Product category: Communications ICs (Wireless)
News Release from: National Semiconductor | Subject: LMX2470
Edited by the Electronicstalk Editorial Team on 08 April 2003
PLLs optimise RF performance for
cellular uses
National Semiconductor has expanded its wireless product offerings with the introduction of a new family of PLLatinum phase lock loops (PLLs) for cellular applications.
National Semiconductor has expanded its wireless product offerings with the introduction of a new family of PLLatinum phase lock loops (PLLs) for cellular applications This new family of delta-sigma fractional-N PLLs uses digital modulation techniques for superior phase noise, spurs and lock time performance in applications requiring exceptionally fine frequency resolution
This article was originally published on Electronicstalk on 5 Jan 2001 at 8.00am (UK)
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With these products, National raises the bar for performance with the lowest power consumption delta-sigma PLLs in the industry.
The first member of this new family is the LMX2470, housed in a 3.5 x 4.5 x 0.6mm ultra-thin chip-scale package ideal for use in 2, 2.5G and 3G mobile handsets, base stations, WLANs and other wireless communication systems.
The LMX2470 is available now.
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Additional members of the product family will be introduced throughout the year.
"National's new LMX247x family of delta-sigma PLLs offers our customers a higher level of performance not found in other PLL products.
The sizable improvement in phase noise, spurs, lock time and power consumption that the new family offers translates into improved radio sensitivity for fewer dropped calls, improved voice and data quality, longer battery life and improved system performance", said Salvatore Napolitano, Product Marketing Manager for National's Wireless Group in Europe.
"Building upon National's leadership in the PLL market, the LMX247x family will allow manufacturers of mobile handsets to meet their designs' increasingly stringent performance and power requirements".
The LMX2470 is the first product offering from National's new family of high-performance delta-sigma PLLs.
It features a maximum RF operating frequency of 2.6GHz and an 800MHz IF.
The LMX2470 is the industry's first delta-sigma PLL that allows users to software select the modulator order.
It is also the industry's only delta-sigma PLL that has true cycle slip reduction and integrated timeout counters for fastlock to minimise software overhead.
The product is highly flexible, with 32 current (charge pump) levels and four levels of comparison frequency reduction.
It is optimised for very low power consumption, with 4.1mA total current at a 2.5V supply voltage.
The LMX2470 has up to a 22bit selectable modulus that enables very high comparison frequencies for excellent normalised phase noise performance of -210dBc/Hz for high system sensitivity.
The onboard crystal doubler can be used to double the crystal frequency to allow larger comparison frequencies, resulting in -213dBc/Hz normalised phase noise.
With low fractional spurs of less than -90dBc, the LMX2470 has the lowest fractional spurs in the industry to minimise crosschannel modulation for greater voice and data accuracy.
The LMX2470's delta-sigma modulation pushes in-band noise and spurs to outside the loop bandwidth.
The higher the modulator order, the more noise and spurs can be pushed to higher frequencies and filtered out by the loop filter.
The LMX2470 is the only delta-sigma PLL in the industry that gives the user the ability to program the modulator up to modulator order 4.
This ability gives the designer the utmost flexibility to optimise the local oscillator's phase noise, spurs and lock time.
The LMX2470 is available now for $2.07 in 1000-off quantities.
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