STMicroelectronics (NYSE: STM), a world leader in the supply of semiconductors for power management applications*, extended its portfolio of power management devices with a new family of flexible and high-performance PWM (Pulse Width Modulation) controllers intended for motherboard and POL (Point of Load) markets. Four new products – L6726A, L6727, L6728 and L6728A – integrate a voltage reference, control logic, gate drivers, monitoring and protection circuits into standard SO-8 or tiny 3x3mm DFN packages. Two of the chips offer additional features for high-level applications, including a PowerGOOD output to report power status and the output voltage sense for accurate over-voltage and under-voltage protection.
The L6726A and L6727 are low-cost single-phase PWM controllers, with embedded high-current drivers, enabling the easy creation of general purpose DC-DC step-down converters with excellent performance for a broad range of applications – from desktop PC sub-systems, such as memories and chipsets, to general-purpose power supplies. With their high level of integration, these compact SO-8 devices allow a significant reduction in the cost and size of the power supply.
The L6728 and L6728A add to the simpler devices the characteristics required by the high-end motherboard market, including plus or minus 0.8% voltage accuracy over line and temperature variations, a PowerGOOD output to provide real-time information on output-voltage status, and the chip-scale 10-lead DFN package. They offer a fixed-frequency 300kHz (L6728) or 600kHz (L6728A) oscillator, for simple but flexible application design. It is the first time that all of these high-level features have been integrated into such a small package, and the devices are particularly suited to servers and niPOL (non-isolated Point of Load) applications.
ST’s development of the new family has been carried out in co-operation with key customers, to ensure the optimum combination of features to meet the cost and technical requirements of this high-volume market. In addition to use on server and PC motherboards, the controllers are ideal for modems, set-top boxes (STBs), consumer applications and advanced DC-DC down-converters.
With embedded high-current, high-speed N-channel MOSFET drivers, the chips can be used in the design of power applications driving a few Amps to more than 30A. They operate over a wide input voltage range of 1.5V to 18V, while the integrated 0.8V voltage reference ensures 1% (L6726A, L6727) or up to 0.8% (L6728, L6728A) output accuracy. Sensorless current monitoring, through a Low-Side Power MOSFET, avoids the cost of an external current-sensing resistor and saves board space, and the single- or dual-level over-current protection has programmable thresholds. A range of other features are designed to increase efficiency and reduce the external component count.
The L6726A and L6727 are in volume production now, and are available in an SO-8 package priced at $0.50 in quantities of 1000. Samples of the L6728 and L6728A are available, with volume production in Q4 2007. They are supplied in a 3x3mm DFN package.
STMicroelectronics is a global leader in developing and delivering semiconductor solutions across the spectrum of microelectronics applications. An unrivalled combination of silicon and system expertise, manufacturing strength, Intellectual Property (IP) portfolio and strategic partners positions the Company at the forefront of System-on-Chip (SoC) technology and its products play a key role in enabling today’s convergence markets. The Company’s shares are traded on the New York Stock Exchange, on Euronext Paris and on the Milan Stock Exchange. In 2006, the Company’s net revenues were $9.85 billion and net earnings were $782 million.
* iSuppli Power Management, July 2006: “ST remained on top of the power management space, on strength of its competencies across a broad range of IC and discrete power management”