general description the MAX3783 is a dual serial multiplexer (mux) and buffer with selectable line-side loopback for system interconnect and serial backplane applications up to 2.7gbps. each independent channel consists of a trans- mitter with fanout of two and a receiver with a 2:1 input mux. selectable loopback paths support system testing. operating from a single 3.3v supply, this device has current-mode logic (cml) inputs and outputs, which can be ac-coupled for pecl compatibility, if desired. the ic is packaged in a compact 48-pin tqfp-ep pack- age with exposed pad. typical power consumption is 1.12w. applications 2.7gbps serial communications system interconnect serial backplane fail-over and protection switching features provides redundant serial i/o 11ps deterministic jitter selectable loopback on-chip 50 ? termination resistors 3.3v power supply two-port integration MAX3783 2.7gbps dual mux/buffer with loopback ________________________________________________________________ maxim integrated products 1 1 2 3 4 5 6 7 8 9 10 11 12 36 35 34 33 32 31 30 29 28 27 26 25 tqfp-ep* MAX3783 13 14 15 16 17 18 19 20 21 22 23 24 48 47 46 45 44 43 42 41 40 39 38 37 gnd sia- sia+ v cc lb1a lb2a lb1b lb2b v cc sib+ sib- gnd selb v cc sob+ sob- v cc lo1b+ lo1b- v cc lo2b+ lo2b- v cc gnd li2a+ li2a- v cc li1a+ li1a- gnd gnd li1b- li1b+ v cc li2b- li2b+ sela v cc soa+ soa- v cc lo1a+ lo1a- v cc lo2a+ lo2a- v cc gnd *exposed pad must be soldered to supply ground on the circuit board pin configuration ordering information 19-2197; rev 0; 10/01 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. typical application circuit appears at end of data sheet. part temp. range pin-package MAX3783ucm 0? to +85? 48 tqfp-ep* * exposed pad
MAX3783 2.7gbps dual mux/buffer with loopback 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v cc = 3.0v to 3.6v, serial data rate = 2.75gbps, t a = 0? to +85?. typical values at v cc = 3.3v, t a = +25?, unless otherwise noted.) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. note 2: typical value measured using a repeating 1010 pattern at 500mbps. note 3: ac specifications are guaranteed by design and characterization. note 4: deterministic jitter is measured with a repeating k28.5 pattern. note 5: with the peak-to-peak input swing on the selected (transmitted) cml input equal to or greater than that on the nonselected inputs. supply voltage, v cc ...............................................-0.5v to 4.0v continuous current at serial outputs...............................?6ma voltage at sel_, lb_ pins ..........................-0.5v to (v cc + 0.5v) common-mode input voltage (si_, li_) .....-0.5v to (v cc + 0.5v) differential input voltage (si_, li_) (note 1) .......................?.8v continuous power dissipation (t a = +85?) 48-pin tqfp-ep (derate 27mw/? above +85?) .........1.76w storage ambient temperature ..........................-55? to +150? lead temperature (soldering, 10s) .................................+300? note 1: the sum of the common-mode voltage and differential voltage on any input pin must be within -0.5v to (v cc + 0.5v). parameter symbol conditions min typ max units maximum serial data rate 2.75 3.125 gbps power dissipation ac-coupled inputs, outputs 1.12 1.68 w supply current i cc 340 466 ma cml differential output voltage v od r l = 50 ? to v cc , or 100 ? differential (note 2) 1200 1500 2200 mvp-p cml differential input voltage v id 200 1600 2200 mvp-p cml output impedance r out single ended 42.5 50 57.5 ? cml input impedance r in differential 85 100 116 ? random jitter (note 3) 1 2 ps rms deterministic jitter (notes 3, 4, 5) 11 25 ps p - p 2.5gbps input (note 3) 70 135 cml output edge speed (20% to 80%) t r , t f 1.25gbps input (note 3) 80 200 ps propagation delay li_ to so_, si_ to lo_, li_ to lo_ (note 3) 340 500 ps multiplexer switch time sel_ or lb_ to valid output 9 ns ttl input current high v ih = +2.0v to (v cc +0.3v) 180 a ttl input current low v il = -0.3v to +0.8v 440 a
MAX3783 2.7gbps dual mux/buffer with loopback _______________________________________________________________________________________ 3 195mv/ div electrical eye diagram 2.75 gbps, 2 23 - 1 prbs pattern MAX3783 toc01 88ps/div 195mv/ div electrical eye diagram 2.75 gbps, k28.5 pattern MAX3783 toc02 88ps/div 195mv/ div electrical eye diagram 3.125 gbps, k28.5 pattern MAX3783 toc03 88ps/div 250 300 400 350 450 500 030 15 45 60 75 90 supply current vs. temperature MAX3783 toc04 temperature ( c) supply current (ma) 1.60 1.55 1.50 1.45 1.40 200 1200 700 1700 2200 cml differential output voltage vs. cml differential input voltage MAX3783 toc05 v id (mv) v od (v) measured using 1010 pattern, 500mbps 0 5 15 10 20 25 deterministic jitter vs. cml differential input voltage MAX3783 toc06 v id (mv) dj (ps) 200 1200 700 1700 2200 3.125gbps 2.75gbps lo2a+ lo2a- lb2a mulitplexer switch time MAX3783 toc07 10ns/div 9ns 10ns typical operating characteristics (v cc = 3.3v, t a = +25 c, unless otherwise noted.)
MAX3783 2.7gbps dual mux/buffer with loopback 4 _______________________________________________________________________________________ pin description pin name function 1, 12, 24, 30, 31, 37 gnd supply ground 2 sia- serial input a negative, cml 3 sia+ serial input a positive, cml 4, 9, 14, 17, 20, 23, 27, 34, 38, 41, 44, 47 v cc +3.3v supply 5 lb1a line out 1a loopback mode select. ttl low selects loopback. 6 lb2a line out 2a loopback mode select. ttl low selects loopback. 7 lb1b line out 1b loopback mode select. ttl low selects loopback. 8 lb2b line out 2b loopback mode select. ttl low selects loopback. 10 sib+ serial input b positive, cml 11 sib- serial input b negative, cml 13 selb serial output b input select, ttl 15 sob+ serial output b positive, cml 16 sob- serial output b negative, cml 18 lo1b+ line out 1b positive, cml 19 lo1b- line out 1b negative, cml 21 lo2b+ line out 2b positive, cml 22 lo2b- line out 2b negative, cml 25 li2b+ line in 2b positive, cml 26 li2b- line in 2b negative, cml 28 li1b+ line in 1b positive, cml 29 li1b- line in 1b negative, cml 32 li1a- line in 1a negative, cml 33 li1a+ line in 1a positive, cml 35 li2a- line in 2a negative, cml 36 li2a+ line in 2a positive, cml 39 lo2a- line out 2a negative, cml 40 lo2a+ line out 2a positive, cml 42 lo1a- line out 1a negative, cml 43 lo1a+ line out 1a positive, cml 45 soa- serial output a negative, cml 46 soa+ serial output a positive, cml 48 sela serial out a input select, ttl ep exposed pad ground. must be soldered to the circuit board for proper thermal and electrical performance (see ep package ).
detailed description the MAX3783 is a 2.7gbps dual serial mux/buffer with selectable line-side loopback for system test. each half of the MAX3783 provides a transmitter with a fanout of two and a receiver with a 2:1 mux, as shown in the func- tional diagram. input stages the input amplifiers accept cml or ac-coupled pecl signals and each input has an on-chip 100 ? differential impedance for optimal termination, as shown in figure 1. control lines ttl-compatible control lines are provided to select the MAX3783 s operating mode (table 1). sela and selb set the mux for channels a and b, respectively, to select li1_ or li2_ to connect to the so_ output. lb1a , lb1b , lb2a, and lb2b enable loopback mode for each of the four lo_ outputs. all control lines are inter- nally pulled high through 15k ? resistors. output buffers the outputs are high-speed cml interfaces with 50 ? back termination, as shown in figure 2. exposed-pad (ep) package the exposed pad on the 48-pin tqfp-ep provides a very low thermal-resistance path for heat removal from the ic. the pad is also electrical ground on the MAX3783 and must be soldered to the circuit board for proper thermal and electrical performance. MAX3783 2.7gbps dual mux/buffer with loopback _______________________________________________________________________________________ 5 MAX3783 cml cml cml 1 0 cml 1 0 v cc v cc cml 1 0 v cc cml 2 soa sela 2 sia 2 2 2 2 li1a li2a lo2a lo1a lb2a lb1a cml cml cml 1 0 cml 1 0 v cc v cc cml 1 0 v cc cml 2 sob selb 2 sib 2 2 2 2 li1b li2b lo2b lo1b lb2b lb1b 15k ? 15k ? 15k ? 15k ? 15k ? 15k ? MAX3783 v cc v cc - 0.5v v cc in+ in- 50 ? 50 ? 1.2k ? figure 1. input structure functional diagram sel_ so_ 0 li2_ 1 li1_ lb_ lo_ 0 li_ 1 si_ table 1. operating modes
MAX3783 chip information transistor count: 2816 process: bipolar 2.7gbps dual mux/buffer with loopback 6 _______________________________________________________________________________________ v cc 50 ? 50 ? 32ma out+ out- MAX3783 figure 2. cml output structure
MAX3783 2.7gbps dual mux/buffer with loopback _______________________________________________________________________________________ 7 MAX3783 lo1a+ lo1a- li1a- li1a+ soa+ soa- sia- sela selb sia+ lo1b+ lo1b- li1b- li1b+ lo2a+ lo2a- li2a- li2a+ lo2b+ lo2b- li2b- li2b+ serdes a in out sob+ sob- sib- gnd sib+ serdes b in out switch 1 in out out in switch 2 in out out in lb1a lb2a lb1b lb2b v cc note: coupling capacitors and bias resistors are optional, shown for lvpecl operation. refer to application notes hfan-01.0 and hfan-01.1 regarding lvpecl/cml interface. this symbol indicates a controlled-impedance transmission line of characteristic impedance z 0 = 50 ?. v cc typical application circuit
MAX3783 2.7gbps dual mux/buffer with loopback package information 48l,tqfp.eps 8 _______________________________________________________________________________________
MAX3783 2.7gbps dual mux/buffer with loopback maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 _____________________ 9 ? 2001 maxim integrated products printed usa is a registered trademark of maxim integrated products. package information (continued)
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