Linear Technology has recently introduced the LTC4266, a quad-channel IEEE 802.3at PSE controller able to source 30W or proprietary power levels and perform the new 2-event classification.  Next generation PSEs will appreciate a number of benefits when using the LTC4266. The accuracy of the LTC4266 affords the use of low-value resistors and low RDS(ON) MOSFETs when managing line current and voltages; this ultimately lowers channel resistance and reduces the dependency on heat sinks. Because MOSFETs are the components that naturally provide the highest likelihood of failing in a PSE circuit, a failed external MOSFET will not “domino” and cause adjacent channels to collapse, such as the case with internal MOSFETs. The LTC4266 is available in a pin-compatible 36-lead SSOP package, so designs using the popular LTC4258 or LTC4259 can be easily replaced. However, the LTC4266 is also available in a small 38-pin 5mm x 7mm QFN package, which is a small quad PSE and ideal for new space-constrained designs.