ensuring the input terminals are at the same potential during power-up, using resistors to keep the inputs at the same rate, and adjusting these resistors for optimal performance.
