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POL converters tout ultra-miniature packaging

Posted: 05 Dec 2012 ?? ?Print Version ?Bookmark and Share

Keywords:POL converter? RAA20770X? MOSFET? server networking equipment?

Renesas Electronics Corp. has announced a line of mini-Point of Load (POL) converters for ASICs and other large-scale logic circuits aimed at personal computers, servers, industrial, office automation and networking equipment. The RAA20770X series devices claim to achieve the industry's highest level of miniaturisation and power density.

The RAA20770X devices claim to perform high-efficiency power conversion during normal load and typically 90 per cent of the time also execute the frequent transitions to low-power mode quickly. As a result, they reduce overall system power consumption and help enable an energy-efficient society.

To satisfy the second requirement, although mounting area is spreading according to electric source increasing, the devices achieve a size reduction of about 75 per cent compared to earlier Renesas products, featuring an ultra-miniature wafer-level chip size package that is essentially the same size as the chip itself. Furthermore, since no wired connections are required within the package, resistance in the wiring is reduced, which contributes to more efficient voltage conversion. The RAA20770X series represents the first devices with this level of integration in this small a package size.

RAA20770X POL converter ICs

RAA20770X POL converter ICs. Claim to achieve the industry's highest level of miniaturisation and power density.

In the RAA20770X products, Renesas adopted a wafer-level chip size package to achieve POL devices that can supply large amounts of current in a miniature form factor making it possible to reduce the IC's internal wiring resistance and package wiring resistance to an absolute minimum. For example, in the RAA207701GBM, which has a maximum rated current of 10A, the package size is an extremely small 2.7 x 3.4mm, which corresponds to a roughly 75 per cent reduction in package size compared to earlier Renesas SiP POL products. Furthermore, the thermal resistance from the package surface to the chip junction area is an extremely low 1C/W, allowing a high thermal dissipation design when used with a heat sink and air flow, added the company.

The RAA20770X devices adopt a constant on-time control method, and in low power consumption modes where the load current is low, they achieve a low power consumption of about 0.5?W. Another advantage of this constant on-time control method is that the POL converter's power consumption can be reduced by lowering the operating frequency, achieving the reduced power consumption of 1.6mW when there is no load and 0.5?W in standby mode. The constant on-time control method also provides the advantage of fast response.

The RAA20770X series devices integrate the various protection functions such as over-current, over-voltage and thermal protection, required in POL convertersall on the same chip. As a result, these devices support safe and highly flexible high-reliability power supply system design with a minimal number of external components for easier design and reduced BOM. Furthermore, the output voltage and operating frequency can be modified to match the application they are used in, offering flexibility for operation in a wide range of applications.

The RAA207703GBM, RAA207704GBM and RAA207705GBM devices include an integrated 5V low dropout regulator (LDO) circuit, which can provide the 5V required internally by the power supply controller, thus eliminating the need for an external power supply. This enables a system to operate from just a single-voltage using, for example, a 12V power supply rail.

In addition to combining the power supply controller and driver controller IC, the RAA20770X series devices integrate, on a single chip, two power MOSFETs that are optimal for POL converters that step down an input voltage of 5V or 12V to the 1V or 3.3V used by large-scale ICs such as ASICs. For example, the RAA207701GBM device features a maximum rated current of 10A, and for a 12V input and 3.3V output, it can achieve high-efficiency power conversion from the low-current area to the high-current areain particular, an 89 per cent efficiency at 10mA, a 95 per cent efficiency at 4A, and a 92 per cent efficiency at 10A.

Samples of the RAA20770X series POL converter ICs will start in December this year. While the sample price for the products will differ depending on the output capacity, the sample price for the RAA207700GBM with a maximum rated current of 15A will be $2.05 per unit. Mass production of the RAA20770X devices is scheduled to begin in March 2013 and is expected to reach a scale of 500,000 units per month in July 2013.

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