Key Selection Information
| Selection Parameter | Confirmed Information |
|---|---|
| Topology | Monolithic linear audio power amplifier |
| Output | 20 W into 4 Ω or 8 Ω at ±25 V stated; >30 W possible into 8 Ω at ±30 V stated condition |
| Supply | 16 V to 60 V total supply range stated |
| Distortion | 0.015% stated at 1 kHz / 20 W condition |
| Power Bandwidth | 70 kHz stated |
| Current Capability | 4 A stated |
| Protection | Internal current limiting, thermal shutdown and output protection diodes |
| Exact Package / Packing | TO-220 (NDH), 5 pins; 45-piece tube; 0°C to +70°C; marking LM1875T |
Product Overview
LM1875T/NOPB is a linear power amplifier for high-fidelity analog audio systems. Unlike Class-D devices, the output transistors operate linearly, which simplifies EMI/output filtering but creates substantially more heat at high output power.
The common 20-W operating point is specified with ±25 V rails into 4-Ω or 8-Ω loads. Higher headline power requires different rail/load conditions and therefore a different thermal dissipation calculation.
The TO-220 package is intended for heatsink attachment. Internal current and thermal protection improve robustness, but sustained high-power operation still depends on heatsink thermal resistance and safe supply/load selection.
For related devices, see HKEQGOO’s Audio Amplifiers category.
Technical Specifications
| Parameter | Verified Information |
|---|---|
| Manufacturer | Texas Instruments |
| Exact MPN | LM1875T/NOPB |
| Topology | Monolithic linear audio power amplifier |
| Output | 20 W into 4 Ω or 8 Ω at ±25 V stated; >30 W possible into 8 Ω at ±30 V stated condition |
| Supply | 16 V to 60 V total supply range stated |
| Distortion | 0.015% stated at 1 kHz / 20 W condition |
| Power Bandwidth | 70 kHz stated |
| Current Capability | 4 A stated |
| Protection | Internal current limiting, thermal shutdown and output protection diodes |
| Exact Package / Packing | TO-220 (NDH), 5 pins; 45-piece tube; 0°C to +70°C; marking LM1875T |
| Manufacturer Status | Active / Production |
| Part Marking | LM1875T |
Functional Highlights
Linear topology offers a simple analog signal path
No high-frequency PWM output filter is required, which can simplify audio/EMI design when efficiency is secondary.
TO-220 enables external heatsinking
The package can move several watts of dissipation to a chassis/heatsink, allowing higher continuous power than small surface-mount linear amplifiers.
Design Considerations
- Calculate worst-case device dissipation and heatsink Rθ before setting supply rails.
- Keep closed-loop gain at or above the datasheet stability requirement.
- Separate high-current speaker returns from small-signal input ground.
Product Status and Exact Order Code
Texas Instruments lists LM1875T/NOPB as Active / Production; TO-220 (NDH), 5 pins; 45-piece tube; 0°C to +70°C; marking LM1875T.
Related Engineering Resources
Quality & Verification Support
Third-party inspection or testing can be arranged according to customer requirements. Testing fees are borne by the buyer. Additional verification requirements can be discussed before shipment. After an order is placed, physical product, label, packaging, and Date Code photos may be provided where appropriate.
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