LMV1024_09 Datasheet, PDF (1/18 Pages) National Semiconductor (TI) – PDM Output with Pre-Amplifier for Electret Microphones

LMV1024/LMV1026 (Stereo)
OBSOLETE
July 20, 2009
PDM Output with Pre-Amplifier for Electret Microphones
General Description
National’s LMV1024 and LMV1026 stereo amplifiers are so-
lutions for the new generation of voice enrichment capabili-
ties. National has integrated sigma delta modulation and
analog cores to improve the voice quality and the perfor-
mance and to support designer’s choices.
Each 20 kHz preamplifier drives a Pulse Density Modulated
(PDM) signal at an over sampled 60 bit stream, offering ver-
satility. These solutions provide immediate conversion to high
performance audio spectrum, thus completing a high quality
audio system. The LMV1024 and LMV1026 operate from
1.6V to 3V.
National’s new adjustable clock frequency technology is de-
signed for stereo, performance and ease of use. The stereo
function is either a rising or falling edge clock command. The
high drive, robust PDM signal directly from an ECM (Electret
Condenser Microphone), upgrades existing lower quality,
low-level signal constraints.
These advanced mixed signal preamplifiers cleanly, accu-
rately and creatively eliminate older, poorer quality systems,
which restricted performance and versatility. The 4-wire PDM
signaling reduces RF noise and simplifies layout. Using
National’s PDM solutions is the choice for higher quality mono
or stereo and multi-array applications.
National’s 518uA circuits deliver stereo portability with audio
quality bandwidth. These solutions enable rapid system eval-
uation and enhance consumer satisfaction. National provides
the LMV1024 and LMV1026 in 6-bump micro SMD packages
with 1 kg adhesion properties.
Features
(Typical V_DD = 1.8V, CLOCK = 1.2 MHz, f_INPUT = 1 kHz,
V_INPUT = 18 mV_PP, unless otherwise specified)
■ ^{Enhanced high-performance, full PDM output from the el-}
ement
■ ^{Stereo chipset and array routing}
■ ^{SNR A-weighted}
59 dB
■ ^{Digital A-weighted noise floor}
−89 dBFS
■ ^{Supply current}
518 µA
■ ^{Clock frequency}
400 kHz to 2.4 MHz
■ ^{Total harmonic distortion}
0.03%
■ ^{Power supply rejection ratio}
100 dB
■ ^{Adhesion technology >1 kg}
■ ^{Highly integrated stereo or mono signaling}
■ ^{Maximized system performance}
■ ^{Reduced components and layout}
■ ^{RF (buzz noise) managed with 4 wire signaling}
■ ^{Thinnest 0.35 mm micro SMD packaging}
Applications
■ ^{Digital output audio subsystems and stereo arrays}
■ ^{Electret condenser microphones with all digital output}
■ ^{Portable communications and small form factor}
■ ^{Digital audio computing or voice security}
■ ^{Automotive or array systems}
■ ^{Headphone and Headset accessories}
Typical Application
For a stereo application, see STEREO OPERATION in the Application Section.
© 2009 National Semiconductor Corporation 201334
201334 Version 3 Revision 4 Print Date/Time: 2009/07/20 17:12:49
20133475
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