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® 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® 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.-National Semiconductor Corporation