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1 of 35 rev: 011206 note: some revisions of this device may incor porate deviations from published specifications known as erra ta. multiple revisions of any device ma y be simultaneousl y available throu g h various sales channels. for information about device errata , click here: www.maxim - ic.com/errata . general description the ds21349 is a fully integrated liu for long- haul or short-haul t1 ap plications over twisted- pair installations. it inte rfaces to two twisted-pair lines?one pair for tran smit and one pair for receive through an appropriate network interface. the device can be configured for control through software or hardware mode. software control is accomplished over a serial port in hardware mode; individual pin settings allow stand-alone operation. the device provides a precise, crystal-less jitter attenuator that can be placed in either the transmit or receive path. applications routers data service units (dsus) channel service units (csus) muxes switches channel banks t1/e1 test equipment pin configuration features fully integrated line interface unit (liu) pin compatible with levelone lxt362 supports both long haul and short haul crystal-less jitter attenuator jitter attenuator pr ogrammable for transmit or receive path meets ansi t1.102, t1.403, t1.408, and at&t 62411 usable receive sensitiv ity of 0db to -36db that allows the device to operate on 0.63mm (22awg) cables up to 6k feet in length five line build-out settings for short-haul applications four csu filters from 0db to -22.5db transmit/receive performance monitors with driver-fail, monitor-open, and loss- of-signal outputs bipolar or nrz interface programmable b8zs encoder/decoder qrss generator/detector local, remote, and analog loopbacks generates and detects in-band loop-up and loop-down codes serial interface provides access to control registers ordering information part temp range pin- package ds21349q 0c to +70c 28 plcc ds21349q+ 0c to +70c 28 plcc ds21349qn -40c to +85c 28 plcc ds21349qn+ -40c to +85c 28 plcc + denotes lead-free/rohs -compliant package. 5 6 7 8 9 10 11 25 24 23 22 21 20 19 12 13 14 15 16 17 18 4 3 2 1 28 27 26 ds21349 top view plcc www.maxim-ic.com ds21349 3.3v t1/j1 line interface unit demo kit available
ds21349 2 of 35 table of contents 1. detailed d escription ................................................................................................. 4 2. operating modes......................................................................................................... 5 3. initialization and rese t............................................................................................ 9 4. register defi nitions .................................................................................................. 10 5. transmi tter................................................................................................................... 1 6 5.1 t ransmit d igital d ata i nterface ............................................................................................... 16 5.2 t ransmit m onitoring .................................................................................................................. 16 5.3 t ransmit i dle m ode ..................................................................................................................... 16 5.4 t ransmit p ulse s hape ................................................................................................................ 16 6. recei ver ....................................................................................................................... ... 17 6.1 r eceive e qualizer ....................................................................................................................... 17 6.2 r eceive d ata r ecovery .............................................................................................................. 17 6.3 r eceive d igital -d ata i nterface ................................................................................................. 17 6.4 r eceive m onitor m ode ............................................................................................................... 17 7. jitter atte nuation ..................................................................................................... 18 8. hardware mode ........................................................................................................... 18 9. software mode ............................................................................................................ 19 9.1 i nterrupt h andling .................................................................................................................... 19 10. diagnostic mode operat ion.................................................................................... 22 10.1 l oopback m odes ......................................................................................................................... 22 10.1.1 local loopba ck (llb)........................................................................................................... ........................22 10.1.2 analog loopbac k (alb).......................................................................................................... ......................22 10.1.3 remote loopbac k (rlb ) .......................................................................................................... ....................22 10.1.4 network loopback ............................................................................................................... .........................23 10.1.5 dual loopback.................................................................................................................. ............................23 10.2 i nternal p attern g eneration and d etection .......................................................................... 24 10.2.1 transmit alarm-indi cation signal (tais) ........................................................................................ ..............24 10.2.2 quasirandom signal source (qrss) ............................................................................................... ............24 10.2.3 in-band network loop-up or loo p-down code generator .........................................................................25 10.3 e rror i nsertion and d etection ................................................................................................. 25 10.3.1 bipolar violation insertion (insbpv) ........................................................................................... .................25 10.3.2 logic error insert ion (insle) .................................................................................................. .....................25 10.3.3 logic error dete ction (qpd).................................................................................................... .....................25 10.3.4 bipolar violation detection (bpv).............................................................................................. ...................25 10.4 a larm m onitoring ....................................................................................................................... 26 10.4.1 receive-carrier loss (rcl) ..................................................................................................... ....................26 10.4.2 alarm-indication-signal detection (ais) ........................................................................................ ...............26 10.4.3 driver-fail moni tor-open (dfmo) ................................................................................................ ................26 10.4.4 jitter attenuator li mit trip (jalt)............................................................................................ .....................26 10.5 o ther d iagnostic r eports ........................................................................................................ 26 10.5.1 receive line-attenuat ion indi cation ............................................................................................ .................26 11. network in terface .................................................................................................... 27 12. dc character istics .................................................................................................... 31 13. package info rmation ................................................................................................ 35 13.1 28-p in plcc (56-g4001-001 ) ...................................................................................................... 35
ds21349 3 of 35 list of figures figure 1-1. block diagram ............................................................................................................................... ........ 4 figure 2-1. hardware mode pinout ........................................................................................................................ 6 figure 2-2. serial port mode pinout ....................................................................................................................... 6 figure 9-1. serial data port operation for read access .................................................................................. 20 figure 9-2. serial data port operation for write access .................................................................................. 20 figure 10-1. loopbacks in the ds21349 block diagram .................................................................................. 24 figure 11-1. basic network interface .................................................................................................................. 28 figure 11-2. t1 transmit pulse template .......................................................................................................... 29 figure 11-3. jitter tolerance ............................................................................................................................... .. 30 figure 11-4. jitter attenuation ............................................................................................................................... 30 figure 12-1. serial bus read timing (mode1 = 1) .......................................................................................... 32 figure 12-2. serial bus write timing (mode1 = 1) .......................................................................................... 32 figure 12-3. ac characteristics for receive side ............................................................................................. 33 figure 12-4. ac characteristics for transmit side ............................................................................................ 34 list of tables table 2-a. operating modes ............................................................................................................................... .... 5 table 2-b. control pins for hardware and software modes .............................................................................. 5 table 2-c. signal descriptions ............................................................................................................................... 7 table 4-a. register map ............................................................................................................................... ......... 10 table 4-b. register bit positions .......................................................................................................................... 10 table 4-c. jitter attenuator selection .................................................................................................................. 11 table 4-d. line code and interface selection ................................................................................................... 11 table 4-e. line build-out selection ..................................................................................................................... 11 table 4-f. data pattern selection ........................................................................................................................ 12 table 9-a. clke pin selection ............................................................................................................................. 19 table 9-b. control and operation mode selection ............................................................................................ 21 table 10-a. diagnostic modes .............................................................................................................................. 2 2 table 11-a. specifications for receive transformer ......................................................................................... 27 table 11-b. specifications for transmit transformer ........................................................................................ 27 table 11-c. transformer turns ratio vs. series resistance .......................................................................... 27
ds21349 4 of 35 1. detailed description the ds21349 is a complete t1 line interface unit (liu) for short-haul and long-haul applications. receive sensitivity adjusts automati cally to the incoming signal and ca n be limited to -18db, -26db, or -36db. the device can generate the necessary dsx- 1 line build-outs or csu line build-outs of 0db, -7.5db, -15db, and -22.5db. the on-board crystal-le ss jitter attenuator requir es a 1.544mhz reference clock. the jitter attenuator fifo is selectable to either 32 bits or 128 bits in depth and can be placed in either the transmit or receive data paths. the ds21349 has diagnostic capa bilities such as loopbacks and qrss pattern generation and detection. the device can al so generate and detect the in-band loop-up and loop-down codes specified in at&t 62411. the device ca n be configured for control using a serial interface, or for hardware mode. th e device fully meets all of the latest t1 specifications including ansi t1.102-1999, ansi t1.403-1999, ansi t1.408, and at&t 62411. figure 1-1. block diagram l o c a l l o o p b a c k r e m o t e l o o p b a c k a n a l o g l o o p b a c k jitter attenuator t r i n g t t i p r r i n g r t i p l i n e d r i v e r s c s u f i l t e r s w a v e s h a p i n g f i l t e r p e a k d e t e c t c l o c k / d a t a r e c o v e r y b 8 z s e n c o d e r l o g i c e r r o r i n s e r t tpos tclk tneg q r s s i n b a n d l o o p g e n . b 8 z s d e c o d e r i n b a n d l o o p c o d e d e t e c t o r q r s s d e t e c t o r rpos rclk rneg m c l k r c l d e t e c t o r rcl/qpd nloop mode0 mode1 power connections hardware interface serial interface int clke sclk sdi sdo cs jasel l0 l1 l2 l3 llb rlb tbl/qrss vsm tvdd vdd gnd gnd t r n a s m i t a i s a i s d e t e c t l o t c m u x v c o / p l l
ds21349 5 of 35 2. operating modes the ds21349 has several pins with multiple functi ons and names according to the selected operating mode. these operating modes are summarized in the tables below. table 2-a. operating modes qrss disabled qrss enabled pin bipolar nrz bipolar nrz 1 mclk 2 tclk 3 tpos tdata insler 4 tneg insbpv insbpv 6 rneg bpv rneg bpv 7 rpos rdata rpos rdata 8 rclk 13 ttip 16 tring 19 rtip 20 rring control pins are affected by seri al port and hardware modes. table 2-b. control pins for hardware and software modes hardware mode serial port mode pin nrz qrss nrz qrss 5 mode1 mode1 9 mode0 mode0 11 jasel n.c. 12 rcl rcl/qpd rcl rcl/qpd 23 l0 int 24 l1 sdi 25 l2 sdo 17 l3 n.c. 18 nloop nloop 26 rlb nlb cs 27 llb alb sclk 28 tais qrss clke
ds21349 6 of 35 figure 2-1. hardware mode pinout figure 2-2. serial port mode pinout 5 6 7 8 9 10 11 25 24 23 22 21 20 19 12 13 14 15 16 17 18 4 3 2 1 28 27 26 l2 l1 l0 gnd vdd rring rtip mode1 rneg rpos rclk mode0 vsm jasel rcl/qpd ttip gnd tvdd tring l3 nloop tneg tpos tclk mclk tais/qrss llb rlb ds21349 5 6 7 8 9 10 11 25 24 23 22 21 20 19 12 13 14 15 16 17 18 4 3 2 1 28 27 26 sdo sdi int gnd vdd rring rtip mode1 rneg rpos rclk mode0 vsm n/c rcl/qpd ttip gnd tvdd tring n/c nloop tneg tpos tclk mclk clke sclk cs ds21349
ds21349 7 of 35 table 2-c. signal descriptions pin name i/o function 1 mclk i master clock. a 1.544mhz clock source with ttl levels is applied at this pin. this clock is used internally for both clock/ data recovery and for jitter attenuation. 1 2 tclk i transmit clock. a 1.544mhz primary clock. used to clock data through the transmit side formatter. can be sourced internally by mclk or rclk. tpos transmit positive data . sampled on the falling edge of tclk for data to be transmitted out onto the line. tdata transmit nrz data. sampled on the falling edge of tclk for data to be transmitted onto the line. 3 insler i transmit insert logic error. rising edge on insler inserts a logic error into the outbound qrss pattern. sample d on falling edge of tclk. tneg transmit negative data. sampled on the fa lling edge of tclk for data to be transmitted out onto the line. 4 insbpv i transmit insert bipolar violation. insbpv is sampled on the falling edge of tclk. rising edge inserts one bpv. 5 mode1 i 2 mode select 1. connect low to select hardware mode. connect high to select serial port mode. see also mode0. rneg receive negative data. updated on the rising edge (ccr2.0 = 0) or the falling edge (ccr2.0 = 1) of rclk with the bipolar data out of the line interface. always valid on rising edge of rclk in hardware mode. 6 bpv o receive bipolar violation. transitions hi gh for one clock cycle marking an inbound bipolar violation. valid on rising edge of rclk. rpos receive positive data. updated on the risi ng edge (ccr2.0 = 0) or the falling edge (ccr2.0 = 1) of rclk with bipolar data out of the line interface. always valid on rising edge of rclk in hardware mode. 7 rdata o receive data. rdata is the nrz output from the line interface. set nrze (ccr1.6) to a 1 for nrz applications. in nrz mode, data is output on rpos while a received error causes a positive-going pulse synchronous with rclk at rneg (section 6 ). 8 rclk o receive clock. buffered recovered clock from the line. synchronous to mclk in absence of signal at rtip and rring. 9 mode0 i 2 mode select 0. set high to disable all out put pins (including the serial control port). set low for normal operation. useful in board level testing. see also mode1. 10 vsm i voltage supply mode. connect high for 3.3v operation. has 10k ? pullup. 11 jasel i 2 jitter attenuator select 0 = place the jitter attenuator on the transmit side 1 = place the jitter attenuator on the receive side float = disable jitter attenuator not used in software mode rcl receive carrier loss. an output that toggles high during a receive carrier loss. 12 qpd o qpd . output high when qrss detector is searching for qrss data pattern. output high for one-half clock cycle on bit error. connect to external counter to count bit errors. 13/ 16 ttip/ tring o transmit tip and ring. analog line driver outputs. these pins connect through a step-up transformer to the line (section 5 ). 14 vss ? ground for transmitter block 15 tvdd ? positive supply. 3.3v 5% for the tr ansmitter block. see also vsm pin 10.
ds21349 8 of 35 pin name i/o function 17 l3 i lbo3. lbo0 through lbo3 are used to select transmitter output pulse, and receiver gain. 18 nloop o network loopback active. output high when rlb is activated by in-band loop-up command present for 5 seconds. output is reset when rlp is deactivated by in-band loop-down command present for 5 seconds. activation of remote loopback through hardware pin 26 or control bit rlb releases the nloop output. 19/ 20 rtip/ rring i receive tip and ring. analog inputs for cloc k recovery circuitry. these pins connect through a 1:1 transformer to the line (section 6 ). 21 vdd ? positive supply. 3.3v 5%. see also vsm pin 10. 22 vss ? signal ground l0 lbo0. lbo0 through lbo3 are used to select transmitter output pulse, and receiver gain. 23 int i/o int . used to alert the host when one or more bits are set in the status register. l1 lbo1. lbo0 through lbo3 are used to select transmitter output pulse, and receiver gain. 24 sdi i serial data input. input for serial addre ss and data stream. sampled on rising of sclk. l2 lbo2. lbo0 through lbo3 are used to select transmitter output pulse, and receiver gain. 25 sdo o serial data output. update d on falling edge of sclk if clke is connected high. updated on rising edge of sclk if clke is connected low. sdo is high-z during write cycle or when cs is high. rlb remote loopback. used to invoke remote loopback. when held high, the transmitter inputs are ignored and inbound data received at rtip and rring is routed to the transmitter outputs, ttip and tring and transmitted at the inbound recovered clock rate. nlb network loopback. enables network loopback detection when rlb floats. 26 cs i 2 chip select. must be low to read or write to the device. cs is an active-low signal. llb local loopback. used to invoke local loopback. when held high, digital inputs tpos and tneg are looped back to rpos and rneg, through the jitter attenuator if enabled. floating this input invokes analog loopback. the analog output signal at ttip and tring is routed to the receive inputs rtip and rring. 27 sclk i 2 serial clock input. input clock to oper ate serial port. max clock rate, 2.048mhz. tais transmit ais. input high forces transmitter to output unframed all ones. unavailable in remote loopback. qrss qrss. floating this pin enables qrss pattern generator and detector. input low enables normal transmission of data. 28 clke i 2 clock edge select 0 = update rneg/rpos on falling edge of rclk, sdo updated on rising edge of sclk. 1 = update rneg/rpos on rising edge of rclk, sdo updated on falling edge of sclk. note 1: g.703 requires an accuracy of 50ppm for t1. tr62411 and ansi spec ifications require an accuracy of 32ppm for t1 interfaces. note 2: input pins have three operating modes.
ds21349 9 of 35 3. initialization and reset during power-up, all control registers are cleared, disa bling the transmitter outputs. the device requires a master clock supplied to the mclk input pin to operat e the pll. this master clock must be independent, free-running, and jitter free. a reset initializes the status and state machines for the rcl, ais, nloop, and qrss blocks. under software control, setting the reset bit (cr2.7) clears all re gisters. allow up to 100 ms for the receiver to recover from initialization.
ds21349 10 of 35 4. register definitions the ds21349 contains eight registers for configuring the device a nd reading status. th ese are accessible using the serial port. table 4-a lists the register names and addresses. reading or writing to the internal registers requires writing one address/command byte prior to transferring register data. the first bit written (lsb ) of the address/command byte specifies whether the access is a read (1) or a write (0). the next 6 bits identify the register address. the last bit (msb) of the address/co mmand byte is the burst mode bit. wh en the burst bit is enabled (set to 1) and a read operation is performed, addre sses 10h through 17h are read sequentially, starting at address 10h. and when the burst bit is enabled and a write opera tion is performed, addresses 10h through 17h are written sequentially, starting at a ddress 10h. burst operation is stopped once address 17h is read. all data transfers are initiated by driving the cs input low. all data transfers are terminated if the cs input transitions high. port control logic is disabled and sdo is tri-stated when cs is high. table 4-a. register map register symbol address control register 1 cr1 b010000 control register 2 cr2 b010001 control register 3 cr3 b010010 interrupt mask register imr b010011 transition status register tsr b010100 status register sr b010101 information register ir b010110 control register 4 cr4 b010111 table 4-b. register bit positions symbol 7 (msb) 6 5 4 3 2 1 0 (lsb) cr1 jasel1 jasel0 encenb unienb l3 l2 l1 l0 cr2 reset pat1 pat0 tais enloop alb llb rlb cr3 ja6hz tpd ? eqzmon20 eqzmon26 ja128 lirst taoz imr z16d jalt dfmo b8zsd qrss ais nloop rcl tsr z16d jalt dfmo b8zsd qrss ais nloop rcl sr ? ? dfmo ? qrss ais nloop rcl ir rl3 rl2 rl1 rl0 lup ldn tscd lotc cr4 ? ? ? ? ? rcl2048 xfmr2 xfmr1 note: set unused bits to 0 for normal operation.
ds21349 11 of 35 cr1 (b010000): control register 1 msb lsb jasel1 jasel0 encenb unienb l3 l2 l1 l0 symbol position function jasel1 cr1.7 jitter attenuator select ( table 4-c ) jasel0 cr1.6 jitter attenuator select ( table 4-c ) encenb cr1.5 b8zs and nrz control ( table 4-d ) unienb cr1.4 bpv and nrz control ( table 4-d ) l3 cr1.3 line build-out control ( table 4-e ) l2 cr1.2 line build-out control ( table 4-e ) l1 cr1.1 line build-out control ( table 4-e ) l0 cr1.0 line build-out control ( table 4-e ) table 4-c. jitter attenuator selection jasel1 jasel0 jitter attenuator function 0 1 transmit path 1 1 receive path x 0 disabled table 4-d. line code and interface selection unienb encenb line code interface 0 0 ami bipolar 1 0 ami nrz x 1 b8zs nrz table 4-e. line build-out selection l3 l2 l1 l0 application output signal rx gain (db) 0 0 0 0 t1 long haul 0db 36 0 0 1 0 t1 long haul -7.5db 36 0 1 0 0 t1 long haul -15db 36 0 1 1 0 t1 long haul -22.5db 36 0 0 0 1 t1 long haul 0db 26 0 0 1 1 t1 long haul -7.5db 26 0 1 0 1 t1 long haul -15db 26 0 1 1 1 t1 long haul -22.5db 26 1 0 0 1 d4 short haul 6v 18 1 0 1 1 t1 short haul dsx-1 (0ft to 133ft) 18 1 1 0 0 t1 short haul dsx-1 (133ft to 266ft) 18 1 1 0 1 t1 short haul dsx-1 (266ft to 399ft) 18 1 1 1 0 t1 short haul dsx-1 (399ft to 533ft) 18 1 1 1 1 t1 short haul dsx-1 (533ft to 655ft) 18
ds21349 12 of 35 cr2 (b010001): control register 2 msb lsb reset pat1 pat0 tais enloop alb llb rlb symbol position function reset cr2.7 resets device states and clears all registers. pat1 cr2.6 selects output data pattern ( table 4-f ). pat0 cr2.5 selects output data pattern ( table 4-f ). tais cr2.4 0 = transmit data normally 1 = transmit unframed all ones enloop cr2.3 0 = disable in-band loop-code detection 1 = enable in-band loop-code detection alb cr2.2 0 = disable analog loopback 1 = enable analog loopback llb cr2.1 0 = disable local loopback 1 = enable local loopback rlb cr2.0 0 = disable remote loopback 1 = enable remote loopback table 4-f. data pattern selection pat0 pat1 data source 0 0 tpos/tneg 0 1 transmit qrss 1 0 in-band loop-up 00001 1 1 in-band loop-down 001 cr3 (b010010): control register 3 msb lsb ja6hz tpd ? eqzmon20 eqzmon26 ja128 lirst taoz symbol position function ja6hz cr3.7 0 = set bandwidth of jitter attenuator to 3hz 1 = set bandwidth of jitter attenua tor to 6hz; not available if ja128 = 1 tpd cr3.6 0 = enable transmitter outputs 1 = disable transmitter outputs ? cr3.5 ? eqzmon20 cr3.4 0 = normal receiver operation 1 = add 20db of resistive gain to inbound signal eqzmon26 cr3.3 0 = normal receiver operation 1 = add 26db of resistive gain to inbound signal ja128 cr3.2 0 = jitter attenuator buffer depth = 32 bits 1 = jitter attenuator buffer depth = 128 bits lirst cr3.1 0 = normal operation 1 = reset the receive liu state machine taoz cr3.0 0 = disable transmit alternate 1s and 0s 1 = enable transmit alternate 1s and 0s
ds21349 13 of 35 imr (b010011): interrupt mask register msb lsb z16d jalt dfmo b8zsd qrss ais nloop rcl symbol position function z16d imr.7 0 = enable 16-zero detect interrupt 1 = disable 16-zero detect interrupt jalt imr.6 0 = enable jitter-attenuator limit-trip interrupt 1 = disable jitter-attenuator limit-trip interrupt dfmo imr.5 0 = enable driver-open interrupt 1 = disable driver-open interrupt b8zsd imr.4 0 = enable b8zs-detect interrupt 1 = disable b8zs-detect interrupt qrss imr.3 0 = enable qrss interrupt 1 = disable qrss interrupt ais imr.2 0 = enable ais interrupt 1 = disable ais interrupt nloop imr.1 0 = enable network-loopback interrupt 1 = disable network-loopback interrupt rcl imr.0 0 = enable receive carrier-loss interrupt 1 = disable receive carrier-loss interrupt tsr (b010100): transition status register msb lsb z16d jalt dfmo b8zsd qrss ais nloop rcl symbol position function z16d tsr.7 set when the receiver detects 16 consecutive 0s; cleared when imr.7 is cleared. jalt tsr.6 set when the jitter attenuator fifo reaches to within 4 bits of its limit; cleared when imr.6 is cleared. dfmo tsr.5 set when sr.5 changes st ate; cleared when imr.5 is cleared. b8zsd tsr.4 set when the receiver detects b8zs codewords; cleared when imr.4 is cleared. qrss tsr.3 set when sr.3 changes stat e; cleared when imr.3 is cleared. ais tsr.2 set when sr.2 changes state; cleared when imr.2 is cleared. nloop tsr.1 set when sr.1 changes stat e; cleared when imr.1 is cleared. rcl tsr.0 set when sr.0 changes stat e; cleared when imr.0 is cleared.
ds21349 14 of 35 sr (b010101): status register msb lsb ? ? dfmo ? qrss ais nloop rcl symbol position function ? sr.7 ? ? sr.6 ? dfmo sr.5 set when transmitter detects open circuit. ? sr.4 ? qrss sr.3 set when the qrss pattern is present at the receiver. ais sr.2 set when the ais pattern is present at the receiver. nloop sr.1 set when the in-band loop-up code is present at the receiver. rcl sr.0 set when receiver has detected consecutive s set forth by cr4.2. cleared when the receiver detects 14 1s in a window of 112 clock cycles. ir (b010110): information register msb lsb rl3 rl2 rl1 rl0 lup ldn tscd lotc symbol position function rl3 ir.7 ? rl2 ir.6 ? rl1 ir.5 ? rl0 ir.4 ? lup ir.3 set when in-band loop -up code is being received. ldn ir.2 set when in-band loop- down code is being received. tscd ir.1 set when transmitter detects a short circuit. lotc ir.0 set when tclk has not transitioned for approximately 5 s. receive level indication: rl0 is the lsb and rl3 is the ms b of a 4-bit nibble that is used to indicate the inbound signal strength. convert the binary to decimal and mu ltiply by -2.5db. the result indicates the approximate attenuation seen at the receiver inputs.
ds21349 15 of 35 cr4 (b010111): control register 4 msb lsb ? ? ? ? ? rcl2048 xfmr2 xfmr1 symbol position function ? cr4.7 ? ? cr4.6 ? ? cr4.5 ? ? cr4.4 ? ? cr4.3 ? rcl2048 cr4.2 0 = rcl threshold: 192 consecutive 0s 1 = rcl threshold: 2048 consecutive 0s xfmr2 cr4.1 set to 0 for use with standard transformers. set to 1 for use with alternate transformers ( table 11-c ) xfmr1 cr4.0 set to 0 for use with standard transformers. set to 1 for use with alternate transformers ( table 11-c )
ds21349 16 of 35 5. transmitter 5.1 transmit digital data interface data is clocked into the device at the tclk rate. in bipolar mode, tpos and tn eg are the data inputs; in nrz mode, tdata is the data i nput. input data can pass through either the jitt er attenuator or the b8zs encoder or both. in software mode, setting en cenb enables b8zs encoding. in hardware mode, floating the mode1 pin enables b8zs encoding. with b8zs encoding enabled, the l0 through l3 inputs determine the coding and is listed in table 4-e . tclk supplies input sync hronization. see section 12 for the tclk and mclk timing requirements. 5.2 transmit monitoring in software mode, the dfmo bit in th e status register is set when an open circuit in the transmitter path is detected. a transition on this bit can provide an in terrupt, and a transition sets the dfmo bit in the transition status register. setting cdfmo in the interr upt mask register, leaving a 1 in that bit location masks the interrupt. 5.3 transmit idle mode transmit idle mode allows multiple transceivers to be connected to a single line for redundant applications. when tclk is not present, transm it idle mode becomes active, and ttip and tring change to high-impedance state. re mote loopback, dual loopback, tais, or detection of network loop-up code in the receive direction temporarily disable the high-impedance state. 5.4 transmit pulse shape as shown in table 4-e , line build-out control inputs (l0 through l3) determine the transmit pulse shape. in software mode, these control inputs are located in control register 1; in ha rdware mode, these control inputs are the l0 through l3 pins. shaped pulses meeting the various t1, ds1, and dsx-1 specifications are applied to the ami line driver for transmission onto the line at ttip and tring. th e transceiver produces dsx-1 pulses for short-haul t1 applications (settings from 0db to 6db of cab le) and ds1 pulses for long-haul t1 applications (settings from 0db to -22.5db). refer to table 4-e for pulse mask specifications.
ds21349 17 of 35 6. receiver a 1:1 transformer provides the inte rface between the twisted pair and receiver inputs rtip and rring. recovered data is output at rp os and rneg (or rdata in nrz m ode), and the recovered clock is output at rclk. see section 12 for receiver timing specifications. 6.1 receive equalizer the receiver can apply up to 36db of gain. control of the equalizer is accomplished by the l0 through l3 control inputs. these control signals are detailed in table 4-e and determine the maximum gain that is applied. in software mode, these c ontrol signals are in control regist er 1; in hardware mode, these control inputs are the l0 through l3 pins. with l0 low, up to 36db of gain can be applied; when l0 is high, 26db can be applied in the gain limit to provide better noise immunity in shorter loop operations. 6.2 receive data recovery the clock and data recovery engine provides input jit ter tolerance that exceeds the requirements of at&t 62411. inbound signal is filtered, equalized, and over-sampled 16 times. then it is applied to the b8zs decoder if enabled. 6.3 receive digital-data interface recovered data is routed to the rcl monitor. in software mode, data also goes through the alarm indication signal (ais) monito r. the jitter attenuator can be enabled or disabled in the receive path or transmit path. received data can be routed to the b8zs decoder or byp assed. finally, the device can send the digital data to the framer as either bipolar or nrz data. 6.4 receive monitor mode the receive equalizer can be used in monitor-mode applications. monitor-mode applications require 20db of resistive attenuati on of the signal, plus an allowance for cable attenuation (less than 20db). in software mode, setting cr3.4 (eqzmon20) enables th e device to operate in monitor-mode applications that require 20db of resistive atte nuation of the signal. setting cr 3.3 (eqzmon26) enables the device to operate in monitor-mode applica tions that require 26db of resist ve attenuation. setting both cr3.3 and cr3.4 enables the device to operate in monitor-mode applications that re quire 32db of resistive attenuation. the monitor mode feature is not available in hardware mode.
ds21349 18 of 35 7. jitter attenuation the jitter attenuator only requires a jitter-free cl ock at 1.544mhz applied to the mclk input. in hardware mode, the jitter attenuator is a 32-bit fifo buffer. pulling the jasel pi n high places the jitter attenuator in the receive path. pu lling the jasel pin low places the jit ter attenuator in the transmit path, floating the jasel pin disables the jitter attenuator. in software mode , clearing cr1.6 (jasel0) disables the jitter attenuator, setting cr 1.6 enables the jitter attenuator. if enabled, clearing cr1.7 (jasel1) places the jitter attenuator in the tr ansmit path, setting cr1.7 places the jitter attenuator in the receive path. the jitter attenuator fifo is 32 bits in length if cr3.2 (ja128) is cleared, 128 bits if set. the device clocks data in the jitter attenuato r using tclk if placed in the transmit path, and rclk if placed in the receive path. data is clocked out of the jitter attenuat or using the dejittered cl ock produced by the internal pll. when the jitter atte nuator is within two bits of overflowing or underflo wing, the jitter attenuator will adjust the output clock by one-eighth of a clock cy cle. the jitter attenuator adds an average delay of 16 bits if the buffer depth is 32 bits in length, 64 bits if the buffer depth is 128 b its in length. in the event of an rcl condition, if the jitter at tenuator is in the receive path then rclk is derived from mclk. transition status register bit tsr .6 (jalt) indicates that the jitter attenuator has adjusted the output clock. this bit is latched, when set it remains set unt il the software reads the bit. the jalt can also produce a hardware interrupt. 8. hardware mode the ds21349 operates in hardware mode when the m ode1 pin is pulled low or floated. in hardware mode, configuration of the device is under control of various input pins. rp os, rneg, and rdata are valid on the rising edge of rclk only. some functi ons such as int, clock edge select, and some diagnostic modes are not available.
ds21349 19 of 35 9. software mode the ds21349 operates in software mode when the mode1 pin is pulled high. in software mode, a microprocessor controls the device and reads its status through the serial port, which provides access to the internal registers. the host pr ocessor can completely configure th e device as well as get diagnostics and status reports through the seri al port. in nrz mode, bipolar viol ation insertions and logic error insertions are controlled by the bpv and insler pins. similarly, the recovered clock, data, and bpv detection are available only at out put pins. all other mode settings and diagnostic information are available through the serial port. figure 9-1 and figure 9-2 show the serial port data structure. the registers are accessible through a 16-bit word compos ed of an 8-bit command and address byte and a subsequent 8-bit data byte. software mode allows c ontrol of the output timing. the clke pin determines when sdo is valid relative to sclk and when receive data is valid relative to rclk. 9.1 interrupt handling in software mode, the ds21349 provides a latched interr upt output pin. when enabled, a change in any of the status register bits generates an interrupt. when an interrupt occurs, the int output pin is driven low. the int output pin structure is an open-drain only. each device that shares the int line requires an external pullup resistor. the interrup t is cleared when the interrupt cond ition no longer ex ists, and a 1 is written to the appropriate bit in the interrupt mask register. leaving a 1 in any of the bits in the interrupt mask register masks that interrupt. clearing that bit re-enables the interrupt. table 9-a. clke pin selection clke pin output output updated on rpos rneg rdata falling rclk low sdo rising sclk rpos rneg rdata rising rclk high sdo falling sclk
ds21349 20 of 35 figure 9-1. serial data port operation for read access figure 9-2. serial data port operation for write access read access clke = 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 a 1 a 2 a 3 a 4 a 5 0 b sclk sdi sdo c s (lsb) (msb) (lsb) (msb) d1 d2 d3 d4 d5 d6 d0 d7 read access clke = 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 a 1 a 2 a 3 a 4 a 5 0 b d1 d2 d3 d4 d5 d6 sclk sdi sdo c s (lsb) (msb) d0 (lsb) d7 (msb) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 sclk c s 0 a 1 a 2 a 3 a 4 a 5 0 b (msb) sdi sdo d1 d2 d3 d4 d5 d7 (lsb) (msb) do d6 (lsb) write access enabled
ds21349 21 of 35 table 9-b. control and operation mode selection mode1 mode0 hardware software nrz bipolar ami b8zs outputs disabled low low on off off on off off no low high on off off on off off yes low open on off on off on off no high low off on x x x x no high high off on x x x x yes high open off on x x x x no open low on off on off off on no open high on off on off off on yes open open on off on off off on no
ds21349 22 of 35 10. diagnostic mode operation the ds21349 offers several diagnostic modes as listed in table 10-a . various diagnostic modes are only available in software mode. in hardware mode, the diagnostic modes are selected by a combination of pin settings. in software mode, the diagnostic modes are selected by setting appropria te bits in the diagnostic control register. table 10-a. diagnostic modes availability software mode diagnostic mode hardware software maskable local loopback (llb) yes yes no analog loopback (alb) yes yes no remote loopback (rlb) yes yes no in-band network loopback (nlb) yes yes yes dual loopback (dloop) yes yes no internal data pattern generation and detection transmit ais (tais) yes yes no quasirandom signal source (qrss) yes yes yes in-band loop-up/down code generator no yes no error insertion and detection bipolar violation insertion (insbpv) yes yes no logic error insertion (insler) yes yes no bipolar violation detection (bpv) yes yes no logic error detection, qrss (qpd) yes yes no alarm condition monitoring receive carrier loss (rcl) monitoring yes yes yes receive alarm indication signal (ais) monitoring no yes yes transmit driver failure monitoring (dfmo) no yes yes jitter attenuator limit trip (jalt) no yes yes other diagnostic reports receive line attenuation indicator (latn) no yes no 10.1 loopback modes 10.1.1 local loopback (llb) when local loopback is enabled (set llb in cr2, or pull the llb pin high), inbound data at the receiver inputs are ignored. tclk and tpos/t neg pass through the jitte r attenuator if enab led and are output at rclk and rpos/rneg. the transmit path is unaffect ed by llb, and will continue to transmit data normally (or ais if tais is enabled). 10.1.2 analog loopback (alb) when analog loopback (alb) is enabled (set alb in cr 2, or float the llb pin), the receiver input pins are disconnected from the clock and data recovery circuit and replac ed by ttip and tring. this tests the entire device including the jitter attenu ator, transmitter, and receiver circuits. 10.1.3 remote loopback (rlb) when remote loopback (rlb) is enabled (set rlb in cr2, or pull rlb pin high), inbound data at the receiver inputs is looped b ack to the transmitter path. data passes th rough the jitter attenuator if enabled. the b8zs encoder and decoder are not included in the loopback path. the rece ive path continues to operate normally.
ds21349 23 of 35 10.1.4 network loopback when enloop is enabled (set enloop in cr2, or float the enloop pin), the in-band loop code detector is enabled. the receiver detects the in-band loop code patterns (00001 = loop up and 001 = loop down) present in the inbo und data. the detectors detect both framed and unframed loop codes. when the loop-up pattern is detected and present for 5 seconds, the device invokes remote loopback. enloop is dropped when: 1) the in-band loop-down pattern is present for 5 seconds. 2) rlb is activated. 3) alb is activated. 10.1.5 dual loopback dual loopback is the simultaneous en abling of rlb and llb. if the jitter attenuator is enabled and, when both loopback paths are enabled, the jitter attenua tor is placed in the local loopback path.
ds21349 24 of 35 figure 10-1. loopbacks in the ds21349 block diagram 10.2 internal pattern generation and detection 10.2.1 transmit alarm-i ndication signal (tais) when tais is enabled (set tais in cr2, or pulling the tais pin high), the transmitter inputs tpos/tneg and tdata are ignored and the devices transmits unframed all ones at the transmitter outputs at the tclk frequency. if tc lk is not present, then the devi ce uses mclk to transmit. both tais and llb can be enabled at the same time. the tr ansmitter input data is l ooped back to the receiver outputs through the jitter atte nuator if enabled and th e unframed all ones patter n is transmitted at ttip and tring. 10.2.2 quasirandom signal source (qrss) the qrss data pattern is descri bed in at&t 62411. the pattern is represented by the polynomial 2 20 - 1 with the additional requirement that no more than 14 consecutive 0s be present in the pattern. when qrss is enabled (pat0 = 0 and pat1 = 1 in cr2 or float the qrss pin), the data at the transmitter inputs tpos/tneg or tdata is ignor ed and replaced by the output of the qrss pattern generator. in addition, logic errors can be inserted into the data pattern with a ri sing edge on the insler input pin. if no logic errors are to be inserted, then the insler pi n must remain low. if the logic error occurs on the same clock cycle as a 1 that has been inserted to s uppress 15 0s, then the logic error is delayed until the next clock cycle. the logic error in sertion is available in both nrz a nd bipolar data modes. enabling the qrss pattern also enables the qrss detector in the receiver. pattern synchronization occurs when there are no errors in 64 bits. when synchronized, the qp d output pin goes low. once synchronized, an error in the pattern causes the qpd output to go high for one -half rclk cycle. in software mode, the level on the clke pin determines the relationship between qpd and rclk. when clke is low, qpd is high when rclk is high. when clke is high, qpd is high when rclk is low. the qpd output can be used to trigger an external bit error counter. when rcl is active or the receiver is not synchronized to the qrss pattern, then qpd maintains an output high. tpos tclk tneg rpos rclk rneg rcl/qpd nloop tring ttip rring rtip mclk line drivers csu filters wave shaping filte r peak detect clock / data recovery rcl detecto r transmit ais b8zs encoder logic error insert qrss b8zs decode r in-band loop code detec t or jitter attenuato r local loopback qrss detecto r vco/pll in-band loop gen. a is detecto r lotc mux remote loopback
ds21349 25 of 35 in software mode, the device can generate an interr upt to indicate that the qr ss pattern synchronization has been declared or lost. clearing the qrss bit in th e interrupt mask register enables the interrupt. use the qpd output to increment an external bit error coun ter and use the interrupt to reset the counter. the qrss bit in the status register is set when the qrss pattern is detected and cleared when pattern is lost (more than 6 bit errors in a window of 64 bits). the qrss bit in the tr ansition status re gister indicates that the qrss status has changed since the last qrss interrupt clear command. 10.2.3 in-band network loop-up or loop-down code generator in-band network loop-up or loop-down transmission is available in software mode only. the loop-up code is transmitted when pat0 = 1 and pat1 = 0 in cr 2. logic errors and bipolar violations can still be inserted when loop codes are being transmitted. 10.3 error insertion and detection 10.3.1 bipolar violati on insertion (insbpv) insbpv is available in nrz mode. sampling occurs on the falling edge of tclk. a rising edge on the nsbpv pin inserts a bpv on the next availa ble mark, except in th e following conditions: 1) if the bpv would violate a b8zs codeword. 2) when llb and tais are both active. in this case, the bp v is looped back to th e bpv pin and the line driver transmits all ones with no violation. 3) when rlb is active. 4) when nloop is active. bpvs can be inserted in both nr z and bipolar data modes when th e ds21349 is configured to transmit internally generated data pattern s (qrss or in-band loop codes). 10.3.2 logic error insertion (insle) when transmitting qrss or in-band loop codes, a logic error is inserted into the outbound data pattern on a rising edge of the insler pin. remember, when tr ansmitting the qrss pattern, logic error insertion is inhibited if the error would replace a 1 with a 0 and result in a stri ng of 15 or more consecutive 0s. 10.3.3 logic error detection (qpd) after qrss pattern synchronization, logic errors ar e reported at the qpd out put pin. if a logic error occurs, the qpd pin goes high for one-half rclk cycle. in software mode, the clke pin determines the phase relationship between qpd and rclk. when cl ke is low, qpd is high when rclk is high. when clke is high, qpd is high when rclk is lo w. to count logic errors , use the qpd output to increment an external error counter. a continuous output high indicates loss of synchronization to the qrss pattern or receive-carrier loss. 10.3.4 bipolar violat ion detection (bpv) when the b8zs encoders and decoders are disabl ed or when configured for nrz mode, bipolar violations are reported at the bp v output pin. bpv goes high for a full clock cycle to in dicate a bipolar violation. when the b8zs encoders and decoders are enabled, bpvs that are not part of codewords are not reported.
ds21349 26 of 35 10.4 alarm monitoring 10.4.1 receive-carrier loss (rcl) the receiver counts inbound 0s and declares rcl when the counter reaches 192. this applies to hardware mode and software mode if the rcl2048 bit is clea red in cr4. in software mode, setting the rcl2048 bit changes the rcl counter to declare receive-carri er loss after 2048 consecutive 0s. once set, the rcl bit will remain set until the receiver detects a 12.5% density of 1s in a sliding window of 112 bits, provided that there are no more th an 98 consecutive 0s in that 112- bit window. when rcl is active, rclk is replaced by mclk. rcl is indicated by an output high on the rcl pin and with a 1 in sr.0. 10.4.2 alarm-indication- signal detection (ais) ais detection is only available in software mode. th e receiver declares receipt of ais when fewer than six 0s are detected in 4632 bits (3ms). ais is cleared when three or more 0s are received in 4632 bits. the ais bit in the status register (sr.2) indicates the presence of ais. wh en the ais status bit changes, the ais bit in the transition status regi ster (tsr.2) is set. a change in the ais status will generate an interrupt if the ais interrupt ma sk bit (imr.2) bit is cleared. 10.4.3 driver-fail m onitor-open (dfmo) the dfmo bit is set in the status register when th e transmitter outputs detect an open circuit. dfmo can generate an interrupt if the dfmo interrupt mask bit (imr.5) is cleared. this is not supported in hardware mode. 10.4.4 jitter attenuator limit trip (jalt) if the incoming jitter exceeds either 120 uip-p (buffer depth is 128 bits ) or 28 uip-p (buffer depth is 32 bits), then the ds21349 will divide the internal nominal 24.704mhz (t1) clock by either 15 or 17 instead of the normal 16 to keep the buffer from overflowing. when the device divides by either 15 or 17, it also sets the jitter attenuator limit trip (j alt) bit in information register 1 (ir1). 10.5 other diagnostic reports 10.5.1 receive line-attenuation indication the device reports the approximate inbound signal strengt h in the status register (ir). the four most significant bits indicate th e signal strength in approximately 2.5db increments.
ds21349 27 of 35 11. network interface transformer specifications are listed in table 11-a and table 11-b . table 11-c illustrates the series resistance necessary for the basic interface and is a ssociated with different transformer turns ratios. smaller turns ratios result in lower power-supply re quirements. however, seri es resistance provides added protection from potentially damaging voltages that can occur during lightning strikes. a basic network interface is illustrated in figure 11-1 . for a complete discussion of network interface design, refer to application note 324: t1/e1 network interface design. table 11-a. specifications for receive transformer specification recommended value turns ratio (all applications) 1:1 2% primary inductance 600 h minimum leakage inductance 1.0 h maximum interwinding capacitance 40pf maximum receive transformer dc resistance primary (device side) secondary 2 ? maximum 2 ? maximum table 11-b. specifications for transmit transformer specification recommended value turns ratio, 3.3v 1:3 2% primary inductance 600 h minimum leakage inductance 1.0 h maximum interwinding capacitance 40pf maximum transmit transformer dc resistance primary (device side) secondary 1.0 ? maximum 2.0 ? maximum table 11-c. transformer turn s ratio vs. series resistance xfmr1 (cr4.0) xfmr2 (cr4.1) operating voltage (v) application n rt ( ? ) long/short 0 0 3.3 d4 1:3 0 1:2 0 0 1 3.3 long/short 1:3 3 1:2.5 0 1 0 3.3 long/short 1:3 1 1:2 0 1 1 3.3 long/short 1:3 3
ds21349 28 of 35 figure 11-1. basic network interface note 1: all resistor values are 1%. note 2: the r r resistors should be 50 ? each for t1 lines. note 3: c = 1 f if using a 1:2 transformer; c = 2 f if using a 1:3 transformer. rtip rring ttip tring receive line n:1 (larger winding toward the network) ds21349 c v dd (21) v ss (22) 0.1f v dd (15) v ss (14) 0.1f +v dd 0.01f 1.544mhz mclk 1:1 0.1f r r r r r t r t transmit line 10f 10f
ds21349 29 of 35 figure 11-2. t1 transmit pulse template 0 -0.1 -0.2 -0.3 -0.4 -0.5 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 -500 -300 -100 0 300 500 700 -400 -200 200 400 600 100 time (ns) normalized amplitude t1.102/87, t1.403, cb 119 (oct. 79), & i.431 template -0.77 -0.39 -0.27 -0.27 -0.12 0.00 0.27 0.35 0.93 1.16 -500 -255 -175 -175 -75 0 175 225 600 750 0.05 0.05 0.80 1.15 1.15 1.05 1.05 -0.07 0.05 0.05 -0.77 -0.23 -0.23 -0.15 0.00 0.15 0.23 0.23 0.46 0.66 0.93 1.16 -500 -150 -150 -100 0 100 150 150 300 430 600 750 -0.05 -0.05 0.50 0.95 0.95 0.90 0.50 -0.45 -0.45 -0.20 -0.05 -0.05 ui time amp. maximum curve ui time amp. minimum curve
ds21349 30 of 35 figure 11-3. jitter tolerance figure 11-4. jitter attenuation frequency (hz) unit intervals (uip-p) 1k 100 10 1 0.1 10 100 1k 10k 100k ds21349 tolerance 1 tr 62411 (dec. 90) frequency (hz) 0db -20db -40db -60db 1 10 100 1k 10k jitter attenuation (db) 100k tr 62411 (dec. 90) prohibited area c u r v e b curve a t1
ds21349 31 of 35 12. dc characteristics absolute maxi mum ratings voltage range on any pin relative to ground -1.0v to +6.0v operating temperature range fo r ds21349qn -40c to +85c storage temperature range -55c to +125c soldering temperature see ipc/ jedec j-std-020 specification stresses beyond those listed under ?absolute maximum ratings? may c ause permanent damage to the device. these are stress rating s only, and functional operation of the device at t hese or any other conditions beyond those indicated in the operational sections of t he specifications is not implied. exposure to the absolute maximum rating c onditions for extended periods may affect device reliability. recommended dc oper ating conditions (t a = -40 c to +85 c) parameter symbol min typ max units logic 1 v ih 2.0 5.5 v logic 0 v il -0.3 +0.8 v supply for 3.3v operation (note 1) v dd 3.135 3.3 3.465 v capacitance (t a = +25c) parameter symbol min typ max units input capacitance c in 5 pf output capacitance c out 7 pf dc characteristics (v dd = 3.3v 5%, t a = -40 c to +85 c.) parameter symbol min typ max units input leakage (note 2) i il -1.0 +1.0 a output leakage (note 3) i lo 1.0 a output current (2.4v) i oh -1.0 ma output current (0.4v) i ol +4.0 ma power dissipation at 3.3v (notes 4, 5) p dd 300 mw note 1: applies to v dd . note 2: 0v < v in < v dd. note 3: applied to int when tri-stated note 4: tclk = mclk = 1.544mhz. note 5: power dissipation for an all-ones data density.
ds21349 32 of 35 ac characteristics: seri al port (mode1 = 1) (v dd = 3.3v 5%, t a = -40 c to +85 c.) ( figure 12-1 and figure 12-2 ) parameter symbol min typ max units setup time cs to sclk t css 50 ns setup time sdi to sclk t sss 50 ns hold time sclk to sdi t ssh 50 ns sclk high/low time t slh 200 ns sclk rise/fall time t srf 50 ns sclk to cs inactive t lsc 50 ns cs inactive time t cm 250 ns sclk to sdo valid t ssv 75 ns sclk to sdo tri-state t ssh 100 ns cs inactive or sclk to sdo tri-state t csh 100 ns figure 12-1. serial bus read timing (mode1 = 1) figure 12-2. serial bus write timing (mode1 = 1) sclk c s high-z sdo t lsc high-z lsb msb t csh t ssv sclk c s t lsc high-z sdo high-z lsb msb t csh t ssv clke = 0 clke = 1 msb sclk sdi c s t css t sss t ssh t srf t slh t lsc t cm lsb lsb msb data byte control byte
ds21349 33 of 35 ac characteristics: receive side (v dd = 3.3v 5%, t a = -40c to +85c.) ( figure 12-3 ) parameter symbol min typ max units rclk period t cp 648 ns t ch rclk pulse width (note 6) t cl 200 ns t ch rclk pulse width (note 7) t cl 150 ns delay rclk to rpos, rneg valid t dd 50 ns note 6: jitter attenuator enabled in the receive path. note 7: jitter attenuator disabled or enabled in the transmit path. figure 12-3. ac characteristics for receive side rclk rpos rneg in software mode: clke = 1 rpos rneg in software and hardware mode: clke = 0 t dd t dd t cl t ch t cp
ds21349 34 of 35 ac characteristics: transmit side (v dd = 3.3v 5%, t a = -40 c to +85 c.) ( figure 12-4 ) parameter symbol min typ max units tclk period t cp 648 ns tclk pulse width t ch t cl 75 ns tpos/tneg setup to tclk falling or rising t su 20 ns tpos/tneg hold from tclk falling or rising t hd 20 ns tclk rise and fall times t r , t f 25 ns figure 12-4. ac characteristics for transmit side tcl k tpos tneg t f t r t cl t ch t cp t su t hd
ds21349 35 of 35 maxim/dallas semiconductor cannot assume res ponsibility for use of any circuitry other than circuitry entirely embodied in a ma xim/dallas semiconductor product. no circuit patent licenses are implied. maxi m/dallas semiconductor reserves the right to change the circuitry and specification s without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ? 2006 maxim integrated products ? printed usa the maxim logo is a registered trademark of maxim integrated produ cts, inc. the dallas logo is a registered trademark of dallas semiconductor. 13. package information (the package drawing(s) in this data sheet may not reflect the most current specifications. the package number provided for each package is a link to the latest package outline information.) 13.1 28-pin plcc ( 56-g4001-001 )

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