Delivering this high level of efficiency over a broad current range of 1 mA to 500 mA, the new ICs will prolong operating time and reduce component count in portable and battery-powered electronics such as cordless phones, wireless handsets, PDAs, two-way pagers, digital cameras, GPS receivers, MP3 players, and medical diagnostic tools, as well as in LCD and OLED bias systems and wireless LANs and routers.
The new devices offer a choice of fixed 2-V, 3.3-V, and 5-V (SiP12502) or adjustable 2-V to 5-V (SiP12503) output voltages with an 0.85-V to 5-V input voltage range. An internal low-resistance power MOSFET switch enables start-up at the low 0.85-V input voltage, and thus maximizes the useful power available from battery cells. The integrated MOSFET is rated for a low 0.24-ohm impedance at a 3.3 V output. An antiringing control switch minimizes EMI and simplifies circuit layout, reducing design time.
The ability to automatically switch between PWM operation under normal load conditions and PFM mode under light load conditions maximizes efficiency of the boost converter ICs. A low shutdown current of less than one microamp further helps to prolong battery life, while overvoltage and thermal shutdown protection help to ensure reliable operation. The converters are powered from the output voltage supply. Integrated features include UVLO and soft start, which addresses inrush current concerns. The fixed-output SiP12502 provides a power-good output on pin 4.
The devices' voltage-mode control loop is internally compensated to further simplify converter design and reduce external parts count. Each device requires only four external components -- an inductor, a diode, and two capacitors -- for a complete step-up converter.
Both boost converter ICs are available in a lead (Pb)-free, 6-pin, thermally enhanced PowerPAK MLP33 (DFN-6, 3x3) package and are specified for an industrial temperature range of -40 to +85 degrees Celsius.
Samples and production quantities of the new SiP12502 and SiP12503 are available now, with lead times of seven to eight weeks for larger orders. Pricing for U.S. delivery in 1,000-piece quantities starts at $0.80.
Vishay Intertechnology, Inc., a Fortune 1,000 Company listed on the NYSE (VSH), is one of the world's largest manufacturers of discrete semiconductors (diodes, rectifiers, transistors, and optoelectronics) and selected ICs, and passive electronic components (resistors, capacitors, inductors, and transducers). Vishay's components can be found in products manufactured in a very broad range of industries worldwide. Vishay is headquartered in Malvern, Pa., and has operations in 17 countries employing over 26,000 people. Vishay can be found on the Internet at http://www.vishay.com.
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