LMH6552 - 1.5 GHz Fully Differential Amplifier from the PowerWise(R) Family

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General Description

The LMH6552 is a high performance fully differential amplifier designed to provide the exceptional signal fidelity and wide large-signal bandwidth necessary for driving 8 to 14 bit high speed data acquisition systems. Using National's proprietary differential current mode input stage architecture, the LMH6552 allows operation at gains greater than unity without sacrificing response flatness, bandwidth, harmonic distortion, or output noise performance.

With external gain set resistors and integrated common mode feedback, the LMH6552 can be configured as either a differential input to differential output or single ended input to differential output gain block. The LMH6552 can be AC or DC coupled at the input which makes it suitable for a wide range of applications including communication systems and high speed oscilloscope front ends. The performance of the LMH6552 driving an ADC14DS105 is 86 dBc SFDR and 74 dBc SNR up to 40 MHz.

The LMH6552 is available in an 8-pin SOIC package as well as a space saving, thermally enhanced 8-Pin LLP package for higher performance.

Applications

•	Differential ADC driver
•	Video over twisted pair
•	Differential line driver
•	Single end to differential converter
•	High speed differential signaling
•	IF/RF amplifier
•	Level shift amplifier
•	SAW filter buffer/driver

Typical Application

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LMH6552+ADC14DS105 combo circuit

Typical Performance

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Frequency Response vs Gain (Diff Input)

Connection Diagram

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LLP connection diagram

 

 

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National Semi Introduces Common-Anode, Current-Mode, High-Brightness LED Driver With PWM Dimming

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National Semiconductor Corp. introduced what it describes as the industry's first common-anode, current-mode, high-brightness light-emitting diode (LED) driver with pulse-width modulation (PWM) dimming. The LM3433, a member of National's PowerWise® energy-efficient product family, drives high-power, high-brightness LEDs in backlighting, projector and solid-state lighting applications.

National's LM3433 LED driver is said to open the way for high-reliability LEDs to be used in large-screen liquid crystal display (LCD) television (TV) backlighting applications where a common anode approach offers a thermal advantage. In another example, the company claims that LEDs can be used in today's shrinking "pocket projector" designs for a wider color gamut, higher reliability and longer life expectancy than the ultra-high performance (UHP) lamps used today.

Luminus' PhlatLight LEDs are a new class of LED for very high-brightness applications where a point source of light is needed. The PhlatLight RGB LED is said to be capable of producing over 3,000 white lumens.

"PhlatLight LEDs are being designed into a number of display and lighting applications," said John Langevin, VP of Sales and Marketing at Luminus. "National's LM3433 driver provides a more complete solution for our customers, enabling use at the intended high performance levels that the PhlatLight chipsets were designed for."

National's LM3433 is a constant on-time dc-dc buck (step-down) constant-current regulator. It outputs a negative constant current for lighting high-power, high-brightness LEDs. The negative voltage option allows the anode of the LED to be tied directly to the ground-referenced chassis for maximum heat sink efficacy. The short constant-on-time architecture allows the use of small external passive components and no output capacitor. Two current control modes modulate LED brightness. An analog current control input is provided so the LM3433 can be adjusted to compensate for LED manufacturing variations. The other current control is a logic-level dimming input for PWM control of LED brightness. The PWM functions by shorting out the LED with a parallel switch, allowing high PWM dimming frequencies up to 40 KHz. Additional features include thermal shutdown, VCC under-voltage lockout and logic-level shutdown mode. The LM3433 is offered in a 24-pin LLP® package.

Available now, the LM3433 is priced at $2.25 each in 1,000-unit quantities.

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Drive handles 5-A BLDC motor without Hall sensor

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The DECS 50/5 controller drives brushless dc motors without Hall sensors and targets pump and fan applications. It can easily apply integrated controlling algorithms, and its wide input voltage range (10 to 50 V) adds flexibility.

The size of a business card, the module can supply a continuous output current of 5 A, yielding a maximum output of 250 W. The device's speed value can be set via a potentiometer or an analog input, and its 1/Q amplifier operates at up to 80,000 rpm. The unit provides control inputs for direction/enable/braking, an operating status LED, and a speed monitor output. ($89 ea/50—available now.)

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ESD protection device clamps 15 kV to 7 V in nanoseconds

 

 

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With a 0.5-pF capacitance, the ESD9L single-line ESD protection device clamps an input ESD waveform of 15 kV to less than 7 V in a matter of nanoseconds—presented as the industry's best performance for such devices. The part comes in a 1.0 x 0.6 x 0.4-mm SOD-923 package—the industry's smallest for such devices—enabling it to safeguard high-speed data lines in portable applications such as cell phones, MP3 players, PDAs, and digital cameras.

The performance improvements were achieved via the company's novel process technology that integrates ultra-low capacitance pin diodes with high-power TVS diodes into a monolithic die. The part is suitable for high-speed applications such as USB2.0 and HDMI. ($0.15 ea/10,000—available now.)

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IR Introduces New Three-Phase 600V Gate Driver ICs

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International Rectifier, IR® introduced the IRS2336xD protected 600V three-phase gate driver ICs with integrated bootstrap functionality for appliance motor control, servo drives, micro-inverter drives, and a wide range of general purpose applications.

"Our latest high-voltage gate drivers are ideal for three-phase applications that require industrial level ruggedness. These new ICs feature IR's proprietary negative Vs immunity circuitry, allowing the devices to withstand the very large negative Vs transients that are seen during high-current switching and short-circuit conditions. Additionally, an advanced input filter improves system performance while the integrated bootstrap functionality reduces the circuit footprint," said IR's HVIC Product Manager David New.

Integrating power MOSFET/IGBT gate drivers with three high-side and three low-side referenced output channels, the IRS2336xD ICs provide 180mA/330mA drive current at up to 20V MOS gate drive capability operating up to 600V.

Part of International Rectifier's G5 HVIC platform, these devices incorporate advanced functionality including negative Vs immunity circuitry to protect the system from catastrophic events that can be seen during high-current switching and short-circuit conditions, critical for industrial systems that require high levels of robustness and reliability. Also, an advanced input filter has been integrated to reject noise and reduce distortion, improving system performance in many motor control applications.

To address the needs of applications suffering for space constraints and to simplify design, the IRS2336xD ICs feature integrated bootstrap functionality. This functionality can reduce the bootstrap power supply from six components to three, while providing VBS over-voltage protection for the system through the use of additional integrated intelligent protection circuitry.

The new devices utilize IR's high-voltage IC process which incorporates high-voltage level-shifting and termination technology to deliver what is described as superior electrical over-stress protection and higher field reliability. In addition to the over-current and over-temperature detection input, these ICs feature under-voltage lock-out protection, integrated deadtime protection, shoot-through protection, a shutdown input, fault-reporting, and are compatible with 3.3V input logic.

Available in 28-pin SOIC and 44-pin PLCC, pricing for the IRS2336xD ICs begin at US $1.89 each in quantities of 100,000 units.

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Linear Tech Adds 36V, 2A, 2.2MHz Step-Down DC-DC Converter In 3 x 3mm DFN

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Linear Technology announced the LT3500, a 2A, 36V step-down switching regulator and a linear controller in a 3 x 3mm DFN package. The LT3500 operates from a V_IN range of 3 to 36V (40V_MAX ), making it suitable for load dump and cold-crank conditions found in automotive applications. Its 2.3A internal switch can deliver up to 2A of continuous output current at voltages as low as 0.8V.

Switching frequency is user programmable from 250kHz to 2.2MHz, enabling the designer to optimize efficiency while avoiding critical noise-sensitive frequency bands. The integrated LDO controller, combined with an NPN transistor, ensures very low noise output from the primary channel or as a second channel. The LT3500's 3 x 3mm DFN-10 package and high switching frequency, which keeps external capacitors and inductor small, is said to provide a very compact, thermally efficient footprint.

The LT3500's main switcher utilizes a 2.3A, 450mV_CESAT switch, with the necessary oscillator, control, logic circuitry and LDO controller integrated into a single die. Special design techniques are said to enable high efficiency over a wide input voltage range while its current mode topology are claimed to enable fast transient response and excellent loop stability. Other features include a power good flag and soft-start capability.

The LT3500EDD pricing starts at $3.25 each for 1,000-piece quantities. The LT3500IDD is tested and guaranteed to operate from a -40 to 125°C operating junction temperature and is priced at $3.90 each. The LT3500HDD is tested and guaranteed to operate from a -40 to 150°C operating junction temperature and is priced at $4.15 each. All versions are available from stock.

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Microchip Tech Introduces Non-Volatile Digital Potentiometers With SPI Interface

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Microchip Technology Inc. announced the MCP4141/2, MCP4241/2, MCP4161/2 and MCP4261/2(MCP41XX/42XX) non-volatile digital potentiometers. The 7- and 8-bit devices have a SPI interface and are specified over the extended industrial temperature range of -40 to 125°. They are available in several industry-standard packages, including the 3 x 3 mm DFN package.

Unlike mechanical potentiometers, the MCP41XX/42XX devices can be controlled digitally, through an SPI interface. This is said to increase system accuracy, flexibility and manufacturing throughput, while decreasing manufacturing costs. Non-volatile memory enables the devices to retain their settings at power down, and their low static current consumption of just 5µA, maximum, is said to help extend battery life.

"We are pleased to expand our mixed-signal product portfolio with the MCP41XX/42XX digital potentiometers," said Bryan Liddiard, Vice President of Marketing with Microchip's Analog and Interface Products Division. "Designers can now benefit from using Microchip's low-power digital potentiometers over the popular SPI interface."

"The MCP41XX/42XX family enables designers to enjoy the numerous benefits associated with digital potentiometers in an affordable way," said John Austin, Senior Product Marketing Manager with Microchip's Analog and Interface Products Division. "With extended temperature range operation and availability in many industry-standard packages, the devices are expected to help designers meet and exceed demands for smaller, better and less-expensive designs."

The MCP41XX/42XX digital potentiometers are well suited for a wide variety of consumer and industrial applications, such as power-supply trim and calibration, set-point and process control, closed-loop servo control, PC peripherals, portable instrumentation, instrumentation offset adjust and signal conditioning.

The products are priced as follows (each, 10,000 piece quanitities): MCP4141/2 (8-pin SOIC, MSOP, PDIP and 3 mm x 3 mm DFN packages) – $0.58; MCP4241 (10-pin 4 mm x 4 mm QFN package & 14-pin SOIC, PDIP, TSSOP packages) – $0.76; MCP4242 (8-pin 3 mm x 3 mm DFN package & 10-pin MSOP package) – $0.76; MCP4161/2 (8-pin 3 mm x 3 mm DFN, MSOP, PDIP and SOIC packages) – $0.69; and MCP4261/2 (8-pin MSOP, PDIP, SOIC and 3 mm x 3 mm DFN packages) – $0.87.

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