40-mW, stereo headphone amplifier with selectable capacitive coupled or OCL output

The LM4911/LM4911Q is an stereo audio power amplifier capable of delivering 40mW per channel of continuous average power into a 16Ω load or 25mW per channel into a 32Ω load at 1% THD+N from a 3V power supply.

Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external components. Since the LM4911/LM4911Q does not require bootstrap capacitors or snubber networks, it is optimally suited for low-power portable systems. In addition, the LM4911/LM4911Q may be configured for either single-ended capacitively coupled outputs or for OCL outputs (patent pending).

The LM4911/LM4911Q features a low-power consumption shutdown mode and a power mute mode that allows for faster turn on time with less than 1mV voltage change at outputs on release. Additionally, the LM4911/LM4911Q features an internal thermal shutdown protection mechanism.

The LM4911/LM4911Q is unity gain stable and may be configured with external gain-setting resistors.

A Q-grade version is available for automotive applications. It is AEC-Q100 grade 2 qualified and packaged in a 10–pin MSOP package (LM4911QMM).

Key Specifications PSRR at 217Hz and 1kHz

65dB (typ)

Output Power at 1kHz with VDD = 2.4V,

1% THD+N into a 16Ω load

25mW (typ)

Output Power at 1kHz with VDD = 3V,

1% THD+N into a 16Ω load

40mW (typ)

Shutdown Current

2.0µA (max)

Output Voltage change on release from

Shutdown VDD = 2.4V, RL = 16Ω (C-Coupled)

1mV (max)

Mute Current

100µA (max)