general description the max3654 analog transimpedance amplifier (tia) is designed for catv applications in fiber-to-the-home (ftth) networks. this high-linearity amplifier is intended for 47mhz to 870mhz subcarrier multiplexed (scm) sig- nals in passive optical networks (pon). a gain-control input supports agc operation with optical inputs hav- ing -6dbm to +2dbm average power. with 62db ? max- imum gain at 47mhz and 18db gain control range, the minimum rf output level is 14dbmv/channel at -6dbm optical input. a compact 4mm x 4mm package includes all of the active rf circuitry required to convert analog pin photocurrent to a 75 ? catv output. this 700mw sige rf ic provides a low-cost, low-power integrated analog catv receiver solution for ftth onts. applications ftth optical network termination (ont) features ? 47mhz to 870mhz operation ? -6dbm to +2dbm optical input range ? 21dbm oip3, 47dbm oip2 ? 5.5pa/ hz ein (amplifier alone) ? 62db gain at 47mhz ? 18db transimpedance (gain) control ? integrated +4db gain tilt (with typical photodiode) ? +5v single-supply operation ? 700mw power dissipation ? -40? to +85? operating temperature range ? 4mm x 4mm tqfn package max3654 47mhz to 870mhz analog catv t ransimpedance amplifier ________________________________________________________________ maxim integrated products 1 19-3745; rev 0; 7/05 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. ordering information part temp range pin- package pkg-code MAX3654ETE+ -40? to +85? 16 tqfn - e p * t1644f-4-a pin configuration appears at end of data sheet. + denotes lead-free package. * ep = exposed pad. drive out+ -6 to +2dbm +5v to +12v 0.001 f 10 h 10 h ferrite bead ferrite bead 1k ? 1k ? 100k ? 0.001 f 0.001 f 0.001 f out- + - in+ in- mute r hyst 75 ? 1:1 hyst vagc opamp max3654 ftth video tia +5v +5v tia t ypical application circuit
ac electrical characteristics (v cc = +4.75v to +5.25v, output zl = 75 ? , typical values at v cc = +5.0v, t a = +25?, unless otherwise noted.) parameter sym b o l conditions min typ max units operating frequency range f 47 870 mhz frequency response flatness 47mhz to 870mhz (notes 2, 6) ?.3 ?.75 db v agc 0.175v 60.5 62 63.5 v agc = 0.500v 51.5 53 54.5 transimpedance, differential (z t ) 47mhz v agc = 1.400v 42 43.5 45 db ? = = 0.175v (notes 4, 6) 8 pa/ hz ht e hteet ht eetututeemute mute 0.8v, 50mhz -58 -45 dbc rf output return loss -s22 47mhz to 870mhz 13 db note 1: dc parameters are tested at +25?, and guaranteed by design and characterization at -40? and +85?. note 2: maximum difference between frequency response at any point and a straight line connecting frequency response at end points. note 3: gain control stability is the maximum variation in transimpedance (over process, voltage, and temperature) for any v agc control voltage. note 4: ac parameters guaranteed by design and characterization. note 5: oip2 and oip3 measured using two tones at f1 = 800mhz and f2 = 850mhz, p out = -16dbm, v agc = 1.4v. note 6: includes the effects of a packaged photodiode having the characteristics shown in figure 2. max3654 47mhz to 870mhz analog catv t ransimpedance amplifier 2 _______________________________________________________________________________________ absolute maximum ratings 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. supply voltage, vcc.............................................-0.3v to +6.0v in+, in-, vagc, out+, out-, mute , hyst.........-0.3v to +5.5v test1, test2........................................................-0.3v to +5.5v output current (out+, out-) ............................................56ma continuous power dissipation, 16-lead tqfn-ep package (t a = +70?) (derate 16.9mw/? above +70?)....1349.1mw operating temperature range ...........................-40? to +85? storage temperature range .............................-55? to +150? lead temperature (soldering,10s) ..................................+300? dc electrical characteristics (v cc = +4.75v to +5.25v, typical values at v cc = +5.0v, t a = +25?, unless otherwise noted.) (note 1) parameter sym b o l conditions min typ max units supply current i cc 136 170 ma gain control input current v agc = 1.4v 50 200 ? mute input high v ih 2.0 v mute input low v il 0.8 v mute input current i il , i ih 30 ?
max3654 47mhz to 870mhz analog catv t ransimpedance amplifier _______________________________________________________________________________________ 3 ** * see photodiode model in figure 2 *for 75 ? input impedance use 25 ? resistors and adtl 1-18-75 +5v in+ in- 1k ? 1k ? mini-circuits adtl 1-18-75 mini-circuits adtl 1-18-75 vagc max3654 0.001 f 0.001 f gain, gain vs. vagc, gain tilt, s22, irn test circuit oip2, oip3 test circuit 0.001 f *murata blm15hd182sn **tdk mlf1608 e100k 10 h 0.001 f in+ in- 75 ? 75 ? 12 ? * +5v out+ out- gnd out+ out- gnd v cc +5v v cc 12 ? * mini-circuits adtl 1-12* vagc max3654 0.001 f 0.001 f 0.001 f 0.001 f ** * figure 1. test circuits for characterization
t ypical operating characteristics (v cc = +5.0v, t a = +25?, unless otherwise noted.) maximum gain vs. frequency (v agc = 0v) frequency (mhz) transimpedance gain (db ? ) max3654 toc01 0 200 400 600 800 1000 60 61 62 63 64 65 66 67 68 gain vs. control voltage vagc (v) transimpedance gain (db ? ) max3654 toc02 0.1 0.2 1.0 1.4 40 45 50 55 60 65 50mhz 870mhz gain tilt vs. control voltage and temperature vagc (v) gain tilt (db) max3654toc03 0 0.4 1 1.6 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 +25 c -40 c +85 c 0.2 0.6 0.8 1.2 1.4 max3654 47mhz to 870mhz analog catv t ransimpedance amplifier 4 _______________________________________________________________________________________ 0.6pf 0.6pf 0.6pf 5 ? 5 ? 1nh 1nh 5nh 5nh 0.1pf 0.1pf figure 2. photodiode and header model out+/- in+/- mute 50db to 56db 44db to 50db 56db to 62db vagc hyst tia max3654 figure 3. functional diagram
max3654 47mhz to 870mhz analog catv t ransimpedance amplifier _______________________________________________________________________________________ 5 t ypical operating characteristics (continued) (v cc = +5.0v, t a = +25?, unless otherwise noted.) gain tilt deviation vs. frequency (referred to a line from 50mhz to 870mhz) frequency (mhz) gain tilt deviation (db) max3654 toc04 0 200 400 600 800 1000 -1.0 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1.0 100 300 500 700 900 differential s22 (normalized to 75 ? ) frequency (mhz) s22 (db) max3654 toc05 0 200 400 600 800 1000 -20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0 input referred noise vs. frequency (maximum gain, vga = 0v) frequency (mhz) noise (pa/(hz) 1/2 ) max3654 toc06 0 200 400 600 800 1000 0 2 4 6 8 10 12 14 16 18 20 100 300 500 700 900 +85 c with photodiode +25 c with photodiode +85 c no photodiode max3654toc07 vagc (v) oip3 (dbm) 1.4 1.2 0.8 1.0 0.4 0.6 0.2 12 14 16 18 20 22 24 26 28 30 10 0 1.6 oip3 vs. control voltage oip2 vs. control voltage max3654toc08 vagc (v) oip2 (dbm) 1.4 1.2 1.0 0.8 0.6 0.4 0.2 30 40 50 60 70 80 20 0 1.6
detailed description the max3654 is a broadband, high-linearity, low-noise transimpedance amplifier. the transimpedance (gain) can be adjusted between 43.5db ? and 62db ? using the voltage at an external control input (vagc). when connected as shown in the typical application circuit , optical input levels from -6dbm to +2dbm will produce a minimum output of 14dbmv/channel, and 4db tilt compensation. gain deviation over frequency from 47mhz to 870mhz is less than ?.75db. low-noise variable gain amplifier the input stage is a low-noise analog transimpedance amplifier (tia) connected differentially to the analog photodiode. desired performance can be achieved with a photodiode having capacitance (c pd ) up to 1pf. vagc and hysteresis control the gain-control pin vagc sets overall tia gain imple- mented as three switchable gain stages, each with a continuously variable gain control, as shown in figure 3. this produces a continuously variable gain ranging from 62db ? (at vagc = 0.175v) to 43.5db ? at (vagc=1.4v). a set of comparators examines the vagc input to select a gain stage. as the voltage at vagc crosses the two locations in the gain vs. vagc curve, where the gain stage changes (350mv and 700mv), there will be small deviations in the output which may lead to a brief interruption of catv signals. see the typical operating characteristics for gain vs. control voltage. a hysteresis control input is provided to limit dithering when the optical level is close to a gain-switching point. the hysteresis level is controlled by the value of r hyst . hysteresis is minimum (0.13db) when this pin is open. rf output and cable tilt compensation with a typical photodiode, the gain at 870mhz is 4db higher than at 47mhz. the overall frequency response of the tia is within ?.75db of a straight line connecting the values at 47mhz and 870mhz. mute in normal operation, the ttl mute pin is held high. when mute is low, the output signal is attenuated by more than 45db. max3654 47mhz to 870mhz analog catv t ransimpedance amplifier 6 _______________________________________________________________________________________ pin description pin name function 1, 4, 9, 12 v cc +5.0v power supply 2 in+ positive analog photodiode input connection. typically connected to photodiode cathode. 3 in- negative analog photodiode input connection. typically connected to photodiode anode. 5 vagc agc control input. range is 0 to 1.4v. see the typical operating characteristics gain vs. control voltage graph. 6 mute mute control input, ttl. mute < 0.8v to mute output. 7 hyst agc hysteresis control input. a resistor from hyst to gnd controls the hysteresis level. 8, 14, 16 gnd ground 10 out- negative rf output. the voltage on this pin decreases with increasing optical power when in+ is connected to the photodiode cathode. 11 out+ positive rf output. the voltage on this pin increases with increasing optical power when in- is connected to the photodiode anode. 13 test1 reserved for test. connect to gnd for normal operation. 15 test2 reserved for test. connect to gnd for normal operation. ep ep exposed pad. the exposed pad must be soldered to the circuit-board ground for proper thermal and electrical performance.
max3654 47mhz to 870mhz analog catv t ransimpedance amplifier _______________________________________________________________________________________ 7 applications information photodiode parasitics the max3654 tia is designed to operate with a low- capacitance analog photodiode. proper system design includes considerations of lead configuration, pad, and through-hole geometry, and pc board layer selection for connections to the ic. the tia is designed to operate correctly when the total capacitance of the photodiode, package, leads and pc board is between 1.0pf and 2.5pf. rf output the differential tia rf output should be connected (ac-coupled) to a balun transformer for normal single- ended output. agc operation for agc operation, the optical average power can be measured from the voltage drop across the lower bias resistor, using high impedance to isolate the photodi- ode as shown in the ev kit schematic. tia gain is inversely proportional to the voltage present at vagc from 0.175v to 1.4v. from 0 to 0.175v, the gain is con- stant and maximum. the nominal gain is given by: when connected as shown in the typical applications circuit , the max3654 will maintain the electrical output constant (15dbmv/ch) for optical signals in the -6dbm to +2dbm range. evaluation kit and pc board layout the factory-assembled ev kit for the max3654 pro- vides two versions: optical input and electrical input. the optical input circuit includes photodiode bias cir- cuitry, an op amp to adjust vagc according to the dc photodiode current (for agc operation), an output balun, and a 75 ? output connector. through-hole pads are provided to attach the triplexer analog photodiode leads. since photodiode capacitance and package lead inductance affect the amount of uptilt, in configu- rations where lead inductance is significantly lower than the value shown in figure 2, the uptilt may be increased by providing discrete inductance on the pc board. when a c pd = 0.5pf (typ) photodiode is mount- ed with 5mm (nominal) leads into through-hole vias as in the ev kit configuration, a 4db uptilt will normally be achieved. it is important to configure the layout with capacitance and inductance in the anode and cathode connection as symmetric as possible. the electrical input circuit is normally configured with a 50 ? input for use with conventional test and measure- ment equipment. if desired, the max3654 input can also be terminated with 75 ? as shown in the ev kit data sheet. the 75 ? ev kit outputs should be connected to 50 ? test and measurement equipment using a mini- mum loss pad. for more information, see the maxim website: max3654 ev kit data sheet http://www.maxim-ic.com/fiber.cfm minimum loss pad http://www.maxim-ic.com/appnotes.cfm/appnote_number/972 zt db db mv vagc mv v vagc v () log () (. . ). ?? =+ ? ? ? ? ? ? ? 62 20 175 0 175 1 4 chip information transistor count: 3376 process: sige bipolar substrate: soi 15 16 14 13 6 5 7 in+ v cc 8 v cc out+ v cc v cc 12 gnd 4 12 11 9 test2 gnd gnd ep* hyst mute vagc max3654 in- out- 3 10 test1 thin qfn 4mm x 4mm top view pin configuration *the exposed pad must be connected to ground.
max3654 47mhz to 870mhz analog catv t ransimpedance amplifier 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. 8 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2005 maxim integrated products printed usa is a registered trademark of maxim integrated products, inc. package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .) for the latest package outline information, go to www.maxim-ic.com/packages.) (tqfn 4mm x 4mm x 0.8mm, package code: t1644.) 24l qfn thin.eps package outline, 21-0139 2 1 d 12, 16, 20, 24, 28l thin qfn, 4x4x0.8mm package outline, 21-0139 2 2 d 12, 16, 20, 24, 28l thin qfn, 4x4x0.8mm
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