Overview
The LM1875T/LF05 is a high-performance, monolithic audio power amplifier designed by Texas Instruments. This device is optimized for consumer audio applications, offering very low distortion and high-quality performance. It is capable of delivering up to 20 watts of power into a 4Ω or 8Ω load, and with appropriate power supplies, it can deliver over 30 watts. The LM1875T/LF05 features advanced protection mechanisms, including internal current limit, thermal shutdown, and protection against AC and DC short circuits, ensuring reliable operation under various conditions.
Key Specifications
| Parameter | Conditions | Typical | Units |
|---|---|---|---|
| Supply Voltage | 16V - 60V | V | |
| Output Power | THD = 1%, RL = 8Ω | 25 W | W |
| Distortion (THD) | POUT = 20W, fo = 1 kHz, RL = 8Ω | 0.015% | % |
| Distortion (THD) | POUT = 20W, fo = 20 kHz, RL = 8Ω | 0.05% | % |
| Input Bias Current | ±0.2 μA | μA | |
| Input Offset Current | 0 ± 0.5 μA | μA | |
| Gain-Bandwidth Product | fo = 20 kHz | 5.5 MHz | MHz |
| Open Loop Gain | DC | 90 dB | dB |
| Power Supply Rejection Ratio (PSRR) | VCC, 1 kHz, 1 Vrms | 95 dB | dB |
| Max Slew Rate | 20W, 8Ω, 70 kHz BW | 8 V/μs | V/μs |
| Current Limit | VOUT = VSUPPLY - 10V | 4 A | A |
| Junction Temperature | 150°C | °C |
Key Features
- High Output Power: Up to 20 watts into a 4Ω or 8Ω load, and over 30 watts with appropriate power supplies.
- Low Distortion: Typically 0.015% at 1 kHz and 20 watts output.
- Wide Power Bandwidth: 70 kHz on ±25V supplies.
- Protection Mechanisms: Internal current limit, thermal shutdown, and protection against AC and DC short circuits.
- Wide Supply Range: Operates from 16V to 60V.
- High Current Capability: Up to 4A.
- Thermal Protection: Sophisticated thermal protection scheme to prevent long-term thermal stress.
Applications
The LM1875T/LF05 is designed for various consumer audio applications, including:
- Home audio systems
- Professional audio equipment
- Public address systems
- Audio amplifiers in automotive systems
- Other high-quality audio applications requiring low distortion and high power output.
Q & A
- What is the maximum output power of the LM1875T/LF05?
The LM1875T/LF05 can deliver up to 20 watts into a 4Ω or 8Ω load, and over 30 watts with appropriate power supplies.
- What is the typical distortion level of the LM1875T/LF05?
The typical distortion level is 0.015% at 1 kHz and 20 watts output.
- What is the power bandwidth of the LM1875T/LF05?
The power bandwidth is 70 kHz on ±25V supplies.
- What protection mechanisms does the LM1875T/LF05 have?
The device features internal current limit, thermal shutdown, and protection against AC and DC short circuits.
- What is the operating supply voltage range of the LM1875T/LF05?
The device operates from 16V to 60V.
- What is the maximum current capability of the LM1875T/LF05?
The maximum current capability is up to 4A.
- How does the thermal protection mechanism work in the LM1875T/LF05?
The device has a sophisticated thermal protection scheme that shuts down the amplifier when the die temperature reaches 170°C and restarts when it drops to about 145°C.
- Why is a heat sink necessary for the LM1875T/LF05?
A heat sink is necessary to prevent thermal shutdown and ensure reliable operation, especially when driving loads.
- What are some common applications of the LM1875T/LF05?
Common applications include home audio systems, professional audio equipment, public address systems, and automotive audio systems.
- How should the PCB layout be designed for the LM1875T/LF05 to prevent oscillation and distortion?
Proper layout involves separating power supply traces from input traces, using separate ground paths for load, output compensation, and low-level grounds, and keeping decoupling capacitors close to the device.
- Can the LM1875T/LF05 drive highly capacitive loads?
The device can drive load capacitances up to 2 μF, but it is recommended to use a series resistor to prevent oscillation.
