march 2010 1 m9999-030810 mic2551a-2.5 micrel, inc. mic2551a-2.5 usb transceiver general description the mic2551a is a single chip transceiver that complies with the physical layer specifcations of the universal serial bus (usb) 2.0. it supports both full speed (12mbps) and low speed (1.5mbps) operation and introduces superior edge rate control, producing crisper eye diagrams. this in turn, eases the task of passing usb compliance testing. a unique, patented, dual supply voltage operation allows the mic2551a to reference the system i/f i/o signals to a supply voltage down to 1.6v while independently powered by the usb v bus . this reduces system operating current and allows the system to operate at its core voltage without additional buffering logic. mic2551a-2.5 is differentiated from mic2551a by a smaller space saving mlf ? package (2.5mm 2.5mm) and 15kv esd protection which eliminates the need for separate esd protection devices on the d+, d- data lines. data sheets and support documentation can be found on micrel's web site at www.micrel.com. typical application usb controller vif oe# rcv vp vm dC d+ vbus vtrm gnd dC d+ usb port gnd tr ansceiver spd 20? 1% v i/o sus vpu v bus 1.5 k 1 .0f con gnd 20? 1% 10f mic2551a typical application circuit features ? 15kv esd protection on v bus , d+ and d- ? smaller 2.5mm 2.5mm mlf ? package ? usb 1.1 and 2.0 compliant transceiver (full speed - 12mbs and low speed - 1.5mbps) operation ? separate i/o supply with operation down to 1.6v ? integrated speed select termination supply ? very-low power consumption to meet usb suspend current requirements ? no power supply sequencing requirements ? software controlled enumeration applications ? pdas ? palmtops ? cell phones ? pc peripherals micrel, inc. ? 2180 fortune drive ? san jose, ca 95131 ? usa ? tel + 1 (408) 944-0800 ? fax + 1 (408) 474-1000 ? http://www.micrel.com microlead frame and mlf are registered trademarks of amkor technology . ordering information part number junction temp. range package - pb free mic2551ayml25 -40c to +85c 2.5mm2.5mm mlf ?
mic2551a-2.5 micrel, inc. m9999-030810 2 march 2010 pin confguration 12 13 14 11 10 9 8 1 2 3 4 7 6 5 rcv vp vm con vpu vtrm d+ d- spd vif vbus gnd sus oe# 14-pin mlf ? (ml) pin description pin number pin name i/o pin description 1 rcv o receive data: output for usb differential data. 2 vp i/o if oe# = 1, vp = receive output (+) if oe# = 0, vp = driver input (+). 3 vm i/o if oe# = 1, vm = receive output (-) if oe# = 0, vm = driver input (-). 4 con i connect (input): controls state of vpu. refer to vpu pin description for detail. 5 gnd ground reference. 6 sus i suspend: active-high. turns off internal circuits to reduce supply current. 7 oe# i output enable: active-low. enables the transceiver to transmit data onto the bus. when inactive, the trasceiver is in the receive mode. 8 d- i/o differential data lines conforming to the usb standard. 9 d+ 10 vtrm o 3.3v reference supply output: requires a minimum 0.1f decoupling capacitor for stability. a 1f capacitor is recommended. 11 vpu o pull-up supply voltage output: used to connect 1.5k? pull-up speed detect resistor. if con = 1, vpu is high impedance. if con = 0, vpu = 3.3v. 12 vbus i usb bus supply voltage: used to power usb transceiver and internal circuitry. 13 vif i system interface supply voltage: used to provide reference supply voltage for system i/o interface signaling. 14 spd i edge rate control: a logic high operates at edge rates for "full speed" operation. a logic low operates edge rates for "low-speed" operation.
march 2010 3 m9999-030810 mic2551a-2.5 micrel, inc. sus oe# d+, dC rcv vp/vm function 0 0 driving active active normal transmit mode. 0 1 receiving active active normal receive mode. 1 0 hi-z 0 not active low power state. 1 1 hi-z 0 active receiving during suspend (low power state) (note 1) note 1. during suspend, vp and vm are active in order to detect out-of-band signaling conditions. table 1. function selection oe# = 0: input output result vp vm d+ dC rcv 0 0 0 0 x se0 0 1 0 1 0 logic 0 1 0 1 0 1 logic 1 1 1 1 1 x undefned oe# = 1: input output result d+ dC vp vm rcv 0 0 0 0 x se0 0 1 0 1 0 logic 0 1 0 1 0 1 logic 1 1 1 1 1 x undefned x - undefned table 2. truth table during normal mode
mic2551a-2.5 micrel, inc. m9999-030810 4 march 2010 absolute maximum ratings (note 1) supply voltage (v bus ) .................................................. 6.5v all other inputs ............................................... C0.5v to 5.5v ambient storage temperature .................. C65c to +150c output current (d+, dC) .......................................... 50ma output current (all others) ........................................ 15ma input current ............................................................. 50ma esd, note 3 v bus , d+, dC ......................................................... 15kv all other pins ............................................................ 2kv operating ratings (note 2) supply voltage (v bus ) ................................... 4.0v to 5.25v ambient operating temperature ................ C40c to +85c package thermal resistance mlf ? ( ja ) ......................................................... 59(c/w) dc electrical characteristics (system and usb interface) (note 6) v if = 3.6v, v bus = 5v unless otherwise noted; t a = 25c. bold indicates specifcations over temperature, -40c to 85c. symbol parameter conditions min typ max units v bus usb supply voltage 4.0 5.25 v v if system i/f supply voltage 1.6 3.6 v v il low-level input voltage, note 4 v if -0.3 0.15v if v v ih high-level input voltage, note 4 0.85v if v if +0.3 v v oh high-level output voltage, note 4 i oh = 20a 0.9v if v v ol low-level output voltage, note 4 i ol = 20a 0.1 v i il input leakage current, note 4 -5 5 a symbol parameter conditions min typ max units spd sus oe# voltage load i if vif supply current 1 0 1 vbus = 5.25v vif = 3.6v 1 5 a 1 0 0 0 0 1 0 0 0 0 1 0 1 0 0 f = 6mhz cload = 50pf, note 6 325 650 a 0 0 0 f = 750mhz cload = 600pf, note 6 40 75 a i vbus vbus supply current 1 0 1 vbus = 5.25v vif = 3.6v 800 1100 a 1 0 0 3000 5000 a 0 0 1 230 350 a 0 0 0 400 700 a 0 1 0 130 200 a 1 0 0 f = 6mhz cload = 50pf, note 6 7.3 10 ma 0 0 0 f = 750mhz cload = 600pf, note 6 3.6 5 ma symbol parameter conditions min typ max units i vpuleak vpu leakage current con = 1, v pu = 0v -5 5 a i vifleak vif leakage current v if = 3.6v, v bus = 0v -5 5 a v pu pull-up output voltage i term = 200a, v bus = 4.0 to 5.25v 3.0 3.3 3.6 v r sw internal pull-up termination i term = 10ma, v bus = 4.0 to 5.25v 10 ?
march 2010 5 m9999-030810 mic2551a-2.5 micrel, inc. dc electrical characteristics (transceiver) (note 6) leakage current i lo hi-z state data line leakage (suspend mode) 0v < v in < 3.3v, sus = 1 -10 10 a input levels v di differential input sensitivity |(d+) - (d-)| 0.2 v v cm differential common mode range includes v di range 0.8 2.5 v v se single-ended receiver threshold 0.8 2.0 v receiver hysteresis 200 mv output levels v ol static output low r l = 1.5k? to 3.6v 0.3 v v oh static output high r l = 1.5k? to gnd 2.8 3.6 v capacitance c in transceiver capacitance pin to gnd 10 pf z rdv driver output resistance steady-state drive 8 16 24 ? ac electrical characteristics (notes 5) driver characteristics (low speed) t r transition rise time c l = 50pf, figure 2 c l = 600pf 75 300 ns t f transition fall time c l = 50pf, figure 2 c l = 600pf 75 300 ns t r , t f rise/fall time matching (t r , t f ) 80 125 % v crs output signal crossover voltage 1.3 2.0 v driver characteristics (full speed) t r transition rise time c l = 50pf, figure 2 4 20 ns t f transition fall time c l = 50pf, figure 2 4 20 ns t r , t f rise/fall time matching (t r , t f ) 90 111.11 % v crs output signal crossover voltage 1.3 2.0 v transceiver timing t pvz oe# to rcvr tri-state delay figure 1 15 ns t pzd receiver tri-state to transmit delay figure 1 15 ns t pdz oe# to drvr tri-state delay figure 1 15 ns t pzv driver tri-state to receiver delay figure 1 15 ns t plh t phl vp, vm to d+, d- propagation delay figure 4 15 ns t plh t ph l d+, d- to rcv propagation delay figure 3 15 ns t plh t phl d+, d- to vp, vm propagation delay figure 3 8 ns note 1. exceeding the absolute maximum rating may damage the device. note 2. the device is not guaranteed to function outside its operating rating. note 3. devices are esd sensitive. handling precautions recommended. human body model, 1.5k in series with 100pf . note 4. specifcation applies to the following pins: sus, spd, con, rcv, vp, vm, oe#. note 5. all ac parameters guaranteed by design but not production tested. note 6. specifcation for packaged product only. symbol parameter conditions min typ max units esd protection iec-1000-4-2 (d+, d-, v bus only) air discharge 10 pulses 15 kv contact discharge 10 pulses 15 kv
mic2551a-2.5 micrel, inc. m9999-030810 6 march 2010 timing diagrams t pvz oe# v p /v m d+/dC transmit receive t pzd t pdz t pzv figure 1. enable and disable times t r rise t ime fall t ime dif ferential data lines 10% 90% 10% 90% t f figure 2. rise and fall times t plh v crs v ss v ol v oh dC d+ v crs dif ferential data lines t phl figure 3. receiver propagation delay t plh v crs v ol v oh dC d+ v crs dif ferential data lines t phl figure 4. driver propagation delay test circuits d.u.t . 25pf figure 5. load for v p , v m , rcv d.u.t . c l 15k 20 vtrm 1.5k figure 6. load for d+, dC
march 2010 7 m9999-030810 mic2551a-2.5 micrel, inc. functional diagram to internal circuitry vbus vterm vpu d+ dC level t ranslator ldo regulator vif con spd oe# rcv vp vm sus gnd mic2551a applications information the mic2551a is designed to provide usb connectivity in mobile systems where available system supply voltages are not able to satisfy usb requirements. the mic2551a can operate interface supply voltages as low as 1.6v and still meet the usb physical layer specifcations. as shown in the circuit above, the mic2551a takes advantage of the usb supply voltage, v bus , to operate the transceiver. the system voltage, v if , is used to set the reference voltage used by the digital i/o lines interfacing to the system controller. internal circuitry provides translation between the usb and system voltage domains. v if will typically be the main supply voltage rail for the controller. in addition, a 3.3v, 10% termination supply voltage, (v pu ), is provided to support speed selection. v pu can be disabled or enabled under software control via the con input. this allows for software-controlled connect or disconnect states. a 1.5k resistor is required to be connected between this pin and the d+ or dC lines to respectively specify high speed or low speed operation.
mic2551a-2.5 micrel, inc. m9999-030810 8 march 2010 power supply confguration the mic2551a can be set up for different power supply confgurations which modify the behavior of the device. both v bus and v if have special thresholds that detect when they are either removed or grounded. table 1 depicts the behavior under the different power supply confguration scenarios that are explained below. normal mode v bus is connected to the 5.0v usb bus voltage and v if is connected to a supply voltage in the range of 1.6v to 3.6v. in this case v trm supplies a 3.3v voltage for powering the speed select resistor via v pu depending on the state of con pin. disconnect mode v if is connected to a supply in a range of 1.6v to 3.6v and v bus is open or grounded. if v bus is opened while transmitting, the data lines (d+, dC) have sharing capability and may be driven with external devices up to approximately 3.6v if and only if suspend is enabled (sus = 1). with v bus ground, d+, dC sharing mode is not permitted. disable mode v bus is connected to the 5.0v usb bus voltage and v if is open. all logic controlled inputs become high impedances, thus minimal current will be supplied by v if if the input pins are pulled up to an external source. alternate power supply confguration option i/o interface using 3.3v in systems where the i/o interface utilizes a 3.3v usb con - troller, an alternate solution is shown in figure 7. no extra components are required; however, the load on v trm must not exceed 10ma. vif vbus i/o vbus v p /v m / rcv/oe# vtrm usb controller v dd 3.3v figure 7. i/o interface using 3.3v signal amplitude respective to v when operating the mic2551a, it is necessary to provide input signals which do not exceed v if + 0.3v. when the suspend pin (sus) is high, power consumption is reduced to a minimum. v trm is not disabled. rcv, v p and v m are still functional to enable the device to detect usb activity. for minimal current consumption in suspend mode, it is recommended that oe# = 1, and spd = 0. the speed pin (spd) sets d+/dC output edge rates by in - creasing or decreasing biasing current sources within the output drivers. for low speed, spd = 0. for full speed, spd = 1. by setting spd = 0 during idle periods, in conjunction with suspend (sus), the lowest quiescent current can be obtained. however, designers must provide a 300ns delay between changing spd from 0 to 1 and transmission of data at full speed. this delay ensures the output drivers have ar - rived at their proper operating conditions. failure to do so can result in leading edge distortion on the frst few data bits transmitted. non-multiplexed bus in order to save pin count for the usb logic controller interface, the mic2551a was designed with v p and v m as bi-directional pins. to interface the mic2551a with a non-multiplexed data bus, resistors can be used for low cost isolation, as shown in figure 8. v po v p v m v mo usb logic controller (sie) v p v m 10k 10k figure 8. mic2551a interface to non-multiplexed data bus
march 2010 9 m9999-030810 mic2551a-2.5 micrel, inc. pcb layout recommendations although the usb standard and applications are not based in an impedance-controlled environment, a properly designed pcb layout is recommended for optimal transceiver perfor - mance. the suggested pcb layout hints are as follows: ? match signal line traces (vp/vm, d+, dC) to 40ps, approximately one-third inch if possible. fr-4 pcb material propagation is about 150ps/ inch, so to minimize skew try to keep vp/vm, d+/dC traces as short as possible. ? for every signal line trace width (w), separate the signal lines by 1.5 C 2 widths. place all other traces at >2 widths from all signal line traces. ? maintain the same number of vias on each dif - ferential trace, keeping traces approximately at same separation distance along the line. ? control signal line impedances to 10%. ? keep r s as close to the ic as possible, with equal distance between r s and the ic for both d+ and dC. confguration mode vbus/vtrm vif notes normal connected connected normal supply confguration and operation. disconnect (d+/d- sharing) open connected vp/vm are high outputs, rcv is low. with oe# = 0 and sus = 1, data lines may be driven with external devices up to 3.6v. with d+, d- foating, i if draws less than 1a. disconnect ground connected vp/vm are high outputs, rcv is low. with d+, d- foating, i if draws less than 1a. disable mode connected open logic controlled input pins are hi-z. no communication is possible until interface voltage is restored. unpowered connected ground inoperative table 1. power supply confguration
mic2551a-2.5 micrel, inc. m9999-030810 10 march 2010 package information 14-pin mlf ? (ml) micrel inc. 2180 fortune drive san jose, ca 95131 usa tel + 1 (408) 944-0800 fa x + 1 (408) 474-1000 w e b http://www.micrel.com this information furnished by micrel in this data sheet is believed to be accurate and reliable. however no responsibility is assumed by micrel for its use. micrel reserves the right to change circuitry and specifcations at any time without notifcation to the customer . micrel products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction 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 result in a signifcant injury to the user . a purchaser's use or sale of micrel products for use in life support appliances, devices or systems is a purchaser's own risk and purchaser agrees to fully indemnify micrel for any damages resulting from such use or sale. ? 2005 micrel incorporated
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