LT4295 IEEE 802.3bt PD Interface with Forward/Flyback Controller Fea T Descrip T n IEEE 802.3af/at/bt(Draft 2.0) Powered Device (PD) The LT 4295 is an IEEE 802.3af/at/bt(Draft 2.0)-com- with Forward/Flyback Controller pliant powered device (PD) interface controller with a n Supports Up to 71 Watt PDs switching regulator controller. The T2P output indicates n 5-Event Classification Sensing the number of classification events received during IEEE n Superior Surge Protection (100V Absolute Maximum) 802.3bt-compliant mutual identification and negotiation n Wide Junction Temperature Range (40C to 125C) of available power. n >94% End-to-End Efficiency with LT4321 Ideal Bridge The LT4295 supports both forward and flyback power n External Hot Swap N-Channel MOSFET for Lowest supply topologies. The flyback topology supports No-Opto Power Dissipation and Highest System Efficiency feedback. Auxiliary input voltages can be accurately sensed n No-Opto Flyback Operation with just a resistor divider connected to the AUX pin. n Auxiliary Power Support as Low as 9V n ++ The LT4295 utilizes an external, low R N-channel Easy Migration of LTPoE PDs to IEEE 802.3bt PDs DS(on) n hot swap MOSFET and supports the LT4320/LT4321 ideal Pin Compatible with LT4276A/B/C n diode bridges, to extend the end-to-end power delivery 28-Lead 4mm 5mm QFN Package efficiency and eliminate costly heat sinks. a T The LT4295 also includes an on-chip detection signature n resistor, thermal protection, slope compensation, and High Power Wireless Data Systems n many user configurable settings including classification Outdoor Security Camera Equipment n signature, inrush current, switcher frequency, gate drive Commercial and Public Information Displays n delay, soft-start, and load compensation. High Temperature Applications ++, L, LT, LTC, LTM, LTPoE Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical a T IEEE 802.3bt 71W (Class 8) PD Controller and Power Supply in Forward Mode + AUX AVAILABLE 37V TO 57V CLASS POWER + + 0 13W V PORT 22F + 5V FMMT723 1 3.84W 13A 0.1F 100H 3.3k 2 6.49W 10nF BAV19WS 10F (T 50ns) RR 3 13W VPORT HS V HS SW V FFS PG IN CC 4 25.5W GATE SRC VCC DLY V CC + AUX ISEN 5 40W 20m LT4295 ISEN 6 51W RCLASS SG ++ RCLASS 7 62W 100pF 0.1F 10k GND FB31 SS ROSC T2P ITHB 8 71W 100k OPTO TO MICROPROCESSOR 4295 TA01 4295f 1 For more information www.linear.com/LT4295 ion pplica ions pplica ion uresLT4295 a Te Maxi Mu M r a T p in c F T (Notes 1, 2) VPORT, HSSRC, V Voltages .....................0.3 to 100V IN TOP VIEW HSGATE Current.................................................. 20mA V Voltage .................................................... 0.3 to 8V CC ++ 28 27 26 25 24 23 RCLASS, RCLASS GND 1 22 DNC Voltages .................................0.3 to 8V (and VPORT) AUX 2 21 V CC SFST, FFSDLY, ITHB, T2P Voltages ......0.3 to V +0.3V CC ++ RCLASS 3 20 PG + ISEN , ISEN Voltages ...........................................0.3V 29 RCLASS 4 19 GND GND FB31 Voltage ..................................................+12V/30V T2P 5 18 SG ++ + RCLASS/RCLASS Current .............................. 50mA V 6 17 ISEN CC AUX Current ........................................................ 1.4mA V 7 16 ISEN CC V 8 15 RLDCMP ROSC Current ..................................................... 100A CC 9 10 11 12 13 14 RLDCMP Current ................................................500A T2P Current .........................................................2.5mA Operating Junction Temperature Range (Note 3) UFD PACKAGE 28-LEAD (4mm 5mm) PLASTIC QFN LT4295I ................................................40C to 85C T = 150C, = 3.4C/W JMAX JC LT4295H ............................................ 40C to 125C EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB Storage Temperature Range .................. 65C to 150C o r Der i n F Ma T