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mic2358ylq ieee 802.3af octal power sourcing equipment controller micrel inc. ? 2180 fortune drive ? san jose, ca 95131 ? usa ? tel +1 (408) 944-0800 ? fax + 1 (408) 474-1000 ? http://www.micre l.com july 2010 m9999-070810 general description the MIC2358YLQYLQ octal network power controller is designed for use in ieee 802.3af-compliant power- sourcing equipment (pse). the device provides standardized powered devices (pd) detection, classification, current-limit, and monitoring of both dc and ac maintain power signatures. the MIC2358YLQYLQ can operate autonomously or be controlled by software through a smbus-compatible interface. its five address inputs support 32 unique mic2358ylq addresses allowing control and monitoring up to 256 powered ethernet ports (32 mic2358ylq devices) by an external management application. for each port, the mic2358ylq uses external n- channel power fets and current sense resistors to deliver and monitor power. state machines have been incorporated into this device for complete configuration, fault reporting, and status on a per-port basis, including port voltage and current. the mic2358ylq also implements micrel?s shared power management and port prioritization which offers more flexible allocation of available power among the ports. throughout this document the term 802.3af is synonymous for ieee std 802.3-2005. datasheets and support documentation can be found on micrel?s web site at: www.micrel.com. features ? fully compliant with the ieee 802.3af power-over- ethernet standard ? controls eight independent 48v-powered ethernet ports ? powered port attributes: ? up to 15.4w delivered per port ? input over-voltage protection (ovp) ? powered device detection and classification ? active current limit ? powered device ac and dc disconnect supported ? operates autonomously or by smbus control ? 5-bit programmable digital addressing allows control of up to 256 ethernet powered ports ? hardware fault interrupt output ? available in a pb-free 64-pin lqfp package applications ? ieee 802.3af compliant enterprise switches/hubs ? ieee 802.3af compliant endpoint and midspan power sources ? pse power injectors ? ip phone systems ? dte power distribution _________________________________________________________________________________________________________ ordering information part number temperature range pb-free package MIC2358YLQYLQ 0 c to +70 c 64-pin lqfp
micrel, inc. mic2358ylq july 2010 2 m9999-070810 functional block diagram ? global level revision history rev. date reason 1.0 12/08/09 initial created 1.1 05/03/10 autonomous enable is low true max current (5v) is 40ma
micrel, inc. mic2358ylq july 2010 3 m9999-070810 pin configuration addr1 addr2 addr3 addr4 addr5 /cs /smbint drtn sdain sdaout scl acsense acdrive drtn nc /reset p8outpos p8outneg p8gate p8sense p7outpos p7outneg p7gate p7sense p6outpos p6outneg p6gate p6sense p5outpos p5outneg p5gate p5sense rdet spmbus aspmref artn artn drtn 48vs drtn nc 5vs dcmps acmps ico altb enable nc p1outpos p1outneg p1gate p1sense p2outpos p2outneg p2gate p2sense p3outpos p3outneg p3gate p3sense p4outpos p4outneg p4gate p4sense 9 10 11 12 13 14 15 16 1 2 3 4 5 6 7 8 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 40 39 38 37 36 35 34 33 48 47 46 45 44 43 42 41 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 64-pin lqfp (v)
micrel, inc. mic2358ylq july 2010 4 m9999-070810 pin description pin number pin name pin function 1 p1outpos port 1 positive 48v terminal input. 2 p1outneg port 1 negative 48v terminal input. 3 p1gate port 1 gate drive output: connect this pin to the gate terminal of port 1?s external power fet. 4 p1sense port 1 sense input: connect this pin the s ource terminal of port 1?s external power fet. 5 p2outpos port 2 positive 48v terminal input. 6 p2outneg port 2 negative 48v terminal input. 7 p2gate port 2 gate drive output: connect this pin to the gate terminal of port 2?s external power fet. 8 p2sense port 2 sense input: connect this pin the s ource terminal of port 2?s external power fet. 9 p3outpos port 3 positive 48v terminal input. 10 p3outneg port 3 negative 48v terminal input. 11 p3gate port 3 gate drive output: connect this pin to the gate terminal of port 3?s external power fet. 12 p3sense port 3 sense input: connect this pin the s ource terminal of port 3?s external power fet. 13 p4outpos port 4 positive 48v terminal input. 14 p4outneg port 4 negative 48v terminal input. 15 p4gate port 4 gate drive output: connect this pin to the gate terminal of port 4?s external power fet. 16 p4sense port 4 sense input: connect this pin the s ource terminal of port 4?s external power fet. 17 nc no connection. 18 enable_l autonomous mode select pin input. when high, all ports are disabled on power up and can only be enabled via smbus interaction. when low, all ports are enabled on power up and device operation will proceed without smbus interaction necessary. internally pulled up to +5v by a 50k ? resistor. 19 altb autonomous mode select pin input. when high all ports will be configured for alt b operation, when low all ports will be configured for alt a operation. internally pulled up to +5v by a 50k ? resistor. 20 ico autonomous mode select pin input. when high, ports will not have power removed if its current exceeds the class-dependent overload current, i.e. overload current will be equal to class 0 level. internally pulled up to +5v by a 50k ? resistor. 21 acmps autonomous mode select pin input. when high, ac maintain power signature feature is enabled. internally pulled up to +5v by a 50k ? resistor. 22 dcmps autonomous mode select pin input. when high, dc maintain power signature feature is enabled. internally pulled up to +5v by a 50k ? resistor. 23 5vs +5v supply voltage: applying a +5v supply relative to 48vrtn powers the mic2358ylq?s internal digital circuits, state machines, and port control circuits. 24 nc no connection. 25 drtn digital ground return. 26 48vs 48v power supply input: in a negative common application, applying a conditioned +48v supply (+44v 48vs +60v) provides the supply voltage to power the mic2358ylq and all eight ports. in a positive common application, apply system com to this pin. 27 drtn digital ground return. 28 artn analog ground return. 29 artn analog ground return.
micrel, inc. mic2358ylq july 2010 5 m9999-070810 pin number pin name pin function 30 spmref shared power management reference resistor. connect an external 250k ? , 1% resistor from this pin-to-artn. 31 spmbus shared power management buss. a resistor connected from this pin to artn sets the total power allocated to all ports in use. for all eight ports, the total maximum allocated power is 123.2w (15.4w x 8 ports). the transfer characteristic for this pin is 2.5v/r spmref per watt. thus, the resistor value is determined by r spmref /p total. 32 rdet pd signature detection resistor. connect a 1k ? 1% resistor from this pin to artn. 33 p5sense port 5 sense input: connect this pin the s ource terminal of port 5?s external power fet. 34 p5gate port 5 gate drive output: connect this pin to the gate terminal of port 5?s external power fet. 35 p5outneg port 5 negative 48v terminal input. 36 p5outpos port 5 positive 48v terminal input. 37 p6sense port 6 sense input: connect this pin the s ource terminal of port 6?s external power fet. 38 p6gate port 6 gate drive output: connect this pin to the gate terminal of port 6?s external power fet. 39 p6outneg port 6 negative 48v terminal input. 40 p6outpos port 6 positive 48v terminal input. 41 p7sense port 7 sense input: connect this pin the s ource terminal of port 7?s external power fet. 42 p7gate port 7 gate drive output: connect this pin to the gate terminal of port 7?s external power fet. 43 p7outneg port 7 negative 48v terminal input. 44 p7outpos port 7 positive 48v terminal input. 45 p8sense port 8 sense input: connect this pin the s ource terminal of port 8?s external power fet. 46 p8gate port 8 gate drive output: connect this pin to the gate terminal of port 8?s external power fet. 47 p8outneg port 8 negative 48v terminal input. 48 p8outpos port 8 positive 48v terminal input. 49 /reset reset input: this active low asserted di gital input is used to reset the mic2358ylq to default settings. there is an internal 50k ? resistor connected from this pin to 5vs. 50 nc do not connect. 51 drtn digital ground. connect this pin to all other mic2358ylq drtn pins at one point. 52 acdrive internal ac oscillator output. accessible from this pin is the mic2358ylq?s internal oscillation specifically required to support ac disconnect. an 83hz square wave with 50% is available. 53 acsense senses the ac drive forced on positive port terminals. connect to v48 through 800 ? and diode even if ac disconnect is not used. please see reference schematic. 54 scl smbus serial clock input. external pull up resistor required. 55 sdaout smbus serial data output. 56 sdain smbus serial data input. external pull up resistor required. 57 drtn digital ground. connect this pin to all other mic2358ylq drtn pins at one point. 58 /smbint smbus interrupt open-drain output. external pull up resistor required. 59 /cs address chip select input. this bit is internally pulled up to +5v by a 50k ? resistor. 60 addr5 smbus address bit 5 (msb): this address bit is the most significant bit of the mic2358ylq?s 5-bit address bank. this bit is internally pulled up to +5v by a 50k ? resistor. 61 addr4 smbus address bit 4: this bit is internally pulled up to +5v by a 50k ? resistor. 62 addr3 smbus address bit 3: this bit is internally pulled up to +5v by a 50k ? resistor. 63 addr2 smbus address bit 2: this bit is internally pulled up to +5v by a 50k ? resistor.
micrel, inc. mic2358ylq july 2010 6 m9999-070810 pin number pin name pin function 64 addr1 smbus address bit 1 (lsb): this address bit is the least significant bit of the mic2358ylq?s 5-bit address bank. this bit is internally pulled up to +5v by a 50k ? resistor.
micrel, inc. mic2358ylq july 2010 7 m9999-070810 absolute maximum ratings (1) pxoutpos, pxoutneg, 48vs ............ -0.3v to +100v pxgate ...................................................... -0.3 v to +6v all other pins................................................ -0.3v to +6v storage temperature (t s ) .....................-65c to +150c esd rating (3) human body model ........................................1000v machine model .................................................100v lead temperature (soldering, 10 sec) lead-free package (yml) ir reflow .......................................260c +0c/-5c operating ratings (2) supply voltage (v in ) ................................... +43v to +60v ambient temperature (t a ) .......................... 0c to +70c junction thermal resistance lqfp64 ( ja ) no air flow......................... 42.34c/w lqfp64 ( jc ) no air flow........................... 12.9c/w dc electrical characteristics (4) (48vs ? artn) = 48v; t a = 25c, unless otherwise noted. bold values indicate specifications apply over the full operating temperature range of 0c < t a < +70c, unless otherwise noted. symbol parameter condition min typ max units power supplies v dd1 5v supply voltage 4.5 5.5 v i dd1 5v supply current 8 40 ma v cc 48v supply voltage 44 60 v i cc 48v supply current 0.05 .2 ma detection, see functional characteristics rsense=1 ? v detect1 detection voltage point 1 15k ? rsig 33k ? 2.8 3.6 9 v v detect2 detection voltage point 2 15k ? rsig 33k ? 3.8 7.2 10 v v detect vdetect2-vdetect1 1 3.6 v t detect1-2 time between test points 1 & 2 2 ms v detectoc open-circuit detection voltage rsig = 332k ? , 5% 2.8 11 30 v i detectsc short-circuit detection current limit rsig = 0 0 2.3 5 ma r sigvalid valid signature resistance 19 26 k ? r sigreject reject signature resistance r<15 r>33 k ? c sigmax maximum valid signature capacitance 0 .15 f classification, see functional characteristics v class classification drive voltage 0ma < iclass < 55ma 15.5 19 20.5 v i class classification current compliance 55 88 100 ma i classth classification current threshold class 0-1 class 1-2 class 2-3 class 3-4 class 4 ? overcurrent 5 13 21 31 45 8 16 25 35 51 ma ma ma ma ma
micrel, inc. mic2358ylq july 2010 8 m9999-070810 dc electrical characteristics (4) (48vs ? artn) = 48v; t a = 25c, unless otherwise noted. bold values indicate specifications apply over the full operating temperature range of 0c < t a < +70c, unless otherwise noted. symbol parameter condition min typ max units global overvoltage protection v govp global overvoltage protection threshold voltage input supply voltage at which all ports are powered off 59.3 v v govphys ovp threshold hysteresis 1.3 v v guvp global undervoltage protection threshold voltage input supply voltage at which all ports report as undervoltage fault 43.5 v v guvphys uvp threshold hysteresis 0.25 v gate n drive v gate external gate drive voltage v gate = v gaten ? artn 4 5 v i gateup gate pin charge current 50 a i gatedn gate pin discharge current 2.7 ma i gateoff gate pin fault mode pull- down current vol = 5.0v 50 65 ma port n sense input r port port sense input resistance portn = on; ppn and pnn measured to artn 0.7 1 1.3 m ? port n current sense rsense=1 ? v suoc start-up current limit threshold voltage 408 424 442 mv v ssoc overload current detection threshold voltage class 0 class 1 class 2 class 3 344 92 160 344 373 102 174 373 396 106 182 396 mv mv mv mv v sc short-circuit current limit threshold voltage 408 424 442 mv v dcmpsmin dc mps disconnect threshold voltage 5.2 8 9.8 mv i sense sense pin bias current 8 50 a internal ac disconnect oscillator f osc oscillator output frequency 79 86 500 hz v oscp-p oscillator output voltage 48vs = 48.0v 3.25 4.4 10 v pp shared power management (spm) v spmref spm voltage reference 2.45 2.5 2.55 v i spmref spm standard unit current rspm = 250k ? 10 a
micrel, inc. mic2358ylq july 2010 9 m9999-070810 dc electrical characteristics (4) (48vs ? artn) = 48v; t a = 25c, unless otherwise noted. bold values indicate specifications apply over the full operating temperature range of 0c < t a < +70c, unless otherwise noted. symbol parameter condition min typ max units digital logic interface v il(smbus) scl, sdain 1.35 v v ih(smbus) scl, sdain 1.58 v i ih(smbus) scl, sdain 0.1 5 a v ol(smbbus) (sdaout,/smbint) i ol = 4ma 0.1 0.4 v v il addr[5:1], autonomous select pins, /rst, /cs 2.5 v v ih addr[5:1], autonomous select pins, /rst, /cs 2.5 v r pullup autonomous select pins, /rst, /cs, addr[5:1] 59 k ? notes: 1. exceeding the absolute maximum rating may damage the device. 2. the device is not guaranteed to function outside its operating rating. 3. devices are esd sensitive. handling precautions recommended. human body model, 1.5k in series with 100pf. 4. specification for packaged product only.
micrel, inc. mic2358ylq july 2010 10 m9999-070810 ac electrical characteristics (4) (48vs ? artn) = 48v; t a = 25c, unless otherwise noted. bold values indicate specifications apply over the full operating temperature range of 0c < t a < +70c, unless otherwise noted. symbol parameter condition min typ max units t det detection duration time to measure pd signature resistance 100 500 ms t pdc classification delay time time to classify the pd. 10 19.5 75 ms t dbo detection backoff delay time alternative b configuration only 2 2.1 16 s t ed detection delay after error 750 1000 10000 ms t poram power on delay, autonomous mode ? from valid detect to port on in autonomous mode 0 39 400 ms t ilimmax maximum ilim duration during port initialization ? ieee 802.3af applications 30 57 75 ms t icutmax maximum icut duration during steady-state operation ? ieee 802.3af applications 50 55 75 ms t mpsdly ac / dc mps disconnect delay time 300 335 /360 400 ms t dcmpspw dc mps disconnect minimum pulse width see v dcmpsmin 50 60 ms smbus interface timing t scl scl (serial clock) period 2.5 s t2 sda setup time to scl high 100 ns t3 sda hold time to scl low 300 ns t4 sda low setup time to scl low 100 ns t5 sda high hold time to scl high 100 ns t ara-int ara to /smbint pin high time 20 300 ns notes: 1. gbnt ? guaranteed by design and characterization, not tested in production. 2. exceeding the absolute maximum rating may damage the device. 3. the device is not guaranteed to function outside its operating rating. 4. devices are esd sensitive. handling precautions recommended. human body model, 1.5k in series with 100pf. 5. specification for packaged product only.
micrel, inc. mic2358ylq july 2010 11 m9999-070810 functional description the mic2358ylq operations are fully compliant with the ieee 802.3af-2005 standard. states referenced in this section are per ieee pse state diagram. see dc and ac electrical characteristics sections for timers, voltage threshold, and current threshold values. autonomous operation the autonomous mode allows for applications that have no central host controller, or have limited supervision of the mic2358ylq. with the enable_l pin low during power-up, the mic2358ylq will initialize and immediately begin checking ports for valid detection signatures, and if present, perform classification and apply power. managed operation in managed mode, the mic2358ylq may be configured and monitored by an external host processor. operations include: pd detection, classification, diagnostics, power budget, power-on, power-off, check status, detect faults, ac/dc disconnect detection, voltage and current measurement per port basis. with the enable_l pin high during device power-up, the mic2358ylq will initialize, but will not begin to perform detection on any port until instructed from an external host controller via smbus. reset at power-up or anytime the mic2358ylq supports both hard and soft reset. upon reset, all ports immediately shut off and internal registers default to values as shown in register description section. upon a reset operation, the mic2358ylq will be configured based on the strap-in pins: enable, dcmps, acmps, ico, and altb (see pin description for configuration details). these register bits may be programmed by the host. any changes to these pins after reset are ignored. power delivery control the primary function of the mic2358ylq is to control power delivery to each pse port. it does this by controlling the gate drive voltage of an external n- channel power fet while monitoring the current through a sense resistor (rs, pnsense) and the output voltage across the positive (pnoutpos) and negative (pnoutneg) terminal pins, where n is the port number (1-8). at power-up, the isolated 48v input supply is coupled to the port in an inrush-controlled manner. power will then be delivered to the connected pd based upon its classification sensed at power-up. the gate drive logic is designed to prevent simultaneous power- up of ports. the sense resistor value was selected to reduce power loss and the voltage. the 1 ? resistor is connected between source and the mic2358ylq sense-artn pins. by measuring this voltage across the sense resistor, the mic2358ylq sense terminal pin specifically monitors current flow during port classification, power-up inrush, power-on short, power-on overload, and dc disconnect detect. it also measures pd load current on demand by the host. pd detection the mic2358ylq will not deliver power until a valid pd is detected. a valid pd has a 25k ? discovery signature as specified in the ieee 802.3af standard. the detection cycle is repeated continuously until a valid pd is detected. the status of pd discovery signature for each port is available to the host. during pd detection, the mic2358ylq uses an internal fet to force probe voltages vdetect1 and vdetect2 across the port?s power terminals (pnoutpos, pnoutneg). the resulting currents to the port are determined by measuring the voltage across an external 1k ? resistor that must be connected to the rdet pin. a two-point v-i slope measurement is used as specified by the ieee 802.3af standard to verify that a valid signature resistance is connected to the port. the ieee802.3af standard requires mid-span pse (alternative b) to support backoff timing. this causes the port to wait a time period specified by tdbo before attempting another detection cycle after every failed pd detection. with the altb pin high during reset or enabled by the host, the mic2358ylq ports are initialized as alternative b. pd classification pd classification enables each pd to request the power level from the pse. per ieee802.3af standard, classification is preceded by successful detection cycle and is optional. pd classifications status for each port is available to the host upon completion of the pd classification process. during classification, the mic2358ylq turns on the external fet and forces probe voltage vclass across the positive and negative terminals of the port. the resulting current is measured across rs. the measured current determines the class of the pd as shown in table 1. successful pd classification does not necessarily guarantee that the pse will be able to deliver power to the pd at a particular port. the mic2358ylq enables the power budget to be managed by the host (managed mode) or the unique shared power management (autonomous mode). the mic2358ylq allows the host
micrel, inc. mic2358ylq july 2010 12 m9999-070810 to predefine a maximum class to determine the power level to be supplied to a detected pd. a pd classification exceeding its maximum class will go to the power_denied state. with the ico pin high during reset, classifications of all ports are forced to class 0. this provides system flexibility for class 1 or class 2 pd devices such as a security camera that violate its class current often due to many motor start-up occasions. ieee 802.3af classification current at pse maximum pd power maximum pse output power per port class description 0 0ma to 5ma 12.95w 15.4w pd does not implement classification, unknown power 1 8ma to 13ma 3.84w 4w low power pd 2 16ma to 21ma 6.49w 7w medium power pd 3 25ma to 31ma 12.95w 15.4w high or full power pd 4 35ma to 45ma 12.95w 15.4w reserved, power as class 0 table 1. ieee 802.3af powered device classes detection timing
micrel, inc. mic2358ylq july 2010 13 m9999-070810 powered state assuming sufficient power budget is available, after a successful pd detection and optional classification cycle. the mic2358ylq enters power_up state and begins applying 48v power to the port in an inrush-controlled manner. if the sense terminal exceeds vsuoc, an internal current-limiting circuit regulates the gate drive voltage, limiting the current to iinrush = vsuoc / rs. if the current-limit condition persists, when the startup timer, tilimmax, times out, the port shuts off and fault condition is reported as short event after a fault free power-up, the mic2358ylq enters power_on state and maintains 48v power to the port in a steady-state manner. during steady-state power delivery, the mic2358ylq constantly checks for overload conditions by monitoring icut = vssoc / rs. if the overload condition persists for a time period greater than t icutmax , the overload timer times out, the port shuts off and an overload event is reported. during steady-state power delivery, if the sense terminal exceeds vsc, an internal current- limiting circuit regulates the gate drive voltage, limiting the current to ilim = vsc / rs. if the current-limit condition persists, when the timer, tilimmax, times out, the port shuts off and fault condition is reported as short event. under all circumstances neither ilim nor iinrush are allowed to exceed their respective maximum threshold. in the test_mode state, the mic2358ylq checks the selected port for short or overload faults with the same method used during power_up and power_on states. disconnect detection disconnect detection ensures that the mic2358ylq pse shuts off power delivery when a pd is disconnected from a port. the ieee 802.3af standard specifies two methods for determining that a pd has disconnected from the pse referred to as dc or ac maintain power signature (mps). with the dcmps pin high during reset or enabled by host, the mic2358ylq dc disconnect detection function starts at beginning of power_up state. if the sense terminal falls below vdcmpsmin for time out period of tmpsdly, the port shuts off and fault condition is reported as dcmps absent event. with the acmps pin high during reset or enabled by host, the mic2358ylq ac disconnect detection function starts at beginning of power_up state. the mic2358ylq produces a low frequency square wave on the acdrive pin. this signal is level-shifted through a single external 47f capacitor, then injected on to the positive terminal of each port through an external 1.96k ? ac current sense resistor. the voltage amplitude of the ac probing signal is measured by the acsense pin of the mic2358ylq. the ac current into each port is measured by sensing the voltage drop across the external ac sense resistor. by combining the sensed voltage and current, the mic2358ylq can then determine if the low-frequency ac impedance on the port is within the limits specified by 802.3af. if the impedance falls outside of the ac maintain power signature limits for longer than tmpsdly, the port shuts off and fault condition is reported as an acmps absent event. if both dc and ac disconnect are enabled on a port, then per section 33.2.10.1 of the 802.3af standard, both the dc and ac maintain power signatures must be present on a port to keep it powered. if either the dc or the ac maintains power signature does not exist for longer than tmpsdly, then the port will be shut off. a port with neither, dc or ac disconnect enabled will not power off automatically when the pd is removed. shared power management in managed mode, an external host management applications manages the available power budget, and maintains which ports are powered up and at what classification. for systems where no host management application is present or where it is not desired to burden, the controller with power budget management tasks, the mic2358ylq performs shared power management to manage the power budget in autonomous mode. the power budget is established by selecting the appropriate values of a pair of resistors. a 250k ? resistor is placed between the spmref pin and ground. the mic2358ylq will apply 2.5v to this resistor to establish a per-watt-of-power reference current (nominally 10a per watt). another resistor is placed from the spmbus pin-to-ground, with a value that establishes the size of the system power budget. the value of the resistor is determined by dividing 2.5v by the reference current (10a), then dividing by the total power budget in watts. for example, if the total power budget is 100w, then the spmbus resistor should be 2.5k ? . then, when the mic2358ylq powers up a port, it will also source a current out of the spmbus pin that is proportional to the maximum power for that port?s classification. as more ports power up, these currents all sum together, and the voltage at spmbus will increase accordingly. once the voltage on spmbus has reached 2.5v, the total power budget has been allocated, and the mic2358ylq will not allow additional ports to power up until an already powered port is powered off.
micrel, inc. mic2358ylq july 2010 14 m9999-070810 the power budget may be managed across multiple mic2358ylq devices by tying together the spmbus pins of each device to a single budget-establishing resistor. to disable shared power management tie the spmbus pin-to-ground or disable spm by the host. port prioritization the mic2358ylq offers port priority to enable additional flexibility in managing the power budget. in managed mode, the host software can assign each port one of four levels of priority: critical, high, medium, or low. during an emergency power supply disruption event such as brown out, the host has the flexibility to globally declare a minimum priority level for a port to be powered following detection of a pd and/or declare a minimum priority level for a port to remain powered. each individual port?s assigned priority level is compared with global priority declaration and if determined of a lower priority level will then go to the power_denied state. if multiple ports are assigned the same priority level (higher than the minimum priority referred to above), and the power supply is inadequate to power all of the ports, then none of the ports will be powered normally. thus it is important to manage the priority levels for the most important levels. the port prioritization power management scheme is complementary to shared power management. supply voltage overvoltage and undervoltage protection the mic2358ylq monitors the input power supply for overvoltage and undervoltage conditions. if the supply voltage reaches vgovp, all ports immediately shut off and overvoltage fault status is reported to host by the global status register (0x45) bit 1, which may be read by the host. if the supply voltage drops off to vguvp, undervoltage fault status is reported to host by the global status register (0x45) bit 2, which may be read by the host. digital logic power the mic2358ylq must be supplied with 5v (vdd). vdd supplies power for most of device internal analog and all internal logic circuitry including smbus interface. all logic inputs and outputs reference to drtn. drtn and artn are completely isolated internally to the mic2358ylq. non-compliant ieee 802.3af features for enhanced system flexibility, the mic2358ylq supports non-compliant ieee 802.3af or legacy pds detection resistance value. this would enable the mic2358ylq to support pre-802.3af standard pd detection schemes. the host can program acceptable lower threshold as low as 400 ? (dec 1x400) by the global_detect_min_register (0x48) and higher threshold as high as 102k ? (dec 255x400) by the global_detect_max_register (0x49). this programming affects all ports and cannot be done per port basis. smbus serial interface the mic2358ylq communicates with a host (master) using the standard 2-wire interface as described in the smbus specification version 2.0. the smbus is an extension of the i2c bus, and the mic2358ylq is also compatible with the i2c bus standard. the i2c interface allows easy application of opto-coupler circuitry to maintain system isolation when a ground based micro-controller host is required. the mic2358ylq features separate input and output data pins (sdain and sdaout) for use with opto-couplers. for applications where opto- isolation is not required, sdain and sdaout are tied together. the smbus standard requires seven-bit device addressing. the mic2358ylq top two most significant address bits are hardwired to 10 with the next five bits specified by strapping five pins on the device. the mic2358ylq uses standard write_byte and read_byte, for communication with its host. the write_byte operation (see figure 1) involves sending the device?s slave address (with the r/w bit low to signal a write operation), followed by the address of the register to be operated upon and the data byte. the read_byte operation (see figure 2) is a composite write and read operation: the host first sends the device?s slave address followed by the register address, as in a write operation. a new start bit must then be sent to the mic2358ylq, followed by a repeat of the slave address with the r/w bit (lsb) set to the high (read) state. the data to be read from the part may then be clocked out. the mic2358ylq expects to be interrogated using the alert response address once it has asserted its interrupt output, /smbint. following an interrupt, a successful response to the a.r.a. or a read operation on event register will cause /smbint to be de- asserted. event will also be cleared by the read operation. reading event following an interrupt is an acceptable substitute for using the a.r.a., if the
micrel, inc. mic2358ylq july 2010 15 m9999-070810 host system does not implement the a.r.a protocol. illustrates a.r.a responding to mic2358ylq interrupts. figure 1. write byte protocol figure 2. read byte protocol figure 3. alert response address protocol
micrel, inc. mic2358ylq july 2010 16 m9999-070810 typical application figure 4. midspan configur ation for 1 port of 8 ports
micrel, inc. mic2358ylq july 2010 17 m9999-070810 register definitions purpose the mic2358ylq uses write registers to configure the operation of the device and read registers to supply information about the operation of the device. these registers are accessed through the smbus interface. register map the smbus can address 128 individual registers, as shown in table 1. each port has eight assigned registers: four that have read/write access, three that are read only, and one that is read only and is cleared after being read. there are 11 global registers: six read/write and five read only. the remaining registers are reserved for factory testing purposes. these test registers may be read without harm, but should not be written. the test register definitions are not included in this document. table 2 shows the internal structure of the registers assigned to each port. table 3 shows the internal structure of the global registers. global registers affect all ports. port registers affect individual ports only. the remainder of this document explains in detail the use of each register, and if appropriate the meaning and use of individual bits within a register. conventions throughout this document, smbus registers are referenced using bold_uppercase. individual bits within a register are referenced using italic_lowercase . states from the state machine diagram are shown in figure 33-6 of the ieee std 802.3af are written using regular_uppercase.
micrel, inc. mic2358ylq july 2010 18 m9999-070810 -0 -1 -2 -3 -4 -5 -6 -7 0x0- port 1 control port 1 option reserved reserved port 1 voltage port 1 current port 1 status port 1 event 0x1- port 3 control port 3 option reserved reserved port 3 voltage port 3 current port 3 status port 3 event 0x2- port 5 control port 5 option reserved reserved port 5 voltage port 5 current port 5 status port 5 event 0x3- port 7 control port 7 option reserved reserved port 7 voltage port 7 current port 7 status port 7 event 0x4- global config global power set-up global event mask smbus status global srq global status global current port reserved 0x5- reserved reserved reserved reserved reserved reserved reserved reserved 0x6- reserved reserved reserved reserved reserved reserved reserved reserved 0x7- reserved reserved reserved reserved reserved reserved reserved reserved read & write read only read only, clear on read table 2. smbus register map -8 -9 -a -b -c -d -e -f 0x0- port 2 control port 2 option reserved reserved port 2 voltage port 2 current port 2 status port 2 event 0x1- port 4 control port 4 option reserved reserved port 4 voltage port 4 current port 4 status port 4 event 0x2- port 6 control port 6 option reserved reserved port 6 voltage port 6 current port 6 status port 6 event 0x3- port 8 control port 8 option reserved reserved port 8 voltage port 8 current port 8 status port 8 event 0x4- global detect min global detect max reserved reserved reserved reserved global id global rev 0x5- reserved reserved reserved reserved reserved reserved reserved reserved 0x6- reserved reserved reserved reserved reserved reserved reserved reserved 0x7- reserved reserved reserved reserved reserved reserved reserved reserved
micrel, inc. mic2358ylq july 2010 19 m9999-070810 port control (-0, -8) port option (-1, -9) port reserved (-2, -a) test (-3, -b) port voltage (-4, -c) port current (-5, -d) port status (-6, -e) port event (-7, -f) bit 7 classify_and_deny bit 6 power_denied bit 5 pse_status valid_signature bit 4 dc_mps max_class invalid_signature bit 3 ac_mps monitor short_circuit bit 2 classify event_hold overload bit 1 force_power pd_class dc_mps_absent bit 0 disable priority ac_mps_absent read & write read only read only, clear on read table 3. port registers global config (0x40) global power set-up (0x41) global event mask (0x42) global smbus status (0x43) global sqr (0x44) global status (0x45) global current port (0x46) global detect min (0x48) global detect max (0x49) global id (0x4e) global rev (0x4f) bit 7 port_8 bit 6 power_ denied port_7 bit 5 valid_ signature port_6 bit 4 ignore_ faults max_ class invalid_ signature port_5 bit 3 enable_ spm short_ circuit port_4 bit 2 ignore_ class_ overload min_ priority_ new_ power overload port_3 current_ port bit 1 alternative _b dc_mps_ absent port_2 current_ port bit 0 restore_ default_ setup min_ priority_ maintain_ power ac_mps_ absent enable_ smbint port_1 smp_ fault current_ port read and write read only table 4. global registers
micrel, inc. mic2358ylq july 2010 20 m9999-070810 port control register smbus address: 0x00, 0x08, 0x10, 0x18, 0x20, 0x28, 0x30, 0x38 read and write bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 ? ? ? dc_mps ac_mps classify force_power disable name default description dc_mps note 1 enables dc maintain power signature detection. ac_mps note 2 enables ac maintain power signature detection. classify 1 enables classification. force_power 0 puts the port into the test_mode state. disable note 3 puts the port into the disable state. notes: 1. initial state determined by dcmps input pin 2. initial state determined by acmps input pin 3. initial state determined by enable input pin. if cleared, puts the port into the idle state. port option register smbus address: 0x01, 0x09, 0x11, 0x19, 0x21, 0x29, 0x31, 0x39 read and write bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 classify_ and_deny max_class monitor event_hold priority name default description classify_and_deny 0 (note 1) the port will be detected and classified, but power will be denied (i.e,. put into power_denied state). max_class 0 maximum class allowed for new power to be supplied to a detected pd. monitor 0 enables readback of the port voltage and current. event_hold 0 prevents the port from starting a new detection cycle when an unmasked event is stored in the event register. priority low port priority level for power management. possible settings are shown below. this setting is used in conjunction with the minimum_priority_new-power and minimum_priority_maintain_power settings in the global power_setup register. port priority levels name value critical 11 high 10 medium 01 low 00 note: 1. bit classify must be enabled in control register
micrel, inc. mic2358ylq july 2010 21 m9999-070810 port voltage register smbus address: 0x04, 0x0c, 0x14, 0x1c, 0x24, 0x2c, 0x34, 0x3c read only the voltage register holds the 8-bit value of the measured port voltage. the lsb is equivalent to 0.25v. the register is only valid if the monitor bit of the port option register is set; otherwise it reads as 0x00. port current register smbus address: 0x05, 0x0d, 0x15, 0x1d, 0x25, 0x2d, 0x35, 0x3d read only the current register holds the 8-bit value of the measured port current. the lsb is equivalent to 2ma. the register is only valid if the monitor bit of the port option register is set; otherwise it reads as 0x00. port status register smbus address: 0x06, 0x0e, 0x16, 0x1e, 0x26, 0x2e, 0x36, 0x3e read only bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 ? pse_status pd_class name description pse_status indicates the port pse status bits from the table 33-16 of ieee std 802.3af . possible values are shown below pd_class indicates the class of a detected pd. possible values are shown below. (note 1) pse status status value disabled 000 searching 001 delivering power 010 test mode 011 test error 100 implementation specific fault 101 reserved 110 reserved 111 pd class class value class 0 000 class 1 001 class 2 010 class 3 011 class 4 100 note: 1. per ieee std 802.3af , pd class defaults to 0 if classification is disabled.
micrel, inc. mic2358ylq july 2010 22 m9999-070810 port event register smbus address: 0x07, 0x0f, 0x17, 0x1f, 0x27, 0x2f, 0x37, 0x3f read only, clear on read bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 ? power_ denied valid_ signature invalid_ signature short_circuit overload dc_mps_absent ac_mps_absent name description power_denied set when the port was not powered, or power was removed, and the state machine enters the power_denied state. valid_signature set when a valid signature is detected. invalid_signature set when an invalid signature is detected. short_circuit set when a short circuit condition occurs. overload set when an overload condition occurs. dc_mps_absent set when the dc maintain power signature drops out. ac_mps_absent set when the ac maintain power signature drops out. notes: 1. port event register bits correspond to pse status register bit[12..7] from table 33-16 of ieee std 802.3af-2005 . mps absent bit is reported separately as dc_mps_absent and ac_mps_absent. 2. port event register is associated with other behaviors of the mic2358ylq. the first behavior is the assertion of the /smbi nt pin (pin 58). if the port has an event occur that is not masked by the global event_ mask register, then the /smbint pin will be asserted, letting th e host know that an event has occurred. 3. the second behavior is the event holding. if the event hold bit in the port option register is clear and an unmasked even t occurs on this port, then the mic2358ylq will attempt another at detection on this port. if the event_hold bit in the port option register is set a nd an unmasked event occurs on this port, then the mic2358ylq will make no further attempts to do detection on this port until the host has cl eared the event_hold bit. this gives the host the opportunity to analyze what caused the event on the port and deal with it accordingly, prior to trying to power up the port again. global configuration register smbus address: 0x40 read and write bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 ? ? ? _ enable_spm ignore_class_ overlaod alternative_b restore_default _setup name default description enable_spm 1 turns on the shared power management feature. ignore_class_overload note 1 inhibits shutdown of port power if its current exceeds the class-dependent overload current, i.e. overload current will be equal to class 0 level. shutdown will still occur if the current exceeds the short-circuit threshold. alternative_b note 2 enables alternative b behavior, which adds a backoff delay following an invalid detection. restore_default_setup 0 software reset. forces the controller to restart and return all settings to default values. this bit will be cleared once the reset is complete. notes: 1. initial state determined by ico input pin. 2. initial state determined by altb input pin.
micrel, inc. mic2358ylq july 2010 23 m9999-070810 global power_setup register smbus address: 0x41 read and write bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 max_class minimum_priority_new_power minimum_priority_maintain_power name default description max_class class 0 (note 1) specifies the maximum class that will be powered after detection of a new powered device. possible values are shown following the port status register description. minimum_priority_new_power low (note 2) sets the minimum priority level for a port to be powered following detection of a powered device. a port with a lower priority will go to the power_denied state. possible values are shown following the port option register description. minimum_priority_maintain_ power low (note 3) sets the minimum priority level for a port to remain powered. a port with a lower priority will go to the power_denied state. possible values are shown following the port option register description. notes: 1. the max_class is defined independently in both global power_setup and port option registers. after a pd has been classified , the detected class is compared to these two values. if the pd is requesting more power than either of the max_class fields, then that port will not be powered. upon power-up or, reset, global max_class and all port max_class default to class 0. examples: the host sets global max_class to class 2, and port 5 max_class to class 1. a pd is plugged into port 1 and classifi es as class 0. this is more power than allowed by global max_class, so power will be denied to port 1. another pd is plugged into port 2 and c lassifies as class 2. this is equal to global max_class and less than port 2's max_class (which defaulted to class 0), so port 2 is powered up. a class 2 pd is plugged into port 5. this is equal to global max_class, but greater than port 5's max_class, so power is denied. then a class 1 pd is plugged into port 5. this is less than global max_class and equal to port 5's max_class, so the port is powered. 2. when a valid pd is detected on a port, that port's priority level is compared to the minimum_priority_new_power field in the global power_setup register. if the port's priority is equal to or greater than the minimum_priority_new_power, then the port will be powered up. otherwise, the port will go to the power_denied state of the state diagram. 3. when the value of the minimum_priority_maintain_power field in the global power_setup register is changed, the mic2358ylq wi ll check this against the priority level of all ports that are currently powered. if a port's priority level is equal to or greater than the minimum_priority_maintain_power, then that port will continue being powered up. if a port's priority level is less than the minimum_priority_maintain_power, then power will be removed from that port and it will go to the po wer_denied state of the stat e diagram. global event_mask register smbus address: 0x42 read and write bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 ? power _denied valid_ signature invalid_ signature short_circuit overload dc_mps_ absebt ac_mps_absent name default description power_denied 1 masks all ports from responding to a power denied event. valid_signature 1 masks all ports from responding to a valid signature event. invalid_signature 1 masks all ports from responding to an invalid signature event. short_circuit 1 masks all ports from responding to a short circuit event. overload 1 masks all ports from responding to an overload event. dc_mps_absent 1 masks all ports from responding to a dc mps dropout event. ac_mps_absent 1 masks all ports from responding to an ac mps dropout event. note: 1. this port is associated with every port event register. if any port has an event occur that is not masked by the global eve nt_mask register, then the /smbint pin will be asserted.
micrel, inc. mic2358ylq july 2010 24 m9999-070810 global smbus_status register smbus address: 0x43 read and write bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 ? ? ? ? ? ? ? enable_smbint name default description enable_smbint 1 cleared once the device has won smbus int response address arbitration. must be set with smbus commands to restore the /smbint functionality. global srq register smbus address: 0x44 read only bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 port_8 port_7 port_6 port_5 port_4 port_3 port_2 port_1 name description port_8 set when an unmasked event is set in the port_event register for port 8. port_7 set when an unmasked event is set in the port_event register for port 7. port_6 set when an unmasked event is set in the port_event register for port 6. port_5 set when an unmasked event is set in the port_event register for port 5. port_4 set when an unmasked event is set in the port_event register for port 4. port_3 set when an unmasked event is set in the port_event register for port 3. port_2 set when an unmasked event is set in the port_event register for port 2. port_1 set when an unmasked event is set in the port_event register for port 1. note: 1. global srq register provides the host a quick starting point to determine which port is reporting occurrence of an event, if any. during service of /smbint or polling, the host can read the global srq register first to determine which port had the event, then read that port' s event register to determine which specific event occurred.
micrel, inc. mic2358ylq july 2010 25 m9999-070810 global status register smbus address: 0x45 read only bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 ? ? ? ? ? uvp ovp spm_fault name description spm_fault set when the port has requested more power than is available as indicated by the shared power management controller. the port state machine will transition to the power_denied state. ovp set when the power supply exceeds global overvoltage protection threshold voltage v govp. uvp set when the power supply drops off below global undervoltage protection threshold voltage v guvp. global current_port register smbus address: 0x46 read only bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 ? ? ? ? ? current_port name description current_port indicates which port is currently being managed by the chip. possible values are shown below. ports status value port 1 000 port 2 001 port 3 010 port 4 011 port 5 100 port 6 101 port 7 110 port 8 111 note: 1. the mic2358ylq implements a single adc to service all ports during detection, classification, measurement of port output v oltage and current. the current_port indicates which particular port is being serviced. this register allows the host with capability to monitor internal ports act ivity timing. global detect_min register smbus address: 0x48 read and write this register is used to program the lower limit of acceptable resistor values for detecting a powered device. the weighting is 400 ? and the default value is 40 dec (0x28 hex). the default value of 40 means the lower limit is 40 x 400 = 16000 ? . setting this register to a different value could cause operation that does not comply with ieee std 802.3af-2003.
micrel, inc. mic2358ylq july 2010 26 m9999-070810 global detect_max register smbus address: 0x49 read and write this register is used to program the upper limit of acceptable resistor values for detecting a powered device. the weighting is 400 ? and the default value is 68 dec (0x44). the default value of 68 means the upper limit is 68 x 400 = 27200 ? . setting this register to a different value could cause operation that does not comply with ieee std 802.3af- 2003. global id register smbus address: 0x4e read only reading this register returns the part id number as 0x58. global rev register smbus address: 0x4f read only reading this register returns the part revision number as 00.
micrel, inc. mic2358ylq july 2010 27 m9999-070810 programming guide there are several ways of turning on a port in a system where the host manages the power budget. the following example outlines one such method. the enable_l pin is high, so that the host can gain control of the mic2358ylq before any attempt is made to power ports. the host sets the classifies and deny and event_hold bits in every port option register, and sets the classify bit in every port control register. the host then unmasks the valid_signature event in the global event_mask register. the host then clears all the disable bits in the port control registers, allowing the ports to begin operation. the host then waits for an event, either by monitoring the global srq register, or by waiting for the /smbint to be asserted. once an event occurs, the host can read the global srq register to figure out which port the event occurred on, then read that port's event register to make sure it was a valid_signature event that occurred on that port (the host may have chosen to unmask other events besides valid_signature). the host then reads the port's status register to find out what level of classification the pd presented to the pse. the host can then decide if it has enough power available to power up this port at that classification level. if the host decides to not to power up the port, then nothing further needs to be done. if the host does decide to power the port, then it must clear the classify_and_deny bit in the port's option register. the next time this port is serviced, it will repeat detection and classification, and power up the port. the host can monitor the port's status register to see that the port gets powered up, then set the classify_and_deny bit in the port's option register so that everything is ready to go for the next time a pd is plugged into this port.
micrel, inc. mic2358ylq july 2010 28 m9999-070810 selection of isolation transformer one simple 1:1 isolation transformer is needed at the line interface. an isolation transformer with integrated common- mode choke is recommended for exceeding fcc requirements. the following table gives recommended transformer characteristics. characteristics name value test condition turns ratio 1 ct : 1 ct open-circuit inductance (min.) 350h 100mv, 100khz, 8ma leakage inductance (max.) 0.4h 1mhz (min.) inter-winding capacitance (max.) 12pf d.c. resistance (max.) 0.9 ? insertion loss (max.) 1.0db 0mhz to 65mhz hipot (min.) 1500vrms the following transformer vendors provide compatible poe magnetic parts for micrel?s device: vendor part auto mdix number of ports pulse h2019, h1197 yes 1 pulse h2017 yes 4 tdk tal-6t127lf(-t) yes 1
micrel, inc. mic2358ylq july 2010 29 m9999-070810 package information 64-pin (10x10x1.4 ) lqfp (v) micrel, inc. 2180 fortune drive san jose, ca 95131 us a tel +1 (408) 944-0800 fax +1 (408) 474-1000 web http:/www.micrel.com the information furnished by micrel in this data sheet is believed to be accurate and reliable. however, no responsibility is a ssumed by micrel for its use. micrel reserves the right to change circuitry and specifications at any time without notification to the customer. micrel products are not designed or authorized for use as components in life support appliances, devices or systems where malfu nction of a product can reasonably be expected to result in personal injury. life support devices or systems are devices or systems that (a ) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to resul t in a significant injury to the user. a purchaser?s use or sale of micrel products for use in life support appliances, devices or systems is a pu rchaser?s own risk and purchaser agrees to fully indemnify micrel for any damages resulting from such use or sale. ? 2010 micrel, incor p orated.

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