MAX5940A/MAX5940B/MAX5940C/MAX5940D 19-2991 Rev 2 2/06 IEEE 802.3af PD Interface Controller For Power-Over-Ethernet General Description Features The MAX5940A/MAX5940B/MAX5940C/MAX5940D pro- Fully Integrated IEEE 802.3af-Compliant PD vide complete interface function for a powered device Interface (PD) to comply with the IEEE 802.3af standard in a PD Detection and Programmable Classification power-over-ethernet system. MAX5940A/MAX5940B/ Signatures MAX5940C/MAX5940D provide the PD with a detection Less than 10A Leakage Current Offset During signature, a classification signature, and an integrated isolation switch with programmable inrush current control. Detection These devices also feature power-mode undervoltage Integrated MOSFET For Isolation and Inrush lockout (UVLO) with wide hysteresis and power- Current Limiting good outputs. The MAX5940A/MAX5940B are available 90V Absolute Maximum Rating with an absolute maximum rating of 80V and the (MAX5940C/MAX5940D) MAX5940C/MAX5940D are rated for an absolute maxi- mum rating of 90V. Gate Output Allows External Control of the An integrated MOSFET provides PD isolation during Internal Isolation MOSFET detection and classification. All devices guarantee a leak- Programmable Inrush Current Control age current offset of less than 10A during the detection Programmable Undervoltage Lockout phase. A programmable current limit prevents high inrush (MAX5940B/MAX5940D Only) current during power-on. The device features power- mode UVLO with wide hysteresis and long deglitch time Wide UVLO Hysteresis Accommodates Twisted- to compensate for twisted-pair cable resistive drop and to Pair Cable Voltage Drop assure glitch-free transition between detection, classifica- PGOOD/PGOOD Outputs to Enable Downstream tion, and power-on/-off phases. DC-DC Converters The MAX5940A/MAX5940C provide an active-high -40C to +85C Operating Temperature Range (PGOOD) open-drain output and a fixed UVLO threshold. The MAX5940B/MAX5940D provide both active-high Ordering Information (PGOOD) and active-low (PGOOD) outputs and have an adjustable UVLO threshold with the default value compli- PIN- ant to the 802.3af standard. All devices are designed to PART TEMP RANGE UVLO PACKAGE work with or without an external diode bridge. MAX5940AESA -40C to +85C 8 SO Fixed The MAX5940A/MAX5940B/MAX5940C/MAX5940D are MAX5940BESA -40C to +85C 8 SO Adjustable available in 8-pin SO packages and are rated over the extended temperature range of -40C to +85C. MAX5940CESA -40C to +85C 8 SO Fixed MAX5940DESA -40C to +85C 8 SO Adjustable Applications IP Phones Security Cameras Wireless Access Nodes IEEE 802.3af Power Devices Pin Configurations appear at end of data sheet. Computer Telephony Typical Operating Circuits D1* DC-DC CONVERTER GND V+ 8 V GND REG C OUT MAX5014 2 RDISC 60V 68nF RCLASS 25.5k GND LOAD SS SHDN MAX5940A 3 6 MAX5940C GATE PGOOD R CL D2* 4 5 -48V V OUT EE CGATE *OPTIONAL. Typical Operating Circuits continued at end of data sheet. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLEIEEE 802.3af PD Interface Controller For Power-Over-Ethernet ABSOLUTE MAXIMUM RATINGS (All voltages are referenced to V , unless otherwise noted.) GND, RCLASS to V .....................................................70mA EE EE GND (MAX5940A/MAX5940B) ...............................-0.3V to +80V UVLO, PGOOD, PGOOD to V .....................................20mA EE GND (MAX5940C/MAX5940D)...............................-0.3V to +90V GATE to V ....................................................................80mA EE OUT, PGOOD ...........................................-0.3V to (GND + 0.3V) Continuous Power Dissipation (T = +70C) A RCLASS, GATE ......................................................-0.3V to +12V 8-Pin SO (derate 5.9mW/C above +70C)..................470mW UVLO........................................................................-0.3V to +8V Operating Temperature Range ...........................-40C to +85C PGOOD to OUT.........................................-0.3V to (GND + 0.3V) Storage Temperature Range .............................-65C to +150C Maximum Input/Output Current (continuous) Junction Temperature......................................................+150C OUT to V ...................................................................500mA Lead Temperature (soldering, 10s) ................................+300C EE Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V = (GND - V ) = 48V, GATE = PGOOD = PGOOD = OUT = OPEN, UVLO = V , T = -40C to +85C, unless otherwise noted. IN EE EE A Typical values are at T = +25C. All voltages are referenced to V , unless otherwise noted.) (Note 1) A EE PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DETECTION MODE Input Offset Current (Note 2) I V = 1.4V to 10.1V 10 A OFFSET IN Effective Differential Input V = 1.4V up to 10.1V with 1V step, IN dR 550 k Resistance (Note 3) OUT = PGOOD = GND CLASSIFICATION MODE Classification Current Turn-Off V V rising 20.8 21.8 22.5 V TH,CLSS IN Threshold (Note 4) Class 0, R = 10k 02 CL Class 1, R = 732 9.17 11.83 CL V = 12.6V to IN Classification Current (Notes 5, 6) I 20V, R = Class 2, R = 392 17.29 19.71 mA CLASS DISC CL 25.5k Class 3, R = 255 26.45 29.55 CL Class 4, R = 178 36.6 41.4 CL POWER MODE Operating Supply Voltage V V = (GND - V)67V IN IN EE Operating Supply Current I Measure at GND, not including R 0.4 1 mA IN DISC MAX5940A/MAX5940C 34.3 35.4 36.6 Default Power Turn-On Voltage V V increasing V UVLO, ON IN MAX5940B/MAX5940D, 37.4 38.6 39.9 UVLO = V EE V decreasing, UVLO = V for IN EE Default Power Turn-Off Voltage V 30 V UVLO, OFF MAX5940B/MAX5940D MAX5940A/MAX5940C 4.2 Default Power Turn-On/Off V HYST, V Hysteresis UVLO MAX5940B/MAX5940D, UVLO = V 7.4 EE External UVLO Programming Set UVLO externally (MAX5940B/ V 12 67 V IN,EX Range MAX5940D only) (Note 7) UVLO External Reference Voltage V 2.400 2.460 2.522 V REF, UVLO UVLO External Reference Voltage HYST Ratio to V 19.2 20 20.9 % REF,UVLO Hysteresis UVLO Bias Current I UVLO = 2.460V -1.5 +1.5 A UVLO 2 MAX5940A/MAX5940B/MAX5940C/MAX5940D