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1 typical a pplica t ion descrip t ion 300mhz to 3.5ghz ultra-high dynamic range downconverting mixer the lt c ? 5551 is a 2.5 v to 3.6 v mixer optimized for rf downconverting mixer applications that require very high dynamic range. the LTC5551 covers the 300 mhz to 3.5ghz rf frequency range with lo frequency range of 200 mhz to 3.5ghz. the LTC5551 provides very high iip3 and p1db with low power consumption. a typical application is a basestation receiver covering 700 mhz to 2.7ghz frequency range. the rf input can be matched for a wide range of frequencies and the if is usable up to 1ghz. a low power mode is activated by pulling the isel pin high, reducing the power consumption by about 1/3, however, with a corresponding reduction in iip3 to approximately +29dbm. the mixer can also be turned on or off by using the en pin. the LTC5551s high level of integration minimizes the total solution cost, board space and system level variation, while providing the highest dynamic range for demanding receiver applications. l, lt , lt c , lt m , linear technology and the linear logo are registered trademarks of linear technology corporation. all other trademarks are the property of their respective owners. protected by u.s. patents, including 8558605. fea t ures a pplica t ions n +36dbm input ip3 n 2.4db conversion gain n low noise figure: <10db n +18dbm ultra high input p1db n 670mw power consumption n 2.5v to 3.6v operation n 50 single-ended rf and lo inputs n 0dbm lo drive level n low power mode n C40c to 105c operation (t c ) n small solution size n enable pin n 16-lead (4mm 4mm) qfn package n gsm, lt e , lt e -advanced basestations n repeaters n dpd observation receiver n public safety radios, military and defense n avionics radios and tcas transponders n active phased-array antennas n white-space radio receiver wideband receiver mixer conversion gain and iip3 vs if frequency (low-side lo) if frequency (mhz) 70 9 iip3 (dbm) g c (db) 12 18 21 24 39 90 5551 ta01b 15 30 33 36 27 1 6 3 4 5 2 270 110 130 150 170 190 210 230 250 g c normal power mode low power mode iip3 rf = 1770mhz to 1970mhz lo = 1700mhz z if = 200 if amp if bias synth v cc 3.3v rf in 22pf 0.56f 470nh 470nh 475 475 1nf 1nf bpf ltc6416 ltc2208 rf lo en 22pf en (0v/3.3v) LTC5551 v cc v cc 3.3v lo 1700mhz ltc6946 3.9pf 2.2pf if + if ? 5551 ta01a 0.56f lo adc 7.5nh ltc 5551 5551fa for more information www.linear.com/LTC5551
2 p in c on f igura t ion a bsolu t e maxi m u m r a t ings supply voltage (v cc , if + , if C ) ..................................... 4v ena ble input voltage ( en ) ................ C 0.3 v to v cc + 0.3 v power select voltage ( isel ) ............ C 0.3 v to v cc + 0.3 v lo input power (0.2 ghz to 3.5 ghz ) ................... +1 0 dbm lo input dc voltage ............................................ 0.1 v rf input power (0.3 ghz to 3.5 ghz ) ................... +2 0 dbm rf input dc voltage ............................................... 0 .1 v temp diode continuous dc input current ............. 10 ma t emp diode input voltage ........................................ 1 v i fbias voltage ......................................................... 2.5 v o perating temperature range (t c ) ........ C40 c to 105 c storage temperature range .................. C 65 c to 150 c junction temperature (t j ) .................................... 150 c caution: this part is sensitive to electrostatic discharge (esd). it is very important that proper esd precautions be observed when handling the LTC5551. (note 1) 16 15 14 13 5 6 7 8 top view 17 gnd uf package 16-lead (4mm 4mm) plastic qfn 9 10 11 12 4 3 2 1tp rf ct gnd temp gnd lo gnd ifbias if + if ? gnd en v cc v cc isel t jmax = 150c, v jc = 6c/w exposed pad ( pin 17) is gnd, must be soldered to pcb o r d er i n f or m a t ion lead free finish tape and reel part marking package description case temperature range LTC5551iuf#pbf LTC5551iuf#trpbf 5551 16-lead (4mm w 4mm) plastic qfn C40c to 105c consult lt c marketing for parts specified with wider operating temperature ranges. consult lt c marketing for information on non-standard lead based finish parts. for more information on lead free part marking, go to: http://www.linear.com/leadfree/ for more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ ltc 5551 5551fa for more information www.linear.com/LTC5551
3 the l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t c = 25c. v cc = 3.3v, en = high, isel = low, p lo = 0dbm, unless otherwise noted. test circuit shown in figure 1. (notes 2, 3) parameter conditions min typ max units lo input frequency range l 200 to 3500 mhz rf input frequency range l 300 to 3500 mhz if output frequency range requires external matching 5 to 1000 mhz rf input return loss z o = 50, 1100mhz to 2700mhz, x1 = 7.5nh, c1 = 2.2pf >12 db lo input return loss z o = 50, 1000mhz to 3500mhz, c2 = 3.9pf >12 db if output impedance differential at 153mhz 950 || 1.2pf r || c lo input power lo = 200mhz to 3500mhz C6 0 6 dbm lo to rf leakage lo = 200mhz to 3500mhz < C25 dbm lo to if leakage lo = 200mhz to 3500mhz < C21 dbm rf to lo isolation rf = 300mhz to 3500mhz >55 db rf to if isolation rf = 300mhz to 3500mhz >23 db 0.3ghz to 3.5ghz downmixer application: if = 153mhz, isel = low, unless otherwise noted. (notes 2, 3) parameter conditions min typ max units power conversion gain rf = 400mhz, high side lo rf = 850mhz, high side lo rf = 1950mhz, low side lo rf = 2700mhz, low side lo 3.2 2.8 2.4 1.7 db db db db conversion gain flatness rf = 1870mhz 100mhz, lo = 1700mhz, if = 170 100mhz 0.2 db conversion gain vs t emperature t c = C40c to 105c, rf = 1950mhz, low side lo C0.013 db/c 2-tone input 3 rd order intercept (?f = 2mhz) rf = 400mhz, high side lo rf = 850mhz, high side lo rf = 1950mhz, low side lo rf = 2700mhz, low side lo 33.2 35.2 35.5 38.1 dbm dbm dbm dbm 2- t one input 2 nd order intercept (?f = 154mhz = f im2 ) rf = 400mhz (477mhz/323mhz), lo = 553mhz rf = 850mhz (927mhz/773mhz), lo = 1053mhz rf = 1950mhz (2027mhz/1873mhz), lo = 1797mhz rf = 2700mhz (2777mhz/2623mhz), lo = 2547mhz 65.8 68.2 58.4 57.1 dbm dbm dbm dbm ssb noise figure rf = 400mhz, high side lo rf = 850mhz, high side lo rf = 1950mhz, low side lo rf = 2700mhz, low side lo 10.6 9.1 9.7 10.9 db db db db ssb noise figure under blocking rf = 850mhz, high side lo, 750mhz blocker at 5dbm rf = 1950mhz, low side lo, 2050mhz blocker at 5dbm 16.5 16.9 db db 1/2 if output spurious product (f rf offset to produce spur at f if = 153mhz) 850mhz: rf = 926.5mhz at C3dbm, lo = 1003mhz 1950mhz: rf = 1873.5mhz at C3dbm, lo = 1797mhz C66 C68 dbc dbc 1/3 if output spurious product (f rf offset to produce spur at f if = 153mhz) 850mhz: rf = 952mhz at C3dbm, lo = 1003mhz 1950mhz: rf = 1848mhz at C3dbm, lo = 1797mhz C97 C93 dbc dbc input 1db compression rf = 400mhz, high side lo rf = 850mhz, high side lo rf = 1950mhz, low side lo rf = 2700mhz, low side lo 17.1 17.8 18.0 18.7 dbm dbm dbm dbm ac e lec t rical c harac t eris t ics the l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t c = 25c. v cc = 3.3v, en = high, p lo = 0dbm, p rf = 0dbm (0dbm/tone for 2-tone tests), unless otherwise noted. test circuit shown in figure 1. (notes 2, 3) ltc 5551 5551fa for more information www.linear.com/LTC5551
4 d c e lec t rical c harac t eris t ics the l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t c = 25c. v cc = 3.3v, en = high, isel = low, unless otherwise noted. test circuit shown in figure 1. (note 2) parameter conditions min typ max units power supply requirements supply voltage (v cc ) l 2.5 3.3 3.6 vdc supply current (isel = low) en = high, no lo applied en = high, with lo applied en = low 148 204 234 100 ma ma a supply current C low power mode (isel = high) en = high, no lo applied en = high, with lo applied en = low 128 142 100 ma ma a enable logic input (en) input high v oltage (on) l 1.2 vdc input low voltage (off) l 0.3 vdc input current C0.3v to v cc + 0.3v C30 100 a turn on time lo applied 0.4 s turn off time lo applied 0.5 s power select logic input (isel) input high voltage (low power mode) l 1.2 vdc input low voltage (high power mode) l 0.3 vdc input current C0.3v to v cc + 0.3v C30 100 a temperature sensing diode (temp) dc voltage at t j = 25c i in = 10a i in = 80a 726 783 mv mv voltage t emperature coefficient i in = 10a i in = 80a l l C1.72 C1.53 mv /c mv/c low power mode, 0.3ghz to 3.5ghz downmixer application: if = 153mhz, isel = high (notes 2, 3) parameter conditions min typ max units power conversion gain rf = 400mhz, high side lo rf = 850mhz, high side lo rf = 1950mhz, low side lo rf = 2700mhz, low side lo 3.0 2.7 2.4 1.7 db db db db input 3 rd order intercept rf = 400mhz, high side lo rf = 850mhz, high side lo rf = 1950mhz, low side lo rf = 2700mhz, low side lo 27.3 28.0 29.3 29.7 dbm dbm dbm dbm ssb noise figure rf = 400mhz, high side lo rf = 850mhz, high side lo rf = 1950mhz, low side lo rf = 2700mhz, low side lo 9.8 8.2 8.3 9.2 db db db db input 1db compression rf = 400mhz, high side lo rf = 850mhz, high side lo rf = 1950mhz, low side lo rf = 2700mhz, low side lo 14.8 16.2 16.7 17.7 dbm dbm dbm dbm the l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25c. v cc = 3.3v, en = high, p lo = 0dbm, p rf = 0dbm (0dbm/tone for 2-tone tests), unless otherwise noted. test circuit shown in figure 1. (notes 2, 3) ac e lec t rical c harac t eris t ics ltc 5551 5551fa for more information www.linear.com/LTC5551
5 note 1: stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. exposure to any absolute maximum rating condition for extended periods may affect device reliability and lifetime. note 2: the LTC5551 is guaranteed functional over the C40c to 105c case temperature range. note 3: ssb noise figure measurements performed with a small-signal noise source, bandpass filter and 6 db matching pad on rf input, bandpass filter and 6db matching pad on the lo input, bandpass filter on the if output and no other rf signals applied. typical d c p er f or m ance c harac t eris t ics en = high, t est circuit shown in figure 1. supply current vs supply voltage, lo = 1800mhz at 0dbm supply current vs supply voltage, no lo applied e lec t rical c harac t eris t ics supply current vs lo frequency (p lo = 0dbm) case temperature (c) ?40 0 i cc (ma) 50 150 200 250 ?15 5551 g01 100 110 10 35 60 85 isel = low isel = high v cc = 3.5v v cc = 3.3v v cc = 3.1v case temperature (c) ?40 0 i cc (ma) 20 140 160 180 ?15 5551 g02 120 60 80 100 40 110 10 35 60 85 isel = low isel = high v cc = 3.5v v cc = 3.3v v cc = 3.1v lo frequency (mhz) 300 0 i cc (ma) 50 250 700 5551 g03 150 200 100 3500 1100 1500 1900 2300 2700 3100 isel = high t c = 105c t c = 85c t c = 25c t c = ?40c isel = low supply current vs v cc lo = 1800mhz at 0dbm v cc (v) 2.5 100 i cc (ma) 130 220 2.6 5551 g04 190 160 3.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 t c = 105c t c = 85c t c = 25c t c = ?40c v cc (v) 2.5 100 i cc (ma) 130 220 2.6 5551 g05 190 160 3.63.5 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 lo = 6dbm lo = 0dbm lo = ?6dbm supply current vs v cc lo = 1800mhz at t c = 25c ltc 5551 5551fa for more information www.linear.com/LTC5551
6 1100mhz to 2700mhz application. v cc = 3.3v, en = high, isel = low, t c = 25c, p lo = 0dbm, p rf = 0dbm (0dbm/tone for two-tone iip3 tests, ? f = 2mhz), if = 153mhz, unless otherwise noted. test circuit shown in figure 1. conversion gain, iip3 and nf vs rf frequency (high side lo) 1950mhz conversion gain, iip3 and nf vs lo power (high side lo) typical ac p er f or m ance c harac t eris t ics 2550mhz conversion gain, iip3 and nf vs lo power (high side lo) rf isolation vs frequency lo leakage vs lo frequency conversion gain, iip3 and nf vs rf frequency (low side lo) 1950mhz conversion gain, iip3 and nf vs lo power (low side lo) 2550mhz conversion gain, iip3 and nf vs lo power (low side lo) input p1db vs rf frequency (low side lo) rf frequency (ghz) 1.1 0 iip3 (dbm), nf (db), g c (db) 3 39 1.3 5551 g06 36 30 33 27 24 21 18 15 12 9 6 2.7 1.5 1.7 1.9 2.1 2.3 2.5 g c iip3 nf t c = 85c t c = 25c t c = ?40c lo input power (dbm) ?6 0 iip3 (dbm), nf (db), g c (db) 36 ?4 5551 g07 32 24 28 20 16 12 8 4 6 ?2 0 2 4 iip3 g c nf t c = 85c t c = 25c t c = ?40c lo input power (dbm) ?6 0 iip3 (dbm), nf (db), g c (db) 40 36 ?4 5551 g08 32 24 28 20 16 12 8 4 6 ?2 0 2 4 iip3 g c nf t c = 85c t c = 25c t c = ?40c rf frequency (ghz) 1.1 0 iip3 (dbm), nf (db), g c (db) 3 36 1.3 5551 g09 30 33 27 24 21 18 15 12 9 6 2.7 1.5 1.7 1.9 2.1 2.3 2.5 g c nf t c = 85c t c = 25c t c = ?40c iip3 lo input power (dbm) ?6 0 iip3 (dbm), nf (db), g c (db) 36 ?4 5551 g10 28 32 24 20 16 12 8 4 6 ?2 0 2 4 nf g c t c = 85c t c = 25c t c = ?40c iip3 lo input power (dbm) ?6 0 iip3 (dbm), nf (db), g c (db) 36 ?4 5551 g11 28 32 24 20 16 12 8 4 6 ?2 0 2 4 iip3 g c nf t c = 85c t c = 25c t c = ?40c rf frequency (ghz) 1.1 10 input p1db (dbm) 13 20 5551 g12 19 18 17 16 15 14 11 12 2.7 1.3 1.5 1.7 1.9 2.1 2.3 2.5 t c = 105c t c = 85c t c = 25c t c = ?40c rf frequency (ghz) 1.1 20 isolation (db) 50 70 5551 g13 60 30 40 2.7 1.3 1.5 1.7 1.9 2.1 2.3 2.5 rf-lo rf-if lo frequency (ghz) 1.1 ?60 lo leakage (dbm) ?30 0 5551 g14 ?20 ?10 ?50 ?40 2.7 1.3 1.5 1.7 1.9 2.1 2.3 2.5 lo-rf lo-if ltc 5551 5551fa for more information www.linear.com/LTC5551
7 ssb noise figure vs rf blocker level conversion gain, iip3 and ssb nf vs temperature conversion gain, iip3, p1db and ssb nf vs supply voltage 1950mhz conversion gain histogram 1950mhz iip3 histogram 1950mhz ssb nf histogram 2-tone if output power, im3 and im5 vs rf input power single-tone if output power, 2 2 and 3 3 spurs vs rf input power 2 2 and 3 3 spurs vs lo power 1100 mhz to 2700mhz application. v cc = 3.3v, en = high, isel = low, t c = 25c, p lo = 0dbm, p rf = 0dbm (0dbm/tone for two-tone iip3 tests, ? f = 2mhz), if = 153mhz, unless otherwise noted. test circuit shown in figure 1. typical ac p er f or m ance c harac t eris t ics rf input power (dbm/tone) ?10 ?100 output power/tone (dbm) ?90 ?80 ?70 ?60 ?50 ?40 ?30 ?20 ?10 20 ?7 5551 g15 10 0 17 ?4 ?1 2 5 8 11 14 im5 im3 if out rf1 = 1949mhz rf2 = 1951mhz lo = 1797mhz rf input power (dbm/tone) ?9 ?90 output power (dbm) ?80 ?70 ?60 ?50 ?40 ?30 ?20 ?10 20 ?6 5551 g16 10 0 18 ?3 0 3 6 9 12 15 3rf-3lo rf = 1848mhz 2rf-2lo rf = 1873.5mhz lo = 1797mhz if out rf = 1950mhz lo input power (dbm) ?6 ?100 relative spur level (dbc) ?90 ?80 ?70 ?60 ?50 ?4 5551 g17 6 ?2 0 2 4 3rf-3lo rf = 1848mhz rf = 1950mhz p rf = ?3dbm lo = 1797mhz 2rf-2lo rf = 1873.5mhz rf blocker power (dbm) ?25 8 ssb nf (db) 10 16 18 12 14 20 22 ?20 5551 g18 10 ?15 ?10 ?5 0 5 p lo = ?6dbm p lo = 0dbm p lo = 6dbm rf = 1950mhz lo = 1797mhz blocker = 2050mhz case temperature (c) ?40 0 iip3 (dbm), nf (db), g c (db) 3 27 30 6 9 33 36 15 12 18 21 24 ?25 ?10 5 5551 g19 110 3520 50 65 80 95 g c low side lo high side lo rf = 1950mhz iip3 nf v cc supply voltage (v) 2.5 8 iip3 (dbm), p1db (dbm), nf (db) g c (db) 11 35 14 17 38 23 20 26 29 32 0 1 5 2 3 4 2.6 2.7 2.8 5551 g20 3.6 3.02.9 3.1 3.2 3.3 3.4 3.5 g c nf iip3 low side lo high side lo rf = 1950mhz p1db conversion gain (db) 1.4 0 distribution (%) 10 20 30 70 50 40 60 1.6 1.8 2.0 5551 g21 3.4 2.42.2 2.6 2.8 3.0 3.2 rf = 1950mhz 85c 25c ?40c iip3 (dbm) 33.2 0 distribution (%) 10 15 5 20 40 30 25 35 33.6 34 34.4 5551 g22 36.4 35.234.8 35.8 36 rf = 1950mhz 85c 25c ?40c ssb noise figure (db) 8.8 0 distribution (%) 10 15 5 20 40 30 25 35 9.2 9.6 10 5551 g23 11.210.810.4 rf = 1950mhz 85c 25c ?40c ltc 5551 5551fa for more information www.linear.com/LTC5551
8 input p1db vs rf frequency conversion gain, iip3, p1db and nf vs supply voltage lo leakage and rf isolation 2-tone if output power, im3 and im5 vs rf input power single tone if output power, 2 2 and 3 3 spurs vs rf input power 2 2 and 3 3 spurs vs lo power conversion gain, iip3 and nf vs rf frequency (low side lo) conversion gain, iip3 and nf vs rf frequency (high side lo) 1950mhz conversion gain, iip3 and nf vs lo power 1100 mhz to 2700mhz application. low power mode. v cc = 3.3v, en = high, isel = high, t c = 25c, p lo = 0dbm, p rf = 0dbm (0dbm/tone for two-tone iip3 tests, ? f = 2mhz), if = 153mhz, unless otherwise noted. test circuit shown in figure 1. typical ac p er f or m ance c harac t eris t ics rf frequency (ghz) 1.1 1 iip3 (dbm), nf (db), g c (db) 31 1.3 5551 g24 22 25 28 19 16 13 10 7 4 2.7 1.5 1.7 1.9 2.52.32.1 nf g c iip3 low power mode 85c 25c ?40c rf frequency (ghz) 1.1 1 iip3 (dbm), nf (db), g c (db) 31 1.3 5551 g25 22 25 28 19 16 13 10 7 4 2.7 1.5 1.7 1.9 2.52.32.1 g c nf iip3 low power mode 85c 25c ?40c lo input power (dbm) ?6 7 nf (db), iip3 (dbm) g c (db) 10 28 31 16 13 19 22 25 0 4 1 2 3 ?4 ?2 0 5551 g26 642 g c iip3 nf low power mode low side lo high side lo rf = 1950mhz rf frequency (ghz) 1.1 10 input p1db (dbm) 13 19 20 15 14 11 12 16 17 18 1.3 1.5 1.7 5551 g27 2.7 2.11.9 2.52.3 low power mode low side lo high side lo rf input power (dbm/tone) ?10 ?90 ?80 output power/tone (dbm) ?70 ?60 ?50 ?40 ?30 ?20 ?10 20 ?8 5551 g30 10 0 16 ?6 ?4 ?2 0 2 4 6 8 10 12 14 im5 low power mode im3 if out rf1 = 1949mhz rf2 = 1951mhz lo = 1797mhz rf input power (dbm/tone) ?10 ?80 output power (dbm) ?70 ?60 ?50 ?40 ?30 ?20 ?10 20 ?7 5551 g31 10 0 17 ?4 ?1 2 5 8 11 14 3rf-3lo rf = 1848mhz 2rf-2lo rf = 1873.5mhz lo = 1797mhz low power mode if out rf = 1950mhz lo input power (dbm) ?6 ?100 relative spur level (dbc) ?90 ?80 ?70 ?60 ?50 5551 g32 6 ?4 ?2 0 2 4 2rf-2lo rf = 1873.5mhz rf = 1950mhz p rf = ?3dbm lo = 1797mhz low power mode 3rf-3lo rf = 1848mhz lo/rf frequency (ghz) 1.1 ?40 lo leakage (dbm) rf isolation (db) ?10 0 ?30 ?20 ?10 50 70 10 30 1.3 1.5 1.7 1.9 5551 g29 2.7 2.1 2.3 2.5 lo-rf low power mode lo-if rf-if rf-lo v cc supply voltage (v) 2.5 8 iip3 (dbm), p1db (dbm), nf (db) g c (db) 11 35 14 17 38 23 20 26 29 32 0 1 2 3 5 4 2.6 2.7 2.8 5551 g28 3.6 3.02.9 3.1 3.2 3.3 3.4 3.5 iip3 nf p1db g c low power mode low side lo high side lo rf = 1950mhz ltc 5551 5551fa for more information www.linear.com/LTC5551
9 input p1db vs frequency 400mhz conversion gain, iip3 and nf vs lo power conversion gain, iip3, p1db and nf vs supply voltage conversion gain, iip3 and ssb nf vs temperature lo leakage and rf isolation 2-tone if output power, im3 and im5 vs rf input power conversion gain, iip3 and nf vs rf frequency (low side lo) conversion gain, iip3 and nf vs rf frequency (high side lo) conversion gain, iip3 and nf vs rf frequency 300 mhz to 650mhz application. v cc = 3.3v, en = high, isel = low, t c = 25c, p lo = 0dbm, p rf = 0dbm (0dbm/tone for two-tone iip3 tests, ? f = 2mhz), if = 153mhz, unless otherwise noted. test circuit shown in figure 1. typical ac p er f or m ance c harac t eris t ics rf frequency (mhz) 300 0 iip3 (dbm), nf (db), g c (db) 36 350 5551 g33 21 24 27 30 33 18 15 12 9 6 3 650 400 450 500 600550 nf g c 85c 25c ?40c iip3 rf frequency (mhz) 300 0 iip3 (dbm), nf (db), g c (db) 36 350 5551 g34 21 24 27 30 33 18 15 12 9 6 3 650 400 450 500 600550 g c nf iip3 85c 25c ?40c rf frequency (mhz) 300 10 input p1db (dbm) 11 14 15 12 13 20 17 16 18 19 5551 g36 650 400350 450 500 550 600 low power mode low side lo high side lo normal power mode lo input power (dbm) ?6 7 nf (db), iip3 (dbm) g c (db) 10 13 16 37 22 19 25 28 31 34 0 1 2 3 5 4 5551 g37 6 ?4 ?2 0 2 4 g c nf iip3 low side lo high side lo rf = 400mhz case temperature (c) ?40 0 iip3 (dbm), nf (db), g c (db) 3 6 9 36 15 12 18 21 24 27 30 33 5551 g39 110 ?25 ?10 5 65 80 95 20 5035 g c nf iip3 low side lo high side lo rf = 400mhz lo/rf frequency (mhz) 300 ?40 lo leakage (dbm) rf isolation (db) ?10 0 ?30 ?20 0 60 80 20 40 350 400 450 5551 g40 650 500 550 600 lo-rf lo-if rf-if rf-lo rf input power (dbm/tone) ?10 ?90 ?80 output power/tone (dbm) ?70 ?60 ?50 ?40 ?30 ?20 ?10 20 ?7 5551 g41 10 0 17 ?4 ?1 2 5 8 11 14 im5 rf1 = 399mhz rf2 = 401mhz lo = 553mhz im3 if out rf frequency (mhz) 300 7 iip3 (dbm), nf (db) g c (db) 10 13 16 31 22 19 25 28 0 1 2 3 8 5 4 6 7 5551 g35 650 400350 450 500 550 600 g c nf iip3 low side lo high side lo low power mode isel = high v cc supply voltage (v) 2.5 8 iip3 (dbm), p1db (dbm), nf (db) g c (db) 11 14 17 38 23 20 26 29 32 35 0 1 2 3 5 4 5551 g38 3.6 2.6 2.7 2.8 3.2 3.3 3.4 3.5 2.9 3.13.0 nf g c iip3 low side lo high side lo rf = 400mhz p1db ltc 5551 5551fa for more information www.linear.com/LTC5551
10 input p1db vs rf frequency 850mhz conversion gain, iip3 and nf vs lo power conversion gain, iip3, p1db and nf vs supply voltage conversion gain, iip3 and ssb nf vs temperature lo leakage and rf isolation 2-tone if output power, im3 and im5 vs rf input power conversion gain, iip3 and nf vs rf frequency (low side lo) conversion gain, iip3 and nf vs rf frequency (high side lo) conversion gain, iip3 and nf vs rf frequency 500 mhz to 1100mhz application. v cc = 3.3v, en = high, isel = low, t c = 25c, p lo = 0dbm, p rf = 0dbm (0dbm/tone for two-tone iip3 tests, ? f = 2mhz), if = 153mhz, unless otherwise noted. test circuit shown in figure 1. typical ac p er f or m ance c harac t eris t ics rf frequency (mhz) 500 0 iip3 (dbm), nf (db), g c (db) 39 36 5551 g42 21 24 27 30 33 18 15 12 9 6 3 1100 600 700 800 1000900 g c nf 85c 25c ?40c iip3 rf frequency (mhz) 500 0 iip3 (dbm), nf (db), g c (db) 36 5551 g43 21 24 27 30 33 18 15 12 9 6 3 1100 600 700 800 1000900 g c 85c 25c ?40c nf iip3 rf frequency (mhz) 500 10 input p1db (dbm) 11 14 15 12 13 20 17 16 18 19 5551 g45 1100 700600 800 900 1000 low power mode normal power mode low side lo high side lo lo input power (dbm) ?6 8 nf (db), iip3 (dbm) g c (db) 11 14 17 38 23 20 26 29 32 35 0 1 2 3 5 4 5551 g46 6 ?4 ?2 0 2 4 g c nf iip3 low side lo high side lo rf = 850mhz case temperature (c) ?40 0 iip3 (dbm), nf (db), g c (db) 3 6 9 39 36 15 12 18 21 24 27 30 33 5551 g48 110 ?25 ?10 5 65 80 95 20 5035 g c nf iip3 low side lo high side lo rf = 850mhz lo/rf frequency (mhz) 500 ?40 lo leakage (dbm) rf isolation (db) ?10 0 ?30 ?20 0 60 80 20 40 600 700 5551 g49 1100 800 900 1000 lo-rf lo-if rf-if rf-lo rf input power (dbm/tone) ?10 ?90 ?80 output power/tone (dbm) ?70 ?60 ?50 ?40 ?30 ?20 ?10 20 ?7 5551 g50 10 0 17 ?4 ?1 2 5 8 11 14 im5 im3 if out rf1 = 849mhz rf2 = 851mhz lo = 1003mhz lo input power (dbm) ?6 8 nf (db), iip3 (dbm) g c (db) 11 14 17 38 23 20 26 29 32 35 0 1 2 3 5 4 5551 g46 6 ?4 ?2 0 2 4 g c nf iip3 low side lo high side lo rf = 850mhz v cc supply voltage (v) 2.5 8 iip3 (dbm), p1db (dbm), nf (db) g c (db) 11 14 17 38 23 20 26 29 32 35 0 1 2 3 5 4 5551 g47 3.6 2.6 2.7 2.8 3.2 3.3 3.4 3.5 2.9 3.13.0 nf p1db g c iip3 low side lo high side lo rf = 850mhz rf frequency (mhz) 500 7 iip3 (dbm), nf (db) g c (db) 10 28 31 16 13 19 22 25 0 8 1 2 3 4 5 6 7 600 700 800 5551 g44 1100 1000900 iip3 nf g c low power mode isel = high low side lo high side lo ltc 5551 5551fa for more information www.linear.com/LTC5551
11 input p1db vs rf frequency 2.7ghz conversion gain, iip3 and nf vs lo power conversion gain, iip3, p1db and nf vs supply voltage 2-tone if output power, im3 and im5 vs rf input power lo leakage and rf isolation conversion gain, iip3 and ssb nf vs temperature conversion gain, iip3 and nf vs rf frequency (low side lo) conversion gain, iip3 and nf vs rf frequency (high side lo) conversion gain, iip3 and nf vs rf frequency 2300 mhz to 3500mhz application. v cc = 3.3v, en = high, isel = low, t c = 25c, p lo = 0dbm, p rf = 0dbm (0dbm/tone for two-tone iip3 tests, ? f = 2mhz), if = 153mhz, unless otherwise noted. test circuit shown in figure 1. typical ac p er f or m ance c harac t eris t ics rf frequency (ghz) 2.3 ?1 iip3 (dbm), nf (db), g c (db) 39 5551 g51 23 27 31 35 19 15 11 7 3 3.5 2.5 2.7 2.9 3.33.1 nf g c 85c 25c ?40c iip3 rf frequency (ghz) 2.3 0 iip3 (dbm), nf (db), g c (db) 36 5551 g52 21 24 27 30 33 18 15 12 9 6 3 3.3 2.5 2.7 2.9 3.1 g c nf iip3 85c 25c ?40c rf frequency (ghz) 2.3 7 iip3 (dbm), nf (db) g c (db) 10 28 31 16 13 19 22 25 ?3 5 ?2 ?1 0 1 2 3 4 2.5 2.7 2.9 5551 g53 3.53.33.1 iip3 nf g c low power mode isel = high low side lo high side lo rf frequency (ghz) 2.3 10 input p1db (dbm) 11 14 15 12 13 20 17 16 18 19 5551 g54 3.5 2.72.5 2.9 3.1 3.3 low power mode normal power mode low side lo high side lo lo input power (dbm) ?6 9 nf (db), iip3 (dbm) g c (db) 12 15 18 39 24 21 27 30 33 36 0 1 2 3 5 4 5551 g55 6 ?4 ?2 0 2 4 nf g c iip3 low side lo high side lo rf = 2.7ghz v cc supply voltage (v) 2.5 9 iip3 (dbm), p1db (dbm), nf (db) g c (db) 12 15 18 39 24 21 27 30 33 36 ?1 0 1 2 4 3 5551 g56 3.6 2.6 2.7 2.8 3.2 3.3 3.4 3.5 2.9 3.13.0 nf p1db g c iip3 low side lo high side lo rf = 2.7ghz case temperature (c) ?40 0 iip3 (dbm), nf (db), g c (db) 3 6 9 39 36 15 12 18 21 24 27 30 33 5551 g57 110 ?25 ?10 5 65 80 95 20 5035 g c nf iip3 low side lo high side lo rf = 2700mhz lo/rf frequency (ghz) 2.3 ?50 lo leakage (dbm) rf isolation (db) ?10 0 ?40 ?30 ?20 0 60 75 15 30 45 2.5 2.7 5551 g58 3.5 2.9 3.1 3.3 lo-rf lo-if rf-lo rf-if rf input power (dbm/tone) ?8 ?90 ?80 output power/tone (dbm) ?70 ?60 ?50 ?40 ?30 ?20 ?10 20 5551 g59 10 0 16 ?5 ?2 1 4 7 10 13 im3 im5 if out rf1 = 2699mhz rf2 = 2701mhz lo = 2547mhz ltc 5551 5551fa for more information www.linear.com/LTC5551
12 p in func t ions tp (pin 1): test point. it is used for manufacture measure- ment only . it is recommended to be connected to ground. rf (pin 2): single-ended input for the rf signal. this pin is internally connected to the primary side of the rf input transformer, which has low dc resistance to ground. a series dc-blocking capacitor should be used to avoid damage to the integrated transformer when dc voltage is present at the rf input. the rf input impedance is matched under the condition that the lo input is driven with a 0dbm 6db source between 0.2ghz and 3.5ghz. ct (pin 3): rf transformer secondary center- tap . this pin must be connected to ground with minimum parasitic resistance and inductance to complete the mixers dc current path. typical dc current is 80 ma with lo disabled and 134ma when lo signal is applied. gnd (pins 4, 9, 11, 13, exposed pad pin 17): ground. these pins must be soldered to the rf ground plane on the circuit board. the exposed pad metal of the package provides both electrical contact to ground and good thermal contact to the printed circuit board. en (pin 5): enable pin. when the input voltage is greater than 1.2 v, the mixer is enabled. when the input voltage is less than 0.3 v or left open, the mixer is disabled. typical input current is less than 30 a. this pin has an internal pull-down resistor. v cc (pins 6, 7): power supply pins. these pins are in- ternally connected and must be externally connected to b lock diagra m a regulated 2.5 v to 3.6 v supply, with bypass capacitors located close to the pin. typical current consumption is 70ma through these pins. isel (pin 8): low power select pin. when this pin is pulled low (<0.3 v) or left open, the mixer is biased at the normal current level for best rf performance. when greater than 1.2 v is applied, the mixer operates at reduced current mode, which provides reasonable performance at lower power consumption. this pin has an internal pull-down resistor. lo (pin 10): single-ended input for the local oscillator. this pin is internally connected to the primary side of the rf input transformer, which has low dc resistance to ground. a series dc blocking capacitor should be used to avoid damage to the integrated transformer when dc voltage is present at the lo input. temp (pin 12): temperature sensing diode. this pin is connected to the anode of a diode that may be used to measure the die temperature, by forcing a current and measuring the voltage. if C (pin 14) and if + (pin 15): open-collector differential outputs for the if amplifier. these pins must be connected to a dc supply through impedance matching inductors, or a transformer center-tap. typical dc current consumption is 67ma into each pin. ifbias (pin 16): this pin allows adjustment of the if amplifier current. typical dc voltage is 2.1 v. this pin should be left floating for optimum performance. rf ct v cc v cc gnd pins are not shown lo isel temp if + ifbias if ? exposed pad 5551 bd if amp 12 10 14 15 16 6 en 5 2 3 7 6 17 lo amp bias ltc 5551 5551fa for more information www.linear.com/LTC5551
13 tes t c ircui t figure 1. standard downmixer test circuit schematic (153mhz if) rf gnd gnd bias tbd board stack-up (nelco n4000-13) 0.015" 0.015" 0.062" t1 4:1 if out 153mhz 50 c8 c9 l2 l1 r2 r1 c5 c4 17 gnd LTC5551 1 6 13 14 15 16 lo in 50 11 12 10 9 c2 c7 isel 0v to 3.3v c6 5 7 8 4 v cc 3.1v to 3.5v en 0v to 3.3v 3 rf in 50 v cc x2 2 ifbias if + if ? lo gnd temp gnd en v cc v cc isel gnd gnd rf ct gnd 5551 f01 c1 c3 x1 application rf match lo match if transformer rf (mhz) lo x1 c1 x2 c2 c3 t1 vendor 300 to 650 hs 15nh 15pf 15pf 15pf 8.2pf tc4-1w-7aln+ mini-circuits 500 to 1100 hs 13nh 6.8pf 4.7pf 8.2pf 2.2pf wbc4-6tlb coilcraft 1100 to 2700 ls, hs 7.5nh 2.2pf C 3.9pf C tc4-1w-7aln+ mini-circuits 2300 to 3500 ls, hs 1.2pf 22pf 2.2nh 3.9pf C tc4-1w-7aln+ mini-circuits ref des value size vendor ref des value size vendor c4, c6 0.56f 0603 murata r1, r2 475, 1% 0402 vishay c5, c7 22pf 0402 avx l1, l2 470nh, 2% 0603 coilcraft 0603ls c8, c9 1nf 0402 avx ltc 5551 5551fa for more information www.linear.com/LTC5551
14 introduction the LTC5551 consists of a high linearity double-balanced mixer core, if buffer amplifier, lo buffer amplifier and bias/enable circuits. see the block diagram section for a description of each pin function. the rf and lo inputs are single-ended. the if output is differential. low side or high side lo injection can be used. the evaluation circuit, shown in figure 1, utilizes bandpass if output matching and an if transformer to realize a 50 single-ended if output. the evaluation board layout is shown in figure 2. a pplica t ions i n f or m a t ion figure 2. evaluation board layout for the rf input to be matched, the lo input must be driven. using components listed in figure 1, the rf input can be matched from 300mhz to 3.5ghz. the measured rf input return loss is shown in figure 4 for lo frequen - cies of 0.5 ghz, 1.0ghz . 1.8 ghz and 2.8 ghz. these lo frequencies correspond to the lower, middle and upper values of the lo range. the rf input impedance and input reflection coefficient, versus rf frequency, is listed in table 1. the reference plane for this data is pin 2 of the ic, with no external matching, and the lo is driven at 1.8ghz. figure 3. rf input schematic figure 4. rf input return loss LTC5551 rf in ct rf to mixer 2 3 5551 f03 c1 x2 x1 rf frequency (ghz) 0.3 35 rf port return loss (db) 30 25 15 20 0 0.6 5551 f04 5 10 3.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3 lo = 0.5ghz lo = 1.0ghz lo = 1.8ghz lo = 2.8ghz 300mhz to 650mhz matching 500mhz to 1100mhz matching 1100mhz to 2700mhz matching 2300mhz to 3500mhz matching rf input the mixers rf input, shown in figure 3, is connected to the primary winding of an integrated transformer. a 50 match can be realized with a - network as shown in figures 1 and 3. the primary side of the rf transformer is dc-grounded internally and the dc resistance of the primary is approximately 4. a dc blocking capacitor is needed if the rf source has dc voltage present. the secondary winding of the rf transformer is inter - nally connected to the mixer core. the center-tap of the transformer secondary is connected to pin 3 ( ct). pin 3 needs to be connected to ground with a minimum parasitic resistance and inductance. ltc 5551 5551fa for more information www.linear.com/LTC5551
15 a pplica t ions i n f or m a t ion table 1. rf input impedance and s11 (at pin 2, no external matching, lo input driven at 1.8ghz) frequency (ghz) input impedance s 11 mag angle 0.3 7.6 + j8.4 0.74 160.4 0.7 11.7 + j15.2 0.65 144.5 1.1 17.7 + j 22.2 0.55 127.4 1.5 29.3 + j27.8 0.41 107.4 1.9 46.7 + j21.8 0.22 85.8 2.3 49.6 C j1.3 0.01 C106.3 2.7 31.1 C j9.0 0.26 C148.2 3.1 18.2 C j1.8 0.47 C175.2 3.5 11.8 + j8.4 0.63 159.8 lo input the mixers lo input circuit, shown in figure 5, consists of a balun transformer and a two-stage high speed limiting differential amplifier to drive the mixer core. the LTC5551 s lo amplifiers are optimized for the 200 mhz to 3.5ghz lo frequency range. lo frequencies above or below this frequency range may be used with degraded performance. the mixers lo input is directly connected to the primary winding of an integrated transformer. the lo is 50 matched from 1 ghz to 3.5 ghz with a single 3.9 pf series figure 5. lo input schematic capacitor on the input. matching to lo frequencies below 1ghz is easily accomplished by adding shunt capacitor c3 shown in figure 5. measured lo input return loss is shown in figure 6. the nominal lo input level is 0 dbm although the limiting amplifiers will deliver excellent performance over a 6db input power range. lo input power of C9 dbm may be used with slightly degraded per formance. the lo input impedance and input reflection coefficient, versus frequency, is shown in table 2. table 2. lo input impedance vs frequency (at pin 10, no external matching) frequency (ghz) input impedance s 11 mag angle 0.3 4.8 + j12.0 0.84 152.7 0.7 13.4 + j28.1 0.67 118.5 1.1 32.7 + j39.1 0.47 88.6 1.5 56.8 + j31.1 0.29 61.5 1.9 62.8 + j9.3 0.14 31.4 2.3 54.1 C j1.4 0.04 C18.3 2.7 45.1 C j1.4 0.05 C163.6 3.1 39.8 + j3.6 0.12 158.6 3.5 37.2 + j10.4 0.19 134.1 figure 6. lo input return loss lo in v cc v cc lo buffer to mixer LTC5551 lo en 5551 f05 10 7 6 5 c2 c3 4ma bias lo frequency (ghz) 0.3 25 20 lo port return loss (db) 15 0 0.6 0.9 5551 f06 5 10 3.6 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3 c2 = 15pf, c3 = 8.2pf c2 = 8.2pf, c3 = 2.2pf c2 = 3.9pf, c3 open ltc 5551 5551fa for more information www.linear.com/LTC5551
16 a pplica t ions i n f or m a t ion if output the if amplifier, shown in figure 7, has differential open- collector outputs (if + and if C ), and a pin for modifying the internal bias ( ifbias). the if outputs must be biased at the supply voltage (v cc ), which is applied through matching inductors l1 and l2. alternatively, the if outputs can be biased through the center tap of a transformer. each if output pin draws approximately 67 ma of dc supply cur - rent (134 ma total ). for the highest performance, high-q wire-wound chip inductors are recommended for l1 and l2. low cost multilayer chip inductors may be substituted, with a slight degradation in performance. figure 7. if amplifier schematic with transformer-based bandpass match figure 8. if output small-signal model table 3. if output impedance vs frequency frequency (mhz) differential output impedance (r if || x if (c if )) 90 954 || Cj1442 (1.2pf) 140 950 || Cj848 (1.2pf) 190 945 || Cj681 (1.2pf) 240 942 || Cj539 (1.2pf) 380 938 || Cj338 (1.2pf) 456 926 || Cj281 (1.2pf) transformer-based bandpass if matching the if output can be matched using the bandpass if matching shown in figures 1 and 7. l1 and l2 resonate with the internal if output capacitance at the desired if frequency. the value of l1, l2 is calculated as follows: l1, l2 = 1/[(2 f if ) 2 ? 2 ? c if ] where c if is the internal if capacitance ( listed in table 3). values of l1 and l2 are tabulated in figure 1 for various if frequencies. for if frequency below 80 mhz, the inductor values become unreasonably high and the high pass impedance matching network described in a later section is preferred, due to its lower inductor values. table 4 summarizes the optimum if matching inductor values vs if center frequency, to be used in the standard downmixer test circuit shown in figure 1. the inductor values listed are less than the ideal calculated values due to the additional capacitance of the 4:1 transformer. measured if output return losses are shown in figure 9. for optimum single-ended performance, the differential if outputs must be combined through an external if trans- former or discrete if balun circuit. the evaluation board (see figures 1 and 2) uses a 4:1 ratio if transformer for impedance transformation and differential to single - ended transformation. it is also possible to eliminate the if trans - former and drive differential filters or amplifiers directly. the if output impedance can be modeled as 950 in parallel with 1.2 pf at if frequencies. an equivalent small- signal model is shown in figure 8. frequency-dependent differential if output impedance is listed in table 3. this data is referenced to the package pins ( with no external components) and includes the effects of ic and package parasitics. 15 14 if + if ? r if c if LTC5551 5551 f08 4:1 t1 if out v cc c8 c9 l2 l1 c4 14 15 16 if amp bias 4ma LTC5551 ifbias if ? if + r3 (option to reduce dc power) 5551 f07 r2 r1 v cc ltc 5551 5551fa for more information www.linear.com/LTC5551
17 a pplica t ions i n f or m a t ion table 4. bandpass matching elements values vs if frequency l1, l2 vs if frequencies if (mhz) l1, l2 (nh) comments 120 810 coilcraft 0603 ls 153 470 coilcraft 0603 ls 240 180 coilcraft 0603 cs 305 120 coilcraft 0603 cs 380 56 coilcraft 0603 cs 456 33 coilcraft 0603 cs the resistors r1 and r2 which are connected between the if + and if C is used to assist the if impedance matching. a lower value of r1, r2 will help improve the if return loss and broaden the if bandwidth. however, it will results in lower conversion gain with minor impact to linearity and noise figure performances. other 4:1 transformers can be used to replace the tc4- 1-7aln+ that is used in the standard demoboards. the insertion loss and parasitics of the transformer will impact the overall circuit performance. for if frequency higher than 300 mhz, the tc4-1-17ln+ from mini-circuits or the wbc4-6tlb from coilcraft is preferred. figure 9. if output return loss bandpass matching with 4:1 transformer highpass if matching the highpass if matching circuits shown in figure 10 can be used when higher conversion gain than that from the standard demoboard is desired. the highpass matching network will have less if bandwidth than the bandpass matching. it also use smaller inductance values; an advantage when designing for if center frequency well lower than 80mhz. referring to the small-signal output network schematic in figure 10, the reactive matching element values ( l1, l2, c8 and c9) are calculated using the following equations. the source resistance (r s ) is the parallel combination of external resistors r 1 + r2 and the internal if resistance, r if taken from table 3. the differential load resistance (r l ) is typically 200, but can be less. c if , the if output capacitance, is taken from table 3. choosing r s in the 380 to 450 range will yield power conversion gains around 4db. ? r s r if ? 2 ? r1 (r1 r2) q r s / r l 1 (r s # r l ) y l q / r s if ? c if l1,l2 1/ 2 ? y l ? if c7,c8 2 / q ? r l ? if to demonstrate the highpass impedance transformer output matching, these equations were used to calculate the element values for a 80 mhz if frequency and 200 differential load resistance. the measured performance with l1, l 2 = 330 nh, c8, c9 = 15 pf is shown in figure 11. the test conditions are: p rf = C6 dbm, p lo = 0 dbm with low side lo injection. if frequency (mhz) 50 25 20 return loss (db) 15 0 100 150 5551 f09 5 10 500 200 250 300 350 400 450 l1, l2 = 470nh l1, l2 = 120nh l1, l2 = 56nh l1, l2 = 33nh ltc 5551 5551fa for more information www.linear.com/LTC5551
18 a pplica t ions i n f or m a t ion figure 11. performance using 80mhz highpass if matching network figure 10. if output circuit for highpass matching element value calculations LTC5551 5551 f10 t1 4:1 if out c9 c8 l2 l1 r2 r1 c4 14 15 v cc if + if ? c if r if rf frequency (ghz) 1.1 20 22 iip3 (dbm) g c (db) 24 38 36 1.3 5551 f11 30 26 34 32 2 4 3 5 10 7 6 9 8 2.7 1.5 1.7 1.9 2.1 2.3 2.5 r1, r2 open r1, r2 = 1k iip3 g c ltc 5551 5551fa for more information www.linear.com/LTC5551
19 a pplica t ions i n f or m a t ion wideband differential if output wide if bandwidth and high input 1 db compression are obtained by reducing the if output resistance with resistors r1 and r2. this will reduce the mixers conversion gain, but will not degrade the iip3 or noise figure. the if matching shown in figure 12 uses 249 resistors and 470 nh supply chokes to produce a wideband 200 differential output. this differential output is suitable for driving a wideband differential amplifier, filter, or a wide- band 4:1 transformer. the complete test circuit, shown in figure 13, uses re- sistive impedance matching attenuators ( l-pads) on the evaluation board to transform each 100 if output to 50. an external 0/180 power combiner is then used to convert the 100 differential output to 50 single-ended, to facilitate measurement. measured conversion gain and iip3 at the 200 differential output are plotted in figure?14. as shown, the conversion gain is flat within 1 db over the 50 mhz to 490 mhz if output frequency range. figure 12. wideband 200 differential output if ? LTC5551 5551 f12 270pf 270pf 249 249 470nh 470nh v cc if + 100 200 load 100 if out 50 if out 200 if + 50 if ? 50 rf en en 7.5nh 22pf 249 249 lo 1.8ghz 0dbm 3.3v 10nf v cc if + LTC5551 if ? 2.2pf rf 1.85ghz to 2.29ghz 270pf 1mhz to 500mhz combiner l-pads and 180 combiner for 50 single-ended measurement 270pf bias if 5551 f13 3.9pf lo lo 0.56f 71.5 69.8 71.5 69.8 470nh 470nh out 0 180 figure 13. test circuit for wideband 200 differential output figure 14. conversion gain and iip3 vs if output frequency for wideband 200 differential if if frequency (mhz) 50 18 20 iip3 (dbm) 22 38 90 130 5551 f14 36 24 26 28 30 34 32 0 1 g c (db) 2 5 3 4 490 170 210 250 290 330 370 410 450 iip3 g c ltc 5551 5551fa for more information www.linear.com/LTC5551
20 the ifbias pin (pin 16) is available for reducing the dc current consumption of the if amplifier, at the expense of reduced performance. this pin should be left open- circuited for optimum performance. the internal bias circuit pro - duces a 4 ma reference for the if amplifier, which causes the amplifier to draw approximately 134 ma. if resistor r3 is connected to pin 16 as shown in figure 7, a portion of the reference current can be shunted to ground, resulting in reduced if amplifier current. for example, r 3 = 1 k will shunt away 1.5 ma from pin 16 and the if amplifier cur - rent will be reduced to approximately 90 ma. the nominal, open-cir cuit dc voltage at pin 16 is 2.1 v. table 5 lists rf performance at 1950mhz vs if amplifier current. table 5. mixer performance with reduced if amplifier current (rf = 1950mhz, low side lo, if = 153mhz, v cc = 3.3v) r3 (k) i cc (ma) g c (db) iip3 (dbm) p1db (dbm) nf (db) open 204 2.4 35.5 18.0 9.7 4.7 194 2.4 35.0 17.9 9.4 2.2 186 2.4 34.2 17.8 9.2 1.0 164 2.4 31.9 17.3 8.7 (rf = 1950mhz, high side lo, if = 153mhz, v cc = 3.3v) r3 (k) i ccif (ma) g c (db) iip3 (dbm) p1db (dbm) nf (db) open 204 2.4 33.0 17.9 10.5 4.7 194 2.3 32.6 17.8 10.2 2.2 186 2.3 32.1 17.6 9.9 1.0 164 2.3 30.5 17.0 9.4 low power mode the LTC5551 can be set to low power mode using a digital voltage applied to the isel pin ( pin 8). this allows the flexibility to reduce current when lower rf performance is acceptable. figure 15 shows a simplified schematic of the isel pin interface. when isel is set low (<0.3 v), the mixer operates at maximum dc current. when isel is set high (>1.2v), the dc current is reduced, thus reducing power consumption. when floating, the isel is pulled low by an internal pull-down resistor, and operates at maximum supply current. the performance in low power mode and nominal power mode are compared in table 6. table 6. performance comparison C low power vs high power mode rf = 1950mhz, low side lo, if = 153mhz, en = high isel i cc (ma) g c (db) iip 3 (dbm) p1db (dbm) nf (db) low 204 2.4 35.5 18.0 9.7 high 139 2.4 29.3 16.7 8.3 enable interface figure 16 shows a simplified schematic of the en pin in- terface. to enable the chip, the en voltage must be higher than 1.2 v. the en voltage at the pin should never exceed the power supply voltage (v cc ) by more than 0.3 v. if this should occur, the supply current could be sourced through the esd diode, potentially damaging the ic. if the en pin is left floating, its voltage will be pulled low by the internal pull- down resistor and the chip will be disabled. figure 16. enable input circuit figure 15. isel interface schematic LTC5551 8 isel v cc 5551 f15 7 bias LTC5551 5 en v cc 5551 f16 6 bias a pplica t ions i n f or m a t ion ltc 5551 5551fa for more information www.linear.com/LTC5551
21 a pplica t ions i n f or m a t ion temperature diode the LTC5551 provides an on-chip diode at pin 12 (temp) for chip temperature measurement. pin 12 is connected to the anode of an internal esd diode with its cathode con - nected to internal ground. the chip temperature can be measured by injecting a constant dc current into pin 12 and measuring its dc voltage. the voltage vs temperature coefficient of the diode is about C1.72 mv/c with 10a current injected into the temp pin. figure 17 shows a typical temperature- voltage behavior when 10a and 80a currents are injected into pin 12. supply voltage ramping fast ramping of the supply voltage can cause a current glitch in the internal esd protection circuits. depending on the supply inductance, this could result in a supply volt - age transient that exceeds the maximum rating. a supply voltage ramp time of greater than 1 ms is recommended. spurious output levels mixer spurious output levels versus harmonics of the rf and lo are tabulated in table 7. the spur levels were measured on a standard evaluation board using the test circuit shown in figure 1. the spur frequencies can be calculated using the following equation: f spur = (m ? f rf )C(n ? f lo ) table 7. if output spur levels (dbc) rf = 1950mhz, p rf = 0dbm, p lo = 0dbm, if = 153mhz, low side lo, v cc = 3.3v, en = high, isel = low, t c = 25c n m 0 1 2 3 4 5 6 7 8 9 0 C26 C36 C40 C40 C61 C70 C57 C60 * 1 C28 0 C43 C26 C60 C43 C64 C49 C62 C63 2 C83 C66 C70 C69 C83 * * C81 * C79 3 * C81 * * * * * * * * 4 * * * * * * * * * * 5 * * * * * * * * * * 6 C84 * * * * * * * * * 7 C82 * * C84 * * * * * * *less than C85dbc figure 17. temp diode voltage vs junction temperature (t j ) temperature (c) ?40 400 450 temperature diode voltage (mv) 500 900 ?20 0 5551 f17 850 550 600 650 700 800 750 20 40 60 80 100 10a 80a ltc 5551 5551fa for more information www.linear.com/LTC5551
22 p ackage descrip t ion please refer to http://www .linear.com/designtools/packaging/ for the most recent package drawings. 4.00 0.10 (4 sides) note: 1. drawing conforms to jedec package outline mo-220 variation (wggc) 2. drawing not to scale 3. all dimensions are in millimeters 4. dimensions of exposed pad on bottom of package do not include mold flash. mold flash, if present, shall not exceed 0.15mm on any side 5. exposed pad shall be solder plated 6. shaded area is only a reference for pin 1 location on the top and bottom of package pin 1 top mark (note 6) 0.55 0.20 1615 1 2 bottom view?exposed pad 2.15 0.10 (4-sides) 0.75 0.05 r = 0.115 typ 0.30 0.05 0.65 bsc 0.200 ref 0.00 ? 0.05 (uf16) qfn 10-04 recommended solder pad pitch and dimensions 0.72 0.05 0.30 0.05 0.65 bsc 2.15 0.05 (4 sides) 2.90 0.05 4.35 0.05 package outline pin 1 notch r = 0.20 typ or 0.35 45 chamfer uf package 16-lead plastic qfn (4mm 4mm) (reference ltc dwg # 05-08-1692 rev ?) ltc 5551 5551fa for more information www.linear.com/LTC5551
23 information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. r evision h is t ory rev date description page number a 12/13 added u.s. patent number corrected transformer t1 part number 1 13 ltc 5551 5551fa for more information www.linear.com/LTC5551
24 ? linear technology corporation 2013 lt 1213 rev a ? printed in usa linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax : (408) 434-0507 www.linear.com/LTC5551 typical a pplica t ion wideband 100 differential if output matching conversion gain and iip3 vs if frequency (low side lo) r ela t e d p ar t s part number description comments mixers and modulators lt ? 5527 400mhz to 3.7ghz, 5v downconverting mixer 2.3db gain, 23.5dbm iip3 and 12.5db nf at 1900mhz, 5v/78ma supply lt5557 400mhz to 3.8ghz, 3.3v downconverting mixer 2.9db gain, 24.7dbm iip3 and 11.7db nf at 1950mhz, 3.3v/82ma supply ltc559x 600mhz to 4.5ghz dual downconverting mixer family 8.5db gain, 26.5dbm iip3, 9.9db nf, 3.3v/380ma supply ltc5569 300mhz to 4ghz, 3.3v dual active downconverting mixer 2db gain, 26.8dbm iip3 and 11.7db nf, 3.3v/180ma supply ltc554x 600mhz to 4 ghz, 5 v downconverting mixer family 8db gain, >25dbm iip3 and 10db nf, 3.3v/200ma supply lt5578 400mhz to 2.7ghz upconverting mixer 27dbm oip3 at 900mhz, 24.2dbm at 1.95ghz, integrated rf output transformer lt5579 1.5ghz to 3.8ghz upconverting mixer 27.3dbm oip3 at 2.14ghz, nf = 9.9db, 3.3v supply, single-ended lo and rf ports ltc5588-1 200mhz to 6ghz i/q modulator 31dbm oip3 at 2.14ghz, C160.6dbm/hz noise floor ltc5585 700mhz to 3ghz wideband i/q demodulator >530mhz demodulation bandwidth, iip2 tunable to >80dbm, dc offset nulling amplifiers ltc6430-15 high linearity differential if amp 20mhz to 2ghz bandwidth, 15.2db gain, 50dbm oip3, 3db nf at 240mhz ltc6431-15 high linearity single-ended if amp 20mhz to 1.7ghz bandwidth, 15.5db gain, 47dbm oip3, 3.3db nf at 240mhz ltc 6412 31db linear analog vga 35dbm oip3 at 240mhz, continuous gain range C14db to 17db lt5554 ultralow distortion if digital vga 48dbm oip3 at 200mhz, 2db to 18db gain range, 0.125db gain steps rf power detectors lt5538 40mhz to 3.8ghz log detector 0.8db accuracy over t emperature, C72dbm sensitivity, 75db dynamic range lt5581 6ghz low power rms detector 40db dynamic range, 1db accuracy over temperature, 1.5ma supply current ltc5582 40mhz to 10ghz rms detector 0.5db accuracy over temperature, 0.2db linearity error, 57db dynamic range ltc5583 dual 6ghz rms power detector up to 60db dynamic range, 0.5db accuracy over temperature, >50db isolation adcs ltc2208 16-bit, 130msps adc 78dbfs noise floor, >83db sfdr at 250mhz ltc2153-14 14-bit, 310msps low power adc 68.8dbfs snr, 88db sfdr, 401mw power consumption rf pll/synthesizer with vco ltc6946-1/ ltc6946-2/ ltc 6946- 3 low noise, low spurious integer-n pll with integrated vco 373mhz to 5.79ghz, C157dbc/hz wb phase noise floor, C100dbc/hz closed-loop phase noise 5551 ta02a LTC5551 2mhz to 2000mhz combiner rf 3.9pf 110 110 560nh 1nf 560nh 2.2pf 7.5nh v cc lo if + if ? 0 180 lo 1.8ghz 0dbm rf 1.85ghz to 2.51ghz 10nf 1nf if ? 50 if + 50 22pf 0.56f 3.3v out if out 50 if frequency (mhz) 50 12 21 iip3 (dbm) g c (db) 24 15 18 39 110 5551 ta02b 30 27 36 33 ?3 0 1 ?2 ?1 6 3 2 5 4 710 170 230 290 350 410 470 530 590 650 iip3 g c normal power mode low power mode ltc 5551 5551fa for more information www.linear.com/LTC5551

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