View SI3461-E02-GM_3102787.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

rev. 1.0 5/10 copyright ? 2010 by silicon laboratories si3461 si3461 s ingle -p ort ieee 802.3 at p o e/p o e+ pse i nterface features applications description the si3461 is a single-port power management controller for ieee 802.3at-compliant powe r sourcing equipment (pse). the si3461 can be powered from a 50 v input using a shunt regulator, or, to save power, it can be powered from 50 v and 3.3 v power supplies. the ieee-required powered device (pd) detection featur e uses a robust 3-point algorithm to avoid false detection events. the si3461's reference design kit also provides full ieee-compliant classification and pd disconnect. intellig ent protection circuitr y includes input under- voltage lockout (uvlo), classification-based current limiting, and output short-circuit protection. th e si3461 is designed to operate completely independently of host processor control. an led status signal is provided to indicate the port status, including detection, power good, and output fault event information. the si3461 is pin- programmable to support four available power levels, endpoint and mid-span applications, and auto-retry or restart after disconnect functions. a comprehensive reference design kit is available (si3461- evb), including a complete schem atic and bill of materials. ? ieee 802.3at tm compliant pse ? autonomous operation requires no host processor interface ? complete reference design available, including si3461 controller and schematic: ?? low-cost bom ?? compact pcb footprint ?? operates directly from a +50 v isolated supply ?? supports up to 30 w maximum output power (class 4) ?? robust 3-point detection algorithm eliminates false detection events ?? ieee-compliant disconnect ?? inrush current control ?? short-circuit output fault protection ?? led status signal (detect, power good, output fault) ? unh interoperability test lab report available ? extended operating range (?40 to +85 c) ? 11-pin quad flat no-lead (qfn) package ?? tiny 3x3 mm pcb footprint; rohs-compliant ? ieee 802.3at endpoints and midspans ? environment a and b pses ? embedded pses ? set-top boxes ? ftth media converters ? cable modem and dsl gateways pin assignments 11-pin qfn (3x3 mm) top view?pads on bottom of package isense status vsense rst deta 1 2 3 4 5 10 9 8 7 6 dc1 clsmark dc2 vdd clsmode gnd si3461 11 11 11 11
si3461 2 rev. 1.0
si3461 rev. 1.0 3 t able of c ontents section page 1. typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 2. si3461 electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 2.1. si3461-evb perform ance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2. pse timing charac teristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 3. typical si3461-evb wavef orms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4. si3461-evb functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.1. reset state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 4.2. operating mode configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 5. operating mode sequencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.1. detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.2. classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 5.3. power-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 5.4. overload protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.5. disconnect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 5.6. uvlo and ovlo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.7. status led function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 6. design considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 6.1. isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 6.2. external component selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 6.3. input dc supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 7. si3461 pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 8. ordering guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 9. package outline: 11-pin qfn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 9.1. solder paste mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 9.2. pcb landing pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 9.3. marking specificati on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 document change list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 contact information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
si3461 4 rev. 1.0 1. typical application schematic figure 1. si3461 typical application schematic si3461 gnd deta v dd +3.3v v out 48 v pse output (to port magnetics) rst vdd detect & mark isense gnd status clsmode dc1 clsmark vsense detect fault pgood dc2 note: refer to the si3461-evb user guide for complete schematic details v in +50v gnd + - +50v classification & gate drive optional 3.3v regulator
si3461 rev. 1.0 5 2. si3461 electri cal specifications the following specifications apply to the si3461 controller. refer to tables 4 and 5 and the si3461-evb user's guide and schematics for additional details about the electr ical specifications of the si3461-evb reference design. table 1. recommended operating conditions description symbol test conditions min typ max unit operating temperature range t a ?40 25 +85 c thermal impedance ? ja no airflow ? 75 ? c/w vdd input supply voltage vdd during all operating modes (detect, classification, disconnect) 2.7 3.3 3.6 v table 2. absolute maximum ratings* parameter conditions max rating unit ambient temperature under bias ?55 to +125 c storage temperature ?65 to +150 c voltage on rst or any i/o pin with respect to gnd vdd > 2.2 v ?0.3 to 5.8 v voltage on vdd with respect to gnd ?0.3 to 4.2 v maximum total current through vdd and gnd 500 ma maximum output current into clsmark, dc1, dc2, clsmode, status, isense, rst, vsense, deta (any i/o pin) 100 ma esd tolerance human body model ?2 kv to +2 kv v lead temperature soldering, 10 seconds maximum 260 c *note: stresses above those listed in this table may cause permanent device damage. this is a stress rating only, and functional operation of the devices at thes e or any conditions above those indicat ed in the operational listings of this specification is not implied. exposure to maximum rating cond itions for extended periods may affect device reliability.
si3461 6 rev. 1.0 table 3. electrical characteristics* description symbol test conditions min typ max unit digital pins: clsmark, dc1, dc2, cl smode, status (output mode), rst output high voltage v oh i oh =?3ma i oh =?10a 0.7 x vdd vdd ? 0.1 ? ? ? ? v output low voltage v ol i ol =8.5ma i ol =10a ? ? ? ? 0.6 0.1 v input high voltage v ih any digital pin 0.7 x vdd v input low voltage v il any digital pin ? ? 0.6 v input leakage current i il v in =0v ? 1 ? a analog pins: isense, vsense, deta, status (input mode) input capacitance ?5?pf input leakage current i il ?1?a *note: vdd = 2.7 to 3.6 v, ?40 to +85 c unless otherwise specified.
si3461 rev. 1.0 7 2.1. si3461-evb perf ormance characteristics when implemented according to the recommended exter nal component and layout guidelines for the si3461-evb, the si3461 enables the following performance specifications in single-port pse applicatio ns. refer to the si3461- evb user's guide and sc hematics for details. table 4. selected electrical specifications (si3461-evb) description symbol test conditions min typ 1 max unit power supplies v in input supply range v in ?40 to +85 c ambient range 45 50 57 v v in input uvlo voltage uvlo uvlo turn-off voltage at v in ? 4 24 5 v v in input ovlo voltage ovlo ovlo turn-off voltage at v in 57 60 ? v vdd supply voltage range v dd si3461 supply voltage range 3.15 3.3 3.45 v output supply voltage v out pse output voltage at v in = 50 v and i out = 350 ma ?49?v supply current i in current into the v dd node (not including shunt regulator) ? 8.0 10.5 ma detection specifications detection voltage v det detection point 1 detection point 2 detection point 3 ?4.0 8.0 4.0 ?v detection current i det short circuit ? ? 3 ma minimum signature resistance r detmin 15 17 19 k ? maximum signature resistance r detmax 26.5 29 33 k ? classification specifications classification voltage v class 0ma < i class < 45 ma 15.5 ? 20.5 v classification cur- rent limit i class measured with 100 ? across v out 55 75 95 ma notes: 1. typical specifications are based on an ambient operating temperature of 25 c and vin = +50 v unless otherwise specified. 2. absolute classification current limits are configurable. see ?5.2. classification? and "5.3. power-up" on page 13. 3. typical icut values are adjusted according to the input vo ltage to provide power limiting with approximately 5% margin against the 802.3 requirements. the maximum icut values are consistent with the i eee requirement that icut maximum is less than 400 ma at the minimum allowed vout of 44 v or 684 ma for poe+ mode at the minimum allowed vout of 50 v. 4. overload current is within limits, typically in less than 1 ms.
si3461 8 rev. 1.0 classification current region i class _ region class 0 0 ? 5 ma class 1 8 ? 13 ma class 2 16 ? 21 ma class 3 25 ? 31 ma class 4 35 ? 45 ma mark voltage v mark 78 . 51 0v mark current i mark_lim short circuit ? ? 9 ma protection and current control overload current threshold 2,3 i cut class 0 and class 4 poe 15,400/v out 16,170/v out 17,600/v out ma class 1 4,000/v out 4,200/v out 4,600/v out ma class 2 7,000/v out 7,350/v out 8,000/v out ma class 3 15,400/v out 16,170/v out 17,600/v out ma class 4 poe+ 30,000/v out 31,500/v out 34,200/v out ma overload current limit 4 i lim class 0/1/2/3 and class 4 poe; output = 100 ? across v out 400 425 450 ma i lim poe+ class 4 poe+; output = 50 ? across v out 684 750 825 ma overload time t lim class 0/1/2/3 and class 4 poe; output = 100 ? across v out 50 60 75 ms class 4 poe+; output = 50 ? across v out 14 17 20 ms disconnect current i min disconnect current 5 7.5 10 ma efficiency system efficiency ? (p in @ v in ) to (p out @ v out ) ? 93 ? % table 4. selected electrical specifications (si3461-evb) (continued) description symbol test conditions min typ 1 max unit notes: 1. typical specifications are based on an ambient operating temperature of 25 c and vin = +50 v unless otherwise specified. 2. absolute classification current limits are configurable. see ?5.2. classification? and "5.3. power-up" on page 13. 3. typical icut values are adjusted according to the input vo ltage to provide power limiting with approximately 5% margin against the 802.3 requirements. the maximum icut values are consistent with the i eee requirement that icut maximum is less than 400 ma at the minimum allowed vout of 44 v or 684 ma for poe+ mode at the minimum allowed vout of 50 v. 4. overload current is within limits, typically in less than 1 ms.
si3461 rev. 1.0 9 2.2. pse timing characteristics when implemented in accordance with the recommended ex ternal components and layout guidelines, the si3461 controller enables the followi ng typical performance characteristics in single-port pse applicat ions. refer to the si3461-evb applications note, schematics, and user's guide for more details. table 5. pse timing description symbol test conditions min typ max unit endpoint detection delay cycle t det_cycle time from pd connection to port to completion of detection process. 90 ? 460 ms detection time t detect time required to measure pd signature resistance. ? 90 ? ms classification delay cycle t class_cycle class 0/1/2/3; time from successful detect mode to classification complete. ? 60 ? ms class 4, two event classification; time from successful detect mode to classification complete. ? 99 ? ms classification time t class class 0/1/2/3 and class 4 poe; ? 30 ? ms class 4 poe+ ? 69 ? ms power-up turn-on delay t pwrup class 0/1/2/3 and class 4 poe; time from when a valid detection is completed until v out power is applied ? 76 ? ms class 4 poe+; time from when a valid detection is completed until v out power is applied ? 112 ? ms midspan detect back- off time t bom 2.0 ? ? s error delay time t ed time from error to restart of detec- tion in auto-restart mode. 2.0 ? ? s disconnect delay t dc_dis ? 350 ? ms note: these typical specifications are based on an ambient operating temperature of 25 c and v in =+50v.
si3461 10 rev. 1.0 3. typical si3461-evb waveforms note: voltages are negative going with respect to the positive input. figure 2. typical si3461-evb waveforms ch1: poe output voltage referenced to the +50v rail detection classification power-on ch1: poe output voltage referenced to the +50v rail detection power-on two event classification mark pulse ch1: poe output voltage referenced to the +50v rail t detect g powering a poe+ device powering a poe device detection time ch1: poe output voltage referenced to the +50v rail detection classification t pwrup t class_cycle ch1: poe output voltage referenced to the +50v rail detection classification t pwrup t class_cycle t bom classification and power-up delay poe+ classification and power-up delay poe midspan backoff after bad classification result poe+ current limit response poe current limit response overload during classification t lim poe+ i lim poe+ t lim poe i lim poe i class
si3461 rev. 1.0 11 4. si3461-evb functional description in combination with low-cost exter nal components, the si3461 controller provides a co mplete pse solution for embedded poe applicat ions. the si3461-evb re ference design o perates from a +50 v is olated power supply and delivers power to the powered device through a fet switch without controllin g the output volt age while in the power-on state. refer to the si3461-evb user's guide and schema tics for descriptions in the following sections. the basic sequence of applying power is shown in figure 3. following is the description of the function that must be performed in each phase. figure 3. basic power-up sequence t det_cycle t class_cycle t pwrup -2.8v -15.5v -10v -20.5v -44v -57v ch1: poe output voltage referenced to the +50v rail detection classification power-on
si3461 12 rev. 1.0 4.1. reset state at power-up or if reset is held low, the si3461 is in an inactive state with the pass fet q4 off. 4.2. operating mode configuration at power-up, the si3461 reads the voltage on the status pi n, which is set by a dip switch and a resistor network. the status pin voltage level configures all of th e si3461's operating modes as summarized in table 6. table 6. operating modes 1,2,3,4 status pin voltage (v) operating mode pse type midspan/ endpoint restart action on fault or overload event condition available power (w) < 0.122 1 midspan restart after disconnection 4 0.122 to 0.338 1 midspan restart after disconnection 7 0.338 to 0.548 1 midspan restart after disconnection 15.4 0.548 to 0.756 2 midspan restart after disconnection 30 0.756 to 0.961 1 midspan auto restart after 2 s 4 0.961 to 1.162 1 midspan auto restart after 2 s 7 1.162 to 1.366 1 midspan auto restart after 2 s 15.4 1.366 to 1.575 2 midspan auto restart after 2 s 30 1.575 to 1.784 1 endpoint restart after disconnection 4 1.784 to 1.990 1 endpoint restart after disconnection 7 1.990 to 2.196 1 endpoint restart after disconnection 15.4 2.196 to 2.407 2 endpoint restart after disconnection 30 2.407 to 2.618 1 endpoint auto restart after 2 s 4 2.618 to 2.838 1 endpoint auto restart after 2 s 7 2.838 to 3.044 1 endpoint auto restart after 2 s 15.4 > 3.044 2 endpoint auto restart after 2 s 30 notes: 1. after power-up, the status pin drives the base of an npn transistor that controls an led. 2. there is a trade-off in selecting the mode setting resistor values between voltage step accuracy and additional worst- case supply current. for high-value resistors, the base current will alter the voltage steps while low-value resistors may place higher load on the status pin while driving the led. the suggested resulting parallel resistance used by the si3461-evb is 2.0 k ? . 3. each mode setting resistor should be connected either to gnd or +3.3 v through the dip switch. care should be taken not to short the +3.3 v supply to gnd. 4. a reset is required after a dip switch position change for the new mode to take effect.
si3461 rev. 1.0 13 5. operating mode sequencing 5.1. detection after power-up the si3461 enters the detection state wit h the pass fet off. prior to turning the fet on, a valid detection sequence must take place. according to the ieee specificat ions, the detection process consists of sensing a nominal 25 k ? signature resistance in parallel with up to 0.15 f of capacitance. to eliminate the possibility of false detection events, the si3461-evb referenc e design performs a ro bust 3-point detection sequence by varying the voltage across the load that connects to the +50 v supply rail and returns to gnd via d3, q14, r26, and r37. r37 serves as a current sensing resistor, and the si3461 monitors the volt age drop across it during the detection process. at the beginning of the detection sequence, v out is at zero; then, it is varied from 4 to 8 v and then back to 4 v for 20+20+50 ms at each respective level. if the pd's signature resistance is in the rgood range of 17 to 29 k ? , the si3461 proceeds to classification and power-up. if the pd resistance is not in this range, the detection sequence repeats continuously. detection is sequenced approximately every 400 ms for endspan and 2.2 seconds for midspan configurations and repeats until rgood is sensed , indicating a valid pd has been detected. the status led (d2) is flashed at a rate of about 1.5 hz to indicate the pse is searching for a valid pd. 5.2. classification after a valid pd is detected, the pse in terrogates the pd to find its power requirement. this pr ocedure is called classification and may be carried out in different ways. the si3461 implements the one-event classification for type1 pds and the two-event classification for type2 pds. for one-event classification, the pass fet q4 is turned on and programmed for an output voltage of 18 v with a current limit of 75 ma for 30 ms. for the two-event cl assification, the 18 v pulse is output twice with an 8.5 v amplitude mark pulse for 10 ms between the two classifica tion pulses. the current measured at the isense input during the classification process dete rmines the class level of the pd (refer to table 4 on page 7 for current ranges). if the si3461-evb has 30 w of available po wer, it attempts to classify a type 2 pd first by the two-event method. if the detected class is other than class 4 or there is less th an 30 w of power available, the si3461 tries to classify a type1 pd using the one-event method. if the class level of the pd is not within the supported r ange as set by the initial voltage on the si3461's status pin (refer to the operating mode configuration section abov e), an error is declared, and the led blinks rapidly at a 10 hz rate. this is refe rred to as classification-based power denial. if the class level is in the supported range, the si3461 proceeds to power-up. this is referred to as classification-based power granting. if the classification level is at a grea ter power than can be supported based on the voltage read by the status pin during start-up, an error condition is reported by flashing the led at a 10 hz rate for two seconds before the state machine goes back to the detection cycle. 5.3. power-up after successful classification, the pass fet is turned on wit h an initial current limit of 425 ma (for all pd classes), and the respective ilim values (indicated in table 4) take effect after the fet is fully turned on. after power-up is complete, power is applied to v out as long as there is not an overcurrent fault, disconnect, or input undervoltage (uvlo) or overvoltage (ovlo) condition. the stat us led is continuously lit when power is applied. if the output power exceeds t he level of the power requested during classification, the si3461 will declare an error and shut down the port, flashing the led rapidly to indica te the error. depending on the initial voltage on the status pin, the si3461 will wait either 2.2 seconds or until the pd has be en disconnected bef ore it enters the detection phase again to look for a valid load.
si3461 14 rev. 1.0 5.4. overload protection the si3461 implements a two-level overload protection scheme. the output current is limited to ilim, and the output is shut down if the current exceeds icut for more than 60 ms. if current limitation persists for more than 15 ms in case of poe+ class 4 loads, the output is shut down to protect the pass fet. current limit values are dynamically set according to the power level granted during the classification process and the effective output voltage (refer to table 4 on page 7 for current limit values). a special 425 ma current limit applies until the fet is fully tu rned on. if the fet does not fully turn on in the first 75 ms due to an overload condition, an error is decl ared. the maximum time that the 425 ma inrush current is supplied is about 70 ms due to a 5 ms period to initially ramp the fet gate voltage. the overload protection is implemented using a timer with a timeout set to 60 ms. if the output current exceeds the i cut threshold, the timer counts up; otherwise, if the output current drops below icut, the timer counts down towards zero at 1/16th the rate. if the timer reaches the se t timeout, an overcurrent fault is declared; the channel is shut down (by turning off the external pass fet), and the status led flashes rapidly at a rate of 10 hz. if the si3461 was configured in the ? automatic restart? mode during start-up, it will au tomatically resume the detection process after 2.2 seconds. in the ?restart after disconnect? mode of operation, the status led will flash rapidly, and the si3461 will not resume detectio n until it senses a resistance higher than 150 k ? . this condition can normally be achieved by removing the ethernet cable from the si3461-evb's rj-45 jack la beled ?poe?. then, the detection process begins; the status led blinks at a rate of 1.5 hz, and the si3461 is allowed to go into classification and power-up mode if a valid pd signature resistance is detected. 5.5. disconnect the si3461 implements a robust disconnect algorithm. if the output current level drops below 7.5 ma typical for more than 350 ms, the si3461 declares a pd disconnect event, and the pass fet is turned off. the si3461 automatically resumes the detection process after 500 ms. 5.6. uvlo and ovlo the si3461-evb referenc e design is optimized for 50 v nominal input voltages (44 v minimum to 57 v maximum). if the input voltage drops below 42 v, a uvlo condition is declared, which generates the error condition (led flashing rapidly). an undervoltage event is a fault condition reported through the status led as a rapid blinking of 10 flashes per second. in the same way, if the input voltage exceeds 60 v, an ovlo condition is declared. in both cases, the output is shut down. the uvlo and ovlo conditions are continuously monitored in all operating states. 5.7. status led function during the normal detection sequence, the status led fl ashes at approximately 1.5 times per second as the detection process continues. after successful power up, the led glows continuously. if there is an error condition (i.e., class level is beyond programmed value or a fault or over current condition has been detected), the led flashes rapidly at 10 times per second. this occurs fo r two seconds for normal error delay, and the detection process will automatically start again after 2.2 s unless a ?restart after disconnect cond ition? was set during the initial configuration. power will not be provided until an open circuit condition is detected. once the si3461-evb detects an open circuit condition, the led blinks at 1.5 times per second. if the powered device (pd) is disconne cted so that a disconne ct event occurs, the led will start flashing at 1.5 times per second once the detect process resumes.
si3461 rev. 1.0 15 6. design considerations 6.1. isolation the si3461-evb's pse output power at vout is not isolated from the in put power source (vin). isolation of pse output power requires that the input be isolated from earth ground. typically , an ac-to-dc power supply is used to provide the 50 v power so the output of this supply is isolated from earth ground. 6.2. external component selection detailed notes on extern al component selectio n are provided in the si3461-evb user's guide schematics and bom. in general, these recommendat ions must be followed closely to ensure output power stability, surge protection (surge protec tion diode), and overa ll ieee 802.3 compliance. 6.3. input dc supply the si3461-evb reference design requires an isolated 50 v nominal dc input voltage (with a minimum of 44 v and a maximum of 57 v). the input power supply should be rated for at least 10% higher power level than the output power level chosen. this is primarily to account for the lo sses in the current-sensing resistor, t he pass fet, and the series protection diode of the si3461-evb refe rence design. for example, to support a class 0 pse, th e input supply should be capable of supplying at least 16.94 w (15.4 w x 1.10 = 16.94 w). the power supply also needs to be able to source 425 ma for 60 ms for normal operation or 885 ma for 15 ms for high power (poe+) operation. the si3461-evb reference design does not regulate the ou tput voltage during the power -on state; therefore, the input dc supply should meet the ripple and no ise specifications of the ieee 802.3 standard. the si3461-evb refe rence design includes an option al 3.3 v shunt regulator that uses the 50 v input to generate the 3.3 v supply voltage for the si3461 controller. alternatively, an external 3.3 v power source may be used.
si3461 16 rev. 1.0 7. si3461 pin descriptions si3461 pin functionality is described in table 7. note th at the information applies to the si3461 device pins, while the si3461-evb user's guide de scribes the inputs and output s of the evaluation system. refer to the complete si3461-evb schematics and bom lis ting for information about the external components needed for the co mplete pse application circuit. table 7. si3461 pin functionality pin # pin name pin type pin function 1 clsmark digital output logic high on this output increa ses the current capability of the detection circuitry while used for mark pulse generation. refer to the si3461-evb schematics. 2 dc1 digital output this is a pwm output providing the dc control voltage for the detection circuitry. it is also combined with the dc2 output in a ratio of 1:256 to provide the gate control voltage of the pass fet. 3 vdd power 3.3 v power supply input. 4 dc2 digital output this is a pwm output that (combined with the dc1 output) pro- vides the gate control voltage of the pass fet with high resolution. 5 clsmode digital output this is an open drain output. wh en high, it enables the feedback path controlling the 18 v classification voltage. 6 deta analog input deta is an analog input pin. during the detection process, the dc1 pin duty cycle is varied to generate filtered dc voltages across the load, and the voltage drop across a current sensing resistor is measured through the deta input. 7 vsense analog input vsense is an analog inpu t used for sensing th e input dc voltage. 8rst digital input active low reset input. when low, it places the si3461 device into an inactive state. when pulled high, the device begins the detec- tion process sequence. 9 isense analog input isense is an analog input connected to a current sense resistor for output current sensing. 11-pin qfn (3x3 mm) top view?pads on bottom of package isense status vsense rst deta 1 2 3 4 5 10 9 8 7 6 dc1 clsmark dc2 vdd clsmode gnd si3461 11 11 11 11
si3461 rev. 1.0 17 10 status analog in/digital out at power-up, the voltage on this pin is sensed to configure the pse available power, mid span/e nd span timing mode and the device's restart behavior when a fault condition is detected. refer to "4.2. operating mode configuration" on page 12. after reading the voltage present at this pin at power-up, the status pin becomes a digital output used to control an external led, which indicates when a detect, power good, or output fault condition has occurred. logic high turns the led on, and logic low turns the led off. refer to "5.7. status led function" on page 14. 11 gnd gnd ground connection for the si3461. table 7. si3461 pin functionality (continued) pin # pin name pin type pin function
si3461 18 rev. 1.0 8. ordering guide ordering part number description package information temperature range (ambient) SI3461-E02-GM single-port pse controller 11-pin, 3 x 3 mm qfn. rohs compliant ?40 to 85 c si3461-kit si3461 evaluation board and reference design kit evaluation board n/a notes: 1. add r to part number to denote tape-an d-reel option (e.g., SI3461-E02-GMr). 2. the ordering part number above is not the same as the devic e mark. see "9.3. marking specification" on page 22 for more information.
si3461 rev. 1.0 19 9. package outline: 11-pin qfn figure 4 illustrates the package details for the si3461. table 8 lis ts the values for the di mensions shown in the illustration. the si3461 is packaged in an industry-st andard, 3x3 mm, rohs-comp liant, 11-pin qfn package. figure 4. qfn-11 package drawing table 8. package diagram dimensions dimension min nom max a 0.80 0.90 1.00 a1 0.03 0.07 0.11 a3 0.25 ref b 0.18 0.25 0.30 d3 . 0 0 b s c . d2 1.30 1.35 1.40 e0 . 5 0 b s c . e3 . 0 0 b s c . e2 2.20 2.25 2.30 l .45 .55 .65 aaa ? ? 0.15 bbb ? ? 0.15 ddd ? ? 0.05 eee ? ? 0.08 notes: 1. all dimensions shown are in millim eters (mm) unless otherwise noted. 2. dimensioning and tolerancing per ansi y14.5m-1994. 3. this drawing conforms to jedec outl ine mo-243, variation veed except for custom features d2, e2, and l which are toleranced per supplier designation. 4. recommended card reflow profile is per the jedec/ipc j-std-020c specification for small body components.
si3461 20 rev. 1.0 9.1. solder paste mask figure 5. solder paste mask 0.50 mm lt e e d e lb k d2 b l d4 0 . 1 0 m m 0.50 mm 0.35 mm 0.30 mm 0.10 mm 0.20 mm 0.30 mm 0.20 mm 0.60 mm 0.70 mm d4 b 0.30 mm 0.35 mm e2 0.20 mm
si3461 rev. 1.0 21 9.2. pcb landing pattern figure 6. typical qfn-11 landing diagram lt e e d e lb k b l d4 0 . 1 0 m m 0.50 mm 0.35 mm 0.30 mm 0.10 mm 0.20 mm d4 b 0.30 mm 0.20 mm e2 d2 0.10 mm
si3461 22 rev. 1.0 9.3. marking specification the top of the si3461 package is marked as shown in figure 7. figure 7. qfn 11 top marking table 9. top marking explanation line 1 marking: pin 1 identifier circle = 0.25 mm diameter product id 6102 61 = si3461; 02 = firmware revision 02 line 2 marking: ettt = trace code assembly trace code e = product revision ttt = assembly trace code line 3 marking: yww = date code assigned by the assembly contractor. y = last digit of current year (ex: 2009 = 9) ww = current work week lead-free designator + 6102 ettt yww+
si3461 rev. 1.0 23 d ocument c hange l ist revision 0.1 to revision 0.2 ? updated "9.3. marking specification" on page 22. revision 0.2 to revision 0.3 ? updated "8. ordering guide" on page 18. revision 0.3 to revision 1.0 ? updated firmware revision to 02. ? updated table 3 on page 6 ?? made consistent with firmware revision 02. ?? corrected previous errors for i oh and v il values. ? updated table 4 on page 7 ?? added min ovlo and max uvlo limits. ?? updated i in so as not to include the shunt regulator current. ?? updated i cut values to be consistent with ieee specification. ? updated table 6 on page 12. ?? update suggested parallel resistance at status pin in note 2.
si3461 24 rev. 1.0 c ontact i nformation silicon laboratories inc. 400 west cesar chavez austin, tx 78701 tel: 1+(512) 416-8500 fax: 1+(512) 416-9669 toll free: 1+(877) 444-3032 please visit the silicon labs technical support web page: https://www.silabs.com/support/pages/contacttechnicalsupport.aspx and register to submit a technical support request. silicon laboratories and silicon labs are trademarks of silicon laboratories inc. other products or brandnames mentioned herein are trademarks or registered trademarks of their respective holders. the information in this document is believed to be accurate in all respects at the time of publication but is subject to change without notice. silicon laboratories assumes no responsibility for errors and omissions, and disclaims responsib ility for any consequences resu lting from the use of information included herein. additionally, silicon laboratorie s assumes no responsibility for the functioning of undescribed features or parameters. silicon laboratories reserves the right to make changes without further notice . silicon laboratories makes no wa rranty, rep- resentation or guarantee regarding the suitability of its products for any particular purpose, nor does silicon laboratories as sume any liability arising out of the application or use of any product or circuit, and s pecifically disclaims any an d all liability, including wi thout limitation conse- quential or incidental damages. silicon laborat ories products are not designed, intended, or authorized for use in applications intended to support or sustain life, or for any other application in which the failure of the silicon laboratories product could create a s ituation where per- sonal injury or death may occur. should buyer purchase or us e silicon laboratories products for any such unintended or unauthor ized ap- plication, buyer shall indemnify and hold silicon laboratories harmless against all claims and damages.

▲Up To Search▲

Price & Availability of SI3461-E02-GM

	To Download SI3461-E02-GM Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .