Product category:
Analogue and Mixed Signal ICs
News Release from: National Semiconductor | Subject: LMV1024 and LMV1026
Edited by the Electronicstalk Editorial
Team on 16 March 2005
Amps go in the mic to improve sound
quality
National Semiconductor has developed two new amplifiers that put high-fidelity sound quality directly inside electret condenser microphones (ECMs).
National Semiconductor has developed two new amplifiers that put high-fidelity sound quality directly inside electret condenser microphones (ECMs) Previously, the large size and high cost associated with this effort kept manufacturers from implementing digital voice technology in wireless products
This article was originally published on Electronicstalk on 5 Jan 2001 at 8.00am (UK)
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National overcame the size-and-cost barrier with the LMV1024 and LMV1026 by putting the digital modulation and gain inside the microphone to dramatically improve sound quality.
By integrating several components and simplifying routing, National's "digital voice in a mic" technology produces superior sound quality, reduces overall system cost and enables the smallest possible form factor.
"With mixed-signal capability so small that it fits inside existing ECMs, National's LMV1024 and LMV1026 amplifiers provide 20kHz CD-quality stereo sound, which has never before been achieved in this form factor", said Erroll Dietz, Vice President of National Semiconductor's Amplifier Products Group.
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"By integrating the sigma delta codec, the amplifier, regulator and several filter components inside the existing 6mm ECM, National reduces the size of the overall solution and provides simplified system design for the customer".
The introduction of National's LMV1024 and LMV1026 amplifiers with digital voice technology follows the company's successful portfolio of analogue "amp in a mic" products, the LMV1012 and LMV1032.
These products transformed the market by replacing the decades-old junction field effect transistor (JFET), dramatically improving audio performance and sensitivity in two- and three-wire ECMs.
Integrating digital output at the microphone is the second step in National's strategy of enabling the world's first four-wire ECM with built-in gain and sigma delta modulation to deliver the best possible audio fidelity.
Applications using this technology are microphones in mobile handsets, PDAs and other portable, wireless applications.
National designed the LMV1024 and LMV1026 by integrating the amplifier and delta sigma modulator inside an ECM.
These next-generation microphone amplifiers produce an over-sampled single bit stream that connects directly to a DSP in a digital audio system.
These amplifiers allow the user the flexibility of adjusting clock frequency ranging between 1 and 3.25MHz.
The LMV1024 and LMV1026 are designed for very robust signal-to-noise ratio (SNR) and acoustic audio sensing.
The output of an ECM eliminates sensitive, low-level analogue signals that form the output of a conventional JFET ECM.
System design routing and layout is simplified due to integration of external components.
The analogue-to-digital conversion of the LMV1024/26 enables customers to design high-performance stereo microphone subsystems.
Sampling now in limited quantities, the LMV1024 and LMV1026 are offered in 6-bump micro SMD packages.
The LMV1024 and LMV1026 are each priced at $0.81 in 1000-unit quantities.
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