LM4929 Datasheet, PDF (1/13 Pages) National Semiconductor (TI) – Stereo 40mW Low Noise Headphone Amplifier with OCL Output

December 2004
LM4929
Stereo 40mW Low Noise Headphone Amplifier
with OCL Output
General Description
The LM4929 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 LM4929 does not require
bootstrap capacitors or snubber networks, it is optimally
suited for low-power portable systems. The LM4929 is con-
figured for OCL (Output Capacitor-Less) outputs, operating
with no DC blocking capacitors on the outputs.
The LM4929 features a low-power consumption shutdown
mode with a faster turn on time. Additionally, the LM4929
features an internal thermal shutdown protection mecha-
nism.
The LM4929 is unity gain stable and may be configured with
external gain-setting resistors.
Key Specifications
j PSRR at 217Hz and 1kHz
j Output Power at 1kHz with V_DD = 2.4V,
1% THD+N into a 16Ω load
j Output Power at 1kHz with V_DD = 3V,
1% THD+N into a 16Ω load
j Shutdown current
j Output Voltage change on release
from Shutdown V_DD = 2.4V, R_L = 16Ω
65dB (typ)
25mW (typ)
40mW (typ)
2.0µA (max)
1mV (max)
Features
n OCL outputs — No DC Blocking Capacitors
n External gain-setting capability
n Available in space-saving MSOP package
n Ultra low current shutdown mode
n 2V - 5.5V operation
n Ultra low noise
Applications
n Portable CD players
n PDAs
n Portable electronics devices
Block Diagram
FIGURE 1. Block Diagram
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation DS201324
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