http://www.epn-online.com/enCopyright 2007 - Reed Business InformationWed, 08 Feb 2012 07:14:16 +0100Wed, 08 Feb 2012 07:14:16 +0100EPN Onlinelchevalier@reedbusiness.frlchevalier@reedbusiness.frhttp://blogs.law.harvard.edu/tech/rsshttp://www.epn-online.com/page/new180005/25v-rated-synchronous-mosfet-controller-for-notebook-and-laptop-power-supplies.htmlnew180005Diodes has announced a 25V rated synchronous MOSFET controller for notebook and laptop power supplies of 90W and above. By enabling the replacement of inefficient Schottky diodes in flyback converters, the ZXGD3104N8 reduces rectifier losses of up to 70%. As a result, the controller helps power supplies more easily attain the 87% Energy Star V2.0 rating, according to the company. With its operating voltages of 5 to 25V, the SO8 packaged MOSFET controller is able to be directly powered from the adaptor's 19V supply rail. Combined with the controller's direct 180V MOSFET drain-sense capability, which eliminates the need for an external clamp circuit, the component count can be reduced and space can be saved, claims the company. The controller's proportional gate-drive operation guards against premature MOSFET turn-off as the drain current decays, thereby maximising circuit efficiency and ensuring body diode conduction losses are minimised, says the company.Thu, 02 Feb 2012 00:00:00 +0100http://www.epn-online.com/page/new179316/ce-approved-compact-latching-relays-are-suitable-for-sequencing-applications.htmlnew179316Switchtec has introduced the SCLR2 16A rated, latching relays that require only a short voltage pulse to change its state. The relays simply hold its present state until pulsed again, which ensures energy saving, says to the company. They are available in two-pole changeover format. It is fitted with a contact position indicator, enabling the clear identification of the current status of the relay's contacts, claims the company. The DIN rail mountable relay is modular, 17.5mm wide and is suitable for panel use. The latching relays are available in 12 and 24V DC, and in 24, 110 and 230V AC. The latching relays are fitted with a manual override pushbutton, allowing to change or override the current position of the contacts without the need for power to be applied, making them suitable for sequencing applications or when there is a loss of power, says the company. The relays conform to IEC and EN 60669, and are CE Approved. They are suitable for applications including pump control, lighting control, duty cycling, energy saving/management, and control panels.Thu, 02 Feb 2012 00:00:00 +0100http://www.epn-online.com/page/new180001/low-profile-type-n-threaded-rf-connectors-for-high-power-applications.htmlnew180001Bomar Interconnect Products has expanded its proprietary line of V-Bite RF edgeboard connector series to include the 161VUS504EFT low-profile, female type N, threaded RF connector. Designed for high-power applications, the threaded RF connectors feature a bottom shield to help eliminate inductance by shielding the open bottom of the connector, claims the company. Further, as they can be soldered directly to the PCB's bottom ground layer, the connectors provide high tolerance to ensure good performance characteristics through 18GHz, according to the company.  The V-Bite series comprises type N, weather-sealed type N, type F, threaded through-panel BNC (bayonet Neill-Concelman) and standard BNC, twin BNC, mini-BNC, and TNC (threaded Neill-Concelman) styles. All components in the series provide unparalleled signal integrity. Designed to snap onto the PCB prior to hand or reflow soldering, the connectors are supported from both below and above the board to disperse rotational torque relief, which reduces rotational stress on the solder area, claims the company. Offered in an impedance of 50Ω, the connectors are suited for joining coaxial cables in a broad range of high-power RF applications requiring a durable, weatherproof connector. They are suitable for use in base stations, cellular antennas, RF and microwave components, satellite communications, broadcast, personal communications services, surge protection, test and measurement instrumentation, microwave radio, WLAN, and radar. Featuring phosphor bronze and gold contacts, and manufactured of machined brass, the V-Bite series' straight-through contact arrangement provides a low reflection factor. The connectors are provided with a Teflon dielectric to facilitate reflow soldering.Wed, 01 Feb 2012 00:00:00 +0100http://www.epn-online.com/page/new180004/surface-mount-multilayer-ceramic-chip-capacitors-for-buck-and-boost-dc-dc-converters-and-voltage-multipliers.htmlnew180004Vishay Intertechnology has announced that it has increased the minimum capacitance values for its VJ HVArc Guard surface mount X7R MLCCs (multilayer ceramic chip capacitors). For low capacitance values, the company offers a C0G and NP0 dielectric option with a voltage range of 1000 to 2500V in five case sizes from 0805 to 2225.The minimum capacitance values for the MLCCs have increased to 470pF in the 0805 case size and to 220pF in the 1206, 1210, 1808, and 1812 case sizes. If low capacitance is required, 1000V X7R MLCCs in the 0805, 1206, and 1210 case sizes can be replaced by C0G MLCCs, which offer a low minimum capacitance of 10pF, claims the company. The MLCCs feature a patented internal design structure that prevents surface arc over high voltages. This design allows for high capacitances and facilitates the use of small case sizes in high-voltage products, says the company.The MLCCs are available with optional polymer terminations that provide increased resistance to board flex cracking. With these terminations, the MLCCs reduce capacitor failures related to mechanical cracking and confine failures to the capacitor, thus reducing the number of damaged components on the circuit board or damage to the complete device itself, claims the company.Manufactured in Noble Metal Electrode technology with a wet build process, the MLCCs are said to be optimised for high-voltage applications including buck and boost DC/DC converters and voltage multipliers for flyback converters in power supplies for cable modems and routers. The MLCCs are compliant to RoHS Directive 2002, 95, EC and halogen-free according to the IEC 61249-2-21 definition.Wed, 01 Feb 2012 00:00:00 +0100http://www.epn-online.com/page/new179309/bulk-metal-foil-chip-resistors-offer-2ppm-c-temperature-coefficient-of-resistance.htmlnew179309Vishay Precision Group has announced that its Vishay Foil Resistors division has released the VSMF series of high-precision BULK METAL foil chip resistors offering good terminations, temperature coefficient of resistance of ±2.0ppm/°C typical from -55 to +125°C with a reference of +25°C, and load-life stability to ±0.01% at +70°C for 2000h at rated power. Offered in 1206, 2010, and 2512 chip sizes, the resistors feature a resistance range from 10Ω to 125kΩ, with tolerances up to ±0.01%. The resistors provide a power rating to 400mW at +70°C and withstand ESD to at least 25kV. They feature a rise time of 1ns with no ringing, a thermal stabilisation time of less than 1s, which is a nominal value achieved within 10ppm of steady-state value, current noise of 0.01µVrms/V of applied voltage less than -40dB, a voltage coefficient of less than 0.1ppm/V, and a thermal EMF of 0.05μV/°C. The RoHS-compliant resistors offer a non-inductive, non-capacitive design.The resistors are claimed to eliminate the problems of cracked substrates and board delamination by providing good terminations for strain relief. In addition, the resistor has good load-life stability, because the resistor's element is a bulk metal alloy that has been applied to a substrate with a process that results in a stress-free adhesion, according to the company.Wed, 01 Feb 2012 00:00:00 +0100http://www.epn-online.com/page/new179311/pll-chip-set-for-frequency-modulated-continuous-wave-sweeper-applications.htmlnew179311Hittite Microwave has released a PLL chip set. The HMC983LP5E DC to 7GHz, fractional-N divider and frequency sweeper and the HMC984LP4E low noise, digital phase-frequency detector and charge pump form a PLL chip set for PLL and FMCW (frequency modulated continuous wave) sweeper applications. The sweeper integrates the programmable 48bit delta-sigma modulator which allows the combined PLL to achieve unparalleled fractional frequency resolution of 180nHz, says the company. A built-in frequency sweeper enables the combined PLL to generate identical, coherent, FMCW frequency sweeps that can be linear, user-defined, automatic or triggered, claims the company. The pump can operate at high phase detector frequencies of 125 and 175MHz in fractional and integer modes, respectively. This capability enables the chip set to utilise wide loop bandwidths which result in good phase noise performance, fast PLL locking times, and fast frequency sweeps, according to the company. The PLL chip set phase noise figure of merit performance is -231dBc/Hz in integer mode and -227dBc/Hz in fractional mode. Although the sweeper and pump can be used separately in stand-alone applications, partitioning the PLL building blocks into two distinct devices achieves good isolation and spurious emissions performance of above -60dBc/Hz inside the loop bandwidth, says the company. Both the sweeper and pump are housed in plastic leadless surface mount packages and provide temperature stability over the -40 to 85°C operating range.Wed, 01 Feb 2012 00:00:00 +0100