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a functional block diagram features data rates from 50mb/s to 10.709gb/s typical rise/fall time 25/23 ps bias current range 3ma to 80 ma modulation current range 5ma to 80 ma monitor photo diode current 50 a to 1100 a closed loop control of both average optical power and extinction ratio laser fail and laser degrade alarms automatic laser shutdown, als dual mpd functionality for wavelength control cml data inputs 50 ? ? ? ? ? internal data terminations +3.3v single supply operation driver supplied in dice format applications sonet oc-192, sdh stm-64 suports 10.667gb/s and 10.709gb/s fec rates 10gb ethernet ieee802.3 one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781/329-4700 www.analog.com fax: 781/326-8703 ? analog devices, inc., 2003 rev. prd january 2003 information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of analog devices. 10.709gb/s laser diode driver chipset general description the ADN2843 chipset uses a unique control algorithm to control both average power and extinction ratio of the laser diode, ld, after initial factory set-up. the chipset consists of two components. the adn2844 contains the control loops, and the adn2845 is the 10.7gb/s data switch. the adn2845 is available in dice format, and adn2844 is available in packaged or dice format. external component count and pcb area are low as both power and extinction ratio control are fully integrated. programmable alarms are provided for laser fail (end of life), and laser degrade (impending fail). preliminary technical data ADN2843 ercap * * pset erset imod_ctrl ibias_ctrl vcc datap datan degrade fail gnd imodp ibias immon idtone mpd vcc ld vcc ibmon aset gnd gnd gnd vcc gnd control adn2844 adn2845 ADN2843 vcc * adn2850 optical supervisor impd impd2 impdmon impdmon2 pavcap imodn lbwset gnd g nd als als d_imod mode
parameter m i n t y p m a x u n i t s conditions laser bias (bias) output current ibias 3 80 ma compliance voltage 1.2 vcc-1.0 v ibias during als 10 a see note#6 als shutdown response time 10 s modulation current (imodp, imodn) see note#1 output current imod 5 80 ma compliance voltage 1.2 vcc v imod during als 10 a rise time 25 p s see note#7 fall time 23 p s see note#7 random jitter 170 fs rms see note#2 total jitter 7.41 ps pk-pk see note#3 monitor pd (mpd,mpd2) current 50 1200 a input voltage 1.6 v power set input (pset) external capacitance 80 pf see note#4 voltage 1.15 1.35 v extinction ratio set input (erset) allowable resistance range 1k 25k voltage 1.15 1.35 v alarm set (aset) allowable resistance range 1.15k 13.5k voltage 1.15 1.35 v hysteresis 5 % control loop time constant 0.22 s lbwset= gnd 2.25 s lbwset = vcc data inputs (datap,datan) vp-p(single ended pk to pk) 300 800 mv input impedance 50 logic inputs (als, lbwset) vih 2.4 v vil 0.8 v alarm outputs (internal 30k to vcc) voh 2.4 v vol 0.4 v idtone fin 10 1000 hz input current range 50 4000 a voltage on idtone vcc-1.5 v ibmon,immon impdmon,impdmon2 ibmon, immon division ratio 100 a / a impdmon,impdmon2 1 a/a impdmon to impdmon2 matching 1 % compliance voltage 0 1.5 v supply vcc 3.0 3.3 3.6 v icc(adn2844) 36 ma see note#5 icc(adn2845) 75 ma see note#5 ?2? rev. prd january 2003 note 1: the adn2845 high speed specifications are measured into a 5ohm load. note 2: rms jitter measured with a 0000 0000 1111 1111 repeating pattern at 10.7gbps rate note 3: peak-to-peak total jitter measured with a 2^13-1 prbs with 80 cids pattern at 10.7gb/s rate note 4: max capacitance refers to capacitance of photo diode and other parasitic capacitance note 5: ibias=0, imod=0. see section on power dissipation for calculation of complete power dissipation note 6: in als mode approx. 15ma is sourced to the laser from the ibias pin which reverse biases the laser note 7: using a 0.5nh ribbon between imodp and the cathode of the laser diode (v cc = 3.0v to 3.6v, all specifications t min to t max unless otherwise noted. typical values as specified at 25?) preliminary technical data ADN2843
rev. prd january 2003 ?3? preliminary technical data ADN2843 absolute maximum ratings 1 (t a = +25c unless otherwise noted) v cc to gnd...................................... 5v datap to gnd..................................3.6v datan to gnd..................................3.6v als to gnd.....................................3.6v imod_control to gnd............3.6v ibias_control to gnd.............3.6v operating temperature range industrial ........................................-40c to +85c storage temperature range................-65c to +150c junction temperature (t j max).........................+150c caution esd (electrostatic discharge) sensitive device. electrostatic charges as high as 4000 v readily accumulate on the human body and test equipment and can discharge without detection. although the adn2841 features proprietary esd protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. therefore, proper esd precautions are recommended to avoid performance degradation or loss of functionality. ordering guide model temperature range package description adn284xxx(1) chipset -40c to +85c adn2844 control loop: 32-lead lfcsp adn2845 d ata switch : dice ADN2843xxx(2) -40c to +85c adn2844 control loop: dice adn2845 d ata switch: dice outline dimensions dimensions shown in mm 32-lead(5x5) lfcsp (exposed paddle) exposed paddle should be soldered to the most negative supply of the -adn2844 (adn2844 also available as bare die)

notes: 1 stresses above those listed under ?absolute maximum ratings? may cause permanent damage to the device. this is a stress rating only, and functional operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. transient currents of up to 100ma will not cause scr latch-up
rev. prd january 2003 ?4? preliminary technical data ADN2843 general laser diodes have current-in to light-out transfer functions as shown in figure 2. two key characteristics of this transfer function are the threshold current, ith, and slope in the linear region beyond the threshold current, referred to as slope efficiency, li. ith i p li = p i current o ptical pow er po pav p1 er = p1 po pav=p1+po 2 figure 1. laser transfer function control a monitor photo diode, mpd, is required to control the ld. the mpd current is fed into the adn2841 to control the power and extinction ratio, continuously adjusting the bias current and modulation current in response to the laser?s changing threshold current and light to current (li) slope (slope efficiency). the ADN2843 uses automatic power control, apc, to maintain a constant power over time and temperature. the ADN2843 uses closed loop extinction ratio control to allow optimum setting of extinction ratio for every device. hence sonet/sdh interface standards can be met over device variation, temperature and time. closed loop modula- tion control eliminates the need to either over modulate the ld or include external components for temperature compensation, thus reducing r&d time and second sourcing issues. the ADN2843 dual loop control has three modes of operation. each mode is given by the configuration of the mode and d_imod pins as shown below: e d o m n o i t a r e p og n i t t e s n i p e d o mo t d e t c e n n o c n i p d o m i _ d ah g i hs a i b i bw o ll r t c _ s a i b i cw o ll r t c _ d o m i setting the ADN2843 in mode a(see figure2) allows operation with lasers which have li non-linearity offering a better accuracy of the extinction ratio control. care should be taken to ensure that the extra capacitance on the ibias pin due to the d_imod connection does not degrade the eye performance. when physical consraints doesn't allow a low capacitance interconnect between d_imod and ibias, the ADN2843 should be configured in mode b(see figure 3). configuring the ADN2843 in mode c allows operation without li non-linearity compensation (see figure4). average power and extinction ratio are set using the pset and erset pins respectively. a resistor is place between the pin and gnd to set the current flowing in each pin. the internal control loops force the pset and erset pins to 1.23v above gnd. the pset resistor is given by the following formula: r pset = 1.23 ( ) i av where i av is average mpd current. the value of the erset resistor is a function of the operation mode of the ADN2843 as follows: for modes a and c, for mode b, note that i erset and i pset will change from laser diode to laser diode, therefore r erset and r pset need to be adjusted for each laser diode. when tunning the laser diode, r pset should be adjusted first with r erset at 25k . once the average power is set, r erset is adjusted to set the desired extinction ratio. once the values r pset and r erset have been adjusted to set the desired average power and extinction ratio, the control loops maintain these values values of average power and extinction ratio over environmental conditions and time. loop time-constant selection the control loop constant can be optimised for operation at data rates of 2.5gb/s and above by setting the lbwset pin low. this results in a faster loop time constant. the required value for the pavcap/ercap capacitors in 22nf in this case. for multi-rate operation, the lbwset pin should be set high and the required value for the pavcap/ercap capacitors is 820nf. this results in a slower loop constant. the pavcap/erca capacitors are connected between the respective pins and gnd. the capacitors should be low leakagemulti-layer ceramic capacitors with an insulation resistance > 100g or an rc > 1000s, whichever is the lower. alarms the ADN2843 alarms are designed to allow interface compli- ance to itu-t-g958 (11/94) section 10.3.1.1.2 (transmitter fail) and section 10.3.1.1.3 (transmitter degrade). the ADN2843 has two alarms, degrade and fail. these alarms are raised when ibias exceeds the respective degrade and fail thresholds. these alarms are active high. a resistor between ground and the aset pin is used to set the current at which these alarms are raised. the current through the aset resistor is a ratio of 1:100 to the fail alarm threshold. 1 1 ? + = er er r r pset erset 1 1 2 ? + = er er r r pset erset
rev. prd january 2003 ?5? preliminary technical data ADN2843 automatic laser shutdown the ADN2843 als allows compliance to itu-t-g958 (11/ 94), section 9.7. when als is asserted, both bias and modulation currents are turned off. in als mode approx. 15ma is sourced to the laser from the ibias pin which reverse biases the laser and ensures that it is turned off. correct operation of als can be confirmed by the fail alarm being raused when als is asserted. note this is the only time that degrade will be low while fail is high. note: for correct als operation, als pin on adn2844 and adn2845 should both be driven. alarm interface the alarm voltages are open collector outputs. an internal pull up resistor of 30k is used to pull the logic high value to vcc. however this can be over driven with an external resistor allowing alarm interfacing to non-vcc levels. non-vcc alarm output levels must be below the vcc used for the ADN2843. monitor currents ibmon, immon mirror the bias, modulation current at a ratio of 1:100 for increased monitoring functionality. impdmon and impdmon2 mirror the current in impd and impd2 respectively with a ratio of 1. all monitors source current from vcc. id_tone the idtone pin is supplied for fibre identification/ supervi- sory channels or forcontrol purposes. this pin modulates the optical one level by adding a current to imod over a possible range of 2% of min imod to 10% of max imod. the id_tone current is set by an external current sink connected to the idtone pin. there is a gain of two between the idtone pin and the imod current. to ratio the idtone current to imod, the input current can be derived from the immon output current. if the idtone function is not being used, this pin must be tied to properly disable it. note that using id tones during transmission may cause optical eye degradation. dual mpd dwdm function the mpd function mirrors the current in mpd to the pset pin and to the impdmon pin with a ratio of 1. if the impd monitor functionis not required, the monitor photo diode can be directly connected to the pset pin, and the impd pin tied to gnd. a second monitor photo diode can be connected to the impd2 pin. its current is mirrored to impdmon2 and also to the pset pin, where it is summed with the current mirrored from impd. the two mpd monitor currents can be used as inputs to a wavelength control function when used in combination with various optical filtering techniques. if impd2 pin is not being used, it should be tied to gnd. power dissipation the power dissipation of the adn2845 can be calculated using the following expressions: icc=75ma+1.75xi mod (ma)+0.3xi bias (ma) p=vcc x icc +v imod x i mod (a)/2 + v ibias x i bias (a) where v imod is the average voltage on the imod pin, and v ibias is the average voltage on the ibias pin . the degrade alarm will be raised at 90% of the fail threshold. example: i fail = 50ma s o i degrade = 45ma i aset = ibia strip = 50ma = 500 a 100 100 **r aset = 1.23 v = 1.23 = 2.46 k i aset 500ma the laser degrade alarm, degrade, is provided to give a warning of imminent laser failure if the laser diode degrades further or environmental conditions continue to stress the ld, eg. increasing temperature. the laser fail alarm, fail, is activated when the transmitter can no longer be guaranteed to be sonet/sdh compliant. this occurs when one of the following conditions arise: - the aset threshold is reached. - the als pin is set high. this shuts off the modulation and bias currents to the ld, resultingin the mpd current dropping to zero. this gives closed loop feedback to the system that als has been enabled.
rev. prd january 2003 ?6? preliminary technical data ADN2843 package outline both the adn2844 and the adn2845 are available as bare die. the adn2844 is also available in 5mmx5mm 32 pin lfcsp. ad n2 8 44 b b o n d p a d s i ze : 115um x 115um b o n d p a d p i t c h : > 104um d i e s i z e : 3 m m x 2 . 3 9 mm 1 i bias_ctrl i mod_ctrl gnd(nc5) i m odp vcc (i m odn t e r m ) datap gnd nc gnd datan nc gnd ibias_ctrl imod_ctrl als gnd vcc vcc vcc adn 2845 1 i b i as nc

gnd3 vcc3 gnd2 d_imod lbwset gnd2(nc2 ) gnd)nc3) gnd(nc4) mode pavcap ercap vcc4 gnd4 aset erset pset gnd(nc3) impd impdmon impdmon2 impd2 idtone ibmon immon als fail degrade gnd(nc6 ) gnd(nc1 )
rev. prd january 2003 ?7? preliminary technical data ADN2843 pin adn2844b function 1 aset alarm current threshold set 2 erset extinction ratio current set 3 pset a verage optical power set pin 4 gnd test input(nc8) 5 impd monitor photo diode current input 6 impdmon mirrored current from impd 7 impdmon2 mirrored current from impd2 (for optional use with twompds) 8 impd2 optional second mpd current input 9 gnd4 negative supply 1 0 vcc4 positive supply 11 ercap extinction ratio loop capacitor 12 pavcap a vearge power loop capacitor 13 mode control loop operating mode logic input 14 gnd test input (nc4) 15 gnd test input (nc3) 16 gnd test input (nc2) 17 gnd test input (nc1) 18 gnd test input (nc6) 1 9 degrade degrade alarm output, open collector, active high 2 0 fail fail alarm output, open collector, active high 2 1 als automatic laser shutdown logic input 22 immon modulation current mirror putput, current source from vcc 23 ibmon bias current mirror output, current source from vcc 24 idtone id t one input current 2 5 gnd3 negative supply 2 6 vcc3 positive supply 27 ibias_ctrl control output current sink 2 8 gnd2 negative supply 29 imod_ctrl control output current sink 30 d_imod control output current sink 31 gnd test input (nc5) 32 lbwset select low loop bandwidth mode (active = vcc) pin adn2845 function 1 datan ac coupled cml data, negative differential terminal 2 gnd negative supply 3 nc no connect - leave floating 4 gnd negative supply 5 datap ac coupled cml data, positive differential terminal 6 als automatic laser shutdown logic input 7 imod_ctrl modulation current control input (control circuit sinks imod/10 from pin to gnd) 8 ibias_ctrl bias current control input (control circuit sinks ibias/10 from pin to gnd) 9 gnd negative supply 10 nc no connect - leave floating 11 ibias bias current 12 imodp modulation current 13 nc no connect - leave floating 14 vcc vcc connection for imodn termination resistor 15 gnd negative supply 16 vcc positive supply 17 vcc positive supply 18 vcc positive supply pin function description
rev. prd january 2003 ?8? preliminary technical data ADN2843 * for digital programming, the adn2850 optical supervisor can be used ? optional monitoring of currents figure 2. ADN2843 application circuit (mode a) best high frequency board layout techniques including power and ground planes should be used. to minimize inductance, keep the connections between the adn2845 and the laser diode as short as possible. place bypass capacitor on laser anode as close to laser as possible. minimise bond lengths for adn2845 pads to achieve low inductance. ribbon bonding can be used to reduce bond inductance. critical bonds are imodp and vcc (pin 14). connecting to adn2845 gnd (pin 13) is optional if it allows inductance on vcc (pin 14) to be further reduced. bypass capacitors should be placed as close as possible to vcc pads. 50 controlled impedance interconnects should be used on the data inputs value of the ac coupling capacitors on the data inputs depends on the frequency content of the data parasitic capacitance on ibias_ctrl and imod_ctrl interconnects should be less than 100pf. if decoupling caps are used on ibias_ctrl and imod_ctrl, they should be tied to vcc rather than gnd. a ferrite of type murata blm11ha601sg is recomended for ibias inductor on adn2845 gnd aset erset pset gnd impd impdmon impdmon2 impd2 gnd4 vcc4 ercap pavcap mode gnd gnd gnd lbwset d_imod imod_ctrl gnd2 ibias_ctrl vcc3 gnd3 idtone ibmon immon fail degrade gnd gnd als 25 32 1 24 8 9 16 17 mpd * vcc imodp vcc . ibias datap nc nc gnd datan gnd ibias_ctrl imod_ctrl gnd als vcc vcc vcc adn2845 10nf 10nf 10nf vcc 100uf tantalum vcc 10nf 10nf vcc vcc vcc gnd vcc * vcc 1k 1k k vcc 1k 10nf 10nf adn2844 b 1 5 6 9 10 14 15 18 ? ? ? 22nf 22nf 10k vcc
rev. prd january 2003 ?9? preliminary technical data ADN2843 * for digital programming, the adn2850 optical supervisor can be used ? optional monitoring of currents figure 3. ADN2843 application circuit (mode b) gnd aset erset pset gnd impd impdmon impdmon2 impd2 gnd4 vcc4 ercap pavcap mode gnd gnd gnd lbwset d_imod imod_ctrl gnd2 ibias_ctrl vcc3 gnd3 idtone ibmon immon fail degrade gnd gnd als 25 32 1 24 8 9 16 17 mpd * vcc imodp vcc . ibias datap nc nc gnd datan gnd ibias_ctrl imod_ctrl gnd als vcc vcc vcc adn2845 10nf 10nf 10nf vcc 100uf tantalum vcc 10nf 10nf vcc vcc vcc gnd vcc * vcc 1k 1k k vcc 1k 10nf 10nf adn2844 b 1 5 6 9 10 14 15 18 ? ? ? 22nf 22nf 10k
rev. prd january 2003 ?10? preliminary technical data ADN2843 * for digital programming, the adn2850 optical supervisor can be used ? optional monitoring of currents figure 4. ADN2843 application circuit (mode c) gnd aset erset pset gnd impd impdmon impdmon2 impd2 gnd4 vcc4 ercap pavcap mode gnd gnd gnd lbwset d_imod imod_ctrl gnd2 ibias_ctrl vcc3 gnd3 idtone ibmon immon fail degrade gnd gnd als 25 32 1 24 8 9 16 17 mpd * vcc imodp vcc . ibias datap nc nc gnd datan gnd ibias_ctrl imod_ctrl gnd als vcc vcc vcc adn2845 10nf 10nf 10nf vcc 100uf tantalum vcc 10nf 10nf vcc vcc vcc gnd vcc * vcc 1k 1k k vcc 1k 10nf 10nf adn2844 b 1 5 6 9 10 14 15 18 ? ? ? 22nf 22nf 10k
rev. prd january 2003 ?11? preliminary technical data ADN2843 !" " " #" $"% &" ""& & &" '&( )*)% & " +" , " -" & adn2845 recommended layout figure 5. adn2845 - recommended layout
rev. prd january 2003 ?12? preliminary technical data ADN2843 diepad coordinates (with origin in the center of the die) adn2845 # d a pe m a n d a p [ x[ x [ x [ x[ x ] m [ y[ y [ y [ y[ y ] m 1n a t a d0 0 . 0 0 5 -0 0 . 0 0 4 2d n g * * 0 0 . 0 0 5 -0 0 . 2 2 2 3c n0 0 . 0 0 5 -0 0 . 0 4d n g * * 0 0 . 0 0 5 -0 0 . 2 2 2 - 5p a t a d0 0 . 0 0 5 -0 0 . 0 0 4 - 6s l a0 0 . 0 0 3 -0 0 . 0 0 6 - 7l r t c _ d o m i0 0 . 0 0 1 -0 0 . 0 0 6 - 8l r t c _ s a i b i0 0 . 0 0 10 0 . 0 0 6 - 9d n g * * 0 0 . 0 0 30 0 . 0 0 6 - 0 1c n * * 0 0 . 0 0 50 0 . 0 0 4 - 1 1s a i b i0 0 . 0 0 50 0 . 0 0 2 - 2 1p d o m i * * 0 0 . 0 0 50 0 . 0 3 - 3 1c n * * 0 0 . 0 0 50 0 . 8 7 1 4 1) n d o m i ( c c v * * 0 0 . 0 0 50 0 . 8 7 3 5 1d n g * * 0 0 . 0 0 30 0 . 0 0 6 6 1c c v * * 0 0 . 0 0 10 0 . 0 0 6 7 1c c v * * 0 0 . 0 0 1 -0 0 . 0 0 6 8 1c c v * * 0 0 . 0 0 3 -0 0 . 0 0 6 ** denotes double bondpad
rev. prd january 2003 ?13? preliminary technical data ADN2843 adn2844 # d a pe m a n d a p [ x[ x [ x [ x[ x ] m [ y[ y [ y [ y[ y ] m 1t e s a0 0 . 4 1 0 10 0 . 9 1 0 1 - 2t e s r e0 0 . 9 6 70 0 . 9 1 0 1 - 3t e s p0 0 . 6 8 40 0 . 9 1 0 1 - 4d n g0 0 . 6 8 10 0 . 9 1 0 1 - 5d p m i0 0 . 2 3 1 -0 0 . 9 1 0 1 - 6n o m d p m i0 0 . 9 7 4 -0 0 . 9 1 0 1 - 72 n o m d p m i0 0 . 1 1 8 -0 0 . 9 1 0 1 - 82 d p m i0 0 . 6 5 0 1 -0 0 . 9 1 0 1 - 94 d n g0 0 . 9 3 3 1 -0 0 . 7 7 8 - 0 14 c c v0 0 . 9 3 3 1 -0 0 . 2 7 6 - 1 1p a c r e0 0 . 9 3 3 1 -0 0 . 9 2 4 - 2 1p a c v a p0 0 . 9 3 3 1 -0 0 . 4 0 2 - 3 1e d o m0 0 . 9 3 3 1 -0 0 . 1 9 4 1d n g0 0 . 9 3 3 1 -0 0 . 5 3 3 5 1d n g0 0 . 9 3 3 1 -0 0 . 0 8 5 6 1d n g0 0 . 9 3 3 1 -0 0 . 4 2 8 7 1d n g0 0 . 1 5 0 1 -0 0 . 9 1 0 1 8 1d n g0 0 . 1 6 7 -0 0 . 9 1 0 1 9 1e d a r g e d0 0 . 6 7 4 -0 0 . 9 1 0 1 0 2l i a f0 0 . 7 0 2 -0 0 . 9 1 0 1 1 2s l a0 0 . 2 0 10 0 . 9 1 0 1 2 2n o m m i0 0 . 7 8 30 0 . 9 1 0 1 3 2n o m b i0 0 . 3 5 60 0 . 9 1 0 1 4 2e n o t d i0 0 . 4 0 90 0 . 9 1 0 1 5 23 d n g0 0 . 9 5 3 10 0 . 5 9 9 6 23 c c v0 0 . 9 5 3 10 0 . 1 8 7 7 2l r t c _ s a i b i0 0 . 9 5 3 10 0 . 3 2 5 8 22 d n g0 0 . 9 5 3 10 0 . 7 1 3 9 2l r t c _ d o m i0 0 . 9 5 3 10 0 . 9 2 - 0 3d o m i _ d0 0 . 9 5 3 14 9 2 - 1 3d n g0 0 . 9 5 3 10 0 . 2 6 5 - 2 3t e s w b l0 0 . 9 5 3 10 0 . 7 0 8 -

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