19-6142; Rev 0; 12/11 估 板 备 有 评 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET MAX5984具有输入欠压锁定(UVLO)、输入过压锁定、高 温检测、启动过程的输出摆率限制以及LED状态指示。 MAX5984提供节省空间的28引脚TQFN (5mm x 5mm)功 率封装，工作在扩展级(-40°C至+85°C)温度范围。 应用 单端口PSE端点应用 单端口PSE电源注入(中跨应用) PoE中继器 交换机/路由器 工业自动化设备 无线LAN接入点/WiMAX®基站 特性 S兼容于IEEE 802.3af/at S高达40W的单端口PSE应用 S集成0.5Ω功率MOSFET和检流电阻 S2事件引脚选择(MAX5984A/MAX5984B) SPD检测和分级 S为5级PD提供可编程限流 S为传统设备提供大电容检测 S具有直流和交流负载断开检测 S电流折返、占空比控制限流 SLED指示端口状态 S直接快速关断控制 S节省空间的28引脚TQFN (5mm × 5mm)封装 典型工作电路 PSE OUTPUT 定购信息 AGND VEE PINSELECT TEMP RANGE MAX5984AETI+ 2-EVENT -40NC to +85NC 28 TQFN-EP* LED MAX5984BETI+** 2-EVENT -40NC to +85NC 28 TQFN-EP* 2-EVENT MAX5984CETI+** PWMEN -40NC to +85NC 28 TQFN-EP* LEGACY MAX5984DETI+ LSCEN -40NC to +85NC 28 TQFN-EP* PART PINPACKAGE -54V +表示无铅(Pb)/符合RoHS标准的封装。 *EP = 裸焊盘。 **未来产品—供货状况请联络厂商。 OUT VEE_DIG OUTP MAX5984A DET MIDSPAN ILIM1 OSC ILIM2 EN IEEE是美国电气和电子工程师学会的注册服务标志。 WiMAX是WiMAX论坛的注册服务标志。 ����������������������������������������������������������������� Maxim Integrated Products 1 本文是英文数据资料的译文，文中可能存在翻译上的不准确或错误。如需进一步确认，请在您的设计中参考英文资料。 有关价格、供货及订购信息，请联络Maxim亚洲销售中心：10800 852 1249 (北中国区)，10800 152 1249 (南中国区)， 或访问Maxim的中文网站：china.maxim-ic.com。 MAX5984 概述 MAX5984是一款单端口、供电设备(PSE)电源控制器，设 计用于IEEE® 802.3af/at兼容PSE。这款器件提供用电设 备(PD)的侦测、分级、限流以及直流/交流负载开路检测。 MAX5984采用自主操作模式，无需任何软件编程，内部 集成了功率MOSFET和检流电阻。器件支持新一代5级、2事 件分级，用于侦测大功率PD。MAX5984为单个端口(5级使 能)提供高达40W功率，并提供传统PD的大电容检测。 MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET ABSOLUTE MAXIMUM RATINGS Maximum Current Into OUT.......................... Internally regulated Continuous Power Dissipation (TA = +70NC) TQFN (derate 34.5mW/NC above +70NC)...............2758.6mW Operating Temperature Range........................... -40NC to +85NC Storage Temperature Range............................. -65NC to +150NC Junction Temperature......................................................+150NC Lead Temperature (soldering, 10s).................................+300NC Soldering Temperature (reflow).......................................+260NC (Voltages referenced to VEE, unless otherwise noted.) AGND, DET, LED...................................................-0.3V to +80V OUT.......................................................-0.3V to (VAGND + 0.3V) OUTP........................................................-6V to (VAGND + 0.3V) VEE_DIG................................................................-0.3V to +0.3V OSC..........................................................................-0.3V to +6V EN, 2-EVENT/PWMEN/LSCEN, MIDSPAN, LEGACY, ILIM1, ILIM2..........................................-0.3V to +4V Maximum Current Into LED.................................................40mA 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. PACKAGE THERMAL CHARACTERISTICS (Note 1) TQFN Junction-to-Ambient Thermal Resistance........................ 29NC Junction-to-Case Thermal Resistance............................... 2NC Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to china.maxim-ic.com/thermal-tutorial. ELECTRICAL CHARACTERISTICS (VAGND - VEE = 32V to 60V, TA = -40NC to +85NC, all voltages are referenced to VEE, unless otherwise noted. Typical values are at VAGND - VEE = 54V, TA = +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 60 V 2.5 4 mA POWER SUPPLIES Operating Voltage Range Supply Current VAGND VAGND - VEE 32 IEE VOUT = VEE, all logic inputs unconnected, measured at AGND in power mode ILIM Maximum ILOAD allowed during current-limit conditions, VOUT = 0V (Note 3) CURRENT LIMIT Current Limit 400 420 441 Class 4 684 720 756 Class 5 if ILIM1 = VEE, ILIM2 = unconnected 807 850 893 Class 5 if ILIM1 = unconnected, ILIM2 = VEE 855 900 945 Class 5 if ILIM1 = VEE, ILIM2 = VEE 902 950 998 mA Foldback Initial OUT Voltage VFLBK_ST VAGND - VOUT below which the current limit starts folding back 27 V Foldback Final OUT Voltage VFLBK_END VAGND - VOUT below which the current limit reaches ITH_FB 10 V VOUT = VAGND 166 mA Minimum Foldback Current Limit Threshold 2 Class 0, 1, 2, 3 ITH_FB 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET (VAGND - VEE = 32V to 60V, TA = -40NC to +85NC, all voltages are referenced to VEE, unless otherwise noted. Typical values are at VAGND - VEE = 54V, TA = +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX Class 0, 1, 2, 3 351 370 389 Class 4 602 634 666 Class 5 if ILIM1 = VEE, ILIM2 = unconnected 710 748 785 Class 5 if ILIM1 = unconnected, ILIM2 = VEE 752 792 832 Class 5 if ILIM1 = VEE, ILIM2 = VEE 794 836 878 TA = +25NC 0.5 0.9 TA = +85NC 0.6 1.3 UNITS OVERCURRENT Overcurrent Threshold ICUT Overcurrent threshold allowed for t P tFAULT, VOUT = 0V (Note 3) mA INTERNAL POWER DMOS On-Resistance RDS(ON) Power-Off OUT Leakage Current IOUT_LEAK Measured from OUT to VEE, IOUT = 100mA I VEN = VEE, VOUT = VAGND 10 FA SUPPLY MONITORS VEE Undervoltage Lockout VEE_UVLO VEE Undervoltage Lockout Hysteresis VEE_UVLOH VEE Overvoltage Lockout VEE_OV VEE Overvoltage Lockout Hysteresis VEE_OVH VAGND - VEE, VAGND increasing Port is shutdown if: VAGND - VEE < VEE_ UVLO - VEE_UVLOH VAGND - VEE > VEE_OV, VAGND increasing Port is shutdown and device resets if the junction temperature exceeds this limit, temperature increasing Thermal Shutdown Threshold TSHD Thermal Shutdown Hysteresis TSHDH Temperature decreasing IBOUT VOUT = VAGND, probing phases 28.5 V 3 V 62.5 V 1 V +150 NC 20 NC OUTPUT MONITOR OUT Input Current IDIS OUTP discharge current, detection and classification off, port shutdown, VOUTP = VAGND - 2.8V 200 Short to VEE Detection Threshold DCNTH VOUT - VEE, VOUT decreasing, enabled during detection 1.5 Short to VEE Detection Threshold Hysteresis DCNHY Idle Pullup Current at OUT 2.0 6 FA 265 FA 2.5 V 220 mV LOAD DISCONNECT DC Load-Disconnect Threshold IDCTH Minimum load current allowed before disconnect (DC disconnect active), VOUT = 0V AC Load-Disconnect Threshold IACTH Current into DET, for IDET < IACTH the port powers off (AC disconnect active) 5 7.5 10 mA 115 130 145 FA 3 MAX5984 ELECTRICAL CHARACTERISTICS (continued) MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET ELECTRICAL CHARACTERISTICS (continued) (VAGND - VEE = 32V to 60V, TA = -40NC to +85NC, all voltages are referenced to VEE, unless otherwise noted. Typical values are at VAGND - VEE = 54V, TA = +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2) PARAMETER SYMBOL MIN TYP MAX UNITS 3.85 4 4.2 V Measured at OSC 26 32 39 FA VACD_EN VOSC - VEE > VACD_EN to activate AC disconnect 270 330 380 mV tDISC Time from IRSENSE < IDCTH (DC disconnect active) or IDET < IACTH (AC disconnect active) to gate shutdown 300 400 ms Detection Probe Voltage (First Phase) VDPH1 VAGND - VDET during the first detection phase 3.8 4 4.2 V Detection Probe Voltage (Second Phase) VDPH2 VAGND - VDET during the second detection phase 9 9.3 9.6 V Current-Limit Protection IDLIM VDET = VAGND during detection, measure current through DET 1.50 1.75 2.00 mA Short-Circuit Threshold VDCP If VAGND - VOUT < VDCP after the first detection phase, a short circuit to AGND is detected 1 V Open-Circuit Threshold ID_OPEN First point measurement current threshold for open condition 8 FA Triangular Wave Peak-to-Peak Voltage Amplitude AMPTRW OSC Pullup/Pulldown Currents IOSC ACD_EN Threshold Load Disconnect Timer CONDITIONS Measured at DET, referred to AGND DETECTION Resistor Detection Window Resistor Rejection Window RDOK RDBAD (Note 4) 19 26.5 Detection rejects lower values 15.5 kI kI Detection rejects higher values 32 VAGND - VDET during classification 16 20 V VDET = VAGND, during classification measure current through DET 65 80 mA CLASSIFICATION Classification Probe Voltage Current-Limit Protection Classification Current Thresholds Mark Event Voltage Mark Event Current Limit 4 VCL IClLIM ICL VMARK IMARK_LIM Classification current thresholds between classes Class 0, Class 1 5.5 6.5 7.5 Class 1, Class 2 13.0 14.5 16.0 Class 2, Class 3 21 23 25 Class 3, Class 4 31 33 35 Class 4 upper limit (Note 5) 45 48 mA 51 VAGND - VDET during mark event 8 10 V VDET = VAGND, during mark event measure current through DET 55 80 mA 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET (VAGND - VEE = 32V to 60V, TA = -40NC to +85NC, all voltages are referenced to VEE, unless otherwise noted. Typical values are at VAGND - VEE = 54V, TA = +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP DIGITAL INPUTS/OUTPUTS (Voltages referenced to VEE) Digital Input Low VIL VIH Internal Input Pullup Current IPU Pullup current to internal digital supply to set default values VLED_LOW ILED_LEAK LED Output Leakage 0.8 2.4 Digital Input High LED Output Low Voltage MAX 3 UNITS V V 5 7 FA ILED = 10mA, PWM disabled, port power-on 0.8 V PWM disabled, shutdown mode, VLED = 60V 10 FA PWM Frequency 25 kHz PWM Duty Cycle 6.25 % TIMING Startup Time tSTART Time during which a current limit set to 420mA is allowed, starts when power is turned on 50 60 70 ms Fault Time tFAULT Maximum allowed time for an overcurrent condition set by ICUT after startup 50 60 70 ms Detection Reset Time tME Time allowed for the port voltage to reset before detection starts 80 90 ms Detection Time tDET Maximum time allowed before detection is completed 330 ms Midspan Mode Detection Delay tDMID Classification Time tCLASS 2 Time allowed for classification Mark Event Time Time allowed for mark event VEEUVLO Turn-On Delay Time VAGND must be above the VEEUVLO thresholds before the device operates Restart Timer tDLY tRESTART Time the device waits before turning on after an overcurrent fault 7 2.2 2.4 s 19 23 ms 9 11 ms 5.2 ms 16 x tFAULT ms Note 2: This device is production tested at TA = +25NC. Limits at TA = -40NC and TA = +85NC are guaranteed by design. Note 3: If ILIM1 and ILIM2 are both unconnected, Class 5 detection is disabled. See the Class 5 PD Classification section and Table 3 for details and settings. Note 4: RDOK = (VOUT2 - VOUT1)/(IDET2 - IDET1). VOUT1, VOUT2, IDET2, and IDET1 represent the voltage at OUT and the current at DET during phase 1 and 2 of the detection, respectively. Note 5: If Class 5 is enabled, this is the classification current thresholds from Class 4 to Class 5. 5 MAX5984 ELECTRICAL CHARACTERISTICS (continued) 典型工作特性 (TA = +25°C, unless otherwise noted.) SUPPLY CURRENT (mA) 2.6 2.5 2.4 2.6 2.5 2.4 30.0 MAX5984 toc03 MEASURED AT AGND UNDERVOLTAGE LOCKOUT (V) MEASURED AT AGND MAX5984 toc02 2.7 MAX5984 toc01 2.7 VEE UNDERVOLTAGE LOCKOUT vs. TEMPERATURE ANALOG SUPPLY CURRENT vs. TEMPERATURE ANALOG SUPPLY CURRENT vs. INPUT VOLTAGE SUPPLY CURRENT (mA) 29.5 29.0 28.5 28.0 27.5 27.0 2.3 2.3 32 36 40 44 48 52 56 -15 -40 60 10 35 60 10 35 TEMPERATURE (°C) VEE OVERVOLTAGE LOCKOUT vs. TEMPERATURE INTERNAL FET RESISTANCE vs. TEMPERATURE 63.5 FET RESISTANCE (mΩ) 63.0 62.5 62.0 61.5 61.0 MAX5984 toc05 1000 MAX5984 toc04 64.0 OVERVOLTAGE LOCKOUT (V) -15 -40 85 TEMPERATURE (°C) VAGND - VEE (V) 800 600 400 60.5 60.0 200 -40 -15 10 35 60 85 -15 10 35 60 TEMPERATURE (°C) FOLDBACK CURRENT-LIMIT THRESHOLD vs. OUTPUT VOLTAGE DC DISCONNECT THRESHOLD vs. TEMPERATURE CLASS 4 600 500 400 300 CLASS 0, 1, 2, 3 200 100 85 MAX5984 toc07 7.4 DC DISCONNECT THRESHOLD (mA) MAX5984 toc06 700 7.2 7.0 6.8 6.6 6.4 0 0 10 20 VAGND - VOUT (V) 6 -40 TEMPERATURE (°C) 800 IRSENSE (mA) MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET 30 40 -40 -15 10 35 TEMPERATURE (°C) 60 85 60 85 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET SHORT-CIRCUIT RESPONSE TIME OVERCURRENT TIMEOUT (240Ω TO 138Ω) MAX5984 toc09 MAX5984 toc08 VAGND - VOUT 20V/div VAGND - VOUT 20V/div 0V 0V IOUT 200mA/div IOUT 200mA/div 0mA 0mA 20ms/div 20ms/div SHORT-CIRCUIT TRANSIENT RESPONSE EN TO OUT TURN-OFF DELAY MAX5984 toc10 MAX5984 toc11 VAGND - VOUT 20V/div VAGND - VOUT 20V/div 0V 0V IOUT 200mA/div 0mA IOUT 5A/div 0mA VEN 5V/div 0V 10µs/div 100µs/div ZERO-CURRENT DETECTION WAVEFORM WITH DC DISCONNECT ENABLED ZERO-CURRENT DETECTION WAVEFORM WITH AC DISCONNECT ENABLED MAX5984 toc12 MAX5984 toc13 VAGND - VOUT 20V/div VAGND - VOUT 20V/div 0V 0V IOUT 100mA/div IOUT 100mA/div 0mA 0mA 40ms/div 40ms/div 7 MAX5984 典型工作特性(续) (TA = +25°C, unless otherwise noted.) MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET 典型工作特性(续) (TA = +25°C, unless otherwise noted.) OVERCURRENT RESTART DELAY STARTUP WITH A VALID PD MAX5984 toc14 MAX5984 toc15 VAGND - VOUT 20V/div VAGND - VOUT 20V/div 0V 0V IOUT 200mA/div IOUT 100mA/div 0mA 0mA 400ms/div 100ms/div DETECTION WITH INVALID PD (25kΩ TO 10µF) DETECTION WITH INVALID PD (15kΩ) MAX5984 toc16b MAX5984 toc16a VAGND - VOUT 1V/div VAGND - VOUT 5V/div 0V 0V IOUT 1mA/div 0mA IOUT 1mA/div 0mA 100ms/div 40ms/div DETECTION WITH INVALID PD (33kΩ) DETECTION WITH INVALID PD (OPEN CIRCUIT) MAX5984 toc16c MAX5984 toc16d VAGND - VOUT 5V/div 0V VAGND - VOUT 5V/div 0V IOUT 1mA/div 0mA 100ms/div 8 IOUT 1mA/div 0mA 100ms/div 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET STARTUP IN MIDSPAN WITH A VALID PD DETECTION IN MIDSPAN WITH INVALID PD (15kΩ) MAX5984 toc17 MAX5984 toc18a VAGND - VOUT 20V/div 0V VAGND - VOUT 5V/div 0V IOUT 100mA/div 0mA IOUT 1mA/div 0mA 100ms/div 400ms/div DETECTION IN MIDSPAN WITH INVALID PD (33kΩ) MAX5984 toc18b DETECTION IN OUTPUT SHORTED TO AGND MAX5984 toc19 VAGND - VOUT 5V/div VAGND - VOUT 5V/div 0V 0V IOUT 1mA/div 0mA IOUT 1mA/div 0mA 40ms/div 400ms/div CLASSIFICATION WITH DIFFERENT PD CLASSES (0 TO 3) CLASSIFICATION WITH DIFFERENT PD CLASSES (4 AND 5) MAX5984 toc20a MAX5984 toc20b VAGND - VOUT 10V/div 0V VAGND - VOUT 10V/div 0V CLASS 3 CLASS 2 0mA CLASS 1 CLASS 0 40ms/div CLASS 5 CLASS 4 IOUT 10mA/div IOUT 20mA/div 0mA 40ms/div 9 MAX5984 典型工作特性(续) (TA = +25°C, unless otherwise noted.) MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET 典型工作特性(续) (TA = +25°C, unless otherwise noted.) STARTUP USING 2-EVENT CLASSIFICATION WITH A VALID PD LED DETECTION FAULT WITH PWM ENABLED MAX5984 toc22a MAX5984 toc21 VAGND - VOUT 10V/div 0V VAGND - VOUT 20V/div IOUT 500mA/div 0mA 0V VAGND - VLED 20V/div IOUT 100mA/div 0mA 0V 200ms/div 100ms/div LED DETECTION FAULT WITH PWM DISABLED MAX5984 toc22b VAGND - VOUT 10V/div 0V IOUT 500mA/div 0mA LED OVERCURRENT FAULT WITH PWM ENABLED MAX5984 toc23a VAGND - VOUT 50V/div 0V IOUT 500mA/div 0mA VAGND - VLED 20V/div 0V VAGND - VLED 20V/div 0V 200ms/div 200ms/div LED OVERCURRENT FAULT WITH PWM DISABLED LED PWM TIMING AND DUTY CYCLE MAX5984 toc23b VAGND - VOUT 50V/div 0V IOUT 500mA/div 0mA MAX5984 toc24 VAGND - VOUT 50V/div 0V IOUT 500mA/div 0mA VAGND - VLED 20V/div VAGND - VLED 20V/div 0V 0V 200ms/div 10 10µs/div 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET AGND N.C. OSC N.C. LED N.C. I.C. TOP VIEW 21 20 19 18 17 16 15 N.C. 22 14 EN DET 23 13 LEGACY N.C. 24 12 VEE_DIG 11 I.C. 10 I.C. 9 I.C. 8 I.C. OUTP 25 MAX5984 OUT 26 OUT 27 *EP + 4 5 6 7 ILIM2 2-EVENT/PWMEN/LSCEN MIDSPAN VEE 3 ILIM1 2 VEE 1 VEE N.C. 28 THIN QFN *EXPOSED PAD, CONNECT TO AGND. 引脚说明 引脚 名称 1, 2, 3 VEE 模拟电源低端输入。在AGND和VEE之间利用外部100V、47μF电容和100V、0.1μF陶瓷电容并联进行 旁路。 4 ILIM1 5级限流数字调节1，以VEE为参考。ILIM1在内部上拉至数字电源。利用ILIM1和ILIM2使能5级操作， 并调节5级限流值。详细信息请参考电气特性表和表3。 5 ILIM2 5级限流数字调节2，以VEE为参考。ILIM2在内部上拉至数字电源。利用ILIM2和ILIM1使能5级操作， 并调节5级限流值。详细信息请参考电气特性表和表3。 2-EVENT (MAX5984A/ MAX5984B) 2事件分级选择，以VEE为参考。2-EVENT在内部上拉至数字电源。不连接时，禁止2事件分级；强制 为低电平时，使能2事件分级。详细信息请参考2事件PD分级部分。只能在器件复位期间更改这一位的 状态。MAX5984C/MAX5984D使能。 PWMEN (MAX5984C) PWM控制逻辑输入，以VEE为参考。PWMEN在内部上拉至数字电源。不连接时，使能内部PWM以 驱动LED引脚；强制为低电平时，禁用内部PWM。MAX5984A/MAX5984B/MAX5984D使能。 LSCEN (MAX5984D) 负载稳定监测功能选择，以VEE为参考。LSCEN内部上拉至数字电源。不连接时，使能负载稳定监测功 能；强制为低电平时，禁止负载稳定监测功能。只能在器件复位期间更改这一位的状态。MAX5984A 禁止，但MAX5984B/MAX5984C使能。 6 功能 11 MAX5984 引脚配置 MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET 引脚说明(续) 引脚 名称 功能 7 MIDSPAN 防冲突检测逻辑输入，以VEE为参考。MIDSPAN在内部上拉至数字电源。不连接时，开启防冲突检测 功能，适用于中跨PSE系统；强制为低电平时，禁用该功能，适用于端点PSE系统。器件上电或复位 后，锁存MIDSPAN逻辑电平。 8–11, 15 I.C. 12 VEE_DIG 数字电源低端输入，外部连接至VEE。 13 LEGACY 传统设备检测逻辑输入，以VEE为参考。LEGACY在内部上拉至数字电源。不连接时，开启传统PD检 测功能；强制为低电平时，禁用该功能。器件上电或复位后，锁存LEGACY逻辑电平。 14 EN 使能输入，以VEE为参考。EN在内部上拉至数字电源。不连接时，使能器件；强制为低电平且至少保 持40μs后，复位器件。当解除复位条件后(由低变高)，MIDSPAN、OSC和LEGACY置为锁存状态。 16, 18, 20, 22, 24, 28 N.C. 浮空，无内部连接。保持N.C.不连接。 17 LED LED指示开漏输出，以VEE为参考。LED引脚吸收10mA电流并直接驱动一个外部LED。提供闪烁功 能，用于表示不同状态(请参考PWM和LED信号部分)。在外部通过一个串联电阻将LED连接至AGND 或外部电源(如果可用，参见图6和图7)。 19 OSC 交流断开三角波输出。利用一个100nF (±10%容差)外部电容将其旁路至VEE，以使能交流断开功能；将 OSC连接至VEE时，禁用交流断开功能，并使能直流断开功能。器件上电或复位后，锁存OSC状态。 21 AGND 23 DET 检测/分级电压输出。DET用于设置标记事件检测和侦测电压的分级，适用于采用交流断开功能时的交 流电流检测。如需使用交流断开功能，须将一个1kΩ和0.47μF的RC串联电路与外部保护二极管并联， 然后连接到OUTP (图7)。 25 OUTP 端口上拉输出。OUTP在必要时能够将端口电压上拉至AGND。若采用交流断开功能，则将OUTP连接 至交流隔离二极管的阳极；如果不使用交流断开功能，则将OUTP连接至OUT (图6和图8)。利用一个 100V、0.1μF的陶瓷电容将OUTP旁路至AGND。 26, 27 OUT 集成MOSFET输出。若采用直流断开功能，则将端口输出连接至OUTP (图6和图8)；若采用交流断开 功能，则将OUT连接至交流隔离二极管的阴极(图7)。 — EP 12 内部连接，将I.C.连接至VEE。 电源高端输入。 裸焊盘。在外部将EP连接至VEE，详细信息请参考布局步骤部分。 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET OSC CURRENT SENSING VOLTAGE PROBING AND CURRENT-LIMIT CONTROL TRIANGLE WAVE GENERATOR OSC STATUS MONITOR EN AGND OUTP LEGACY MIDSPAN DETECTION AND CLASSIFICATION CONTROL PORT STATE MACHINE (SM) REGISTER FILE VOLTAGE SENSING 9-BIT ADC AC DISCONNECT ENABLE CENTRAL LOGIC UNIT (CLU) AGND VEE DET ANALOG BIAS AND SUPPLY MONITOR OUT FOLDBACK CONTROL A=1 GATE DRIVE INTERNAL SUPPLIES AC DETECTOR AC DISCONNECT SIGNAL (ACD) VOLTAGE REFERENCES ACD REFERENCE CURRENT CURRENT REFERENCES THRESHOLD SETTINGS LED MAX5984 2-EVENT/PWMEN/LSCEN 2-EVENT/PWMEN/LSCEN 详细说明 MAX5984是一款单端口PSE电源控制器，设计用于IEEE 802.3af/IEEE 802.3at兼容的PSE。器件提供PD侦测、分 级、限流以及直流和交流负载断开检测功能。MAX5984 可自动工作，无需任何软件编程，并具有集成功率MOSFET 和检流电阻。该器件还支持最新的5级和二次事件分级， 用于对大功率PD进行检测和分级。MAX5984可为单个端 口提供高达40W的功率(使能5级)，并为传统PD提供大电 容检测。 INTERNAL MOSFET CURRENT LIMIT, OVERCURRENT, AND OPENCIRCUIT SENSING, AND FOLDBACK CONTROL INTERNAL RSENSE CLASS 5 ENABLE/DISABLE, OVERCURRENT AND CURRENT LIMIT CONTROL ILIM1 ILIM2 MAX5984提供输入UVLO、输入过压锁定、过热检测、启 动过程中的输出电压摆率限制以及LED状态指示。 复位 MAX5984在以下任何条件下复位： 1) 上电。一旦VEE上升到UVLO门限以上，则清除复位条件。 2) 硬件复位。在上电之后的任何时间，只要EN输入驱动 至低电平(> 40μs，典型值)，则触发复位。一旦EN输入 再次驱动至高电平，器件将退出复位状态。 3) 热关断。器件在+150°C时进入热关断状态。一旦温度 下降到130°C以下，器件将退出热关断模式并复位。 13 MAX5984 简化框图 MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET 复位期间，MAX5984锁存MIDSPAN、LEGACY和OSC状态。 正常工作期间，忽略这些输入的变化。 中跨模式 中跨模式下，器件按照检测阶段的定时工作。定时电路使 能且发生检测失效时，端口在尝试再次检测之前等待2s至 2.4s。将MIDSPAN置为高电平，然后给器件上电或复位 以开启中跨模式。默认情况下，MIDSPAN输入在内部上 拉至高电平。强制MIDSPAN为低电平时，禁用该功能。 检 测 期 间，MAX5984保 持 内 部MOSFET关 闭， 并 通 过 DET输出两路检测电压。测量通过DET的电流以及OUT处 的电压。按照IEEE 802.3af/802.3at标准的规定，采用两 点斜率测量法验证连接到端口的设备。 按照IEEE 802.3af/802.3at标准规定，一个与DET输入串联 的外部二极管将PD检测限制在第一象限。为了防止损坏 非PD设备并保护其自身免受输出短路的损坏，MAX5984 在PD检测期间将流入DET的电流限制为最大2mA。 自动工作 MAX5984在解除复位条件后自动工作。器件进行检测和分 级，一旦在端口检测到有效PD，则自动为端口供电。若 端口没有连接有效的PD，MAX5984则继续重复检测程序， 直到连接有效PD为止。 PD检测 正常工作期间，MAX5984在输出端检测有效PD。根据IEEE 802.3af/802.3at标准的规定，有效PD具有25kΩ的检测特 征电阻。表1所示为IEEE 802.3at标准规定的PSE检测有效 PD指示的技术指标。 中跨模式下，MAX5984在每次检测失效并再次尝试检测 之前将等待至少2.0s。在退出复位状态后会立即开始第一 次检测。 大电容检测 上电或解除复位条件后，锁存LEGACY输入状态。LEGACY 输入在内部上拉至高电平，使能大电容检测功能。如果 不需要大电容检测，则将LEGACY连接至VEE禁用该功能。 若使能大电容检测功能，则可接受高达47μF (典型值)的PD 特征电容。 表1. PSE PD检测模式电气要求(IEEE 802.3at) PARAMETER Open-circuit voltage Short-circuit current SYMBOL MIN VOC ISC MAX UNITS 30 V In detection mode only 5 mA In detection mode only 10 V Valid test voltage VVALID 2.8 Voltage difference between test points DVTEST 1 V tBP 2 ms Time between any two test points Slew rate VSLEW 0.1 V/Fs Accept signature resistance RGOOD 19 26.5 kI Reject signature resistance RBAD < 15 > 33 kI 500 kI Open-circuit resistance ROPEN Accept signature capacitance CGOOD Reject signature capacitance CBAD 10 Signature offset voltage tolerance VOS 0 2.0 V Signature offset current tolerance IOS 0 12 FA 14 150 nF FF ADDITIONAL INFORMATION This timing implies a 500Hz maximum probing frequency 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET 5级PD分级 MAX5984支持高于IEEE 802.3at标准的大功率模式，必要 时可提供一个额外的分级(5级)。如需使能5级检测，并选择 表2. PD的PSE分级(IEEE 802.3at标准的表 33.9) MEASURED ICLASS (mA) CLASSIFICATION 0 to 5 Class 0 > 5 and < 8 Can be Class 0 or 1 8 to 13 Class 1 > 13 and < 16 Either Class 1 or 2 16 to 21 Class 2 > 21 and < 25 Either Class 2 or 3 25 to 31 Class 3 > 31 and < 35 Either Class 3 or 4 35 to 45 Class 4 > 45 and < 51 Either Class 4 or Invalid 相应的限流/过流门限，则必须根据表3所列的组合设置ILIM1 和ILIM2。一旦使能5级功能，分级期间，如果MAX5984 检测到超过4级上限电流，则将PD分级置于5级PD。对于 任何介于51mA至分级限流门限之间的分级电流，均将PD 分级为5级。 5级过流门限和限流值采用ILIM1和ILIM2设置。ILIM1和 ILIM2均以VEE为参考，并在内部上拉至数字电源。ILIM1 和ILIM2不 连 接 时， 则 禁 用5级 检 测， 并 完 全 符 合IEEE 802.3at标准分级；将这两个引脚中的一个或两者均连接 至VEE则使能5级检测功能，并调节相应的过流门限和限流 值(表3)。 2事件PD分级 如果第一次分级事件得到的结果为0级至3级，那么就只会 发生单次分级事件，如图1所示。然而，如果结果是4级或5 级(当使能时)，器件就会执行第二次分级事件，如图2所示。 在分级循环之间，MAX5984根据IEEE 802.3at标准的要求 执行第一次和第二次事件标记，在DET强制输出-9.0V检 测电压。MAX5984A/MAX5984B/MAX5984E默认情况下 禁止2事件功能，而MAX5984E不能通过引脚选择。 用电状态 当MAX5984进入用电状态时，tFAULT和tDISC定时器被复 位。启动定时器超时，器件则进入正常用电状态，允许直 接为PD供电。 表3. 5级过流门限和限流值设置 ILIM2 CONFIGURATION OVERCURRENT THRESHOLD (mA) CURRENT LIMIT (mA) Unconnected Unconnected Class 5 disabled Class 5 disabled VEE Unconnected 748 850 Unconnected VEE 792 900 VEE VEE 836 950 ILIM1 CONFIGURATION 15 MAX5984 PD分级 在PD分 级 模 式 下，MAX5984在DET输 出 一 路 检 测 电 压 (-18V， 典 型 值)并 测 量 流 入DET的 电 流。 测 得 的 电 流 决 定了PD的分级。若ILIM1和ILIM2引脚均处于浮空状态， MAX5984则根据IEEE 802.3at标准的表33.9对PD进行分 级(表2)。若测得的电流超过51mA，MAX5984则不对PD 供电，而是返回到再次尝试新检测之前的空闲状态。 MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET 80ms 150ms tDET(1) 150ms tDET(2) 19ms tCLASS t 0V -4V -9.3V -18V -48V VOUT 图1. 检测、分级和端口上电序列 9ms 9ms 80ms 150ms 150ms 19ms 19ms tDET(1) tDET(2) tCLASS(1) tCLASS(2) t 0V -4V -9.3V -18V -48V VOUT 图2. 检测、二次事件分级和端口上电序列 16 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET 关断端口。对于连续出现超出应力的情况，一个tFAULT周 期后立即进入故障保护状态。 在由于过流故障而发生关断后，tFAULT计数器不会立即 复 位， 而 是 开 始 减 小。 只 有 当tFAULT计 数 器 达 到 零 时， MAX5984才允许向端口供电。该特性为内部MOSFET提 供了一种自动端口供电占空比保护，避免过热。 正常供电状态下，ILIM和ICUT门限根据分级结果自动设置 (关于根据检测电流进行分级的结果请参考表2，关于相应 门限的信息请参考电气特性 表)。启动期间，ILIM总是设置 为420mA，与检测到的分级无关。 正常用电状态下，MAX5984检查是否存在过流，电流由 下式确定：ICUT = ~88% ILIM。tFAULT计数器设置所允许 的最大连续过流周期。该计数器在启动和正常用电状态下 均递增，但条件不同。启动过程中，当IRSENSE超过ILIM时 递增；正常用电状态下，当IRSENSE超过ICUT时递增。当 IRSENSE下降至低于ILIM或ICUT时，该计数器以较慢的速度 下降。tFAULT计数器以较慢的速率下降能够检测重复性的 短期过流事件。当计数器达到tFAULT限值时，MAX5984则 折返限流 在启动和正常工作期间，内部电路检测端口电压，并在 (VAGND - VOUT) < 27V时减小限流值和过流门限。折返功 能有助于减小内部MOSFET的功耗。当(VAGND - VOUT) < 10V时，限流值最终会减小至ITH_FB (图3)。 IRSENSE ILIM ITH_FB 10V 27V VAGND - VOUT 图3. 折返限流特性 17 MAX5984 过流保护 MAX5984具有一个内部检测电阻RSENSE (请参见简化框图 部分)，该电阻连接在内部MOSFET的源极和VEE之间，用 于监测负载电流。正常工作条件下，通过RSENSE的电流 (IRSENSE)不会超过门限ILIM。如果IRSENSE超过ILIM，内部 限流电路会调整内部MOSFET的栅极电压，限制电流。瞬 态条件下，如果IRSENSE超过ILIM达到2A，将激活快速下拉 电路，迅速地从电流过冲状态中恢复。 MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET 数字逻辑 电或复位，则使能交流断开功能。当交流断开功能使能时， 必须采用一个隔离二极管串联到OUT，并将RC电路并联 至DET二极管，如图7所示。 MAX5984在内部产生数字供电电源(以VEE为参考)，为内 部逻辑电路供电。所有逻辑输入、输出均以VEE为参考。 关于数字输入门限的信息请参考电气特性 表。如果数字逻 辑输入由外部驱动，数字逻辑标称电平为3.3V。 交流断开功能采用一个内部三角波发生器提供检测信号， 然后将产生的4VP-P幅值波形输出至DET。在DET上侦测 的输出信号的共模电压低于AGND 5V。如果流入DET的交 流电流峰值低于IACTH且保持时间超过tDISC，器件将关断 端口。 欠压和过压保护 MAX5984具有欠压和过压保护功能。内部VEE欠压锁定 (VEE_UVLO)电路保持端口关闭并使MAX5984处于复位状态， 直到VAGND - VEE超过28.5V (典型值)且保持时间达2.5ms以 上。当(VAGND - VEE)超过62.5V (典型值)时，内部VEE过压 (VEE_OV)电路则关断端口。 PWM和LED信号 MAX5984包括一个多功能LED驱动器，用于提示用户端 口的状态。LED为漏极开路多功能输出，以VEE为参考， 在驱动外部LED时可吸收高达10mA (典型值)的电流。当 端口连接到一个有效PD并供电时，点亮LED。若端口没有 供电或断开时，则关闭LED。 直流断开监测 将OSC强制为VEE，并对器件上电或复位，则激活直流负载 断开监测功能。如果IRSENSE (通过RSENSE的电流)下降至直 流负载断开门限IDCTH以下且保持时间超过tDISC，器件则关 断端口电源。 对于其它两种情况，MAX5984则以闪烁状态报告端口的 状态。每次闪烁两下表示端口供电期间发生了过流故障， 时序特征如图4所示；每次闪烁5下则表示在检测期间发现 较低或较高的无效特征电阻，时序特性如图5所示。 交流断开监测 MAX5984具 有 交 流 负 载 断 开 监 测 功 能。 用 一 个100nF (±10%容差)的外部电容将OSC旁路至VEE，然后对器件上 PORT POWERED ON LED ON PORT POWERED DOWN, DUE TO OVERCURRENT FAULT LED OFF LED ON LED OFF LED ON 223ms 74ms 223ms 74ms PORT POWERED ON AGAIN LED OFF LED ON 图4. 端口供电期间发生过流故障时的LED码时序 INVALID HIGH OR LOW DISCOVERY SIGNATURE RESISTANCE DETECTED LED ON LED OFF LED ON LED OFF LED ON LED OFF LED ON LED OFF LED ON 74ms 223ms 74ms 223ms 74ms 223ms 74ms 223ms 74ms SEQUENCE REPEATS 图5. 由于较高或较低的特征电阻造成检测故障时的LED码时序 18 LED OFF 1.4s 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET 1) 在尽量靠近MAX5984的位置放置输入旁路电容和输出 旁路电容(AGND与OUTP之间的0.1μF陶瓷电容)。 2) 对于功率耗散器件(例如MAX5984)以及大功率通路中的 外部二极管，采用大尺寸SMT元件焊盘。 3) 大功率通路尽量采用短而宽的走线。 4) 参考MAX5971评估板进行设计和布局。 热关断 5) 裸焊盘(EP)必须均匀焊接至PCB接地层，以确保正常的 工作和散热。在裸焊盘下方采用多个过孔，改善散热。 建 议 过 孔 的 间 隔 为1.0mm至1.2mm， 并 采 用 小 孔 径 (0.30mm至0.33mm)的电镀(1oz铜)过孔。 如果MAX5984的管芯温度达到+150°C，就会产生过热故 障，关断器件。管芯温度必须冷却至130°C以下时才会清 除过热故障条件。清除热关断条件后，器件复位。 应用信息 布局步骤 严谨的PCB布局是实现高效率和低EMI的关键。遵守以下 布局原则有助于获得最佳性能。 1N4448 SMJ58A 10mH 0.1µF 100V 2.2MI PSE OUTPUT 47µF 100V 0.1µF 100V LED 5.1kI AGND OUT LED EN MAX5984C OUTP 1nF -54V VEE 1N4448 VEE_DIG DET LEGACY ILIM1 MIDSPAN ILIM2 1kI -54V 1kI OSC PWMEN 图6. 典型工作电路1 (直流负载断开检测、内部PWM使能用于LED指示、使能5级检测) 19 MAX5984 MAX5984还具有内部方波、PWM信号发生器。PWM的 典型频率为25kHz，典型占空比大约为6.25%。PWMEN 用 来 使 能 或 禁 止PWM。PWMEN在 内 部 上 拉 至 数 字 电 源，可以使其保持浮空，使能内部PWM。使能时，LED 脉冲则由PWM驱动以降低功耗，并提高系统效率。强制 PWMEN为低电平时禁用内部PWM，直接驱动LED。 MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET 1N4448 SMJ58A 10mH 0.1µF 100V 2.2MI PSE OUTPUT 47µF 100V 0.1µF 100V LED 5.1kI AGND LED OUT EN OUTP S1B MAX5984C 1nF VEE -54V 1N4448 0.47FF 100V 1kI VEE_DIG DET LEGACY ILIM1 MIDSPAN ILIM2 1kI -54V 1kI PWMEN OSC 0.1µF 图7. 典型工作电路2 (交流负载断开检测、内部PWM使能用于LED指示、使能5级检测) 47µF 100V 0.1µF 100V SMJ58A 0.1µF 100V 2.2MI PSE OUTPUT AGND VEE -54V OUT VEE_DIG EN OUTP MAX5984A/B/D 1N4448 1nF LED 2-EVENT/ LSCEN DET LEGACY ILIM1 MIDSPAN ILIM2 OSC 图8. 典型工作电路3 (符合IEEE 802.3at标准，具有直流负载断开检测、不带LED指示的最小应用电路) 20 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET PROCESS: BiCMOS 封装信息 如需最近的封装外形信息和焊盘布局(占位面积)，请查询china. maxim-ic.com/packages。 请 注 意， 封 装 编 码 中 的“+”、“#” 或“-”仅表示RoHS状态。封装图中可能包含不同的尾缀字符， 但封装图只与封装有关，与RoHS状态无关。 封装类型 封装编码 外形编号 焊盘布局编号 28 TQFN-EP T2855+6 21-0140 90-0026 21 MAX5984 芯片信息 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET MAX5984 修订历史 修订号 修订日期 0 12/11 说明 最初版本。 修改页 — Maxim北京办事处 北京8328信箱 邮政编码100083 免费电话：800 810 0310 电话：010-6211 5199 传真：010-6211 5299 Maxim不对Maxim产品以外的任何电路使用负责，也不提供其专利许可。Maxim保留在任何时间、没有任何通报的前提下修改产品资料和规格的权利。 22 © Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 2011 Maxim Integrated Products Maxim是Maxim Integrated Products，Inc.的注册商标。 MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET - 概述 Login Register 产品 方案 设计 销售联络 技术支持 公司简介 简体中文 (cn) 简体中文 (cn) 我的Maxim Maxim > 产品 > 热插拔、PoE和电源开关 > MAX5984 MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET 高度集成方案有效简化PSE设计 概述 技术文档 定购信息 用户说明 (0) 所有内容 状况 数据资料 型号 状况 英文 MAX5984 状况：生产中。 中文 概述 下载 Rev. 0 (PDF, 2.6MB) E-Mail 下载 Rev. 0 (PDF, 2.7MB) E-Mail MAX5984是一款单端口、供电设备(PSE)控制器，设计用于IEEE® 802.3af/at兼容PSE。这款器件提供用电设 备(PD)的侦测、分级、限流以及直流/交流负载开路检测。MAX5984采用自主操作模式，无需任何软件编程，内部 集成了功率MOSFET和检流电阻。器件支持新一代5级、2事件分级，用于侦测大功率PD。MAX5984为单个端 口(5级使能)提供高达40W功率，并提供传统PD的大容量检测。 MAX5984具有输入欠压锁定(UVLO)、输入过压锁定、高温检测、启动过程的输出摆率限制以及LED状态指示。 MAX5984提供节省空间的28引脚TQFN (5mm x 5mm)功率封装，工作在扩展级(-40°C至+85°C)温度范围。 关键特性 兼容于IEEE 802.3af/at 高达40W的单端口PSE应用 集成0.5Ω功率MOSFET和检流电阻 2事件引脚选择(MAX5984A/MAX5984B) PD检测和分级 为5级PD提供可编程限流 为传统设备提供大容量检测 具有直流/交流负载开路检测 电流折返、占空比控制限流 LED指示端口状态 直接快速关断控制 节省空间的28引脚TQFN (5mm × 5mm)封装 应用/使用 工业自动控制 PoE Repeaters 单端口PSE端点应用 单端口PSE电源(中跨系统) 交换机/路由器 Wireless LAN Access Point/WiMAX® Base Stations 没有找到你需要的产品吗？ 应用工程师帮助选型，下个工作日回复 参数搜索 应用帮助 信息索引 概述 技术文档 定购信息 相关产品 概述 关键特性 应用/使用 关键指标 图表 注释、注解 数据资料 技术文档 评估板 可靠性报告 软件/模型 价格与供货 样品 在线订购 封装信息 无铅信息 类似功能器件 类似应用器件 评估板 类似型号器件 配合该器件使用的产品 http://china.maxim-ic.com/datasheet/index.mvp/id/7615[2012-08-28 8:47:05] MAX5984 单端口、40W、IEEE 802.3af/at PSE控制器，集成MOSFET - 概述 参考文献： 19- 6142 Rev. 0; 2012- 01- 11 本页最后一次更新: 2012- 01- 11 联络我们：信息反馈、提出问题 | 隐私权政策 | 法律声明 | Distributor Portal © 2012 Maxim Integrated Products版权所有 http://china.maxim-ic.com/datasheet/index.mvp/id/7615[2012-08-28 8:47:05] 19-6142; Rev 0; 12/11 TION KIT EVALUA BLE AVAILA Single-Port, 40W, IEEE 802.3af/at PSE Controller with Integrated MOSFET Features SIEEE 802.3af/at Compliant The MAX5984 provides input undervoltage lockout (UVLO), input overvoltage lockout, overtemperature detection, output voltage slew-rate limit during startup, and LED status indication. SCurrent Foldback and Duty Cycle-Controlled Current Limit The MAX5984 is available in a space-saving, 28-pin TQFN (5mm x 5mm) power package, and is rated for the extended (-40NC to +85NC) temperature range. SUp to 40W for Single-Port PSE Applications SIntegrated 0.5I Power MOSFET and Sense Resistor S2-Event Pin-Select (MAX5984A/MAX5984B) SPD Detection and Classification SProgrammable Current Limit for Class 5 PDs SHigh-Capacitance Detection for Legacy Devices SSupports Both DC and AC Load Removal Detections SLED Indicator for Port Status SDirect Fast-Shutdown Control Capability SSpace-Saving, 28-Pin TQFN (5mm x 5mm) Package Applications Typical Operating Circuit Single-Port PSE End-Point Applications Single-Port PSE Power Injectors (Midspan Applications) PoE Repeaters PSE OUTPUT Switches/Routers Industrial Automation Equipment Wireless LAN Access Point/WiMAX® Base Stations AGND -54V VEE VEE_DIG LED Ordering Information PINSELECT PINTEMP RANGE PACKAGE MAX5984AETI+ 2-EVENT -40NC to +85NC 28 TQFN-EP* MAX5984BETI+** 2-EVENT -40NC to +85NC 28 TQFN-EP* MAX5984CETI+** PWMEN -40NC to +85NC 28 TQFN-EP* MAX5984DETI+ LSCEN -40NC to +85NC 28 TQFN-EP* PART OUT 2-EVENT OUTP MAX5984A LEGACY DET MIDSPAN ILIM1 OSC ILIM2 EN +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. **Future product—Contact factory for availability. IEEE is a registered service mark of the Institute of Electrical and Electronics Engineers, Inc. WiMAX is a registered service mark of WiMAX Forum Corp. ________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX5984 General Description The MAX5984 is a single-port, power-sourcing equipment (PSE) power controller designed for use in IEEE® 802.3af/at-compliant PSE. This device provides powered device (PD) discovery, classification, current limit, and DC and AC load-disconnect detections. The MAX5984 operates automatically without the need for any software programming and features an integrated power MOSFET and sense resistor. The device also supports new Class 5 and 2-Event classification for detection and classification of high-power PDs. The MAX5984 provides up to 40W to a single port (Class 5 enabled) and still provides highcapacitance detection for legacy PDs. MAX5984 Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET ABSOLUTE MAXIMUM RATINGS (Voltages referenced to VEE, unless otherwise noted.) AGND, DET, LED...................................................-0.3V to +80V OUT.......................................................-0.3V to (VAGND + 0.3V) OUTP........................................................-6V to (VAGND + 0.3V) VEE_DIG................................................................-0.3V to +0.3V OSC..........................................................................-0.3V to +6V EN, 2-EVENT/PWMEN/LSCEN, MIDSPAN, LEGACY, ILIM1, ILIM2..........................................-0.3V to +4V Maximum Current Into LED.................................................40mA Maximum Current Into OUT.......................... Internally regulated Continuous Power Dissipation (TA = +70NC) TQFN (derate 34.5mW/NC above +70NC)...............2758.6mW Operating Temperature Range........................... -40NC to +85NC Storage Temperature Range............................. -65NC to +150NC Junction Temperature......................................................+150NC Lead Temperature (soldering, 10s).................................+300NC Soldering Temperature (reflow).......................................+260NC 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. PACKAGE THERMAL CHARACTERISTICS (Note 1) TQFN Junction-to-Ambient Thermal Resistance........................ 29NC Junction-to-Case Thermal Resistance............................... 2NC Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. ELECTRICAL CHARACTERISTICS (VAGND - VEE = 32V to 60V, TA = -40NC to +85NC, all voltages are referenced to VEE, unless otherwise noted. Typical values are at VAGND - VEE = 54V, TA = +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 60 V 2.5 4 mA POWER SUPPLIES Operating Voltage Range Supply Current VAGND VAGND - VEE 32 IEE VOUT = VEE, all logic inputs unconnected, measured at AGND in power mode ILIM Maximum ILOAD allowed during current-limit conditions, VOUT = 0V (Note 3) CURRENT LIMIT Current Limit Class 0, 1, 2, 3 400 420 441 Class 4 684 720 756 Class 5 if ILIM1 = VEE, ILIM2 = unconnected 807 850 893 Class 5 if ILIM1 = unconnected, ILIM2 = VEE 855 900 945 Class 5 if ILIM1 = VEE, ILIM2 = VEE 902 950 998 mA Foldback Initial OUT Voltage VFLBK_ST VAGND - VOUT below which the current limit starts folding back 27 V Foldback Final OUT Voltage VFLBK_END VAGND - VOUT below which the current limit reaches ITH_FB 10 V VOUT = VAGND 166 mA Minimum Foldback Current Limit Threshold ITH_FB 2 _______________________________________________________________________________________ Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET (VAGND - VEE = 32V to 60V, TA = -40NC to +85NC, all voltages are referenced to VEE, unless otherwise noted. Typical values are at VAGND - VEE = 54V, TA = +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX Class 0, 1, 2, 3 351 370 389 Class 4 602 634 666 Class 5 if ILIM1 = VEE, ILIM2 = unconnected 710 748 785 Class 5 if ILIM1 = unconnected, ILIM2 = VEE 752 792 832 Class 5 if ILIM1 = VEE, ILIM2 = VEE 794 836 878 TA = +25NC 0.5 0.9 TA = +85NC 0.6 1.3 UNITS OVERCURRENT Overcurrent Threshold ICUT Overcurrent threshold allowed for t P tFAULT, VOUT = 0V (Note 3) mA INTERNAL POWER DMOS On-Resistance RDS(ON) Power-Off OUT Leakage Current IOUT_LEAK Measured from OUT to VEE, IOUT = 100mA I VEN = VEE, VOUT = VAGND 10 FA SUPPLY MONITORS VEE Undervoltage Lockout VEE_UVLO VEE Undervoltage Lockout Hysteresis VEE_UVLOH VEE Overvoltage Lockout VEE_OV VEE Overvoltage Lockout Hysteresis VEE_OVH VAGND - VEE, VAGND increasing Port is shutdown if: VAGND - VEE < VEE_ UVLO - VEE_UVLOH VAGND - VEE > VEE_OV, VAGND increasing Port is shutdown and device resets if the junction temperature exceeds this limit, temperature increasing Thermal Shutdown Threshold TSHD Thermal Shutdown Hysteresis TSHDH Temperature decreasing IBOUT VOUT = VAGND, probing phases 28.5 V 3 V 62.5 V 1 V +150 NC 20 NC OUTPUT MONITOR OUT Input Current IDIS OUTP discharge current, detection and classification off, port shutdown, VOUTP = VAGND - 2.8V 200 Short to VEE Detection Threshold DCNTH VOUT - VEE, VOUT decreasing, enabled during detection 1.5 Short to VEE Detection Threshold Hysteresis DCNHY Idle Pullup Current at OUT 2.0 6 FA 265 FA 2.5 V 220 mV LOAD DISCONNECT DC Load-Disconnect Threshold IDCTH Minimum load current allowed before disconnect (DC disconnect active), VOUT = 0V AC Load-Disconnect Threshold IACTH Current into DET, for IDET < IACTH the port powers off (AC disconnect active) 5 7.5 10 mA 115 130 145 FA _______________________________________________________________________________________ 3 MAX5984 ELECTRICAL CHARACTERISTICS (continued) MAX5984 Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET ELECTRICAL CHARACTERISTICS (continued) (VAGND - VEE = 32V to 60V, TA = -40NC to +85NC, all voltages are referenced to VEE, unless otherwise noted. Typical values are at VAGND - VEE = 54V, TA = +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2) PARAMETER SYMBOL MIN TYP MAX UNITS 3.85 4 4.2 V Measured at OSC 26 32 39 FA VACD_EN VOSC - VEE > VACD_EN to activate AC disconnect 270 330 380 mV tDISC Time from IRSENSE < IDCTH (DC disconnect active) or IDET < IACTH (AC disconnect active) to gate shutdown 300 400 ms Detection Probe Voltage (First Phase) VDPH1 VAGND - VDET during the first detection phase 3.8 4 4.2 V Detection Probe Voltage (Second Phase) VDPH2 VAGND - VDET during the second detection phase 9 9.3 9.6 V Current-Limit Protection IDLIM VDET = VAGND during detection, measure current through DET 1.50 1.75 2.00 mA Short-Circuit Threshold VDCP If VAGND - VOUT < VDCP after the first detection phase, a short circuit to AGND is detected 1 V Open-Circuit Threshold ID_OPEN First point measurement current threshold for open condition 8 FA Triangular Wave Peak-to-Peak Voltage Amplitude AMPTRW OSC Pullup/Pulldown Currents IOSC ACD_EN Threshold Load Disconnect Timer CONDITIONS Measured at DET, referred to AGND DETECTION Resistor Detection Window Resistor Rejection Window RDOK RDBAD (Note 4) 19 26.5 Detection rejects lower values 15.5 kI kI Detection rejects higher values 32 VAGND - VDET during classification 16 20 V VDET = VAGND, during classification measure current through DET 65 80 mA CLASSIFICATION Classification Probe Voltage Current-Limit Protection Classification Current Thresholds Mark Event Voltage Mark Event Current Limit VCL IClLIM ICL VMARK IMARK_LIM Classification current thresholds between classes Class 0, Class 1 5.5 6.5 7.5 Class 1, Class 2 13.0 14.5 16.0 Class 2, Class 3 21 23 25 Class 3, Class 4 31 33 35 Class 4 upper limit (Note 5) 45 48 51 mA VAGND - VDET during mark event 8 10 V VDET = VAGND, during mark event measure current through DET 55 80 mA 4 _______________________________________________________________________________________ Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET (VAGND - VEE = 32V to 60V, TA = -40NC to +85NC, all voltages are referenced to VEE, unless otherwise noted. Typical values are at VAGND - VEE = 54V, TA = +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 0.8 V DIGITAL INPUTS/OUTPUTS (Voltages referenced to VEE) Digital Input Low VIL Digital Input High VIH 2.4 IPU Pullup current to internal digital supply to set default values LED Output Low Voltage VLED_LOW LED Output Leakage ILED_LEAK Internal Input Pullup Current 3 V 5 7 FA ILED = 10mA, PWM disabled, port power-on 0.8 V PWM disabled, shutdown mode, VLED = 60V 10 FA PWM Frequency 25 kHz PWM Duty Cycle 6.25 % TIMING Startup Time tSTART Time during which a current limit set to 420mA is allowed, starts when power is turned on 50 60 70 ms Fault Time tFAULT Maximum allowed time for an overcurrent condition set by ICUT after startup 50 60 70 ms Detection Reset Time tME Time allowed for the port voltage to reset before detection starts 80 90 ms Detection Time tDET Maximum time allowed before detection is completed 330 ms Midspan Mode Detection Delay tDMID Classification Time tCLASS Mark Event Time Time allowed for mark event VEEUVLO Turn-On Delay Restart Timer 2 Time allowed for classification tDLY tRESTART Time VAGND must be above the VEEUVLO thresholds before the device operates Time the device waits before turning on after an overcurrent fault 7 2.2 2.4 s 19 23 ms 9 11 ms 5.2 ms 16 x tFAULT ms Note 2: This device is production tested at TA = +25NC. Limits at TA = -40NC and TA = +85NC are guaranteed by design. Note 3: If ILIM1 and ILIM2 are both unconnected, Class 5 detection is disabled. See the Class 5 PD Classification section and Table 3 for details and settings. Note 4: RDOK = (VOUT2 - VOUT1)/(IDET2 - IDET1). VOUT1, VOUT2, IDET2, and IDET1 represent the voltage at OUT and the current at DET during phase 1 and 2 of the detection, respectively. Note 5: If Class 5 is enabled, this is the classification current thresholds from Class 4 to Class 5. _______________________________________________________________________________________ 5 MAX5984 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) ANALOG SUPPLY CURRENT vs. INPUT VOLTAGE SUPPLY CURRENT (mA) 2.6 2.5 2.4 MEASURED AT AGND 2.6 2.5 2.4 30.0 MAX5984 toc03 2.7 UNDERVOLTAGE LOCKOUT (V) MEASURED AT AGND VEE UNDERVOLTAGE LOCKOUT vs. TEMPERATURE MAX5984 toc02 ANALOG SUPPLY CURRENT vs. TEMPERATURE MAX5984 toc01 2.7 SUPPLY CURRENT (mA) 29.5 29.0 28.5 28.0 27.5 2.3 32 36 40 44 48 52 56 2.3 60 27.0 -15 -40 VAGND - VEE (V) 10 35 60 85 10 35 TEMPERATURE (°C) INTERNAL FET RESISTANCE vs. TEMPERATURE 63.5 FET RESISTANCE (mΩ) 63.0 62.5 62.0 61.5 61.0 MAX5984 toc05 1000 MAX5984 toc04 64.0 OVERVOLTAGE LOCKOUT (V) -15 -40 TEMPERATURE (°C) VEE OVERVOLTAGE LOCKOUT vs. TEMPERATURE 800 600 400 60.5 60.0 200 -40 -15 10 35 60 85 -40 -15 10 35 60 TEMPERATURE (°C) TEMPERATURE (°C) FOLDBACK CURRENT-LIMIT THRESHOLD vs. OUTPUT VOLTAGE DC DISCONNECT THRESHOLD vs. TEMPERATURE CLASS 4 600 500 400 300 CLASS 0, 1, 2, 3 200 100 0 0 10 20 VAGND - VOUT (V) 30 40 85 MAX5984 toc07 700 7.4 DC DISCONNECT THRESHOLD (mA) MAX5984 toc06 800 IRSENSE (mA) MAX5984 Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET 7.2 7.0 6.8 6.6 6.4 -40 -15 10 35 60 TEMPERATURE (°C) 6 _______________________________________________________________________________________ 85 60 85 Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET SHORT-CIRCUIT RESPONSE TIME OVERCURRENT TIMEOUT (240Ω TO 138Ω) MAX5984 toc09 MAX5984 toc08 VAGND - VOUT 20V/div VAGND - VOUT 20V/div 0V 0V IOUT 200mA/div IOUT 200mA/div 0mA 0mA 20ms/div 20ms/div SHORT-CIRCUIT TRANSIENT RESPONSE EN TO OUT TURN-OFF DELAY MAX5984 toc10 MAX5984 toc11 VAGND - VOUT 20V/div VAGND - VOUT 20V/div 0V 0V IOUT 200mA/div 0mA IOUT 5A/div 0mA VEN 5V/div 0V 10µs/div 100µs/div ZERO-CURRENT DETECTION WAVEFORM WITH DC DISCONNECT ENABLED ZERO-CURRENT DETECTION WAVEFORM WITH AC DISCONNECT ENABLED MAX5984 toc12 MAX5984 toc13 VAGND - VOUT 20V/div VAGND - VOUT 20V/div 0V 0V IOUT 100mA/div IOUT 100mA/div 0mA 0mA 40ms/div 40ms/div _______________________________________________________________________________________ 7 MAX5984 Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) MAX5984 Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) OVERCURRENT RESTART DELAY STARTUP WITH A VALID PD MAX5984 toc14 MAX5984 toc15 VAGND - VOUT 20V/div VAGND - VOUT 20V/div 0V 0V IOUT 200mA/div IOUT 100mA/div 0mA 0mA 400ms/div 100ms/div DETECTION WITH INVALID PD (25kΩ TO 10µF) DETECTION WITH INVALID PD (15kΩ) MAX5984 toc16b MAX5984 toc16a VAGND - VOUT 1V/div VAGND - VOUT 5V/div 0V 0V IOUT 1mA/div 0mA IOUT 1mA/div 0mA 100ms/div 40ms/div DETECTION WITH INVALID PD (OPEN CIRCUIT) DETECTION WITH INVALID PD (33kΩ) MAX5984 toc16d MAX5984 toc16c VAGND - VOUT 5V/div VAGND - VOUT 5V/div 0V 0V IOUT 1mA/div 0mA 100ms/div IOUT 1mA/div 0mA 100ms/div 8 _______________________________________________________________________________________ Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET STARTUP IN MIDSPAN WITH A VALID PD DETECTION IN MIDSPAN WITH INVALID PD (15kΩ) MAX5984 toc17 MAX5984 toc18a VAGND - VOUT 20V/div 0V VAGND - VOUT 5V/div 0V IOUT 100mA/div 0mA IOUT 1mA/div 0mA 100ms/div 400ms/div DETECTION IN MIDSPAN WITH INVALID PD (33kΩ) MAX5984 toc18b DETECTION IN OUTPUT SHORTED TO AGND MAX5984 toc19 VAGND - VOUT 5V/div VAGND - VOUT 5V/div 0V 0V IOUT 1mA/div 0mA IOUT 1mA/div 0mA 40ms/div 400ms/div CLASSIFICATION WITH DIFFERENT PD CLASSES (0 TO 3) CLASSIFICATION WITH DIFFERENT PD CLASSES (4 AND 5) MAX5984 toc20a MAX5984 toc20b VAGND - VOUT 10V/div 0V VAGND - VOUT 10V/div 0V CLASS 3 CLASS 2 0mA CLASS 1 CLASS 0 40ms/div CLASS 5 CLASS 4 IOUT 10mA/div IOUT 20mA/div 0mA 40ms/div _______________________________________________________________________________________ 9 MAX5984 Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) MAX5984 Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) STARTUP USING 2-EVENT CLASSIFICATION WITH A VALID PD MAX5984 toc21 LED DETECTION FAULT WITH PWM ENABLED MAX5984 toc22a VAGND - VOUT 20V/div 0V VAGND - VOUT 10V/div 0V IOUT 500mA/div 0mA IOUT 100mA/div VAGND - VLED 20V/div 0mA 0V 100ms/div 200ms/div LED DETECTION FAULT WITH PWM DISABLED MAX5984 toc22b VAGND - VOUT 10V/div 0V IOUT 500mA/div 0mA LED OVERCURRENT FAULT WITH PWM ENABLED MAX5984 toc23a VAGND - VOUT 50V/div 0V IOUT 500mA/div 0mA VAGND - VLED 20V/div 0V VAGND - VLED 20V/div 0V 200ms/div 200ms/div LED OVERCURRENT FAULT WITH PWM DISABLED LED PWM TIMING AND DUTY CYCLE MAX5984 toc23b VAGND - VOUT 50V/div 0V IOUT 500mA/div 0mA MAX5984 toc24 VAGND - VOUT 50V/div 0V IOUT 500mA/div 0mA VAGND - VLED 20V/div VAGND - VLED 20V/div 0V 0V 200ms/div 10µs/div 10 ������������������������������������������������������������������������������������� Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET AGND N.C. OSC N.C. LED N.C. I.C. TOP VIEW 21 20 19 18 17 16 15 N.C. 22 14 EN DET 23 13 LEGACY N.C. 24 12 VEE_DIG OUTP 25 11 I.C. 10 I.C. 9 I.C. 8 I.C. MAX5984 OUT 26 OUT 27 *EP + 4 5 6 7 ILIM2 2-EVENT/PWMEN/LSCEN MIDSPAN VEE 3 ILIM1 2 VEE 1 VEE N.C. 28 THIN QFN *EXPOSED PAD, CONNECT TO AGND. Pin Description PIN NAME FUNCTION Analog Low-Side Supply Input. Bypass with an external 100V, 47FF capacitor in parallel with a 100V, 0.1FF ceramic capacitance between AGND and VEE. 1, 2, 3 VEE 4 ILIM1 Class 5 Current-Limit Digital Adjust 1. Referenced to VEE. ILIM1 is internally pulled up to the digital supply. Use ILIM1 with ILIM2 to enable Class 5 operation and to adjust the Class 5 current-limit value. See the Electrical Characteristics table and Table 3 for details. 5 ILIM2 Class 5 Current-Limit Digital Adjust 2. Referenced to VEE. ILIM2 is internally pulled up to the digital supply. Use ILIM2 with ILIM1 to enable Class 5 operation and to adjust the Class 5 current-limit value. See the Electrical Characteristics table and Table 3 for details. 6 2-EVENT (MAX5984A/ MAX5984B) 2-Event Classification Select. Referenced to VEE. 2-EVENT is internally pulled up to the digital supply. Leave unconnected to disable 2-Event classification. Force low to enable the 2-Event classification. See the 2-Event PD Classification section for more details. Change status of this bit only when the part is in reset state. The MAX5984C/MAX5984D are enabled. PWMEN (MAX5984C) PWM Control Logic Input. Referenced to VEE. PWMEN is internally pulled up to the digital supply. Leave unconnected to enable the internal PWM to drive the LED pin. Force low to disable the internal PWM. The MAX5984A/MAC5984B/MAX5984D are enabled. LSCEN (MAX5984D) Load Stability Check Function Select. Referenced to VEE. LSCEN is internally pulled up to the digital supply. Leave unconnected to enable the load stability check function. Force low to disable the load stability check function. Change status of this bit only when the part is in reset state. The MAX5984A is disabled but the MAX5984B/MAX5984C are enabled. ______________________________________________________________________________________ 11 MAX5984 Pin Configuration MAX5984 Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET Pin Description (continued) PIN 7 NAME MIDSPAN FUNCTION Detection Collision Avoidance Logic Input. Referenced to VEE. MIDSPAN is internally pulled up to the digital supply. Leave unconnected to activate the detection collision avoidance circuitry for midspan PSE systems. Force low to disable this function for an end-point PSE system. The MIDSPAN logic level latches after the device is powered up or after a reset condition. 8–11, 15 I.C. 12 VEE_DIG Digital Low-Side Supply Input. Connect to VEE externally. 13 LEGACY Legacy Detection Logic Input. Referenced to VEE. LEGACY is internally pulled up to the digital supply. Leave unconnected to activate the legacy PD detection. Force low to disable this function. The LEGACY logic level latches after the device is powered up or after a reset condition. 14 EN Enable Input. Referenced to VEE. EN is internally pulled up to the digital supply. Leave unconnected to enable the device. Force low for at least 40Fs to reset the device. The MIDSPAN, OSC, and LEGACY states latch-in when the reset condition is removed (low-to-high transition). 16, 18, 20, 22, 24, 28 N.C. No Connection. Not internally connected. Leave N.C. unconnected. LED LED Indicator Open-Drain Output. Referenced to VEE. LED can sink 10mA and can drive an external LED directly. Blinking functionality is provided to signal different conditions (see the PWM and LED Signals section). Connect LED to AGND externally or to an external supply (if available) through a series resistance (Figures 6 and 7). 19 OSC AC Disconnect Triangular Wave Output. Bypass with a 100nF (Q10% tolerance) external capacitor to VEE to enable the AC disconnect function. Connect OSC to VEE to disable the AC disconnect function and to activate the DC disconnect function. The OSC state latches after the device is powered up or after a reset condition. 21 AGND 17 23 DET 25 OUTP 26, 27 OUT — EP Internally Connected. Connect I.C. to VEE. High-Side Supply Input Detection/Classification Voltage Output. DET is used to set the detection mark event and classification probe voltages and for the AC current sensing when using the AC disconnect function. To use the AC disconnect function, place a 1kI and 0.47FF RC series in parallel with the external protection diode to OUTP (Figure 7). Port Pullup Output. OUTP is used to pull up the port voltage to AGND when needed. If AC disconnect is used, connect OUTP to the anode of the AC-blocking diode. If AC disconnect is not used, connect OUTP to OUT (Figures 6 and 8). Bypass OUTP to AGND with a 100V, 0.1FF ceramic capacitor. Integrated MOSFET Output. If DC disconnect is used, connect the port output to OUTP (Figures 6 and 8). If the AC disconnect function is used, connect OUT to the cathode of the AC-blocking diode (Figure 7). Exposed Pad. Connect EP to VEE externally. See the Layout Procedure section for details. 12 ������������������������������������������������������������������������������������� Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET OSC CURRENT SENSING VOLTAGE PROBING AND CURRENT-LIMIT CONTROL TRIANGLE WAVE GENERATOR OSC STATUS MONITOR EN AGND OUTP LEGACY MIDSPAN DETECTION AND CLASSIFICATION CONTROL PORT STATE MACHINE (SM) REGISTER FILE VOLTAGE SENSING 9-BIT ADC AC DISCONNECT ENABLE CENTRAL LOGIC UNIT (CLU) AGND VEE DET ANALOG BIAS AND SUPPLY MONITOR OUT FOLDBACK CONTROL A=1 GATE DRIVE INTERNAL SUPPLIES AC DETECTOR AC DISCONNECT SIGNAL (ACD) VOLTAGE REFERENCES ACD REFERENCE CURRENT CURRENT REFERENCES THRESHOLD SETTINGS LED 2-EVENT/PWMEN/LSCEN MAX5984 2-EVENT/PWMEN/LSCEN Detailed Description The MAX5984 is a single-port, PSE power controller designed for use in IEEE 802.3af/IEEE 802.3at-compliant PSE. This device provides PD discovery, classification, current limit, and DC and AC load-disconnect detections. The MAX5984 operates automatically without the need for any software programming and features an integrated power MOSFET and sense resistor. The device also supports new Class 5 and 2-event classification for detection and classification of high-power PDs. The MAX5984 provides up to 40W to a single port (Class 5 enabled) and still provides high-capacitance detection for legacy PDs. INTERNAL MOSFET CURRENT LIMIT, OVERCURRENT, AND OPENCIRCUIT SENSING, AND FOLDBACK CONTROL INTERNAL RSENSE CLASS 5 ENABLE/DISABLE, OVERCURRENT AND CURRENT LIMIT CONTROL ILIM1 ILIM2 The MAX5984 provides input UVLO, input overvoltage lockout, overtemperature detection, output voltage slewrate limit during startup, and LED status indication. Reset The MAX5984 is reset by any of the following conditions: 1) Power-up. Reset condition is cleared once VEE rises above the UVLO threshold. 2)Hardware reset. Reset occurs once the EN input is driven low (> 40µs typ) any time after power-up. The device exits the reset condition once the EN input is driven high again. 3)Thermal shutdown. The device enters thermal shutdown at +150NC. The device exits thermal shutdown and is reset once the temperature drops below 130NC. ______________________________________________________________________________________ 13 MAX5984 Simplified Diagram MAX5984 Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET During a reset, the MAX5984 latches in the state of MIDSPAN, LEGACY, and OSC. During normal operation, changes to these inputs are ignored. During detection, the MAX5984 keeps the internal MOSFET off and forces two probe voltages through DET. The current through DET is measured as well as the voltage at OUT. A two-point slope measurement is used, as specified by the IEEE 802.3af/802.3at standard, to verify the device connected to the port. Midspan Mode In midspan mode, the device adopts cadence timing during the detection phase. When cadence timing is enabled and a failed detection occurs, the port waits between 2s and 2.4s before attempting to detect again. Midspan mode is activated by setting MIDSPAN high and then powering or resetting the device. By default, the MIDSPAN input is internally pulled high. Force MIDSPAN low to disable this function. An external diode, in series with the DET input, restricts PD detection to the first quadrant as specified by the IEEE 802.3af/802.3at standard. To prevent damage to non-PD devices, and to protect itself from an output short circuit, the MAX5984 limits the current into DET to less than 2mA maximum during PD detection. In midspan mode, the MAX5984 waits at least 2.0s before attempting another detection cycle after every failed detection. The first detection, however, happens immediately after exiting a reset condition. Automatic Operation The MAX5984 operates automatically after the reset condition is cleared. The device performs detection and classification, and powers up the port automatically once a valid PD is detected at the port. If a valid PD is not connected at the port, the MAX5984 repeats the detection routine continuously until a valid PD is connected. High-Capacitance Detection The status of the LEGACY input is latched during powerup or after reset condition is cleared. The LEGACY input is internally pulled high enabling high-capacitance detection. Unless high-capacitance detection is needed, connect LEGACY to VEE to disable this function. If highcapacitance detection is enabled, PD signature capacitances up to 47FF (typ) are accepted. PD Detection During normal operation, the MAX5984 probes the output for a valid PD. A valid PD has a 25kI discovery signature characteristic as specified in the IEEE 802.3af/802.3at standard. Table 1 shows the IEEE 802.3at specification for a PSE detecting a valid PD signature. Table 1. PSE PD Detection Modes Electrical Requirements (IEEE 802.3at) PARAMETER SYMBOL MIN MAX UNITS ADDITIONAL INFORMATION Open-circuit voltage VOC 30 V In detection mode only Short-circuit current ISC 5 mA In detection mode only 10 V Valid test voltage VVALID 2.8 Voltage difference between test points DVTEST 1 V tBP 2 ms Time between any two test points Slew rate VSLEW 0.1 V/Fs Accept signature resistance RGOOD 19 26.5 kI Reject signature resistance RBAD < 15 > 33 kI Open-circuit resistance ROPEN 500 Accept signature capacitance CGOOD Reject signature capacitance CBAD 10 Signature offset voltage tolerance VOS 0 2.0 V Signature offset current tolerance IOS 0 12 FA This timing implies a 500Hz maximum probing frequency kI 150 nF FF 14 ������������������������������������������������������������������������������������� Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET Class 5 PD Classification The MAX5984 supports high power beyond the IEEE 802.3at standard by providing an additional classification (Class 5) if needed. To enable Class 5 detection and select the corresponding current-limit/overcurrent thresholds, ILIM1 and ILIM2 must be set based on the combinations detailed in Table 3. Once Class 5 is Table 2. PSE Classification of a PD (Table 33.9 of the IEEE 802.3at Standard) MEASURED ICLASS (mA) CLASSIFICATION 0 to 5 Class 0 > 5 and < 8 Can be Class 0 or 1 8 to 13 Class 1 > 13 and < 16 Either Class 1 or 2 16 to 21 Class 2 > 21 and < 25 Either Class 2 or 3 25 to 31 Class 3 > 31 and < 35 Either Class 3 or 4 35 to 45 Class 4 > 45 and < 51 Either Class 4 or Invalid enabled, during classification, if the MAX5984 detects currents in excess of the Class 4 upper limit threshold, the PD is classified as a Class 5 PD. The PD is guaranteed to be classified as a Class 5 device for any classification current from 51mA up to the classification current-limit threshold. The Class 5 overcurrent threshold and current limit is set with ILIM1 and ILIM2. ILIM1 and ILIM2 are both referenced to VEE and are internally pulled up to the digital supply. Leave ILIM1 and ILIM2 unconnected to disable Class 5 detection and to be fully compliant to IEEE 802.3at standard classification. Class 5 detection is enabled, and the corresponding overcurrent threshold and current limit is adjusted, by connecting one or both to VEE (Table 3). 2-Event PD Classification If the result of the first classification event is Class 0 through Class 3, then only a single classification event occurs, as shown in Figure 1. However, if the result is Class 4 or Class 5 (when enabled), the device performs a second classification event, as shown in Figure 2. Between the classification cycles, the MAX5984 performs a first and second mark event as required by the IEEE 802.3at standard, forcing a -9.0V probing voltage at DET. The 2-Event function is disabled by default in the MAX5984A/MAX5984B/MAX5984E. However, it is not pin-selectable in the MAX5984E. Powered State When the MAX5984 enters a powered state, the tFAULT and tDISC timers are reset. When the startup timer has timed out, the device enters a normal powered condition, allowing power delivery to the PD. Table 3. Class 5 Overcurrent Threshold and Current-Limit Settings ILIM1 CONFIGURATION ILIM2 CONFIGURATION OVERCURRENT THRESHOLD (mA) CURRENT LIMIT (mA) Unconnected Unconnected Class 5 disabled Class 5 disabled VEE Unconnected 748 850 Unconnected VEE 792 900 VEE VEE 836 950 ______________________________________________________________________________________ 15 MAX5984 PD Classification During the PD classification mode, the MAX5984 forces a probe voltage (-18V typ) at DET and measures the current into DET. The measured current determines the class of the PD. If the ILIM1 and ILIM2 pins are both left unconnected, the MAX5984 classifies the PD based on Table 33.9 of the IEEE 802.3at standard (Table 2). If the measured current exceeds 51mA, the MAX5984 does not power the PD, but returns to the idle state before attempting a new detection cycle. MAX5984 Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET 80ms 150ms tDET(1) 150ms tDET(2) 19ms tCLASS t 0V -4V -9.3V -18V -48V VOUT Figure 1. Detection, Classification, and Port Power-Up Sequence 9ms 9ms 80ms 150ms 150ms 19ms 19ms tDET(1) tDET(2) tCLASS(1) tCLASS(2) t 0V -4V -9.3V -18V -48V VOUT Figure 2. Detection, 2-Event Classification, and Port Power-Up Sequence 16 ������������������������������������������������������������������������������������� Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET the tFAULT limit, the MAX5984 powers down the port. For a continuous overstress, a fault occurs exactly after a period of tFAULT. After a power-off due to an overcurrent fault, the tFAULT timer is not immediately reset but starts decrementing. The MAX5984 allows the port to be powered on only when the tFAULT counter reaches zero. This feature sets an automatic port power duty-cycle protection to the internal MOSFET to avoid overheating. In the normal powered state, the ILIM and ICUT thresholds are set automatically according to the classification result (see Table 2 for classification results based on detection current and the Electrical Characteristics table for the corresponding thresholds). During startup, ILIM is always set to 420mA regardless of the detected class. In the normal powered state, the MAX5984 checks for overcurrent conditions, as determined by ICUT = ~88% of ILIM. The tFAULT counter sets the maximum allowed continuous overcurrent period. This timer is incremented both in startup and in normal powered state, but under different conditions. During startup, the counter increases when IRSENSE exceeds ILIM, while in the normal powered state the counter increases when IRSENSE exceeds ICUT. It decreases at a slower pace when IRSENSE drops below ILIM or ICUT. A slower decrement for the tFAULT counter allows for detection of repeated shortduration overcurrent events. When the counter reaches Foldback Current During startup and normal operation, an internal circuit senses the port voltage and reduces the current-limit value and the overcurrent threshold when (VAGND VOUT) < 27V. The foldback function helps to reduce the power dissipation on the internal MOSFET. The current limit eventually reduces down to ITH_FB when (VAGND VOUT) < 10V (Figure 3). IRSENSE ILIM ITH_FB 10V 27V VAGND - VOUT Figure 3. Foldback Current Characteristics ______________________________________________________________________________________ 17 MAX5984 Overcurrent Protection The MAX5984 has an internal sense resistor, RSENSE (see the Simplified Diagram), connected between the source of the internal MOSFET and VEE to monitor the load current. Under normal operating conditions, the current through RSENSE (IRSENSE) never exceeds the threshold ILIM. If IRSENSE exceeds ILIM, an internal current-limiting circuit regulates the gate voltage of the internal MOSFET, limiting the current. During transient conditions, if IRSENSE exceeds ILIM by more than 2A, a fast pulldown circuit activates to quickly recover from the current overshoot. MAX5984 Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET Digital Logic a blocking diode in series to OUT and an RC circuit in parallel to the DET diode must be used, as shown in Figure 7. The MAX5984 internally generates digital supplies (referenced to VEE) to power the internal logic circuitry. All logic inputs and outputs are referenced to VEE. See the Electrical Characteristics table for digital input thresholds. If digital logic inputs are driven externally, the nominal digital logic level is 3.3V. The AC disconnect uses an internal triangle wave generator to supply the probing signal. Then the resulting 4VP-P amplitude wave is forced on DET. The common mode of the output signal probed on DET is 5V below AGND. If the AC current peak into DET falls below IACTH for more than tDISC, the device powers down the port. Undervoltage and Overvoltage Protection The MAX5984 contains undervoltage and overvoltage protection features. An internal VEE undervoltage lockout (VEE_UVLO) circuit keeps the port off and the MAX5984 in reset until VAGND - VEE exceeds 28.5V (typ) for more than 2.5ms. An internal VEE overvoltage (VEE_OV) circuit shuts down the port when (VAGND - VEE) exceeds 62.5V (typ). PWM and LED Signals The MAX5984 includes a multifunction LED driver to inform the user of the port status. LED is an open-drain, multifunction output referenced to VEE and can sink up to 10mA (typ) while driving an external LED. The LED is turned on when the port is connected to a valid PD and powered. If the port is not powered or is disconnected, the LED will be off. DC Disconnect Monitoring Force OSC to VEE and power or reset the device to activate DC load-disconnect monitoring. If IRSENSE (the current across RSENSE) falls below the DC load-disconnect threshold, IDCTH, for more than tDISC, the device turns off port power. For two other conditions, the MAX5984 blinks a code to communicate the port status. A series of two flashes indicates an overcurrent fault occurred during port power-on, and has a timing characteristic detailed by Figure 4. A series of five flashes indicates that during detection an invalid low or high discovery signature resistance was detected and has a timing characteristic detailed by Figure 5. AC Disconnect Monitoring The MAX5984 features AC load-disconnect monitoring. Bypass OSC with a 100nF (Q10% tolerance) external capacitor to VEE and power or reset the device to enable AC disconnect. When AC disconnect is enabled, PORT POWERED ON LED ON PORT POWERED DOWN, DUE TO OVERCURRENT FAULT LED OFF LED ON LED OFF LED ON 223ms 74ms 223ms 74ms PORT POWERED ON AGAIN LED OFF LED ON Figure 4. LED Code Timing for Overcurrent Fault During Port Power-On INVALID HIGH OR LOW DISCOVERY SIGNATURE RESISTANCE DETECTED LED ON LED OFF LED ON LED OFF LED ON LED OFF LED ON LED OFF LED ON 74ms 223ms 74ms 223ms 74ms 223ms 74ms 223ms 74ms LED OFF 1.4s SEQUENCE REPEATS Figure 5. LED Code Timing for Detection Fault Due to High- or Low-Discovery Signature Resistance 18 ������������������������������������������������������������������������������������� Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET 1) Place the input bypass capacitance and the output bypass capacitor (0.1µF ceramic capacitor from AGND to OUTP) as close as possible to the MAX5984. 2) Use large SMT component pads for power dissipating devices such as the MAX5984 and the external diodes in the high-power path. 3)Use short, wide traces whenever possible for highpower paths. 4)Use the MAX5971 Evaluation Kit as a design and layout reference. 5) The exposed pad (EP) must be soldered evenly to the PCB ground plane for proper operation and power dissipation. Use multiple vias beneath the exposed pad for maximum heat dissipation. A 1.0mm to 1.2mm pitch is the recommended spacing for these vias and they should be plated (1oz copper) with a small barrel diameter (0.30mm to 0.33mm). Thermal Shutdown If the MAX5984 die temperature reaches +150NC, an overtemperature fault is generated and the device shuts down. The die temperature must cool down below 130NC to remove the overtemperature fault condition. After a thermal shutdown condition clears, the device is reset. Applications Information Layout Procedure Careful PCB layout is critical to achieve high efficiency and low EMI. Follow these layout guidelines for optimal performance. 1N4448 SMJ58A 10mH 0.1µF 100V 2.2MI PSE OUTPUT 47µF 100V 0.1µF 100V LED 5.1kI AGND OUT LED EN MAX5984C OUTP 1nF -54V VEE 1N4448 VEE_DIG DET LEGACY ILIM1 MIDSPAN ILIM2 1kI -54V 1kI OSC PWMEN Figure 6. Typical Operating Circuit 1 (DC Load Removal Detection, Internal PWM Enabled for LED Indication, and Class 5 Detection Enabled) ______________________________________________________________________________________ 19 MAX5984 The MAX5984 also contains an internal square wave, PWM signal generator. The PWM runs at a typical frequency of 25kHz with an approximate typical duty cycle of 6.25%. PWMEN is used to enable or disable the PWM. PWMEN is internally pulled up to the digital supply, and can be left unconnected to enable the internal PWM. When enabled, the LED pulses are driven by the PWM to reduce the power dissipation and increase the system efficiency. Force PWMEN low to disable the internal PWM; the LED is then driven directly. MAX5984 Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET 1N4448 SMJ58A 10mH 0.1µF 100V 2.2MI PSE OUTPUT 47µF 100V 0.1µF 100V LED 5.1kI AGND LED OUT EN OUTP S1B MAX5984C 1nF VEE -54V 1N4448 0.47FF 100V 1kI VEE_DIG DET LEGACY ILIM1 MIDSPAN ILIM2 1kI -54V 1kI PWMEN OSC 0.1µF Figure 7. Typical Operating Circuit 2 (AC Load Removal Detection, Internal PWM Enabled for LED Indication, and Class 5 Detection Enabled) 47µF 100V 0.1µF 100V SMJ58A 0.1µF 100V 2.2MI PSE OUTPUT AGND VEE -54V OUT VEE_DIG EN OUTP MAX5984A/B/D 1N4448 1nF LED 2-EVENT/ LSCEN DET LEGACY ILIM1 MIDSPAN ILIM2 OSC Figure 8. Typical Operating Circuit 3 (IEEE 802.3at Compliant, Minimal Application Circuit with DC Load Removal Detection and No LED Indication) 20 ������������������������������������������������������������������������������������� Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET PROCESS: BiCMOS Package Information For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 28 TQFN-EP T2855+6 21-0140 90-0026 ______________________________________________________________________________________ 21 MAX5984 Chip Information MAX5984 Single-Port, 40W, IEEE 802.3af/802.3at PSE Controller with Integrated MOSFET Revision History REVISION NUMBER REVISION DATE 0 12/11 DESCRIPTION Initial release PAGES CHANGED — Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 22 © Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.