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78p2252 stm-1/oc-3 transceiver june 2002 description the 78p2252 is a transceiver ic designed for 155.52mbit/s (oc-3 or stm-1) transmission. it is used at the interface to a fiber optic module. interface to digital framer circuits is accomplished via a serial pecl or parallel cmos interface. the 78p2252 is built in a bicmos technology allowing for high performance with low power operation. the device automatically adjusts for operations with either a 3.3v or 5v power supply and is packaged in a 64-pin tqfp. features ? compliant with itu-t g.958 jitter tolerance, telcordia tr-nwt-00253, ansi t1.105.03- 1994, and ansi t1.105.05-1994 ? integrated clock recovery unit (cru) ? serial pecl interface ? four and eight bit parallel cmos interfaces ? pecl interfaces for connection to fiber optic modules for sonet oc3 applications ? integrated clock multiplier pll ? advanced bicmos process ? available in 64tqfp package block diagram crystal oscillator clock generator clock recovery bias x t a l 2 x t a l 1 r f o eclinn eclinp ecloutn ecloutp ckin txck txckp,n txdtp,n rxdtp,n rxckp,n l l b a c k rlback l f txdt[7:0] rxdt[7:0] rxck 8 b i t / $ b i t p a r / s e r h u b / h o s t
78p2252 stm-1/oc-3 transceiver 2 functional description the 78p2252 contains all the necessary transmit and receive circuitry for connection between 155.52mbit/s signals and digital framer/deframer ics. digital interface the digital interface of the 78p2252 can operate as a serial pecl, 4-bit parallel cmos, or 8-bit parallel cmos interface. these modes are controlled by the par/ ser and 8bit/ $bit pins as shown in the following table. mode par/ ser ser ser ser 8bit/ $bit $bit $bit $bit data pins clock pins clock frequency (mhz) serial 0 x txdtp,n rxdtp,n txckp,n rxckp,n 155.52 4-bit parallel 1 0 txdt[3:0] rxdt[3:0] txck rxck 38.88 8-bit parallel 1 1 txdt[7:0] rxdt[7:0] txck rxck 19.44 transmitter operation the transmitter accepts serial or parallel data and generates an nrz coded pecl signal for transmission to a fiber optic module. when set to serial mode via par/ ser pin, serial data is input from the digital framer/deframer ic to the 78p2252 on the txdtp and txdtn pins at pecl levels. the data is clocked in with a line rate frequency clock generated by the 78p2252 on the txckp and txckn pins. when set to parallel mode, parallel data is input from the digital framer/deframer ic to the 78p2252 on the txdt[7:0] pins. eight bits or four bits of data are used depending the setting of the 8bit/ $bit pin. o in eight bit parallel mode, data is read on pins txdt[7:0]. o in four bit parallel mode, data is read on pins txdt[3:0]. the parallel input data is clocked in with the generated clock output txck. the txck automatically adjusts to either one-eighth or one- fourth the standard line rate frequency, depending on the state of the 8bit/ $bit pin. receiver operation the receiver accepts nrz coded, serial data at 155.52mbit/ from the fiber optic module via the ecl inputs, eclinp and eclinn. a clock signal is recovered using a low jitter pll circuit. in serial mode, the received data is output on the rxdtp and rxdtn pins and the recovered clock is output on the rxckp and rxckn pins at the line rate frequency. in parallel mode, the received data is converted to either eight bit or four bit parallel formats, determined by the state of the 8bit/ $bit pin . the first bit received will arrive on the most significant output pin, rxdt[7] in eight bit mode and rxdt[3] in four bit mode. in parallel mode, the recovered clock in output on the rxck pin at either one-eighth or one-fourth the line rate frequency, depending on the state of the 8bit/ $bit pin.
78p2252 stm-1/oc-3 transceiver 3 loopback operation remote and local loopback modes in the 78p2252 are controlled by the rlback and llback pins respectively. when in remote (digital) loopback mode (rlback logic high), the received data is internally routed onto the transmitter inputs. note that any input data on the txdtp,n pins or txdt[7:0] pins is ignored in remote loopback mode. crystal oscillator clock generator clock recovery bias x t a l 2 x t a l 1 r f o eclinn eclinp ecloutn ecloutp ckin txck txckp,n txdtp,n rxdtp,n rxckp,n l l b a c k rlback l f txdt[7:0] rxdt[7:0] rxck 8 b i t / $ b i t p a r / s e r h u b / h o s t remote (digital) loopback when in local (analog) loopback mode (llback logic high), the transmit output signals are internally routed to the receiver inputs. note that local loopback mode is disabled when hub/ host is low or rlback is high. crystal oscillator clock generator clock recovery bias x t a l 2 x t a l 1 r f o eclinn eclinp ecloutn ecloutp ckin txck txckp,n txdtp,n rxdtp,n rxckp,n l l b a c k rlback l f txdt[7:0] rxdt[7:0] rxck 8 b i t / $ b i t p a r / s e r h u b / h o s t local (analog) loopback reference clock the hub/ host pin selects the source of the reference signal used for the internal transmit clock generator. in hub mode (hub/ host logic high), the transmit clock reference is derived from either a crystal oscillator applied to the xtal1 and xtal2 pins or a reference clock input applied at the ckin pin. the reference frequency should be one-eighth the line rate frequency at 19.44mhz and should be applied in one of the following configurations. xtal1 xtal2 ckin xtal1 xtal2 ckin hub mode configurations using crystal -- or -- using external clock in host mode (hub/ host logic low), the transmit clock reference is derived from the recovered receive clock. note that the recovered receive clock is also used as the reference clock when remote loopback is enabled. llback rlback hub/ host host host host reference clock 0 0 1 ckin or xtal1,2 1 0 1 ckin or xtal1,2 x 1 1 recovered rx clock x x 0 recovered rx clock
78p2252 stm-1/oc-3 transceiver 4 pin description legend type description type description a analog pin pi pecl digital input ci cmos digital input po pecl digital output co cmos digital output s supply pin transmit pins name pin type description txdtp txdtn 19 20 pi transmit data inputs - serial mode. txckp txckn 22 23 po transmit clock output - serial mode. txdt[7:0] 11-18 ci transmit data inputs ? parallel mode. txdt[7:4] are ignored in 4 bit mode. txck 10 co reference clock output ? serial mode. transmit clock output ? parallel mode. ecloutp ecloutn 56 55 po transmit outputs. receive pins name pin type description eclinp eclinn 52 51 pi receiver inputs. rxckp rxckn 25 26 po recovered receive clock ? serial mode. rxck 38 co recovered receive clock ? parallel mode. rxdtp rxdtn 27 28 po receive data ? serial mode. rxdt[7:0] 30-37 co receive data ? parallel mode. in 4 bit mode rxdt[3:0] are used and rxdt[7:4] are pulled low. reference clock pins name pin type description xtal1 xtal2 5 6 a crystal pins. these pins should be left floating if using reference clock input ckin. ckin 9 ci reference clock input. this pin should be grounded if using the crystal oscillator inputs.
78p2252 stm-1/oc-3 transceiver 5 pin description (continued) control and status pins name pin type description rlback 41 ci remote (digital) loopback enable. when logic high, loops receiver output data to transmitter inputs. llback 42 ci local (analog) loopback enable. when logic high, loops transmitter output to receiver input. note: disabled when hub/ host is low or rlback is high. hub/ host 2 ci in hub mode (input high) the transmit reference clock is derived from the ckin pin or the crystal oscillator. in host mode (input low) the transmit reference clock is derived from the recovered receive clock. 8bit/ $bit 63 ci when in parallel mode, logic high selects 8-bit mode and logic low selects 4-bit mode. ignored in serial mode. par/ ser 62 ci selects parallel mode when high, serial mode when low. analog pins name pin type description rfo 46 a external reference resistor. see application information section for more info. lf 44 a pll loop filter capacitor. see application information section for more info. power supply pins it is recommended that all vcc pins be connected to a single power supply plane and all gnd pins be connected to a single ground plane. name pin type description vcc 3, 8, 24, 40, 43, 53, 54, 57 s power supply. gnd 1, 4, 7, 21, 29, 39, 45, 47, 48, 50, 58, 59, 60, 61, 64 s ground.
78p2252 stm-1/oc-3 transceiver 6 electrical specifications absolute maximum ratings operation beyond these limits may permanently damage the device. parameter rating supply voltage 7 vdc storage temperature -65 to 150 c pin voltage -0.3 to (v cc +0.3) vdc pin current 100 ma recommended operating conditions unless otherwise noted all specifications are valid over these temperatures and supply voltage ranges. parameter rating dc voltage supply, vcc 3.3 0.3 vdc; 5 0.5 vdc ambient operating temperature -40 to 85c dc characteristics: parameter symbol conditions min nom max unit supply current (parallel mode) icc vcc = 3.3v vcc = 5.0v 140 150 165 175 ma supply current (serial mode) icc vcc = 3.3v vcc = 5.0v 210 280 245 330 ma
78p2252 stm-1/oc-3 transceiver 7 electrical specifications (continued) digital input characteristics pins of type ci parameter symbol conditions min nom max unit input voltage low vil vcc/2 - 0.9 v input voltage high vih vcc/2 + 0.9 v input current iil, iih -10 10 a input capacitance cin 10 pf pins of type pi parameter symbol conditions min nom max unit input voltage low vil relative to vcc -1.5 v input voltage high vih relative to vcc -1.1 v digital output characteristics pins of type co parameter symbol conditions min nom max unit output voltage low vol 0.6 0.7 v output voltage high voh below vcc 0.6 0.7 v transition time tt 3.5 ns pins of type po parameter symbol conditions min nom max unit output voltage low vol vcc reference biased at vcc -1.5v with 50 ohm -1.7 -1.4 -1.3 v output voltage high voh vcc reference biased at vcc -1.5v with 50 ohm -1.1 -0.9 -0.7 v rise time tr 1 3 ns fall time tf 1 3 ns
78p2252 stm-1/oc-3 transceiver 8 electrical specifications (continued) digital timing characteristics transmit interface ? serial mode txckp - txckn txdtp - txdtn t sus t hs parameter symbol conditions min nom max unit transmit setup time t sus serial mode 1.5 ns transmit hold time t hs serial mode 1.5 ns txckp,n duty cycle 40 60 % transmit interface ? 8-bit parallel mode txck txdt[7:0] t sup t hp parameter symbol conditions min nom max unit transmit setup time t sup parallel mode 3.5 ns transmit hold time t hp parallel mode 2.5 ns txck duty cycle 40 60 %
78p2252 stm-1/oc-3 transceiver 9 electrical specifications (continued) digital timing characteristics receive interface ? serial mode rxckp - rxckn rxdtp - rxdtn t props parameter symbol conditions min nom max unit receive propagation delay t props serial mode 2.4 3.0 ns rxckp,n duty cycle 40 60 % receive interface ? 8-bit parallel mode rxck rxdt[7:0] t propp parameter symbol conditions min nom max unit receive propagation delay t propps parallel mode 4.0 6.0 ns rxckp,n duty cycle 40 60 %
78p2252 stm-1/oc-3 transceiver 10 electrical specifications (continued) reference clock interface ckin txckp - txckn t props parameter symbol conditions min nom max unit ckin to txckp/n delay t props serial mode 3.1 4.6 5.6 ns ckin txck t propp parameter symbol conditions min nom max unit ckin to closes phase of txck delay t propp parallel 8 bit mode 1.6 3.7 5.7 ns
78p2252 stm-1/oc-3 transceiver 11 electrical specifications (continued) transmitter output jitter the transmit jitter specification ensures compliance with itu-t g.958 and ansi t1.105.03-1994 for stm-1 and oc-3 rates. the corner frequency of the transmit pll is nominally 3.0 mhz. transmitter output jitter detector measured jitter amplitude 500 hz 1.3 mhz 20db/decade parameter condition min nom max unit transmitter output jitter 200 hz to 3.5 mhz 0.075 ui pp
78p2252 stm-1/oc-3 transceiver 12 electrical specifications (continued) receiver jitter tolerance oc-3 jitter tolerance specifications are in ansi t1.105.05-1994 and telcordia tr-nwt-000253, issue 2, dec. 1991. stm-1 specifications are in itu-t g.825. they are identical except that stm-1 specifies both jitter and wander. the stm-1 specification is the tightest and covers the largest frequency range. parameter condition min nom max unit receiver jitter tolerance note 1: not tested in production 12 hz to 178 hz 1.6mhz to 15.6mhz 125mhz to 19.3 hz 500hz to 6.5khz 65khz to 3.5mhz 2800 311 39 1.5 0.15 ui 0.01 0.1 1 10 100 1000 10000 1.e-06 1.e-05 1.e-04 1.e-03 1.e-02 1.e-01 1.e+00 1.e+01 1.e+02 1.e+03 1.e+04 1.e+05 1.e+06 1.e+07 stm-1 e4
78p2252 stm-1/oc-3 transceiver 13 electrical specifications (continued) receiver jitter transfer function the receiver clock recovery loop filter characteristics such that the receiver has the following transfer function. the corner frequency of the pll is approximately 100 khz. these specifications are not tested in production. -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1.00e+03 1.00e+04 1.00e+05 1.00e+06 1.00e+07 parameter condition min nom max unit receiver jitter transfer function below 100 khz 0.1 db jitter transfer function roll-off note 1: not tested in production 20 db per decade
78p2252 stm-1/oc-3 transceiver 14 application information external components: component pin(s) value units tolerance reference resistor rfo 31.6 k ? 1% filter capacitor lf1 470 nf 5% crystal specifications: component value units tolerance center frequency 19.44 mhz +/- 20ppm load capacitor ? xtal1 to ground; xtal2 to ground please check datasheet of crystal manufacturer for optimal load capacitor values. 27 pf schematics the latest typical application schematics are available in the form of application notes and/or demo board manuals. please contact tdk semiconductor for more information. pecl interface components: component value units tolerance output bias resistor, r bias v cc = 5v v cc = 3.3v 250 140 ? ? 5% 5% termination resistor, r term 100 ? 5% when the pecl signals travel one inch or less, lower power operation can be achieved by increasing r bias and eliminating r term . r bias r bias r term figure 1. pecl interface
78p2252 stm-1/oc-3 transceiver 15 mechanical specifications 64-tqfp (jedec lqfp) mechanical specification
78p2252 stm-1/oc-3 transceiver 16 package pin designations (top view) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 gnd gnd rfo gnd lf vcc llback rlba ck vcc gnd rxck rxdt0 rxdt1 rxdt2 rxdt3 rxdt4 17 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 gnd hub/ host vcc gnd xtal1 xtal2 gnd vcc ckin txck txdt7 txdt6 txdt5 txdt4 txdt3 txdt2 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 txdt1 txdt0 txdtp txdtn gnd txckp txckn vcc rxckp rxckn rxtdp rxtdn gnd rxdt7 rxtd6 rxdt5 gnd 8bit/ $bit par/ ser gnd gnd gnd gnd vcc ecloutp ecloutn vcc vcc eclinp eclinn gnd gnd 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 64-pin tqfp (jedec lqfp) 78P2252-IGT ordering information part description order number packaging mark 78p2252 64- pin thin quad flatpack 78P2252-IGT 78P2252-IGT no responsibility is assumed by tdk semiconductor corporation for use of this product nor for any infringements of patents and trademarks or other rights of third parties resulting from its use. no license is granted under any patents, patent rights or trademarks o f tdk semiconductor corporation and the company reserves the right to make changes in specifications at any time without notice. acco rdingly, the reader is cautioned to verify that you are referencing the most current data sheet before placing orders. to do so, see our web site at http://www.tsc.tdk.com or contact your local tdk semiconductor representative. tdk semiconductor corporation, 2642 michelle drive, tustin, ca 92780-7019, (714) 508-8800, fax: (714) 508-8877 ? 2002 tdk semiconductor corporation 6/13/02- rev. h caution: use handling procedures necessary for a static sensitive component.

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