New High-Speed Amplifiers from National Semiconductor's PowerWise Line of Energy-Efficient Products Provide the Industry's Highest Performance at the Lowest Power

Amplifiers Combine with National's ADCs, Clock Conditioners and Power Management ICs on Three Reference Design Boards Targeted at Wireless Infrastructure, Test and Measurement, and Defense and Space Applications

SANTA CLARA, Calif., Sept. 24 -- National Semiconductor Corporation (NYSE:NSM) today introduced three new energy-efficient, high-speed differential amplifiers that are well-suited for a wide variety of communications, test, instrumentation, and defense and space applications. These amplifiers are part of National's PowerWise(R) line of energy-efficient analog integrated circuits (ICs) that deliver outstanding performance-to-power ratios. The creation of the PowerWise line demonstrates National's heightened focus on products that enable more energy-efficient designs for design engineers.

The LMH6552 is the industry's highest-bandwidth, current feedback differential amplifier at 1.5 GHz, with the industry's lowest power consumption at 112 mW. This translates to dissipating 44 percent less power than competitive products. The LMH6515 digital-controlled variable gain amplifier (DVGA) offers an excellent 8 dB noise figure and a 40 dBm output intercept point (OIP3) at 70 MHz for WCDMA, GSM and WiMAX receiver signal paths, at 20 percent lower power than the competition. The LMH6555 enables an 8-bit, 3 Giga-sample data acquisition system with less than half the power consumption of competitive solutions.

National offers these high-speed amplifiers as part of an analog signal-path solution to help system designers jump start development and accelerate their designs. The LMH6552, LMH6515 and LMH6555 are combined with National's analog-to-digital converters (ADCs), clock conditioners and power management ICs on three reference design boards targeting WiMAX and 2G/3G wireless base stations, test and measurement equipment, and high-speed communications systems used in defense and space applications. Each reference design board is optimized for power and performance to manage high-speed signal conditioning and processing across the entire analog signal path. These boards are supported by National's WaveVision hardware and software as well as application specifications, schematic diagrams, bills of materials (BOMs) and layout guidelines.

Key Features - LMH6552 1.5 GHz Current Feedback Differential Amplifier

The LMH6552 differential amplifier's proprietary, patent-pending circuitry delivers high-gain operation without compromising bandwidth, harmonic distortion or output noise performance. This reduces component count and system power by eliminating the need for multiple gain stages. The LMH6552 also provides a wide 1.5 GHz bandwidth along with an industry-leading 0.1 dB gain flatness to 450 MHz. Low total harmonic distortion of -90 dBc at 20 MHz and -74 dBc at 70 MHz and superior noise performance of 1.1 nV/sqrtHz enable the LMH6552 to drive 14-bit ADCs at frequencies up to 70 MHz. The LMH6552 can be configured as either a differential-input-to-differential-output gain block or single-ended-input-to-differential-output gain block. It also can be AC- or DC-coupled at the input, making the amplifier suitable for a wide range of applications including communication systems and high-speed data acquisition front-ends. The LMH6552 is available in an 8-pin SOIC package and a space-saving, thermally enhanced 8-pin LLP(R) package.

Key Features - LMH6515 Digital-Controlled Variable Gain Amplifier

The LMH6515 DVGA maximizes dynamic range of the signal path in IF sampling applications. The amplifier's high linearity, with a third-order intercept point (OIP3) of 40 dBm at 70 MHz, and low noise make it well-suited for both broadband and narrowband receiver paths. It features a noise figure of 8 dB, consumes just 100 mA and operates at a supply voltage of 5V. The LMH6515's small 4 mm by 4 mm, 16-pin LLP package simplifies design and reduces board space by more than 75 percent compared to using a discrete attenuator plus amplifier. In receiver applications, the LMH6515 offers a maximum gain of 26 dB and a wide 31 dB gain adjustment range, with 600 MHz (-3 dB) bandwidth. It delivers gain adjustments in precise 1 dB gain steps -- accurate to within 0.05 dB -- to increase the dynamic range performance of communications systems. This precision enables accurate balancing with other blocks in the signal path.

Key Features - LMH6555 Differential Driver

The LMH6555 is the industry's only differential driver optimized for DC-coupled, 8-bit data acquisition applications with input frequencies up to 750 MHz. It provides an industry-leading 53 dB SFDR performance at 750 MHz and requires no external circuitry for output clamping, common-mode control and gain. The driver converts singled-ended signals into differential signals while providing a fixed gain of 13.7 dB and a wide 1.2 GHz bandwidth. The LMH6555 also provides 0.5 dB gain flatness to 330 MHz, a noise figure of 15 dB at 3.3V, and second and third harmonic distortion of -53 dBc and -54 dBc at 750 MHz -- all essential requirements for DC-coupled oscilloscope and data acquisition systems. The amplifier's unique architecture allows it to operate as a fully differential driver or as a single-ended-to-differential converter. Its linearity and 100-Ohm differential load drive capability, as well as assurance against overdriving ADC inputs, make this amplifier well-suited for driving National's ultra-high-speed ADCs. The LMH6555 is available in a 16-pin LLP package.

About the ADC14DS105KARB Low IF Receiver Reference Design Board

The ADC14DS105KARB is a low IF receiver subsystem reference design board that utilizes a pair of LMH6552 differential drivers and a dual ADC to enable immediate evaluation of a quadrature direct conversion or near-zero IF receiver for signal frequencies from DC to 40 MHz. This receiver architecture is commonly used in WiMAX and WCDMA receiver systems. The 1 GHz input bandwidth of the ADC and the 1.5 GHz differential amplifier gain stage enable large signal-to-noise ratio (SNR) of 73.3 decibels full scale (dBFS) and spurious free dynamic range (SFDR) greater than 85 dBFS for input signals up to 40 MHz. In addition to the LMH6552, the board includes National's ADC14DS105 dual 14-bit, 105 mega-sample per second (MSPS) low-distortion, low-noise ADC with serialized low-voltage differential signaling (LVDS) outputs; LMK02000 low-jitter clock conditioner; as well as several energy-efficient power management ICs.

About the ADC14V155KDRB High IF Receiver Reference Design Board

The ADC14V155KDRB is a high IF receiver reference design board that utilizes an LMH6515 DVGA and ADC to enable immediate evaluation of a high dynamic range IF sampling application. It provides variable gain IF amplification and digitization in wireless infrastructure systems and frequency domain analyzers. This flexible subsystem provides excellent sensitivity for input signal frequencies up to 240 MHz. It achieves small-signal SNR of 72 dBFS and SFDR greater than 90 dBFS with a 169 MHz input frequency. Large signal performance yields SNR of 68.3 dBFS and SFDR of 77 dBFS at 169 MHz. In addition to the LMH6515, the board includes National's ADC14V155 14-bit, 155 MSPS ADC with dual data rate, parallel LVDS outputs; LMK03001C low-jitter precision clock conditioner with an integrated voltage-controlled oscillator (VCO) that provides 190 femtosecond (fs) jitter over an integration bandwidth of 100 Hz to 20 MHz; as well as several energy-efficient power management ICs.

About the ADC083000RB 8-Bit 3 GSPS Data Acquisition Reference Design Board

The ADC083000RB is an 8-bit, 3 giga-sample per second (GSPS) data acquisition reference design board that utilizes an LMH6555 high-speed differential driver and ADC to enable immediate evaluation of these parts for test and measurement equipment and very high-speed communications systems used in defense and space applications. The subsystem receives an AC- or DC-coupled analog input signal and captures the digital output of the ADC into a field-programmable gate array (FPGA). This captured data can be analyzed using National's WaveVision software on a Windows PC via a USB 2.0 connection. Operating at 3 GSPS, this reference board achieves effective number of bits (ENOB) exceeding 7.0 and SFDR of 53.5 dB at signal frequencies up to 1.4 GHz in AC-coupled communications applications. In addition to the LMH6555, this board includes National's ADC083000 8-bit, 3 GSPS, ultra-high-speed ADC, which consumes less than half the power (1.9W) of competitive ADCs; LMX2531 single-chip phase-locked loop (PLL) and VCO, which consumes 111 mW and provides an industry-best phase noise of -116 dBc/ Hz at a 100 kHz offset, allowing the ADC083000 to deliver its maximum dynamic range; as well as energy-efficient power management ICs.

Pricing and Availability

Available now and priced in 1,000-unit quantities, the LMH6515 is $5.25 and the LMH6552 is $3.95. The LMH6555 is also available now and priced at $5.95 each in 100-unit quantities. For more information and easy-to-order samples, visit, and National's Amplifiers Made SimpleSM WEBENCH(R) online design tool supports a large selection of amplifiers. To explore these solutions, visit To learn more about designing with amplifiers, visit our library at

The three reference design boards are available now and priced in single-unit quantities. The ADC14V155KDRB and ADC14DS105KARB reference design boards cost $800 each and the ADC083000RB is $4,900. Reference design files are available at no cost. For more information on National's signal path design resources or to purchase a National reference design board, visit

About National's PowerWise Brand

National's PowerWise brand reflects the company's energy-efficient product portfolio. It signifies products with outstanding performance-to-power at the component level, as well as products that provide an outstanding, energy-efficient solution when coupled with other National parts. National's PowerWise family of products features energy-efficient power management, operational amplifiers, interface and data conversion products. For more information about National's PowerWise brand, visit:

About National Semiconductor

National Semiconductor, the industry's premier analog company, creates high-value analog devices and subsystems. National's leading-edge products include power management circuits, display drivers, audio and operational amplifiers, interface products and data conversion solutions. National's key analog markets include wireless handsets, displays, communications infrastructure, medical, automotive, industrial, and test and measurement applications. Headquartered in Santa Clara, Calif., National reported sales of $1.93 billion for fiscal 2007, which ended May 27, 2007. Additional company and product information is available at

PowerWise, WEBENCH, LMH and LLP are registered trademarks and Amplifiers Made Simple are trademarks of National Semiconductor Corporation.

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