(MAX5953x) IEEE 802.3af PD Interface and PWM Controllers

www.DataSheet4U.com 19-3945; Rev 0; 1/06 IEEE 802.3af PD Interface and PWM Controllers with Integrated Power MOSFETs General Description The MAX5953A/MAX5953B/MAX5953C/MAX5953D integrate a complete power IC solution for Powered Devices (PD) in a Power-Over-Ethernet (PoE) system, in compliance with the IEEE 802.3af standard. The MAX5953A/MAX5953B/MAX5953C/MAX5953D provide the PD with a detection signature, a classification signature, and an integrated isolation switch with programmable inrush current control. These devices also integrate a voltage-mode PWM controller with two power MOSFETs connected in a two-switch voltageclamped DC-DC converter configuration. An integrated MOSFET provides PD isolation during detection and classification. All devices guarantee a leakage current offset of less than 10µA during the detection phase. A programmable current limit prevents high inrush current during power-on. The devices feature power-mode undervoltage lockout (UVLO) with wide hysteresis and long deglitch time to compensate for twisted-pair-cable resistive drop and to assure glitch-free transition between detection, classification, and power-on/-off phases. The MAX5953A/MAX5953C have an adjustable UVLO threshold with the default value compliant to the 802.3af standard, while the MAX5953B/MAX5953D have a lower and fixed UVLO threshold compatible with some legacy pre-802.3af power-sourcing equipment (PSE) devices. The DC-DC converters are operable in either forward or flyback configurations with a wide input voltage range from 11V to 76V and up to 15W of output power. The voltage-clamped power topology enables full recovery of stored magnetizing and leakage inductive energy for enhanced efficiency and reliability. When using the high-side MOSFET, the controller can be configured as a buck converter. A look-ahead signal for driving secondary-side synchronous rectifiers can be used to increase efficiency. A wide array of protection features include UVLO, over-temperature shutdown, and shortcircuit protection with hiccup current limit for enhanced performance and reliability. Operation up to 500kHz allows for smaller external magnetics and capacitors. The MAX5953A/MAX5953B/MAX5953C/MAX5953D are available in a high-power (2.22W), 7mm x 7mm thermally enhanced thin QFN package. Features ♦ Powered Device Interface Fully Integrated IEEE 802.3af-Compliant PD Interface PD Detection and Programmable Classification Signatures Less than 10µA Leakage Current Offset During Detection Integrated MOSFET for Isolation and Inrush Current Limiting Gate Output Allows External Control of the Internal Isolation MOSFET Programmable Inrush Current Control Programmable Undervoltage Lockout (MAX5953A/MAX5953C) ♦ DC-DC Converter Clamped, Two-Switch Power IC for High Efficiency Integrated High-Voltage 0.4Ω Power MOSFETs Up to 15W Output Power Bias Voltage Regulator with Automatic HighVoltage Supply Turn-Off 11V to 76V Wide Input Voltage Range Feed-Forward Voltage-Mode Control for Fast Input Transient Rejection Programmable Undervoltage Lockout Overtemperature Shutdown Indefinite Short-Circuit Protection with Programmable Fault Integration Integrated Look-Ahead Signal for SecondarySide Synchronous Rectification > 90% Efficiency with Synchronous Rectification Up to 500kHz Switching Frequency ♦ High-Power (2.22W), 7mm x 7mm Thermally Enhanced Lead-Free Thin QFN Package MAX5953A/MAX5953B/MAX5953C/MAX5953D Ordering Information PART MAX5953AUTM+* MAX5953BUTM+ MAX5953CUTM+* MAX5953DUTM+* PIN-PACKAGE 48 TQFN 48 TQFN 48 TQFN 48 TQFN PKG CODE T4877-6 T4877-6 T4877-6 T4877-6 Applications IEEE 802.3af Powered Devices IP Phones Wireless Access Nodes Internet Appliances Security Cameras Computer Telephony Operating junction temperature range is 0°C to +125°C. +Denotes lead-free package. *Future product—contact factory for availability. Pin Configuration and Typical Operating Circuit appear at end of data sheet. 1 ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. www.DataSheet4U.com IEEE 802.3af PD Interface and PWM Controllers with Integrated Power MOSFETs MAX5953A/MAX5953B/MAX5953C/MAX5953D ABSOLUTE MAXIMUM RATINGS V+ to VEE ................................................................-0.3V to +90V OUT, PGOOD, PGOOD to VEE .....................-0.3V to (V+ + 0.3V) RCLASS, GATE to VEE ...........................................-0.3V to +12V UVLO to VEE ............................................................ -0.3V to +8V PGOOD to OUT ........................................... -0.3V to (V+ + 0.3V) HVIN, INBIAS, DRNH, XFRMRH, XFRMRL to GND.................................................-0.3V to +80V BST to GND ........................................................... -0.3V to +95V BST to XFRMRH .................................................... -0.3V to +12V PGND to GND .......................................................-0.3V to +0.3V DCUVLO, RAMP, CSS, OPTO, FLTINT, RCFF, RTCT to GND..................................................... -0.3V to +12V SRC, CS to GND...................................................... -0.3V to +6V REGOUT, DRVIN to GND .......................................-0.3V to +12V REGOUT to HVIN .................................................. -80V to +0.3V REGOUT to INBIAS ............................................... -80V to +0.3V PPWM to GND....................................-0.3V to (VREGOUT + 0.3V) *As per JEDEC 51 standard. 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. Maximum Input/Output Current (Continuous) OUT to VEE ....................................................................500mA V+, RCLASS to VEE .........................................................70mA UVLO, PGOOD, PGOOD to VEE .....................................20mA GATE to VEE ....................................................................80mA REGOUT to GND ............................................................50mA DRNH, XFRMRH, XFRMRL, SRC to GND (Average), TJ = +125°C..................................................................0.9A PPWM to GND ..............................................................±20mA Continuous Power Dissipation* (TA = +70°C) 48-Pin TQFN 7mm X 7mm (derate 27.8mW/°C above +70°C) .............................2222mW θJA ................................................................................36°C/W Operating Ambient Temperature Range ................0°C to +85°C Operating Junction Temperature Range ..............0°C to +125°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-60°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C ELECTRICAL CHARACTERISTICS (VIN = (V+ - VEE) = 48V, GATE = PGOOD = PGOOD = unconnected, GND = OUT, HVIN = V+, UVLO = VEE, TJ = 0°C to +125°C, unless otherwise noted. Typical values are at TJ = +25°C. All voltages are referenced to VEE, unless otherwise noted.) (Note 1) PARAMETER DETECTION MODE Input Offset Current Effective Differential Input Resistance (Note 3) CLASSIFICATION MODE Classification Current Turn-Off Threshold VTH,CLASS VIN rising (Note 4) VIN = 12.6V to 20V, RDISC = 25.5kΩ (Notes 5, 6) Class 0, RRCLASS = 10kΩ Class 1, RRCLASS = 732Ω Class 2, RRCLASS = 392Ω Class 3, RRCLASS = 255Ω Class 4, RRCLASS = 178Ω 20.8 0 9.17 17.29 26.45 36.6 21.8 22.5 2 11.83 19.71 29.55 41.4 67 0.4 37.4 34.3 30 38.6 35.4 1 40.2 36.9 V mA V V mA V IOFFSET dR VIN = 1.4V to 10.1V (Note 2) VIN = 1.4V, up to 10.1V with 1V step 550 10 µA kΩ SYMBOL CONDITIONS MIN TYP MAX UNITS POWERED DEVICE (PD) INTERFACE Classification Current ICLASS POWER MODE Operating Supply Voltage Operating Supply Current Default Power Turn-On Voltage Default Power Turn-Off Voltage VIN IIN VUVLO, ON VUVLO,OFF VIN = (V+ - VEE) Measure at V+, not including RDISC, GATE = VEE, HVIN = GND = OUT VIN increasing MAX5953A/MAX5953C MAX5953B/MAX5953D VIN decreasing, MAX5953A/MAX5953C 2 _______________________________________________________________________________________ www.DataSheet4U.com IEEE 802.3af PD Interface and PWM Controllers with Integrated Power MOSFETs ELECTRICAL CHARACTERISTICS (continued) (VIN = (V+ - VEE) = 48V, GATE = PGOOD = PGOOD = unconnected, GND = OUT, HVIN = V+, UVLO = VEE, TJ = 0°C to +125°C, unless otherwise noted. Typical values are at TJ = +25°C. All voltages are referenced to VEE, unless otherwise noted.) (Note 1) PARAMETER Default Power Turn-On/Off Hysteresis Voltage External UVLO Programming Range UVLO External Reference Voltage UVLO External Reference Voltage Hysteresis UVLO Bias Current UVLO Input Ground-Sense Threshold UVLO Input Ground-Sense Glitch Rejection Power Turn-Off Voltage, Undervoltage Lockout Deglitch Time Isolation Switch n-Channel MOSFET On-Resistance Isolation Switch n-Channel MOSFET Off-Threshold Voltage GATE Pulldown Switch Resistance GATE Charging Current GATE High Voltage PGOOD Assertion VOUT Threshold (Note 10) PGOOD, PGOOD Assertion VGATE Threshold PGOOD, PGOOD Output Low Voltage PGOOD Leakage Current PGOOD Leakage Current tOFF_DLY VIN, VUVLO falling (Note 9) Output current = 300mA, VGATE = 5.6V, measured between OUT and VEE VGATE - VEE, OUT = V+, output current < 1µA Power-off mode, VIN = +12V VGATE = 2V IGATE = 1µA VOUT - VEE decreasing, VGATE = 5.75V Hysteresis VGATE - VEE increasing Hysteresis ISINK = 2mA, VOUT ≤ (V+ - 5V) (Note 11) GAT