february 2010 doc id 9883 rev 7 1/9 9 usbuf01p6 ipad? emi filter and line term ination for usb upstream ports features monolithic device with recommended line termination for usb upstream ports integrated r t series termination and c t bypassing capacitors. integrated esd protection small package size benefits emi / rfi noise suppression required line termination for usb upstream ports esd protection exceeding iec 61000-4-2 level 4 high flexibility in the des ign of high density boards tailored to meet usb 2.0 standard (low speed and full speed data transmission) complies with the following standards: iec 61000-4-2 level4: ? 15 kv (air discharge) ? 8 kv (contact discharge) mil std 883e-method 3015-7: ? class 3, c = 100 pf, r = 1500 ? 3 positive strikes, 3 negative strikes (f = 1 hz) applications emi filter and line termination for usb upstream ports on: usb hubs pc peripherals figure 1. functional diagram (top view) description the usb specification requires upstream ports to be terminated with pull-up resistors from the d+ and d- lines to v bus . for the implementation of usb systems, the radiat ed and conducted emi should be kept within the required levels as stated by the fcc regulations. in addition to the requirements of termination and emc compatibility, the computin g devices ar e required to be tested for esd susceptibility. the usbuf01p6 provides the recommended line termination while implementi ng a low pass filter to limit emi levels and providing esd protection which exceeds iec 61000-4-2 level 4 standard. the device is packaged in a sot-666, which is the smallest available lead-frame package (45% smaller than the standard sot323). tm: ipad is a trademear k of stmicroelectronics sot-666ip 3.3 v rp ct rt ct rt d1 gnd d2 d4 d3 3.3 v www.st.com
characteristics usbuf01p6 2/9 doc id 9883 rev 7 1 characteristics table 1. absolute maximum rating (t amb = 25 c) symbol parameter value unit v pp esd discharge iec 61000-4-2 air discharge iec 61000-4-2 contact discharge mil std 883e - method 3015-7 16 9 25 kv t j junction temperature 150 c t stg storage temperature range -55 to +150 c t l maximum lead temperature for soldering during 10 s at 5 mm for case 260 c t op operating temperature range -40 to + 85 c table 2. electrical characteristics (t amb = 25 c) symbol parameter v rm stand-off voltage v br breakdown voltage v cl clamping voltage i rm leakage current i pp peak pulse current t voltage temperature coefficient v f forward voltage drop rd dynamic resistance symbol test conditions min. typ. max. unit v br i r = 1 ma 6 10 v i rm v rm = 3.3 v per line 500 na r t tolerance 10% 33 r p tolerance 10% 1.5 k c t tolerance 20% 47 pf i v i f i rm i pp v rm v f v br slope = 1/rd v cl
usbuf01p6 technical information doc id 9883 rev 7 3/9 2 technical information figure 2. usb standard requirements 2.1 application example figure 3. implementation of st solutions for usb ports host or hub port twisted pair shielded zo = 90ohms 5m max hub 0 or full-speed function untwisted unshielded 3m max full speed connection low speed connection 3.3v 3.3v d+ d- d+ d- d+ d- d+ d- 1.5k 1.5k hub 0 or low-speed function low-speed usb transceiver full-speed or low-speed usb transceiver 15k rt rt ct ct host or hub port full-speed or low-speed usb transceiver 15k rt rt ct ct rt rt ct ct full-speed usb transceiver rt rt ct ct 15k 15k d+ d- cable host/hub usb por transceiver t d- d+ d+ d- upstream por t downstream port usbdf01w5 d+ d- rt d+ in gnd d- in d+ out d- out rt rd rd ct ct gnd 3.3 v rp ct rt ct rt d1 gnd d2 d4 d3 3.3v peripheral transceiver usbuf01p6 d+ d- cable host/hub usb por transceiver t d- d+ d+ d- upstream por t downstream port usbdf01w5 d+ d- rt d+ in gnd d- in d+ out d- out rt rd rd ct ct gnd 3.3 v rp ct rt ct rt d1 gnd d2 d4 d3 3.3v peripheral transceiver usbuf01p6 full speed connection low speed connection
technical information usbuf01p6 4/9 doc id 9883 rev 7 2.1.1 emi filtering current fcc regulations require that class b computing devices meet specified maximum levels for both radiated and conducted emi. radiated emi covers the frequency range from 30 mhz to 1 ghz. conducted emi covers the 450 khz to 30 mhz range. for the types of device compliant with the usb standard, the most difficult test to pass is usually the radiated emi test. for this reason the usbuf01p6 device aims to minimize radiated emi. the differential signal (d+ and d-) of usb devices does not contribute significantly to radiated or conducted emi because the magnetic field of each conductor cancels out the other. the inside of a pc product is very noisy a nd designers must minimize noise coupling from the different sources. d+ and d- must not be routed near high speed lines (clock spikes). induced common mode noise can be minimized by running pairs of usb signals parallel to each other and running grounded guard trace on each side of the signal pair from the usb controller to the usbuf device. if possible, locate the usbuf device physically near the usb connectors. distance between the usb controller and the usb connector must be minimized. the 47 pf (c t ) capacitors are used to divert high frequency energy to ground and for edge control, and are placed between the driver chip and the series termination resistors (r t ). both c t and r t should be placed as close to the driver chip as is practicable. the usbuf01p6 ensures a filtering protection against electro-magnetic and radio frequency interference thanks to its low-pass filter structure. this filter is characterized by the following parameters: cut-off frequency insertion loss high frequency rejection. figure 4. usbuf01p6 typical attenuation curve figure 5. measurement configuration f/hz 1.0m 3.0m 10.0m 30.0m 100.0m 300.0m 1.0g 3.0g -25.00 -22.50 -20.00 -17.50 -15.00 -12.50 -10.00 -7.50 -5.00 -2.50 0.00 db - - - - - - - - - - test board 50 vg 50 uux
usbuf01p6 technical information doc id 9883 rev 7 5/9 2.1.2 esd protection in addition to the requiremen ts of termination and emc comp atibility, computing devices are required to be tested for esd susc eptibility. this test is desc ribed in iec 61000-4-2 and is already in place in europe. this test requires that a device tolerates esd events and remains operational without user intervention. the usbuf01p6 is particularly optimized to perform esd protection. esd protection is based on the use of device which clamps at: this protection function is split into 2 stages. as shown in figure 6. the esd strikes are clamped by the first stage s1 and then its remaining overvoltage is applied to the second stage through the resistor r t . such a configuration makes the output voltage very low. figure 6. usbuf01p6 esd clamping behavior figure 7. measurement board to have a good approximation of the remaining voltages at both v input and v output stages, we give the typical dynamical resistance value r d . taking into account the following hypothesis: r t >r d , r g >r d and r load >r d , gives these formulas: the calculation done for v g = 8 kv, r g = 330 (iec 61000-4-2 standard), v br = 7 v (typ.) and r d = 2 (typ.) gives: v input = 55.48 v v output = 10.36 v v cl v br r d i pp ? + = esd surge vinput voutput rload rg rt s1 rd v br v br v pp device to be protected usbuf01p6 rd s2 test board esd surge 15kv air discharge vin vout u vinput r g v br r d v g ? + ? r g ----------------------------------------------- = voutput r t v br r d vinput ? + ? r t --------------------------------------------------------- - =
technical information usbuf01p6 6/9 doc id 9883 rev 7 this confirms the very low remaining voltage across the device to be protected. it is also important to note that in this approximation the parasitic inductance effect was not taken into account. this could be a few tenths of volts during a few ns at the v input side. this parasitic effect is not present at the v output side due the low current involved after the resistance r t . the measurements done hereafter show very clearly ( figure 8 and figure 9 ) the high efficiency of the esd protection: no influence of the parasitic inductances on v output stage v output clamping voltage very close to v br (breakdown voltage) in the positive way and -v f (forward voltage) in the negative way note: the usbuf01p6 acts not only for positive esd surges but also for negative ones. for these kinds of disturbances it clamps close to ground voltage as shown in figure 9. figure 8. remaining voltage at both stages s1 (v input ) and s2 (v output ) during positive esd surge figure 9. remaining voltage at both stages s1 (v input ) and s2 (v output ) during negative esd surge
usbuf01p6 package information doc id 9883 rev 7 7/9 3 package information epoxy meets ul94, v0 lead-free package in order to meet environmental requirements, st offers these devices in different grades of ecopack ? packages, depending on their level of environmental compliance. ecopack ? specifications, grade definitions and product status are available at: www.st.com . ecopack ? is an st trademark. figure 10. sot-666ip footprint (dimensions in mm) table 3. sot-666ip dimensions ref. dimensions millimeters inches min. typ. max. min. typ. max. a 0.53 0.57 0.60 0.021 0.22 0.024 a3 0.13 0.17 0.18 0.005 0.007 0.007 b 0.17 0.25 0.007 0.009 b1 0.27 0.34 0.011 0.013 d 1.50 1.66 1.70 0.059 0.065 0.067 e 1.50 1.65 1.70 0.059 0.065 0.067 e1 1.10 1.20 1.30 0.043 0.047 0.051 e0.50 0.020 l1 0.11 0.19 0.26 0.004 0.007 0.010 l2 0.10 0.23 0.30 0.004 0.009 0.012 l3 0.05 0.10 0.002 0.004 l4 0.83 0.033 angle 8 10 12 8 10 12 d b angle l3 l1 l4 e b1 e1 l2 e a a3 pin 1 0.30 0.50 2.60 0.62 0.99 0.21 1.40 0.20
ordering information usbuf01p6 8/9 doc id 9883 rev 7 3.1 mechanical specifications 4 ordering information 5 revision history lead plating mat tin lead plating thickness 7 m min, 20 m max lead coplanarity 10 m max body material molded epoxy flammability ul94, v0 table 4. ordering information order code marking package weight base qty delivery mode usbuf01p6 u sot-666ip 2.9 mg 3000 tape and reel table 5. document revision history date revision changes september-2003 1 first issue. 01-jun-2004 2 sot-666 internal pad version package change. 08-jun-2005 3 minor format changes; no content changed. 10-mar-2006 4 footprint and dimension graphic improved in packaging information. ecopack statem ent added. reformatted to current standard. 16-aug-2006 5 updated sot-666ip package dimensions in table 3. 29-aug-2006 6 typing error in table 2 on page 2: change w and kw unit to and k unit. 18-feb-2010 7 updated gnd pin annotation in figures 1 and 3 . added pin numbering indication to illustration and updated dimension values in ta bl e 3 . updated mechanical specifications in section 3.1 .
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