9-5336; Rev 0; 6/10 TION KIT EVALUA BLE IL AVA A Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C The device provides four operating modes to suit different system requirements. By default, auto mode allows the device to operate automatically at its default settings without any software. Semiautomatic mode automatically detects and classifies a device connected to the port after initial software activation, but does not power the port until instructed to by software.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C ABSOLUTE MAXIMUM RATINGS (Voltages referenced to VEE, unless otherwise noted.) AGND, DET, LED...................................................-0.3V to +80V OUT........................................................-0.3V to (AGND + 0.3V) OUTP.........................................................-6V to (AGND + 0.3V) VEE_DIG.................................................................-0.3V to +0.3V OSC...............................
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C (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.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C 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 CONDITIONS MIN TYP MAX UNITS 5 7.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C (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.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C 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 CONDITIONS MIN TYP MAX UNITS ADC PERFORMANCE (Power-On Mode) Resolution 9 Bits Range 1.507 A LSB Step Size 2.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C ANALOG SUPPLY CURRENT vs. INPUT VOLTAGE 2.5 2.4 2.6 2.5 2.4 30.0 MAX5971B toc03 MEASURED AT AGND UNDERVOLTAGE LOCKOUT (V) SUPPLY CURRENT (mA) 2.6 VEE UNDERVOLTAGE LOCKOUT vs. TEMPERATURE MAX5971B toc02 2.7 MAX5971B toc01 MEASURED AT AGND 29.5 29.0 28.5 28.0 27.5 2.3 40 44 48 52 56 2.3 60 27.0 -15 -40 VAGND - VEE (V) 10 35 60 85 -15 -40 TEMPERATURE (°C) 10 35 60 85 TEMPERATURE (°C) VEE OVERVOLTAGE LOCKOUT vs.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.
Single-Port, 40W, IEEE 802.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C STARTUP USING 2-EVENT CLASSIFICATION WITH A VALID PD LED DETECTION FAULT WITH PWM ENABLED MAX5971B toc21 MAX5971B toc22a VAGND - VOUT 10V/div 0V VAGND - VOUT 20V/div 0V MAX5971B Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C N.C. OSC N.C. LED N.C. I.C. TOP VIEW AGND MAX5971B Pin Configuration 21 20 19 18 17 16 15 N.C. 22 14 EN DET 23 13 LEGACY N.C. 24 12 VEE_DIG 11 AD0 10 INT 9 SCL 8 SDA OUTP 25 MAX5971B OUT 26 OUT 27 *EP + 4 5 6 7 ILIM2 PWMEN MIDSPAN VEE 3 ILIM1 2 VEE 1 VEE N.C. 28 THIN QFN *CONNECT TO VEE. Pin Description PIN 1, 2, 3 NAME VEE FUNCTION Analog Low-Side Supply Input.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C PIN NAME FUNCTION 2-Wire Serial Interface Input Clock Line. Referenced to VEE. Connect to VEE if the I2C interface is not used. 9 SCL 10 INT 11 AD0 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.
MAX5971B Single-Port, 40W, IEEE 802.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C 4) Thermal Shutdown. The device enters thermal shutdown at 150NC. The device exits thermal shutdown and is reset once the temperature drops below 130NC. At the end of a reset event, the MAX5971B latches in the state of MIDSPAN, LEGACY, and OSC. During normal operation, changes to the MIDSPAN and LEGACY inputs are ignored, and these inputs can be changed at any time prior to the end of a reset state.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C execution, the command is cleared from the register(s). PWR_ON has highest priority. Setting PWR_ON to 1 at any time causes the device to immediately enter the powered mode. Setting DET_EN and CLASS_EN to 1 at the same time causes detection to be performed first. Once in the powered state, the device ignores DET_EN or CLASS_EN commands. When switching to manual mode from another mode, DET_EN and CLASS_EN default to low.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Powered Device Classification (PD Classification) During PD classification, the MAX5971B forces a probe voltage (-18V, typ) at DET and measures the current into DET. The measured current determines the class of the PD. After each classification cycle, the MAX5971B sets CL_END (R04h[4] and R05h[4]) to 1 and reports the classification results in the classification status bits, CLASS[2:0] (R0Ch[6:4], see Table 13).
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C 80ms 150ms tDET(1) 150ms tDET(2) 19ms tCLASS t 0V -4V -9.3V -18V -54V 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 -54V VOUT Figure 2.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C the MAX5971B powers down the port and asserts the IMAX_FLT bits (R06h[0] and R07h[0]). For a continuous overstress, a fault occurs exactly after a period of tFAULT. The timing is software programmable through the timing register (R16h, Table 23). After a power-off due to an overcurrent fault, the tFAULT timer is not immediately reset but starts decrementing. The MAX5971B allows the port to be powered on only when the tFAULT counter reaches zero.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Foldback Current As a response to an interrupt, the controller can read the status of the event register(s) to determine the cause of the interrupt and take appropriate action. Each interrupt event register is paired with a clear-on-read (CoR) register. When an interrupt event register is read through the corresponding CoR register, the interrupt register is reset to 0.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C 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 at DET falls below IACTH for more than tDISC, the device powers down the port and asserts LD_DISC (R06h[4] and R07h[4]). The AC loaddisconnect threshold (IACTH) is programmable using the AC_TH[2:0] bits (R23h[2:0], see Table 32 for settings).
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C The MAX5971B also contains an internal square wave, PWM signal generator. The PWM runs at a typical frequency of 25kHz with a default duty cycle of 6.25%. The duty cycle is programmable from 6.25% up to 25% through the PWM_TH[1:0] bits (R24h[5:4], Tables 33 and 34). 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.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Bit Transfer Each clock pulse transfers one data bit (Figure 8). The data on SDA must remain stable while SCL is high. Acknowledge The acknowledge bit is a clocked 9th bit (Figure 9), which the recipient uses to handshake receipt of each byte of data. Thus each byte transferred effectively requires 9 bits.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C data it is delivering. If it is not, it then backs off and frees the data line. This litigation protocol always allows the part with the lowest address to complete the transmission. The microcontroller then responds to that interrupt and takes proper action. The MAX5971B does not reset its own interrupt at the end of the alert response protocol.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C If multiple data bytes are transmitted before a STOP condition is detected, these bytes are stored in subsequent MAX5971B internal registers as the control byte address autoincrements (Figure 13). If the control byte address can no longer increment, any subsequent data sent continues to write to that address.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Operation with Multiple Masters When the MAX5971B operates on a 2-wire interface with multiple masters, a master reading the MAX5971B should use repeated starts between the write that sets the MAX5971B’s address pointer, and the read(s) that take the data from the location(s). It is possible for master 2 to take over the bus after master 1 has set up the MAX5971B’s address pointer but before master 1 has read the data.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C The Event Registers (R02h to R08h) Power Event Register (R02h/R03h) The power event register (R02h/R03h, Table 9) records changes in the power status of the port. On power-up or after a reset condition, the power event register is set to a default value of 00h. Any change in PGOOD (R10h[4]) sets PG_CHG to 1. Any change in PWR_EN (R10h[0]) sets PWEN_CHG to 1.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Detect Event Register (R04h/R05h) The detect event register (R04h/R05h, Table 10) records detection/classification events for the port. On power-up or after a reset condition, the detect event register is set to a default value of 00h. DET_END and CL_END are set high whenever detection/classification is completed. As with the other event registers, the detect event register has two addresses.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C A thermal shutdown circuit monitors the temperature of the die and resets the MAX5971B if the temperature exceeds +150NC. TSD is set to 1 after the MAX5971B returns to normal operation. When VEE is below its UVLO threshold, the MAX5971B is in reset mode and securely holds the port off. When VEE rises above its UVLO threshold, the device comes out of reset and the VEE_UVLO bit in the supply event register is set to 1.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Table 14. Detection Result Decoding Chart DET_ST[2:0] (ADDRESS = 0Ch) DETECTED 000 None Detection status unknown (default) 001 DCP Positive DC supply connected at the port (VAGND - VOUT_ < 1V) 010 HIGH CAP 011 RLOW 100 DET_OK 101 RHIGH High resistance at the port (RDET > 33kI) 110 OPEN Open port (IDET < 20FA) 111 DCN Negative DC bias on the port (VOUT - VEE < 2V) DESCRIPTION High capacitance at the port (> 8.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Configuration Registers (R12h to R17h) Mode Register (R12h) The mode register (R12h, Table 18) contains two bits that set the MAX5971B mode of operation. Table 19 details how to set the mode of operation for the device. On a power-up or after a reset condition, the mode register is set to a default value of 03h. Use software to program the mode of operation.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Disconnect Enable Register (R13h) The disconnect enable register (R13h, Table 20) is used to enable AC and DC load-disconnect detection. On power-up or after a reset condition, this register is reset to a default value of 000x to 000x, where the status latched in from the OSC input determines if AC or DC disconnect is set (see the AC/DC Disconnect Monitoring sections for details).
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Timing Register (R16h) The timing register (R16h, Table 23) is used to program the restart, startup, overcurrent, and load-disconnect timers for the port. On a power-up or after a reset condition, the timing register is set to a default value of 00h. To program the timer values, set the bits in R16h to scale the tDISC, tFAULT, tSTART, and tRESTART to a multiple of their nominal value specified in the Electrical Characteristics table.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Table 24. Timer Values for Timing Register BIT [1:0] (ADDRESS = 16h) tRESTART tDISC tSTART tFAULT 00 16 x tFAULT tDISC nominal (350ms, typ) tSTART nominal (60ms, typ) tFAULT nominal (60ms, typ) 01 32 x tFAULT ¼ x tDISC nominal ½ x tSTART nominal ½ x tFAULT nominal 10 64 x tFAULT ½ x tDISC nominal 2 x tSTART nominal 2 x tFAULT nominal 11 0 x tFAULT 2 x tDISC nominal 4 x tSTART nominal 4 x tFAULT nominal Table 25.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C ADDRESS = 19h DESCRIPTION SYMBOL BIT NO. TYPE Reserved 7 — Reserved Reserved 6 — Reserved Reserved 5 — Reserved PWR_OFF 4 R/W Reserved 3 — Reserved Reserved 2 — Reserved Reserved 1 — Reserved PWR_ON 0 R/W A logic-high powers off the port A logic-high powers on the port Table 27. Global Pushbutton Register ADDRESS = 1Ah SYMBOL BIT NO.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C SMODE Register (R1Ch) The SMODE register (R1Ch, Table 29) contains the port hardware control flag. On a power-up or after a reset condition, this register is set to a default value of 0x00h. Enable the SMODE function by setting EN_WHDOG (R1Fh[7], Table 31) to 1. The SMODE bit goes high when the watchdog counter reaches zero and the port switches over to hardware-controlled mode.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Set EN_WHDOG (R1Fh[7], Table 31) to 1 to enable the watchdog function. When the watchdog counter reaches zero, the hardware-controlled mode activates and sets the port to the operating mode determined by the HWMODE bit (R1Fh[0]). A 0 in HWMODE places the port into shutdown mode by setting the P_M[1:0] bits (R12h[1:0]) to 00. A 1 in HWMODE places the port into auto mode by setting the P_M[1:0] bits to 11.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C mode. When DET_BY is set to 1 however, the MAX5971B can power the port without doing the detection routine. AC_TH[2:0] (R23h[2:0]) allows direct programming of the AC disconnect threshold. The threshold is defined as a current since the comparator verifies that the peak current pulses sensed at the DET input exceeds a preset threshold. The current threshold is defined as follows: IAC_TH = 85.28FA + 10.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C ICUT Register (R2Ah) The ICUT register (R2Ah, Table 36) is used to adjust the device current limit and corresponding overcurrent thresholds. On a power-up or after a reset condition, this register is set to a default value of 0x00h. The MAX5971B can automatically set the ICUT register (see Table 4) or ICUT[2:0] can be manually written to by the software (see Table 37) to manually adjust the current-limit and overcurrent thresholds. Table 35.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Current Readout Registers (R30h to R37h) Port Current Registers (R30h to R31h) The port current registers (R30h to R31h, Tables 38 and 39) provide port current readout during classification and normal power mode. On a power-up or after a reset condition, these registers are both set to a default value of 0x00h. The port current readout has 9 bits of overall resolution.
Single-Port, 40W, IEEE 802.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C Table 40.
Single-Port, 40W, IEEE 802.
MAX5971B Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C 1N4448 10mH 0.1µF 100V SMJ58A 2.2MI PSE OUTPUT 47µF 100V 0.1µF 100V LED AGND LED OUT 5.1kI OUTP EN 1N4448 1nF MAX5971B DET VEE -54V 1kI VEE_DIG ILIM1 -54V 1kI LEGACY ILIM2 MIDSPAN OSC 1kI PWMEN SDA 0.1µF 0.47µF 100V SCL AD0 INT SERIAL INTERFACE Figure 16. Typical Operating Circuit 2 (AC Load Removal Detection, Internal PWM Enabled for LED Indication, and Class 5 Detection Enabled) 47µF 100V 0.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C PROCESS: BiCMOS Package Information For the latest package outline information and land patterns, 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.
Single-Port, 40W, IEEE 802.3af/at, PSE Controller with I2C MAX5971B Revision History REVISION NUMBER REVISION DATE 0 6/10 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.
