Product category:
Analogue and Mixed Signal ICs
News Release from: National Semiconductor | Subject: LMH6552, LMH6515 and LMH6555
Edited by the Electronicstalk Editorial
Team on 26 September 2007
Differential amplifiers suit defence
applications
The LMH6552 is the industry's highest-bandwidth, current feedback differential amplifier at 1.5GHz, with the industry's lowest power consumption at 112 mW.
National Semiconductor has introduced three new energy-efficient, high-speed differential amplifiers that are well-suited for a wide variety of communications, test, instrumentation, defence and space applications These amplifiers are part of National's PowerWise line of energy-efficient analogue integrated circuits (ICs).
This article was originally published on Electronicstalk on 5 Jan 2001 at 8.00am (UK)
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The LMH6552 is the industry's highest-bandwidth, current feedback differential amplifier at 1.5GHz, with the industry's lowest power consumption at 112mW.
This translates to dissipating 44% less power than competitive products.
The LMH6515 digital-controlled variable gain amplifier (DVGA) offers an 8dB noise figure and a 40dBm output intercept point (OIP3) at 70MHz for WCDMA, GSM and WiMAX receiver signal paths, at 20% lower power than the competition.
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The LMH6555 enables an 8bit, 3Gsample data acquisition system with less than half the power consumption of competitive solutions.
National offers these high-speed amplifiers as part of an analogue signal-path solution to help system designers jump start development and accelerate their designs.
The LMH6552, LMH6515 and LMH6555 are combined with National's analogue-to-digital convertors (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 defence and space applications.
Each reference design board is optimised for power and performance to manage high-speed signal conditioning and processing across the entire analogue 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.
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 1.5GHz bandwidth along with an industry-leading 0.1dB gain flatness to 450MHz.
Low total harmonic distortion of -90dBc at 20MHz and -74dBc at 70MHz and noise performance of 1.1nV/sqrtHz enable the LMH6552 to drive 14bit 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 eight-pin SOIC package and a space-saving, thermally enhanced eight-pin LLP package.
The LMH6515 DVGA maximises 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 70MHz, and low noise make it well-suited for both broadband and narrowband receiver paths.
It features a noise figure of 8dB, consumes just 100mA and operates at a supply voltage of 5V.
The LMH6515's 4 x 4 mm, 16-pin LLP package simplifies design and reduces board space by more than 75% compared to using a discrete attenuator plus amplifier.
In receiver applications, the LMH6515 offers a maximum gain of 26dB and a wide 31dB gain adjustment range, with 600MHz (-3dB) bandwidth.
It delivers gain adjustments in precise 1dB gain steps, accurate to within 0.05dB, to increase the dynamic range performance of communications systems.
This precision enables accurate balancing with other blocks in the signal path.
The LMH6555 is the industry's only differential driver optimised for DC-coupled, 8bit data acquisition applications with input frequencies up to 750MHz.
It provides an industry-leading 53dB SFDR performance at 750MHz 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 13.7dB and a 1.2GHz bandwidth.
The LMH6555 also provides 0.5dB gain flatness to 330MHz, a noise figure of 15dB at 3.3V, and second and third harmonic distortion of -53dBc and -54dBc at 750MHz, all essential requirements for DC-coupled oscilloscope and data acquisition systems.
The amplifier's architecture allows it to operate as a fully differential driver or as a single-ended-to-differential convertor.
Its linearity and 100ohm 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.
The ADC14DS105KARB is a low IF receiver subsystem reference design board that uses 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 40MHz.
This receiver architecture is commonly used in WiMAX and WCDMA receiver systems.
The 1GHz input bandwidth of the ADC and the 1.5GHz differential amplifier gain stage enable large signal-to-noise ratio (SNR) of 73.3dB full-scale (dBFS) and spurious free dynamic range (SFDR) greater than 85dBFS for input signals up to 40MHz.
In addition to the LMH6552, the board includes National's ADC14DS105 dual 14bit, 105 mega-sample per second (MSPS) low-distortion, low-noise ADC with serialised low-voltage differential signaling (LVDS) outputs; LMK02000 low-jitter clock conditioner; as well as several energy-efficient power management ICs.
The ADC14V155KDRB is a high IF receiver reference design board that uses an LMH6515 DVGA and ADC to enable immediate evaluation of a high dynamic range IF sampling application.
It provides variable gain IF amplification and digitisation in wireless infrastructure systems and frequency domain analysers.
This flexible subsystem provides excellent sensitivity for input signal frequencies up to 240MHz.
It achieves small-signal SNR of 72dBFS and SFDR greater than 90dBFS with a 169MHz input frequency.
Large signal performance yields SNR of 68.3dBFS and SFDR of 77dBFS at 169MHz.
In addition to the LMH6515, the board includes National's ADC14V155 14bit, 155 MSPS ADC with dual data rate, parallel LVDS outputs.
The LMK03001C low-jitter precision clock conditioner with an integrated voltage-controlled oscillator (VCO) provides 190fs jitter over an integration bandwidth of 100Hz to 20MHz.
The ADC083000RB is an 8bit, 3 giga-sample per second (GSPS) data acquisition reference design board that uses 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 defence and space applications.
The subsystem receives an AC-or DC-coupled analogue input signal and captures the digital output of the ADC into a field-programmable gate array (FPGA).
This captured data can be analysed 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 53.5dB at signal frequencies up to 1.4GHz in AC-coupled communications applications.
In addition to the LMH6555, this board includes National's ADC083000 8bit, 3 GSPS, ultra-high-speed ADC, which consumes less than half the power (1.9W) of competitive ADCs.
It also includes the LMX2531 single-chip phase-locked loop (PLL) and VCO, which consumes 111mW and provides phase noise of -116dBc/ Hz at a 100kHz offset, allowing the ADC083000 to deliver its maximum dynamic range.
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