LTC4279 + Single Port PoE/PoE / ++ LTPoE PSE Controller FEATURES DESCRIPTION n Compliant with IEEE 802.3at Type 1 and 2 The LTC 4279 is an autonomous single port power sourc- n ++ Supports LTPoE Up to 90W ing equipment (PSE) controller designed for use in IEEE n ++ Supports Dual-Signature PDs 802.3at Type 1, Type 2 and LTPoE compliant Power n Fully Autonomous Operation without Microcontroller over Ethernet (PoE) systems. The LTC4279 provides fully n ++ Very Low Power Dissipation autonomous IEEE 802.3 and LTPoE compliant operation 0.1 Sense Resistance without a microcontroller. The LTC4279 simplifies PSE Low R External MOSFET implementation, requiring only a single supply and a small DS(ON) n Very High Reliability 4-Point PD Detection number of passive support components. 2-Point Forced Voltage and Forced Current The LTC4279 delivers lowest-in-industry heat dissipation n Robust Short-Circuit Protection by utilizing a low-R external MOSFET and a 0.1 DS(ON) n Cable Surge Protected 80V OUT Pin sense resistor, eliminating the need for expensive heat n Classification Dependent I and I Current CUT LIM sinks and increasing efficiency. Thresholds n PD discovery uses a proprietary dual-mode 4-point detec- Supports 2-Pair and 4-Pair Output Power n tion mechanism ensuring excellent immunity from false UltraPWR Mode Supports Custom PDs Up to 123W n PD detection. Midspan PSEs are supported with physical Pin-Selectable Detection Backoff Timer for Midspans n layer classification and a 2.5 second backoff timer. Pin Programmable Legacy PD Detection n Pin Programmable Maximum Power Mode Legacy and custom PDs are supported with pin-selectable n Status LED Pin LEGACY and UltraPWR modes. LEGACY mode detects n Available in 20-Pin QFN and 16-Pin SO Packages and powers pre-IEEE specification PDs. UltraPWR mode aggressively turns on and powers custom PDs requiring APPLICATIONS high inrush and/or operational currents. ++ L, LT, LTC, LTM, Linear Technology, the Linear logo and LTPoE are registered trademarks of n PoE PSE Endpoints (Switch/Router) Analog Devices, Inc. All other trademarks are the property of their respective owners. n PoE Midspan Power Injectors n Power Forwarders n Femto Cells n Security Systems TYPICAL APPLICATION MAXIMUM PD INPUT POWER R (1%) PM + Type 1 (13W) 2.37k 0.22F PORT S1B 100V 10 AGND Type 2 (25.5W) 3.32k X7R TVS BULK LED OUT ++ LTC4279 LTPoE 38.7W 4.64k R RESET GATE GATE ++ LTPoE 52.7W 5.90k PWRMODE 1F SENSE 100V MID ++ LTPoE 70W 7.87k C BULK X7R LEGACY 0.1 ++ LTPoE 90W 10.0k R PM DUALPD VSSK V SMAJ58A EE UltraPWR (Up to 123W*) 13.0k 4279 TA01 V EE *Depending on V PSE 4279fa 1 For more information www.linear.com/LTC4279LTC4279 ABSOLUTE MAXIMUM RATINGS (Notes 1 and 4) Supply Voltages SENSE ........................................ V 20V to V + 80V EE EE AGND V ........................................... 0.3V to 80V Operating Ambient Temperature Range EE VSSK ................................... V 0.3V to V + 0.3V LTC4279I .............................................40C to 85C EE EE LEGACY, MID, DUALPD, LED, Junction Temperature (Note 2) ............................ 125C RESET, GATE, PWRMODE ......... V 0.3V to V + 80V Storage Temperature Range .................. 65C to 150C EE EE OUT ............................................ V 80V to V + 80V Lead Temperature (Soldering, 10 sec) ...................300C EE EE PIN CONFIGURATION TOP VIEW TOP VIEW 20 19 18 17 MID 1 16 RESET DNC 1 16 DUALPD DNC 2 15 DNC DNC LEGACY 2 15 DNC 3 14 DUALPD DNC 3 14 DNC 21 VSSK 4 13 LEGACY V V 4 EE 13 PWRMODE EE SENSE 5 12 PWRMODE VSSK 5 12 DNC GATE 6 11 DNC SENSE 6 11 DNC OUT 7 10 V EE 7 8 9 10 AGND 8 9 LED S PACKAGE 16-LEAD PLASTIC SO UFD PACKAGE T = 125C, = 80C/W, = 30C/W JMAX JA JC 20-LEAD (4mm 5mm) PLASTIC QFN T = 125C, = 43C/W, = 3.4C/W JMAX JA JC EXPOSED PAD (PIN 21) IS V EE