Power Electronics

New Products

DC-DC Converter

The FAN5355 device from Fairchild is a high-frequency, ultrafast transient response synchronous stepdown dc-dc converter optimized for low-power applications using small low-cost inductors and capacitors. The IC supports up to 800 mA or 1 A of load current. With an output-voltage range adjustable by an I2C interface from 0.75 V to 1.975 V, the FAN5355 operates at a 3-MHz (nominal) fixed switching frequency using either its internal oscillator or external SYNC frequency.

During light-load conditions, the converter includes a pulse-frequency-modulation (PFM) mode to enhance light-load efficiency. The regulator transitions smoothly between the PFM and pulse-width-modulation modes with no glitches on VOUT. The normal PFM mode offers the lowest quiescent current, at the expense of setpoint accuracy. The enhanced PFM mode features higher accuracy, as well as a 25-kHz minimum PFM frequency. The FAN5355 is available in 10-lead MLP and 12-bump CSP packages.
Fairchild Semiconductor
San Jose, Calif.

www.fairchildsemi.com

Power-Management IC

From Maxim Integrated Products, the MAX8819A is a highly integrated power-management IC. The device integrates a single-cell Li-ion/Li-polymer charger with proprietary Smart Power Selector circuitry that seamlessly distributes power within the system. To reduce the bill-of-material cost, the IC integrates three 2-MHz stepdown converters and one stepup converter with serial-step dimming control for powering two to six white light-emitting diodes.

The Smart Power Selector circuitry manages power distribution between a battery, USB/ac-dc adapter and system load. When a USB or ac-dc adapter is connected, the input power that is not used by the system load is used to charge the battery. In addition, Smart Power Selector circuitry allows the system to operate with no battery or a deeply discharged battery. All necessary power switches and current-sense circuitry are included on the chip; no external MOSFETs are required. The MAX8819A is available in a 4-mm 3 4-mm 3 0.8-mm, 28-pin TQFN package that is fully specified over the -40°C to 85°C extended temperature range. Pricing starts at $3.65 each in quantities of 1000.
Maxim Integrated Products
Sunnyvale, Calif.

www.maxim-ic.com

Lighting Management System

Analog Devices' ADP5520 lighting management system is a power-efficient, customizable display management solution designed to improve the viewing quality and extend the battery life of portable electronics. The single-chip lighting management system enables a 20% reduction in battery power consumption through the use of an intelligent lighting control that automatically detects ambient-light levels and adjusts backlight brightness according to changing lighting environments. An adaptive ambient-light management feature adjusts too-bright or washed-out screens autonomously, according to configurable lighting profiles. This reduces current drain and extends battery life by minimizing the processor involvement in backlight monitoring. Housed in a 24-pin LFCS package, the ADP5520 is priced at $1.66 each in 1000-unit quantities.
Analog Devices
Norwood, Mass.

www.analogdevices.com

MOSFET Gate Drivers

Intersil's ISL6622, ISL6622A and ISL6622B series of 12-V to 5-V synchronous rectified buck MOSFET drivers provide light-load efficiency for Intel VR11.1 systems. The drivers provide a 3-A sinking capacity and feature rapid rise and fall times that support up to 1 MHz of frequency switching. This delivers very high overall efficiency.

Combined with Intersil's VR11.1 PWM controllers and with n-channel MOSFETs, the ISL6622's advanced PWM protocol supplies a complete core-voltage regulator solution for advanced microprocessors. The ISL6622 enables diode emulation operation during PSI mode for enhanced light-load efficiency and allows discontinuous conduction mode by detecting when the inductor current reaches zero. When zero is detected, the low-side MOSFET is turned off to prevent sinking current. The ISL6622/A/B drivers are available in 8-lead SOIC packages priced at $1 each and in 10-lead DFN packages priced at $1.07 each, all in 1000-unit quantities.
Intersil
Milpitas, Calif.

www.intersil.com

Low-Noise Op Amp

The OPA827 series of JFET operational amplifiers from Texas Instruments combine dc precision with ac performance. These amplifiers offer low-offset voltage, very low drift overtemperature, low bias current and very low 0.1-Hz to 10-Hz noise. They operate over a ±4-V to ±18-V input-voltage range on a low supply current. The OPA827 is available in both SO-8 and MSOP-8(1) surface-mount packages.
Texas Instruments
Dallas

www.ti.com

H-Bridge Driver ICs

ROHM Electronics' BD62xx Series of H-bridge driver ICs offer designers a simple upgrade path to PWM speed control using either analog or digital inputs. The ICs provide both a TTL-compatible interface to an external microcontroller unit, as well as an internal VREF-PWM conversion circuit allowing the implementation of energy-saving PWM control from an analog voltage input. The series is offered in three maximum operating voltage classes, 7 V, 18 V and 36 V, with current ratings in each class of 0.5 A, 1 A and 2 A.

BiCMOS topology is used to optimize performance and minimize power consumption. The p-channel/n-channel output configuration eliminates the need for an internal charge pump and external capacitors to operate the high-side switch. Internal shutdown circuitry reduces standby current to less than 1 µA. All the ICs in the series come in low-profile surface-mount packages with the maximum height ranging from 1.15 mm (SSOP) to 2.2 mm (HRP7).
ROHM Electronics
San Diego

www.rohm.com

Hall Sensors

From Infineon Technologies, the TLE4997 and TLE4998 sensors offer the highest accuracy of Infineon's linear Hall sensors and are fully automotive qualified. Additionally, the TLE4997 sensor provides unique temperature compensation and the TLE4998 sensor adds unique compensation of stress over lifetime.

The analog-output TLE4997 is rated for output noise that is smaller by a factor of two than the output noise of competitor products. The fully digital output of the TLE4998 has a sensitivity stability three to four times better than that of sensors without stress compensation. Also, the offset drift stability of both sensors over the full temperature range of -40°C to 150°C is two to three times better than the offset drift stability of other sensors available on the market.

The TLE4997 is housed in a PG-SSO-3-10 leaded package. The TLE4998 is available in two additional leaded packages: the PG-SSO-4-1 and the PG-SSO-3-9 package.
Infineon Technologies
Munich, Germany

www.infineon.com

Schottky Rectifiers

NXP Semiconductors' range of MEGA Schottky rectifiers are housed in the company's new FlatPower packages, SOD123W and SOD128. As a result of the packages' clip bond technology, the MEGA devices deliver high-power capability comparable to standard SMA packages. Boosting the best-in-class low forward voltage drop, the new types allow a high peak current of more than 50 A and achieve power dissipation up to 1 W. At the same time, the height of both packages is reduced by 50% compared to SMA packages, thus enabling much smaller designs.

The SOD123W supports this trend with a body size of 2.6 mm 3 1.7 mm 3 1 mm. The dimensions of the SOD128 are 3.8 mm 3 2.5 mm 3 1 mm. Both packages are footprint-compatible to SMA and SMB packages, providing an ideal solution for a 1:1 replacement. Six 30-V and 40-V low forward-voltage types in the new FlatPower packages are ready for production. Another six 20-V and 30-V low forward-voltage types will be released in the first quarter of 2009. An additional 15 types with up to 60 V and low forward voltage are in development for release in the third quarter of 2009. Pricing ranges from $5 each to $9 each in quantities of 100.
NXP Semiconductors
Eindhoven, Netherlands

www.nxp.com

Transient Voltage Suppressor

The RClamp 3654P from Semtech is an electrostatic discharge (ESD) protection product for battery-charging USB ports on mobile phones. Unlike other devices on the market, the RClamp 3654P has a separate 28-V transient voltage suppressor (TVS) diode to protect the VBUS voltage against fault conditions when the standard USB port is being used for battery charging. The RClamp3654P complies with China's new standard for USB charging, making it an ideal component for products targeting that market, or for products that are sold into multiple markets including China. It also meets or exceeds the IEC-61000-4-2 specification and is RoHS and WEEE compliant.

With a 1.6-mm 3 1.6-mm 3 0.6-mm footprint, the RClamp3654P is also an ideal solution for space-constrained cell phones. The TVS is available immediately in production quantities and is priced at $0.30 each in 1000-piece quantities.
Semtech
Camarillo, Calif.

www.semtech.com

Double-Layer Capacitors

AVX's BestCap Series now includes ultralow equivalent series resistance double-layer capacitors with a temperature range from -40°C to 75°C. Ideal for wireless applications, the capacitor series features high capacitance values and power-pulse characteristics for high-current, short-pulse applications. The BestCap double-layer capacitors are available in three different standard sizes with voltage ratings from 3 V to 15 V and a capacitance range from 6.8 mF to 1 F.

The three standard sizes for the BestCap capacitor are 20 mm 3 15 mm (BZ05), 28 mm 3 17 mm (BZ01) and 48 mm 3 30 mm (BZ02). The BZ05 size offers the most aggressive capacitance value offering of 68 mF at 5.5 V and 6.8 mF at 15 V. The BZ02 has the largest capacitance value with 1 F at 5.5 V and 68 mF at 15 V. Typical pricing starts at $2.90 each.
AVX
Myrtle Beach, S.C.

www.avx.com

Stepdown Switching Regulator

From Linear Technology, the LT3972 is a 3.5-A, 33-VIN stepdown switching regulator with burst-mode operation to keep quiescent current under 75 µA. The LT3972 operates within a 3.6-V to 33-V input-voltage range, with overvoltage lockout protection against transients as high as 62 V. Its internal 4.6-A switch can deliver up to 3.5 A of continuous output current at voltages as low as 0.79 V. Its burst-mode operation provides ultralow quiescent current. The switching frequency is user programmable from 200 kHz to 2.4 MHz, enabling the designer to maximize efficiency while avoiding critical noise-sensitive frequency bands.

The LT3972's 3-mm 3 3-mm DFN-10 package (or thermally enhanced MSOP-10E) and high switching frequency keep external inductors and capacitors small, providing a compact, thermally efficient footprint. Pricing for the LT3972EDD and LT3972EMSE starts at $4.25 and $4.35 each, respectively, in 1000-piece quantities. The LT3972IDD and LT3972IMSE are priced at $5.10 and $5.22 each, respectively, in quantities of 1000.
Linear Technology
Milpitas, Calif.

www.linear.com

Customized Switch and Sensing

Molex uses its CapSense technology, based on Cypress Semiconductor's PSoC chip architecture, for capacitive switch and proximity sensing solutions. A single CapSense capacitive assembly can replace dozens of mechanical switches and controls with a touch-sensitive interface. Capacitive designs can now be customized with discrete switch buttons, rotary and linear sliders, and track pads. Molex is able to provide several circuit substrate options. Unique backlighting and cosmetic options also are available.
Molex
Lisle, Ill.

www.molex.com

PWM Controller

The L6591 PWM controller from STMicroelectronics is an integrated controller optimized for zero-voltage switching asymmetrical half-bridge converters, which enable smaller, lower-cost power supplies delivering high efficiency from standby to full load, thereby reducing heat and power loss. For use in off-line power supplies, the L6591 implements all of the functional blocks necessary to control a soft-switching half-bridge converter.

Zero-voltage switching eliminates turn-on switching losses and minimizes EMI emissions, and also enables efficient operation up to 500 kHz. This allows small external filter components for compact overall dimensions. In addition, the L6591 implements pulse skipping under light-load and no-load conditions, and has a quiescent current lower than 3mA.

The controller combines high integration and comprehensive power-saving features with high voltage-handling capability, up to 700 V, in a small-outline SO16N surface-mount package. Pricing starts at $1.50 each in quantities of 2500.
STMicroelectronics
Geneva, Switzerland

www.st.com

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