MAX5941A/MAX5941B 19-3069 Rev 4 6/06 IEEE 802.3af-Compliant Power-Over-Ethernet Interface/PWM Controller for Power Devices General Description Features The MAX5941A/MAX5941B integrate a complete power Powered Device Interface IC for powered devices (PD) in a power-over-ethernet Fully Integrated IEEE 802.3af-Compliant PD (PoE) system. The MAX5941A/MAX5941B provide a PD Interface interface and a compact DC-DC PWM controller suitable PD Detection and Programmable Classification for flyback and forward converters in either isolated or Signatures nonisolated designs. Less than 10A Leakage Current Offset During The MAX5941A/MAX5941B PD interface complies with Detection the IEEE 802.3af standard, providing the PD with a detec- tion signature, a classification signature, and an integrat- Integrated MOSFET for Isolation and Inrush ed isolation switch with programmable inrush current Current Limiting control. These devices also feature power-mode under- Gate Output Allows External Control of the voltage lockout (UVLO) with wide hysteresis and power- Internal Isolation FET good status outputs. Programmable Inrush Current Control The MAX5941A/MAX5941B also integrate all the building blocks necessary for implementing DC-DC fixed- Programmable Undervoltage Lockout frequency isolated power supplies. These devices are a PWM Controller current-mode controller with an integrated high startup Wide Input Range: 18V to 67V circuit suitable for isolated telecom/industrial voltage- range power supplies. A high-voltage startup circuit Current-Mode Control allows the PWM controller to draw power directly from the Leading-Edge Blanking 18V to 67V input supply during startup. The switching fre- Internally Trimmed 275kHz 10% Oscillator quency is internally trimmed to 275kHz 10%, thus Soft-Start reducing magnetics and filter components. The MAX5941A allows an 85% operating duty cycle and can be used to implement flyback converters. The MAX5941B Ordering Information limits the operating duty cycle to less than 50% and can be used in single-ended forward converters. The PIN- M A X DU T Y PART TEMP RANGE MAX5941A/MAX5941B are designed to work with or with- PACKAGE C YC L E (% ) out an external diode bridge in front of the PD. MAX5941AESE -40C to +85C 16 SO (S16M-6) 85 The MAX5941A/MAX5941B are available in 16-pin SO MAX5941ACSE 0C to +70C 16 SO (S16M-6) 85 packages. MAX5941BESE -40C to +85C 16 SO (S16M-6) 50 Applications MAX5941BCSE 0C to +70C 16 SO (S16M-6) 50 IP Phones Wireless Access Nodes Pin Configuration Internet Appliances TOP VIEW Computer Telephony V+ 1 16 V CC Security Cameras V 2 15 NDRV DD Power Devices in Power-Over-Ethernet/ Power-Over-MDI OPTO 3 14 V- 4 MAX5941A SS SHDN 13 CS MAX5941B ULVO 5 12 GND Typical Operating Circuit appears at end of data sheet. RCL 6 11 PGOOD GATE 7 10 PGOOD V 8 9 OUT EE SO 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-Compliant Power-Over-Ethernet Interface/PWM Controller for Power Devices ABSOLUTE MAXIMUM RATINGS (All voltages are referenced to V , unless otherwise noted.) UVLO, PGOOD, PGOOD to V .....................................20mA EE EE GND........................................................................-0.3V to +90V GATE to V ....................................................................80mA EE OUT, PGOOD ...........................................-0.3V to (GND + 0.3V) V , V .........................................................................20mA DD CC RCL, GATE .............................................................-0.3V to +12V NDRV Continuous ...........................................................25mA UVLO........................................................................-0.3V to +8V NDRV (Pulsed for less than 1s) .......................................1A PGOOD to OUT.........................................-0.3V to (GND + 0.3V) Continuous Power Dissipation (T = +70C) A V+ to V-...................................................................-0.3V to +90V 16-Pin SO (derate 9.1mW/C above +70C)................727mW V to V-.................................................................-0.3V to +40V Operating Temperature Range DD V to V-..............................................................-0.3V to +12.5V CC MAX5941 CSE ..................................................0C to +70C OPTO, NDRV, SS SHDN, CS to V-.............-0.3V to (V + 0.3V) MAX5941 ESE ...............................................-40C to +85C CC Maximum Input/Output Current (Continuous) Storage Temperature Range .............................-65C to +150C OUT to V ...................................................................500mA EE Junction Temperature......................................................+150C GND, RCL to V ............................................................70mA 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 = OPEN, V- tied to OUT, V+ tied to GND, UVLO = V , T = T to +T , IN EE EE A MIN MAX unless otherwise noted. 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 PD INTERFACE DETECTION MODE V = 1.4V to 10.1V, G N D = V - = OU T = V + I N Input Offset Current I 10 A OFFSET (Note 2) Effective Differential Input V = 1.4V up to 10 .1V w i th 1V step, O U T = I N dR 550 k Resistance P GO OD = GN D = O U T = V + ( N ote 3) CLASSIFICATION MODE Classification Current Turn-Off V V rising (Note 4) 20.8 21.8 22.5 V TH,CLSS IN Threshold Class 0, R = 10k 02 CL Class 1, R = 732 9.17 11.83 CL V = 12.6V IN Classification Current (Notes 5, 6) I to 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 Default Power Turn-On Voltage V V increasing, UVLO = V 37.4 38.6 40.1 V UVLO, ON IN EE Default Power Turn-Off Voltage V V decreasing, UVLO = V 30 V UVLO, OFF IN EE Default Power Turn-On/Off V HYST, 7.4 V Hysteresis UVLO External UVLO Programming V Set UVLO externally (Note 7) 12 67 V IN,EX Range UVLO External Reference Voltage V V increasing 2.400 2.460 2.522 V REF, UVLO UVLO 2 MAX5941A/MAX5941B