protection products 1 www.semtech.com protection products stf203-22 usb upstream port filter& tvs for emi filtering and esd protection description features schematic & pin configuration revision 11/16/2001 the stf203-22 is a combination emi filter and line termination device with integrated tvs diodes for use on upstream usb ports. it is constructed using a proprietary technology that allows passive components and tvs diodes to be integrated in the same package. each device will provide termination , filtering , and esd protection for one upstream usb port. the stf203- 22 is an easily implemented solution for meeting the requirements of revision 1.1 of the universal serial bus specification. usb line termination is achieved with 22 ? series resistors on both the d+ and d- usb lines. these resistors preserve signal integrity by matching the cable impedance to that of the differential driver. the 1.5k ? pull-up resistor completes the termination circuit on each line. this resistor is required by the usb specifi- cation to identify the equipment as either a full-speed (connected to d+ line) or low-speed (connected to d- line) device. the 47pf capacitors are used to bypass high frequency energy to ground and for edge rate control of the usb signals. finally, the stf203-22 contains tvs diodes for esd protection of both (d+ & d-) data lines and the voltage bus (v bus ). the tvs diodes provide effective suppression of esd voltages in excess of 15kv (air discharge) and 8kv (contact discharge) per iec 61000-4-2, level 4. the small size and integrated feature of the stf203- 22 minimizes required board space. the stf203-22 is suitable for use in usb hubs, computers, peripherals, and portable devices. applications mechanical characteristics usb ports portable electronics cellular handsets pda pagers digital cameras peripherals notebook, and handheld computers bidirectional emi/rfi filtering and line termination with integrated esd protection esd protection for usb power (v bus ) and data lines (d+ & d-) to iec 61000-4-2 level 4 filtering and termination for two usb data lines series resistors for impedance matching low tvs operating voltage (5.25v) low leakage current small sc70-6l package solid-state technology eiaj sc70-6l package molding compound flammability rating: ul 94v-0 marking : marking code packaging : tape and reel per eia 481 sc70-6l (top view) circuit diagram . 1 5 3 6 2 4 d (from connector) d (from connector) d (to ic) d (to ic)
2 ? 2001 semtech corp. www.semtech.com protection products stf203-22 absolute maximum rating electrical characteristics g n i t a rl o b m y se u l a vs t i n u r e w o p e t a t s - y d a e t sp k p 0 0 1w m 2 - 4 - 0 0 0 1 6 c e i r e p e g r a h c s i d r i a d s ev p p 6 1v k 2 - 4 - 0 0 0 1 6 c e i r e p e g r a h c s i d t c a t n o c d s ev p f 0 1v k e r u t a r e p m e t g n i r e d l o s d a e lt l ) . c e s 0 1 ( 0 6 2c e r u t a r e p m e t g n i t a r e p ot j 5 2 1 + o t 0 4 -c e r u t a r e p m e t e g a r o t st g t s 0 5 1 + o t 5 5 -c 2 2 - 3 0 2 f t s2 2 - 3 0 2 f t s 2 2 - 3 0 2 f t s 2 2 - 3 0 2 f t s2 2 - 3 0 2 f t s r e t e m a r a pr e t e m a r a p r e t e m a r a p r e t e m a r a pr e t e m a r a pl o b m y sl o b m y s l o b m y s l o b m y sl o b m y ss n o i t i d n o cs n o i t i d n o c s n o i t i d n o c s n o i t i d n o cs n o i t i d n o cm u m i n i mm u m i n i m m u m i n i m m u m i n i mm u m i n i ml a c i p y tl a c i p y t l a c i p y t l a c i p y tl a c i p y tm u m i x a mm u m i x a m m u m i x a m m u m i x a mm u m i x a ms t i n us t i n u s t i n u s t i n us t i n u e g a t l o v f f o - d n a t s e s r e v e r s v tv m w r 5 2 . 5v e g a t l o v n w o d k a e r b e s r e v e r s v tv r b i t a m 1 =6 v t n e r r u c e g a k a e l e s r e v e r s v ti r v m w r c 5 2 = t , v 5 2 . 5 = v n e e w t e b s u b d n a n i p d n u o r g 5a t n e r r u c e g a k a e l e s r e v e r s v ti r v m w r c 5 2 = t , v 3 . 3 = a t a d y n a n e e w t e b . d n u o r g d n a n i p ) - d , + d ( 1a ) 2 2 - 3 0 2 f t s ( e c n a t s i s e r s e i r e sr s e n i l h c a e0 22 24 2 ? e c n a t s i s e r p u l l u pr p u e n i l h c a e5 3 . 15 . 15 6 . 1k ? r o t i c a p a cce n i l h c a e7 4f p e c n a t i c a p a c l a t o tc t o t r o t u p n i n e e w t e b d n u o r g o t t u p t u o v r z h m 1 = f , v 0 = 0 6f p
3 ? 2001 semtech corp. www.semtech.com protection products stf203-22 typical characteristics esd clamping (8kv contact) typical insertion loss esd clamping (15kv air) analog crosstalk (d+ to d-) ch1 s 21 log mag 3 db/ ref 0 db start .030 000 mhz stop 3 000.000 000 mhz prm ch1 s 21 log mag 20 db/ ref 0 db start .030 000 mhz stop 3 000.000 000 mhz prm
4 ? 2001 semtech corp. www.semtech.com protection products stf203-22 figure 1 - stf203-22 circuit diagram device connection the stf203-22 is designed to provide termination, emi filtering and esd protection for two usb i/o lines. the equivalent circuit diagram is shown in figure 1. the device is connected as follows: 1. 1. 1. 1. 1. full-speed devices: for full-speed devices the pull-up resistor is connected to the d+ line. route the d+ line from the connector to pin 1 of the stf203-22. pin 6 is connected to the d+ line of the ic. route the d- line from the connector to pin 3. pin 4 is connected to the d- line of the ic. pin 5 is connected to the voltage supply line (v bus ). pin 2 is connected to ground. 2. 2. 2. 2. 2. low-speed devices : : : : : for low speed devices the pull-up resistor is connected to the d- line. route the d- line from the connector to pin 1 of the stf203-22. pin 6 is connected to the d- line of the ic. route the d+ line from the connector to pin 3. pin 4 is connected to the d+ line of the ic. pin 5 is connected to the voltage supply line (v bus ). pin 2 is connected to ground. usb port design considerations the universal serial bus (usb) specification requires termination and filtering components for proper opera- tion. in addition, an open usb socket is vulnerable to hazardous esd discharges in excess of 15kv. these discharges can occur on the data lines or the voltage bus. the stf203-22 is an easily implemented solution that is designed to meet the termination & emi filter requirements of the usb specification revision 1.1. it also provides esd protection to iec 61000-4-2, level 4. usb line termination is achieved with series resistors on both the d+ and d- lines. these resistors preserve signal integrity by matching the cable impedance to that of the differential driver. a 1.5k ? pull-up resistor is used to identify an upstream port on either the d+ (full speed devices) or the d- (low speed devices) data line. capacitors are used to bypass high frequency energy to ground and for edge rate control of the usb signals. tvs diodes are added for esd protection of both (d+ & d-) data lines and the voltage bus (v bus ). the stf203-22 integrates all of the components necessary for line termination, bidirectional emi filter- ing, and esd protection on upstream ports. this figure 2 - stf203-22 connection diagram (full speed devices) integrated solution simplifies design and requires minimal board space. board placement & layout guidelines. designing a usb hub to meet emi & esd immunity requirements requires a combination of optimum component placement, trace routing, and good circuit design practices. some general guidelines are given below: avoid running d+ & d- signal line traces near high speed clock lines or similar signal lines. avoid running critical signal lines near board edges. locate the usb controller chip near the usb connectors. place the stf203-22 near the usb connector to restrict transient coupling. minimize the path length between the usb connec- tor and the stf203-22 1 2 34 5 6 stf203 -22 from connector . applications information
5 ? 2001 semtech corp. www.semtech.com protection products stf203-22 outline drawing land pattern
6 ? 2001 semtech corp. www.semtech.com protection products stf203-22 contact information semtech corporation protection products division 652 mitchell rd., newbury park, ca 91320 phone: (805)498-2111 fax (805)498-3804 marking ordering information r e b m u n t r a p s e i r e s r e t s i s e r l e e r r e p y t qe z i s l e e r c t . 2 2 - 3 0 2 f t s2 2 ? 0 0 0 , 3h c n i 7 123 4 5 6 322
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