Linear Technology has launched a new PD interface controller to meet the market demand for high-power applications

Today's new class of power-intensive applications (e.g., picocells, base stations, signage, and outdoor thermal cameras), the PD power delivery limited by PoE+ to only 25.5W is not enough. Linear Technology Corporation today officially launched the LTPoE++++, PoE+ and PoE-compatible powered device (PD) interface controller LT4275 for applications requiring up to 90W of transmit power.

 

Linear Technology's LTPoE++ standard expands this power budget to four different power levels (38.7W, 52.7W, 70W, and 90W) to meet the needs of this market and enable a complete high-power LTPoE++ system. The LTPoE++ standard uses a classification scheme that simply implements LTPoE++ Power Delivery Equipment (PSE) controllers and LTPoE++ PD controllers to reliably communicate with each other while maintaining interoperability with IEEE standard devices. The LT4275A (LTPoE++), LT4275B (PoE++) and LT4275C (PoE) efficiently power PD loads with a single IC.

Unlike traditional PD controllers with integrated power MOSFETs, the LT4275 controls an external MOSFET to significantly reduce overall PD heat and maximize power efficiency, which is especially important at higher power levels. This new approach allows the user to vary the size of the MOSFETs to meet the specific thermal and efficiency requirements of the application, and also allows the use of low RDS(ON) 30mΩ MOSFETs if necessary. The LT4275 recognizes and delivers the PSE as Type 1 hardware compliant with the IEEE 802.3af 13W power level, Type 2 hardware compliant with the IEEE 802.3at 25.5W power level, or LTPoE++ hardware with the 38.7W to 90W power level. In terms of high-efficiency power distribution, PD users can configure a classification that represents PD power usage. The absolute maximum input voltage rating of 100V means that the LT4275 makes it easy to subject the PD to the most common Ethernet voltage surges and protect the PD from such surges. A programmable auxiliary supply pin with characteristic damage information provides support down to 9V. The LT4275 also includes a power good output, internal signature resistors, undervoltage lockout and full thermal protection.

 

Available in industrial and automotive versions, the LT4275 supports -40°C to 85°C and -40°C to 125°C operating temperature ranges, respectively, in small RoHS compatible 10-lead MSOP or 3mm × 3mm DFN packages.

 

The LT4275 provides an upgrade path to Linear Technology's existing PD products, including the LTC4265 PoE++ PD controller, and seamlessly connects to any of Linear Technology's latest PSE controllers, including the single LTC4274, 4-port LTC4266 and 12-port LTC4270/LTC4271 chipsets.

 

LT4275 Performance Summary:

IEEE 802.3af/at and LTPoE++ powered device (PD) controllers

* LTPoE++ supports power stages up to 90W

* The LT4275A supports all of the following standards:

* LTPoE++ 38.7W, 52.7W, 70W, and 90W

* IEEE 802.3at 25.5W compliant

* Meets IEEE 802.3af requirements up to 13W

* The LT4275B is IEEE 802.3at/af compliant

* The LT4275C is IEEE 802.3af compliant

* 100V absolute maximum input voltage

* Integrated characteristic resistor

* External Hot Swap? N-channel MOSFETs achieve the lowest power consumption and highest system efficiency

* Programmable auxiliary power supply supports voltages as low as 9V

* Available in 10-pin MSOP and 3mm × 3mm DFN packages

 

LT4275 application market

* High power wireless data system

* Outdoor security camera equipment

* Commercial and public information displays

* High temperature industrial applications

 

LT4275 price and availability

The LT4275 is available in 1,000-piece quantities of $1.45 each and is available in volume volume.