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Features
Fast 0.1ms (typ) and 1.0ms (max) turn-on and turn-off time
Eliminates SE amplifier output coupling capacitors
Advanced "click and pop" suppression circuitry
Stereo headphone amplifier mode
Low-power standby and ultra-low current micropower shutdown modes
Thermal shutdown protection circuitry
2.4V to 5.5V operation
Unity-gain stable
Gain set with external resistors
Space-saving micro SMD package, exposed-DAP LLP, and TSSOP
Description The unity-gain stable LM4854 is both a mono differential output (for bridge-tied loads, or BTL) audio power amplifier and a single-ended (SE) stereo headphone amplifier. Operating on a single 5V supply, the mono BTL mode delivers 1.1W (typ) to an 8 load, 1.7W (typ) to a 4 load (Note 1) at 1% THD+N. In SE stereo mode, the amplifier will deliver 85mW to 32 loads. The LM4854 features a new circuit topology that suppresses output transients ('click and pops') and eliminates SE-mode output coupling capacitors, saving both component and board space costs. The LM4854 has three inputs: one pair for a two-channel stereo signal and the third for a single-channel mono input.
The LM4854 is designed for PDA, cellular telephone, notebook, and other handheld portable applications. It delivers high quality output power from a surface-mount package and requires few external components. Other features include an active-low micropower shutdown mode, an "instant-on" low power standby mode, and thermal shutdown protection.
The LM4854 is available in the very space-efficient 12-lead micro SMD, exposed-DAP LLP for higher power applications, and TSSOP packages.
Key Specification
| LLP BTL output power (RL = 3.2 and THD+N = 1%) | |
| VDD = 3.0V | 1.0W (typ) |
| VDD = 5.0V | 1.9W (typ) |
| LLP BTL output power (RL = 4 and THD+N = 1%) | |
| VDD = 3.0V | 900mW (typ) |
| VDD = 5.0V | 1.7W (typ) |
| LLP BTL output power (RL = 8 and THD+N = 1%) | |
| VDD = 3.0V | 380mW (typ) |
| VDD = 5.0V | 1.1W (typ) |
| SE output power (RL = 32 and THD+N = 1.0%) | |
| VDD = 3.0V | 32mW (typ) |
| VDD = 5.0V | 93mW (typ) |
| Micropower shutdown supply current | |
| VDD = 3.0V | 0.005µA (typ) |
| VDD = 5.0V | 0.05µA (typ) |
| Standby supply current | |
| VDD = 3.0V | 16µA (typ) |
| VDD = 5.0V | 27µA (typ) |
| PSRR (f = 1kHz, 3.0V <= VDD <= 5.0V, (Fig. 1)) | |
| BTL | 60dB (typ) |
| SE | 66dB (typ) |
Applications
PDAs
Notebook computers
Cellular phones
Handheld portable electronic devices
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