LMV1024 Datasheet, PDF (1/17 Pages) National Semiconductor (TI) – PDM Output with Pre-Amplifier for Electret Microphones

November 2005
LMV1024/LMV1026 (Stereo)
PDM Output with Pre-Amplifier for Electret Microphones
General Description
National’s LMV1024 and LMV1026 stereo amplifiers are
solutions for the new generation of voice enrichment capa-
bilities. 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
versatility. 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. Us-
ing 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
evaluation and enhance consumer satisfaction. National pro-
vides 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)
n Enhanced high-performance, full PDM output from the
element
n Stereo chipset and array routing
n SNR A-weighted
59 dB
n Digital A-weighted noise floor
−89 dBFS
n Supply current
518 µA
n Clock frequency
400 kHz to 2.4 MHz
n Total harmonic distortion
0.03%
n Power supply rejection ratio
n Adhesion technology >1 kg
100 dB
n Highly integrated stereo or mono signaling
n Maximized system performance
n Reduced components and layout
n RF (buzz noise) managed with 4 wire signaling
n Thinnest 0.35 mm micro SMD packaging
Applications
n Digital output audio subsystems and stereo arrays
n Electret condenser microphones with all digital output
n Portable communications and small form factor
n Digital audio computing or voice security
n Automotive or array systems
n Headphone and Headset accessories
Typical Application
For a stereo application, see STEREO OPERATION in the Application Section.
© 2005 National Semiconductor Corporation DS201334
20133475
www.national.com