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Updated: July 8th, 2008 05:26 PM CDT

National Semiconductor's New 12-Bit ADCs for WiMAX Provide the Industry's Highest SFDR of 84.1 dB at 250 MHz Input Frequency

via PRNewswire

SANTA CLARA, Calif., Aug. 20 /PRNewswire-FirstCall/ -- National Semiconductor Corporation (NYSE: NSM) today introduced two 12-bit 170mega-sample per second (MSPS) analog-to-digital converters (ADCs) and a 14-bit,155 MSPS ADC, each with a full-power bandwidth of 1.1 GHz. Available in dualdata rate, low-voltage differential signaling (LVDS) and CMOS output options,the ADCs are targeted at demanding WiMAX and 3G wireless communicationsapplications. In high intermediate frequency (IF) sampling receiverapplications, the 1.1 GHz bandwidth capability of these ADCs provides highspurious free dynamic range (SFDR) and signal-to-noise ratio (SNR) performancethat extends well beyond 250 MHz input frequencies. This enables the systemdesigner to digitize the signal at the first IF, thereby eliminating a downconversion stage, which reduces component count and system power.

The 12-bit ADC12C170 with parallel CMOS outputs and 12-bit ADC12V170 withdual data rate, parallel LVDS outputs offer the industry's highest SFDR above250 MHz input frequencies. Compared to competitive devices, the ADC12C170 at84.1 dB offers 5.5 dB better SFDR and the ADC12V170 at 83 dB offers 3.8 dBbetter SFDR at an input frequency of 250 MHz.

At 1.1 GHz, the ADC14V155 delivers 57 percent higher full-power bandwidththan competing 14-bit ADCs. The device also provides an industry-leading SFDRof 85 dB and SNR of 69.5 dB at an input frequency of 238 MHz. The ADC14V155,with dual data rate, parallel LVDS outputs is the latest addition toNational's high-speed 14-bit ADC family, joining the ADC14155, with CMOSoutputs, introduced in mid-2006.

These ADCs are well-matched to work with National's high-speed op amps andhighly-integrated clock conditioners, such as the single-chip LMK03000, toprovide a complete signal-path system solution.

Key Features - ADC12C170 and ADC12V170

The ADC12C170 and ADC12V170 employ a differential, pipelined architectureand operate in single-ended or differential clock modes. At an input frequencyof 70 MHz, the ADC12C170 provides 85.4 dB SFDR and 67.2 dB SNR, while theADC12V170 provides 85.8 dB SFDR and 67.2 dB SNR. The ADC12C170 operates from a3.3V supply and typically consumes 715 mW, while the ADC12V170 typicallyconsumes 781 mW. Both ADCs include a power-down feature to reduce powerconsumption to 5 mW. The combination of high SFDR performance and low powermakes them well suited for digital pre-distortion techniques to improve poweramplifier efficiency in base station applications. The ADC12C170 and ADC12V170are supplied in a 48-pin LLP(R) package and are pin-equivalent to the 14-bitADC14155 and ADC14V155, respectively.

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