Low-profile power chips aim for PoE deployment

Power Integrations has expanded its DPA-Switch family of integrated circuits, introducing a low-profile option for the power over Ethernet market and other high-voltage DC/DC applications.

Power Integrations has expanded its DPA-Switch family of integrated circuits, introducing a low-profile option for the power over Ethernet (PoE) market and other high-voltage DC/DC applications.

The new ultra-low-profile S-PAK package gives a footprint saving of 40% and a height reduction of 55% compared with the existing TO-263 package, while offering equivalent thermal impedance.

PoE enables the delivery of power to networked devices such as IP phones, wireless access points and security cameras, eliminating the need for an AC power connection.

Typically delivered at 48V, PoE power must be converted to a lower voltage inside the client device.

By integrating most of the complex aspects of DC/DC power conversion onto a monolithic chip, DPA-Switch ICs enable PoE convertors with lower component count, smaller board footprint and shorter design cycles compared with discrete designs and competing IC-based solutions.

It is also the only solution scaleable for applications ranging up to 100 watts, allowing substitution of different DPA-Switch parts to address all current PoE classes (Classes 0 to 3), as well as future, higher-power PoE-Plus standards.

Supplied with a 100% matte tin finish, the new S-PAK (JEDEC MO-169) package, which is designated by the letter S in the part number, is lead-free, RoHS compliant and meets J-STD-020C 260C solder reflow requirements.

In addition to the S-PAK, DPA-Switch devices are available in DIP-8, SMD-8 and six-lead TO-263 versions.

"Whenever a new technology requires both infrastructure and client devices in order to grow, a chicken-and-egg problem develops as the owners of each end try to ratchet up their installation with minimal waste", noted Doug Bailey, Vice President of Marketing for Power Integrations.

"The PoE market has now broken through that barrier".

"Around 50 million enterprise ports are enabled with PoE today, with an estimated 200 million expected to be shipping annually by 2007".

"Since each port represents a potential socket for an Ethernet-powered device, the client side of the market is ready for very rapid expansion".

All four members of the DPA-Switch family are available in the new S-PAK.

DPA423SN, for applications with maximum power output of 18W, is optimised for Class 1 and Class 2 PoE applications, whereas the DPA424SN (35W maximum power) is optimised for Class 0 and Class 3 applications.

With maximum outputs of 70 and 100W, respectively, the DPA425SN and DPA426SN are positioned to support future IEEE802.3af expansion for PoE-Plus high-power classes targeted at devices such as notebook computers.

The most highly integrated high-voltage DC/DC convertor IC available today, DPA-Switch features an internal 220V MOSFET as well as voltage-mode control, cycle-by-cycle current limit, output overload protection and auto-restart.

Other features include remote on/off control, cycle skipping at light loads, low EMI, hysteretic thermal shutdown and fully integrated soft-start.

Design support tools, including reference designs, are available for the DPA-Switch family on the company's website.

Pricing for the new products in 1000-piece quantities ranges from $1.36 each for the DPA423SN, an 18W part, to $2.66 for the 100W rated DPA426SN.

Production quantities are available 8 weeks ARO.

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