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1 LT5527 5527f cellular, wcdma, td-scdma and umts infrastructure gsm900/gsm1800/gsm1900 infrastructure 900mhz/2.4ghz/3.5ghz wlan mmds, wimax high linearity downmixer applications high signal level downmixer for multi-carrier wireless infrastructure 400mhz to 3.7ghz high signal level downconverting mixer 50 ? single-ended rf and lo ports wide rf frequency range: 400mhz to 3.7ghz* high input ip3: 24.5dbm at 900mhz 23.5dbm at 1900mhz conversion gain: 3.2db at 900mhz 2.3db at 1900mhz integrated lo buffer: low lo drive level high lo-rf and lo-if isolation low noise figure: 11.6db at 900mhz 12.5db at 1900mhz very few external components enable function 4.5v to 5.25v supply voltage range 16-lead (4mm 4mm) qfn package features descriptio u applicatio s u typical applicatio u the lt ? 5527 active mixer is optimized for high linearity, wide dynamic range downconverter applications. the ic includes a high speed differential lo buffer amplifier driving a double-balanced mixer. broadband, integrated transformers on the rf and lo inputs provide single- ended 50 ? interfaces. the differential if output allows convenient interfacing to differential if filters and amplifi- ers, or is easily matched to drive 50 ? single-ended, with or without an external transformer. the rf input is internally matched to 50 ? from 1.7ghz to 3ghz, and the lo input is internally matched to 50 ? from 1.2ghz to 5ghz. the frequency range of both ports is easily extended with simple external matching. the if output is partially matched and usable for if frequencies up to 600mhz. the LT5527s high level of integration minimizes the total solution cost, board space and system-level variation. lo power (dbm) C9 2 g c , ssb nf (db), iip3 (dbm) lo-rf leakage (dbm) 6 10 14 18 C5 C1 C7 C3 1 5527 ta01b 3 22 4 8 12 16 20 24 C75 C65 C55 C45 C35 C25 C70 C60 C50 C40 C30 C20 iip3 ssb nf lo-rf g c if = 240mhz low side lo t a = 25 c v cc = 5v bias en rf if + if C 100nh 100nh 4.7pf 220nh if output 240mhz rf input v cc2 v cc1 lo input C3dbm (typ) 1nf 1 f 1nf 4.7pf 5v 5527 ta01a LT5527 gnd 1.9ghz conversion gain, iip3, ssb nf and lo-rf leakage vs lo power , ltc and lt are registered trademarks of linear technology corporation. all other trademarks are the property of their respective owners. *operation over a wider frequency range is possible with reduced performance. consult factory for information and assistance.
2 LT5527 5527f supply voltage (v cc1 , v cc2 , if + , if C ) ...................... 5.5v enable voltage ............................... C0.3v to v cc + 0.3v lo input power (380mhz to 4ghz) .................. +10dbm lo input dc voltage ............................ C1v to v cc + 1v rf input power (400mhz to 4ghz) .................. +12dbm rf input dc voltage ............................................ 0.1v operating temperature range ............... C 40 c to 85 c storage temperature range ................ C 65 c to 125 c junction temperature (t j )................................... 125 c consult ltc marketing for parts specified with wider operating temperature ranges. absolute axi u rati gs w ww u package/order i for atio uu w (note 1) LT5527euf order part number uf part marking 5527 t jmax = 125 c, ja = 37 c/w exposed pad (pin 17) is gnd must be soldered to pcb v cc = 5v, en = high, t a = 25 c, unless otherwise specified. test circuit shown in figure 1. (note 3) 16 15 14 13 5 6 7 8 top view 17 uf package 16-lead (4mm 4mm) plastic qfn 9 10 11 12 4 3 2 1 nc nc rf nc gnd if + if C gnd nc lo nc nc en v cc2 v cc1 nc dc electrical characteristics parameter conditions min typ max units rf input frequency range no external matching (midband) 1700 to 3000 mhz with external matching (low band or high band) 400 3700 mhz lo input frequency range no external matching 1200 to 3500 mhz with external matching 380 mhz if output frequency range requires appropriate if matching 0.1 to 600 mhz rf input return loss z o = 50 ? , 1700mhz to 3000mhz >10 db lo input return loss z o = 50 ? , 1200mhz to 3400mhz >12 db if output impedance differential at 240mhz 407 ? ||2.5pf r||c lo input power 1200mhz to 3500mhz C8 C3 2 dbm 380mhz to 1200mhz C5 0 5 dbm ac electrical characteristics test circuit shown in figure 1. (notes 2, 3) parameter conditions min typ max units power supply requirements (v cc ) supply voltage 4.5 5 5.25 v dc supply current v cc1 (pin 7) 23.2 ma v cc2 (pin 6) 2.8 ma if + + if C (pin 11 + pin 10) 52 60 ma total supply current 78 88 ma enable (en) low = off, high = on shutdown current en = low 100 a input high voltage (on) 3v dc input low voltage (off) 0.3 v dc en pin input current en = 5v dc 50 90 a turn-on time 3 s turn-off time 3 s
3 LT5527 5527f parameter conditions min typ max units conversion gain rf = 450mhz, if = 140mhz, high side lo 2.5 db rf = 900mhz, if = 140mhz 3.4 db rf = 1700mhz 2.3 db rf = 1900mhz 2.3 db rf = 2200mhz 2.0 db rf = 2650mhz 1.8 db rf = 3500mhz, if = 380mhz 0.3 db conversion gain vs temperature t a = C 40 c to 85 c, rf = 1900mhz C0.018 db/ c input 3rd order intercept rf = 450mhz, if = 140mhz, high side lo 23.2 dbm rf = 900mhz, if = 140mhz 24.5 dbm rf = 1700mhz 24.2 dbm rf = 1900mhz 23.5 dbm rf = 2200mhz 22.7 dbm rf = 2650mhz 20.8 dbm rf = 3500mhz, if = 380mhz 18.2 dbm single-sideband noise figure rf = 450mhz, if = 140mhz, high side lo 13.3 db rf = 900mhz, if = 140mhz 11.6 db rf = 1700mhz 12.1 db rf = 1900mhz 12.5 db rf = 2200mhz 13.2 db rf = 2650mhz 13.9 db rf = 3500mhz, if = 380mhz 16.1 db lo to rf leakage f lo = 400mhz to 2100mhz C44 dbm f lo = 2100mhz to 3200mhz C36 dbm lo to if leakage f lo = 400mhz to 700mhz C40 dbm f lo = 700mhz to 3200mhz C50 dbm rf to lo isolation f rf = 400mhz to 2200mhz >43 db f rf = 2200mhz to 3700mhz >38 db rf to if isolation f rf = 400mhz to 800mhz >42 db f rf = 800mhz to 3700mhz >54 db 2rf-2lo output spurious product 900mhz: f rf = 830mhz at C5dbm, f if = 140mhz C60 dbc (f rf = f lo + f if /2) 1900mhz: f rf = 1780mhz at C5dbm, f if = 240mhz C65 dbc 3rf-3lo output spurious product 900mhz: f rf = 806.67mhz at C5dbm, f if = 140mhz C73 dbc (f rf = f lo + f if /3) 1900mhz: f rf = 1740mhz at C5dbm, f if = 240mhz C63 dbc input 1db compression rf = 450mhz, if = 140mhz, high side lo 9.5 dbm rf = 900mhz, if = 140mhz 8.9 dbm rf = 1900mhz 9.0 dbm ac electrical characteristics standard downmixer application: v cc = 5v, en = high, t a = 25 c, p rf = 5dbm (?dbm/tone for 2-tone iip3 tests, ? f = 1mhz), f lo = f rf ?f if , p lo = 3dbm (0dbm for 450mhz and 900mhz tests), if output measured at 240mhz, unless otherwise noted. test circuit shown in figure 1. (notes 2, 3, 4) note 1: absolute maximum ratings are those values beyond which the life of a device may be impaired. note 2: 450mhz, 900mhz and 3500mhz performance measured with external lo and rf matching. see figure 1 and applications information. note 3: specifications over the C40 c to 85 c temperature range are assured by design, characterization and correlation with statistical process controls. note 4: ssb noise figure measurements performed with a small-signal noise source and bandpass filter on rf input, and no other rf signal applied.
4 LT5527 5527f w u typical ac perfor a ce characteristics midband (no external rf/lo matching) v cc = 5v, en = high, p rf = ?dbm (?dbm/tone for 2-tone iip3 tests, ? f = 1mhz), p lo = 3dbm, if output measured at 240mhz, unless otherwise noted. test circuit shown in figure 1. conversion gain, iip3 and nf vs rf frequency rf frequency (mhz) 1700 g c , ssb nf (db), iip3 (dbm) 12 16 20 24 2500 5527 g01 8 4 10 14 18 22 ssb nf g c 6 2 0 1900 2100 2300 2700 t a = 25 c if = 240mhz low side lo high side lo iip3 lo frequency (mhz) 1200 C90 lo leakage (dbm) C80 C70 C60 C50 C30 1500 1800 2100 2400 5527 g02 2700 3000 C40 C85 C75 C65 C55 C35 C45 lo-rf lo-if t a = 25 c p lo = C3dbm rf frequency (mhz) 1700 isolation (db) C60 C50 C40 C30 2500 5527 g03 C70 C80 C65 C55 rf-lo rf-if C45 C35 C75 C85 C90 1900 2100 2300 2700 t a = 25 c lo leakage vs lo frequency rf isolation vs rf frequency conversion gain and iip3 vs temperature (low side lo) temperature ( c) C50 15 iip3 (dbm) g c (db) 17 19 21 C25 0 25 50 5527 g04 75 23 25 16 18 20 22 24 0 2 4 6 8 10 1 3 5 7 9 iip3 g c 100 if = 240mhz 1700mhz 1900mhz 2200mhz conversion gain and iip3 vs temperature (high side lo) temperature ( c) C50 15 iip3 (dbm) g c (db) 17 19 21 C25 0 25 50 5527 g05 75 23 25 16 18 20 22 24 0 2 4 6 8 10 1 3 5 7 9 iip3 g c 100 if = 240mhz 1700mhz 1900mhz 2200mhz 1900mhz conversion gain, iip3 and nf vs supply voltage supply voltage (v) 4.5 g c , ssb nf (db), iip3 (dbm) 12 18 20 iip3 ssb nf g c 5.5 5527 g06 10 8 0 4.75 5 5.25 4 24 22 16 14 6 2 low side lo if = 240mhz C40 c 25 c 85 c 1700mhz conversion gain, iip3 and nf vs lo power 2200mhz conversion gain, iip3 and nf vs lo power lo input power (dbm) C9 1 g c , ssb nf (db), iip3 (dbm) 5 9 13 17 25 C7 C5 C3 C1 5527 g07 13 21 3 7 11 15 23 19 iip3 g c low side lo if = 240mhz C40 c 25 c 85 c ssb nf 1900mhz conversion gain, iip3 and nf vs lo power lo input power (dbm) C9 0 g c , ssb nf (db), iip3 (dbm) 4 8 12 16 24 C7 C5 C3 C1 5527 g08 13 20 2 6 10 14 22 18 iip3 g c low side lo if = 240mhz C40 c 25 c 85 c ssb nf lo input power (dbm) C9 0 g c , ssb nf (db), iip3 (dbm) 4 8 12 16 24 C7 C5 C3 C1 5527 g09 13 20 2 6 10 14 22 18 low side lo if = 240mhz C40 c 25 c 85 c ssb nf iip3 g c
5 LT5527 5527f w u typical ac perfor a ce characteristics midband (no external rf/lo matching) v cc = 5v, en = high, p rf = ?dbm (?dbm/tone for 2-tone iip3 tests, ? f = 1mhz), p lo = 3dbm, if output measured at 240mhz, unless otherwise noted. test circuit shown in figure 1. if output power, im3 and im5 vs rf input power (2 input tones) rf input power (dbm/tone) C21 output power/tone (dbm) C70 C10 0 10 C15 C9 C6 5527 g10 C90 C30 C50 C80 C20 C100 C40 C60 C18 C12 C3 0 t a = 25 c rf1 = 1899.5mhz rf2 = 1900.5mhz lo = 1660mhz if out im3 im5 rf input power (dbm) C15 output power (dbm) C35 C15 15 5 9 5527 g11 C55 C75 C45 C25 C5 C65 C85 C95 C9 C3 3 C12 C18 C6 0 6 12 if out (rf = 1900mhz) t a = 25 c lo = 1660mhz if = 240mhz 2rf-2lo (rf = 1780mhz) 3rf-3lo (rf = 1740mhz) lo input power (dbm) C9 C100 relative spur level (dbc) C90 C80 C70 C7 C5 C3 C1 5527 g12 1 C60 C50 C95 C85 C75 C65 C55 3 3rf-3lo (rf = 1740mhz) t a = 25 c lo = 1660mhz if = 240mhz p rf = C5dbm 2rf-2lo (rf = 1780mhz) if out , 2 2 and 3 3 spurs vs rf input power (single tone) 2 2 and 3 3 spurs vs lo power (single tone) high band (3500mhz application with external rf matching) v cc = 5v, en = high, p rf = ?dbm (?dbm/tone for 2-tone iip3 tests, ? f = 1mhz), low side lo, p lo = 3dbm, if output measured at 380mhz, unless otherwise noted. test circuit shown in figure 1. conversion gain, iip3 and ssb nf vs rf frequency 3500mhz conversion gain, iip3 and ssb nf vs lo power low band (450mhz application with external rf/lo matching) v cc = 5v, en = high, p rf = ?dbm (?dbm/tone for 2-tone iip3 tests, ? f = 1mhz), p lo = 0dbm, if output measured at 140mhz, unless otherwise noted. test circuit shown in figure 1. conversion gain, iip3 and nf vs rf frequency 450mhz conversion gain, iip3 and nf vs lo power lo leakage vs lo frequency rf frequency (mhz) 400 g c , ssb nf (db), iip3 (dbm) 12 18 20 500 5527 g18 10 8 0 425 450 475 4 24 22 iip3 ssb nf g c 16 14 6 2 high side lo t a = 25 c if = 140mhz lo input power (dbm) C6 0 g c , ssb nf (db), iip3 (dbm) 4 8 12 16 24 C4 C2 0 2 5527 g19 46 20 2 6 10 14 22 18 iip3 g c high side lo if = 140mhz C40 c 25 c 85 c ssb nf lo frequency (mhz) 400 C80 lo leakage (dbm) C70 C60 C50 C40 C30 C20 600 800 1000 1200 5527 g20 lo-if (450mhz app) lo-rf (450mhz app) lo-rf (900mhz app) t a = 25 c p lo = 0dbm lo-if (900mhz app) rf frequency (mhz) 3300 0 g c , ssb nf (db), iip3 (dbm) 2 6 8 10 20 14 3400 3500 5527 g13 4 16 18 12 3600 3700 iip3 low side lo if = 380mhz t a = 25 c g c ssb nf lo input power (dbm) C9 C1 g c , ssb nf (db), iip3 (dbm) 3 7 11 C7 C5 C3 C1 5527 g14 1 15 19 iip3 ssb nf g c 1 5 9 13 17 3 low side lo if = 380mhz t a = 25 c lo/rf frequency (mhz) 3000 lo leakage (dbm) rf-lo isolation (db) C50 C40 3800 5527 g15 C60 C70 3200 3400 3600 C20 C30 lo-rf lo-if rf-lo 30 40 20 10 60 50 lo leakage and rf-lo isolation vs lo and rf frequency
6 LT5527 5527f w u typical ac perfor a ce characteristics low band (900mhz application with external rf/lo matching) v cc = 5v, en = high, p rf = ?dbm (?dbm/tone for 2-tone iip3 tests, ? f = 1mhz), p lo = 0dbm, if output measured at 140mhz, unless otherwise noted. test circuit shown in figure 1. conversion gain, iip3 and nf vs rf frequency (900mhz low side application) 900mhz conversion gain, iip3 and nf vs lo power (low side lo) rf frequency (mhz) 750 1 g c , ssb nf (db), iip3 (dbm) 5 9 13 17 25 800 850 900 950 5527 g21 1000 1050 21 3 7 11 15 23 19 iip3 g c ssb nf low side lo t a = 25 c if = 140mhz lo input power (dbm) C6 1 g c , ssb nf (db), iip3 (dbm) 5 9 13 17 25 C4 C2 0 2 5527 g22 46 21 3 7 11 15 23 19 iip3 g c low side lo if = 140mhz C40 c 25 c 85 c ssb nf if out , 2 2 and 3 3 spurs vs rf input power (single tone) rf input power (dbm) C18 output power (dbm) C40 C20 0 20 6 5527 g23 C60 C80 C50 C30 C10 10 C70 C90 C100 C12 C6 0 C15 9 C9 C3 3 12 if out (rf = 900mhz) t a = 25 c lo = 760mhz if = 140mhz 3rf-3lo (rf = 806.67mhz) 2rf-2lo (rf = 830mhz) conversion gain, iip3 and nf vs rf frequency (900mhz high side application) 900mhz conversion gain, iip3 and nf vs lo power (high side lo) 2 2 and 3 3 spurs vs lo power (single tone) rf frequency (mhz) 750 1 g c , ssb nf (db), iip3 (dbm) 5 9 13 17 25 800 850 900 950 5527 g24 1000 1050 21 3 7 11 15 23 19 g c ssb nf high side lo t a = 25 c if = 140mhz iip3 lo input power (dbm) C6 1 g c , ssb nf (db), iip3 (dbm) 5 9 13 17 25 C4 C2 0 2 5527 g25 46 21 3 7 11 15 23 19 iip3 g c high side lo if = 140mhz C40 c 25 c 85 c ssb nf lo input power (dbm) C6 C90 relative spur level (dbc) C80 C70 C60 C4 C2 02 5527 g26 4 C50 C40 C85 C75 C65 C55 C45 6 3rf-3lo (rf = 806.67mhz) t a = 25 c lo = 760mhz if = 140mhz p rf = C5dbm 2rf-2lo (rf = 830mhz) w u typical dc perfor a ce characteristics test circuit shown in figure 1. supply current vs supply voltage supply voltage (v) 4.5 71 supply current (ma) 72 74 75 76 82 79 4.75 5 5527 g16 73 80 81 78 C40 c 0 c 60 c 85 c 5.25 5.5 25 c shutdown current vs supply voltage supply voltage (v) 4.5 0.1 shutdown current ( a) 1 85 c 60 c25 c 0 c C40 c 10 100 4.75 5 5527 g17 5.25 5.5
7 LT5527 5527f uu u pi fu ctio s nc (pins 1, 2, 4, 8, 13, 14, 16): not connected internally. these pins should be grounded on the circuit board for improved lo-to-rf and lo-to-if isolation. rf (pin 3): 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. if the rf source is not dc blocked, then a series blocking capacitor must be used . the rf input is internally matched from 1.7ghz to 3ghz. operation down to 400mhz or up to 3700mhz is possible with simple external matching. en (pin 5): enable pin. when the input enable voltage is higher than 3v, the mixer circuits supplied through pins 6, 7, 10 and 11 are enabled. when the input voltage is less than 0.3v, all circuits are disabled. typical input current is 50 a for en = 5v and 0 a when en = 0v. the en pin should not be left floating. under no conditions should the en pin voltage exceed v cc + 0.3v, even at start-up. v cc2 (pin 6): power supply pin for the bias circuits. typical current consumption is 2.8ma. this pin should be externally connected to the v cc1 pin and decoupled with 1000pf and 1 f capacitors. v cc1 (pin 7): power supply pin for the lo buffer circuits. typical current consumption is 23.2ma. this pin should be externally connected to the v cc2 pin and decoupled with 1000pf and 1 f capacitors. gnd (pins 9, 12): ground. these pins are internally connected to the backside ground for improved isolation. they should be connected to the rf ground on the circuit board, although they are not intended to replace the primary grounding through the backside contact of the package. if , if + (pins 10, 11): differential outputs for the if signal. an impedance transformation may be required to match the outputs. these pins must be connected to v cc through impedance matching inductors, rf chokes or a transformer center tap. lo (pin 15): single-ended input for the local oscillator signal. this pin is internally connected to the primary side of the lo transformer, which is internally dc blocked. an external blocking capacitor is not required. the lo input is internally matched from 1.2ghz to 5ghz. operation down to 380mhz is possible with simple external matching. exposed pad (pin 17): circuit ground return for the entire ic. this must be soldered to the printed circuit board ground plane. block diagra w 15 7 11 3 6 5 10 double-balanced mixer linear amplifier limiting amplifiers lo v cc2 v cc1 en if + 12 gnd 17 exposed pad if C 9 gnd 5525 bd bias rf v cc1 regulator
8 LT5527 5527f test circuits if out 240mhz 5527 f01 16 15 14 13 56 78 12 11 10 9 nc nc gnd gnd en en v cc2 v cc1 nc rf lo nc nc 1 2 3 4 external matching for low frequency lo only nc nc if + if C rf in lo in l1 t1 l2 c4 z o 50 ? c1 c2 c3 3 v cc gnd LT5527 l4 c5 l (mm) external matching for low band or high band only rf gnd gnd bias r = 4.4 0.018" 0.018" 0.062" 2 1 4 5 ?? if out 240mhz 5527 f02 16 15 14 13 56 78 12 11 10 9 nc nc gnd gnd en en v cc2 v cc1 nc rf lo nc nc 1 2 3 4 external matching for low frequency lo only nc nc if + if C rf in lo in l1 l2 l3 c4 z o 50 ? c1 c2 c6 c3 c7 discrete if balun v cc gnd LT5527 l4 c5 l (mm) external matching for low band or high band only ref des value size part number ref des value size part number c1 1000pf 0402 avx 04025c102jat l4, c4, c5 0402 see applications information c2 1 f 0603 avx 0603zd105kat l1, l2 82nh 0603 toko llq1608-a82n c3 2.7pf 0402 avx 04025a2r7cat t1 4:1 m/a-com etc4-1-2 (2mhz to 800mhz) figure 1. downmixer test schematic?tandard if matching (240mhz if) ref des value size part number ref des value size part number c1, c3 1000pf 0402 avx 04025c102jat l4, c4, c5 0402 see applications information c2 1 f 0603 avx 0603zd105kat l1, l2 100nh 0603 toko llq1608-ar10 c6, c7 4.7pf 0402 avx 04025a4r7cat l3 220nh 0603 toko llq1608-ar22 figure 2. downmixer test schematic?iscrete if balun matching (240mhz if) application lo match rf match rf lo l4 c4 l c5 450mhz high side 6.8nh 10pf 4.5mm 12pf 900mhz low side 3.9nh 5.6pf 1.3mm 3.9pf 900mhz high side 2.7pf 1.3mm 3.9pf 3500mhz low side 4.5mm 0.5pf
9 LT5527 5527f applicatio s i for atio wu uu introduction the LT5527 consists of a high linearity double-balanced mixer, rf buffer amplifier, high speed limiting lo buffer amplifier and bias/enable circuits. the rf and lo inputs are both single ended. the if output is differential. low side or high side lo injection can be used. two evaluation circuits are available. the standard evalu- ation circuit, shown in figure 1, incorporates transformer- based if matching and is intended for applications that require the lowest lo-if leakage levels and the widest if bandwidth. the second evaluation circuit, shown in fig- ure 2, replaces the if transformer with a discrete if balun for reduced solution cost and size. the discrete if balun delivers comparable noise figure and linearity, higher conversion gain, but degraded lo-if leakage and reduced if bandwidth. rf input port the mixers rf input, shown in figure 3, consists of an integrated transformer and a high linearity differential amplifier. the primary terminals of the transformer are connected to the rf input pin (pin 3) and ground. the secondary side of the transformer is internally connected to the amplifiers differential inputs. one terminal of the transformers primary is internally grounded. if the rf source has dc voltage present, then a coupling capacitor must be used in series with the rf input pin. the rf input is internally matched from 1.7ghz to 3ghz, requiring no external components over this frequency range. the input return loss, shown in figure 4a, is typi- cally 10db at the band edges. the input match at the lower band edge can be optimized with a series 2.7pf capacitor at pin 3, which improves the 1.7ghz return loss to greater than 20db. likewise, the 2.7ghz match can be improved to greater than 30db with a series 1.5nh inductor. a series 1.5nh/2.7pf network will simultaneously optimize the lower and upper band edges and expand the rf input bandwidth to 1.1ghz-3.3ghz. measured rf input return losses for these three cases are also plotted in figure 4a. alternatively, the input match can be shifted down, as low as 400mhz or up to 3700mhz, by adding a shunt capacitor (c5) to the rf input. a 450mhz input match is realized with c5 = 12pf, located 4.5mm away from pin 3 on the evalu- ation boards 50 ? input transmission line. a 900mhz in- put match requires c5 = 3.9pf, located at 1.3mm. a 3500mhz input match is realized with c5 = 0.5pf, located rf in z o = 50 ? l = l (mm) c5 rf 5527 f03 external matching for low band or high band only to mixer 3 figure 3. rf input schematic figure 4. rf input return loss with and without external matching rf frequency (ghz) 0.2 C30 rf port return loss (db) C25 C20 C15 C10 1.2 2.2 3.2 4.2 5527 f04b C5 0 0.7 1.7 2.7 3.7 no external matching 900mhz c5 = 3.9pf l = 1.3mm 450mhz c5 = 12pf l = 4.5mm 3.5ghz c5 = 0.5pf l = 4.5mm (4b) series shunt matching (4a) series reactance matching frequency (ghz) 0.2 C30 rf port return loss (db) C25 C20 C15 C10 1.2 2.2 3.2 4.2 5527 f04a C5 0 0.7 1.7 2.7 3.7 series 1.5nh series 2.7pf no external matching series 1.5nh series 2.7pf
10 LT5527 5527f at 4.5mm. this series transmission line/shunt capacitor matching topology allows the LT5527 to be used for mul- tiple frequency standards without circuit board layout modifications. the series transmission line can also be replaced with a series chip inductor for a more compact layout. input return loss for these three cases (450mhz, 900mhz and 3500mhz) are plotted in figure 4b. the input return loss with no external matching is repeated in figure 4b for comparison. rf input impedance and s11 versus frequency (with no external matching) is listed in table 1 and referenced to pin 3. the s11 data can be used with a microwave circuit simulator to design custom matching networks and simu- late board-level interfacing to the rf input filter. table 1. rf input impedance vs frequency frequency input s11 (mhz) impedance mag angle 50 4.8 + j2.6 0.825 173.9 300 9.0 + j11.9 0.708 152.5 450 11.9 + j15.3 0.644 144.3 600 14.3 + j18.2 0.600 137.2 900 19.4 + j23.8 0.529 123.2 1200 26.1 + j29.8 0.467 107.4 1500 37.3 + j33.9 0.386 89.3 1850 57.4 + j29.7 0.275 60.6 2150 71.3 + j10.1 0.193 20.6 2450 64.6 C j13.9 0.175 C36.8 2650 53.0 C j21.8 0.209 C70.3 3000 35.0 C j21.2 0.297 C111.2 3500 20.7 C j9.0 0.431 C155.8 4000 14.2 + j6.2 0.564 164.8 5000 10.4 + j31.9 0.745 113.3 lo input port the mixers lo input, shown in figure 5, consists of an integrated transformer and high speed limiting differential amplifiers. the amplifiers are designed to precisely drive the mixer for the highest linearity and the lowest noise figure. an internal dc blocking capacitor in series with the transformers primary eliminates the need for an external blocking capacitor. the lo input is internally matched from 1.2ghz to 5ghz, although the maximum useful frequency is limited to 3.5ghz by the internal amplifiers. the input match can be shifted down, as low as 750mhz, with a single shunt capacitor (c4) on pin 15. one example is plotted in figure 6 where c4 = 2.7pf produces an 850mhz to 1.2ghz match. lo input matching below 750mhz requires the series inductor (l4)/shunt capacitor (c4) network shown in figure 5. two examples are plotted in figure 6 where l4 = 3.9nh/c4 = 5.6pf produces a 650mhz to 830mhz match and l4 = 6.8nh/c4 = 10pf produces a 540mhz to 640mhz match. the evaluation boards do not include pads for l4, so the circuit trace needs to be cut near pin 15 to insert l4. a low cost multilayer chip inductor is adequate for l4. the optimum lo drive is C3dbm for lo frequencies above 1.2ghz, although the amplifiers are designed to accom- modate several db of lo input power variation without significant mixer performance variation. below 1.2ghz, applicatio s i for atio wu uu lo in c4 l4 lo v cc2 v bias limiter 5527 f05 external matching for low band only to mixer 15 lo frequency (ghz) 0.1 C30 lo port return loss (db) C25 C20 C15 C10 0 15 5527 f06 C5 l4 = 6.8nh c4 = 10pf l4 = 3.9nh c4 = 5.6pf l4 = 0nh c4 = 2.7pf no external matching figure 5. lo input schematic figure 6. lo input return loss
11 LT5527 5527f 0dbm lo drive is recommended for optimum noise figure, although C3dbm will still deliver good conversion gain and linearity. custom matching networks can be designed using the port impedance data listed in table 2. this data is refer- enced to the lo pin with no external matching. table 2. lo input impedance vs frequency frequency input s11 (mhz) impedance mag angle 50 30.4 C j355.7 0.977 C15.9 300 8.7 C j52.2 0.847 C86.7 450 9.4 C j25.4 0.740 C124.8 600 11.5 C j8.9 0.635 C158.7 900 19.7 + j12.8 0.463 146.7 1200 34.3 + j24.3 0.330 106.9 1500 49.8 + j21.3 0.209 78.5 1850 53.8 + j8.9 0.093 61.7 2150 50.4 + j3.2 0.032 80.5 2450 45.1 + j0.3 0.052 176.5 2650 41.1 + j2.4 0.101 163.1 3000 41.9 + j8.1 0.124 129.8 3500 49.0 + j12.0 0.120 87.9 4000 55.4 + j8.6 0.096 53.2 5000 33.2 + j8.7 0.226 146.7 if output port the if outputs, if + and if C , are internally connected to the collectors of the mixer switching transistors (see fig- ure 7). both pins must be biased at the supply voltage, which can be applied through the center tap of a trans- former or through matching inductors. each if pin draws 26ma of supply current (52ma total). for optimum single- ended performance, these differential outputs should be combined externally through an if transformer or a discrete if balun circuit. the standard evaluation board (see figure 1) includes an if transformer for impedance transformation and differential to single-ended transfor- mation. a second evaluation board (see figure 2) realizes the same functionality with a discrete if balun circuit. the if output impedance can be modeled as 415 ? in parallel with 2.5pf at low frequencies. an equivalent small-signal model (including bondwire inductance) is shown in figure 8. frequency-dependent differential if output impedance is listed in table 3. this data is refer- enced to the package pins (with no external components) and includes the effects of ic and package parasitics. the if output can be matched for if frequencies as low as several khz or as high as 600mhz. table 3. if output impedance vs frequency differential output frequency (mhz) impedance (r if || x if ) 1 415||-j64k 10 415||-j6.4k 70 415||-j909 140 413||-j453 240 407||-j264 300 403||-j211 380 395||-j165 450 387||-j138 500 381||-j124 the following three methods of differential to single- ended if matching will be described: ? direct 8:1 transformer ? lowpass matching + 4:1 transformer ? discrete if balun applicatio s i for atio wu uu 11 10 if + l1 4:1 l2 5527 f07 if C v cc c3 v cc if out 50 ? figure 7. if output with external matching 11 10 if + 0.7nh 0.7nh 5527 f08 if C 2.5pf r s 415 ? figure 8. if output small-signal model
12 LT5527 5527f direct 8:1 if transformer matching for if frequencies below 100mhz, the simplest if match- ing technique is an 8:1 transformer connected across the if pins. the transformer will perform impedance transfor- mation and provide a single-ended 50 ? output. no other matching is required. measured performance using this technique is shown in figure 9. this matching is easily implemented on the standard evaluation board by short- ing across the pads for l1 and l2 and replacing the 4:1 transformer with an 8:1 (c3 not installed). chip inductors (l1 and l2) improve the mixers conver- sion gain by a few tenths of a db, but have little effect on linearity. measured output return losses for each case are plotted in figure 10 for the simple 8:1 transformer method and for the lowpass/4:1 transformer method. table 4. if matching element values if frequency l1, l2 if plot (mhz) (nh) c3 (pf) transformer 1 1 to 100 short tc8-1 (8:1) 2 140 120 etc4-1-2 (4:1) 3 190 110 2.7 etc4-1-2 (4:1) 4 240 82 2.7 etc4-1-2 (4:1) 5 380 56 2.2 etc4-1-2 (4:1) 6 450 43 2.2 etc4-1-2 (4:1) applicatio s i for atio wu uu if output frequency (mhz) 10 g c (db), iip3 (dbm), ssb nf (db) 13 17 21 25 50 5527 f09 9 5 11 15 19 23 7 3 1 20 30 40 60 70 80 90 100 rf = 900mhz high side lo at 0dbm v cc = 5v dc t a = 25 c c4 = 2.7pf, c5 = 3.9pf iip3 ssb nf g c figure 9. typical conversion gain, iip3 and ssb nf using an 8:1 if transformer lowpass + 4:1 if transformer matching the lowest lo-if leakage and wide if bandwidth are realized by using the simple, three element lowpass match- ing network shown in figure 7. matching elements c3, l1 and l2, in conjunction with the internal 2.5pf capacitance, form a 400 ? to 200 ? lowpass matching network which is tuned to the desired if frequency. the 4:1 transformer then transforms the 200 ? differential output to a 50 ? single-ended output. this matching network is most suitable for if frequencies above 40mhz or so. below 40mhz, the value of the series inductors (l1 and l2) becomes unreasonably high, and could cause stability problems, depending on the inductor value and parasitics. therefore, the 8:1 transformer tech- nique is recommended for low if frequencies. suggested lowpass matching element values for several if frequencies are listed in table 4. high-q wire-wound if frequency (mhz) C30 if port return loss (db) C20 C10 0 C25 C15 C5 100 200 300 400 5527 f10 500 50 1 2 3 45 6 0 150 250 350 450 figure 10. if output return losses with lowpass/transformer matching discrete if balun matching for many applications, it is possible to replace the if transformer with the discrete if balun shown in figure 2. the values of l1, l2, c6 and c7 are calculated to realize a 180 degree phase shift at the desired if frequency and provide a 50 ? single-ended output, using the equations listed below. inductor l3 is calculated to cancel the internal 2.5pf capacitance. l3 also supplies bias voltage to the if + pin. low cost multilayer chip inductors are ad- equate for l1 and l2. a high q wire-wound chip inductor is recommended for l3 to maximize conversion gain and minimize dc voltage drop to the if + pin. c3 is a dc blocking capacitor.
13 LT5527 5527f applicatio s i for atio wu uu ll rr cc rr l x if out if if if out if if 12 67 1 3 , ? , ?? = = = compared to the lowpass/4:1 transformer matching tech- nique, this network delivers approximately 0.8db higher conversion gain (since the if transformer loss is elimi- nated) and comparable noise figure and iip3. at a 15% offset from the if center frequency, conversion gain and noise figure degrade about 1db. beyond 15%, conver- sion gain decreases gradually but noise figure increases rapidly. iip3 is less sensitive to bandwidth. other than if bandwidth, the most significant difference is lo-if leak- age, which degrades to approximately C 38dbm compared to the superior performance realized with the lowpass/4:1 transformer matching. discrete if balun element values for four common if frequencies are listed in table 5. the corresponding measured if output return losses are shown in figure 11. the values listed in table 5 differ from the calculated values slightly due to circuit board and component parasitics. typical conversion gain, iip3 and lo-if leak- age, versus rf input frequency, for all four if frequency examples is shown in figure 12. typical conversion gain, iip3 and noise figure versus if output frequency for the same circuits are shown in figure 13. table 5. discrete if balun element values (r out = 50 ? ) if frequency l1, l2 c6, c7 l3 (mhz) (nh) (pf) (nh) 190 120 6.8 220 240 100 4.7 220 380 56 3 68 450 47 2.7 47 for fully differential if architectures, the if transformer can be eliminated. an example is shown in figure 14, where the mixers if output is matched directly into a saw filter. supply voltage to the mixers if pins is applied if frequency (mhz) C30 if port return loss (db) C20 C10 0 C25 C15 C5 150 250 350 450 5527 f11 550 100 50 200 300 400 500 190mhz 240mhz 380mhz 450mhz figure 11. if output return losses with discrete balun matching rf input frequency (mhz) 1700 g c (db), iip3 (dbm) lo-if leakage (dbm) 14 18 22 26 2500 5527 f12 10 6 12 16 20 24 8 4 2 C30 C20 C10 0 C40 C50 C60 1900 2100 2300 2700 190if 240if 380if 450if low side lo (C3dbm) t a = 25 c iip3 lo-if g c figure 12. conversion gain, iip3 and lo-if leakage vs rf input frequency using discrete if balun matching if output frequency (mhz) 150 g c , ssb nf (db), iip3 (dbm) 12 18 20 550 5527 f13 10 8 0 250 350 450 200 300 400 500 4 26 24 22 iip3 g c 16 14 6 2 190if 240if 380if 450if low side lo (C3dbm) t a = 25 c ssb nf figure 13. conversion gain, iip3 and ssb nf vs if output frequency using discrete if balun matching
14 LT5527 5527f applicatio s i for atio wu uu through matching inductors in a band-pass if matching network. the values of l1, l2 and c3 are calculated to resonate at the desired if frequency with a quality factor that satisfies the required if bandwidth. the l and c values are then adjusted to account for the mixers internal 2.5pf capacitance and the saw filters input capacitance. in this case, the differential if output imped- ance is 400 ? since the bandpass network does not transform the impedance. additional matching elements may be required if the saw filters input impedance is less than or greater than 400 ? . contact the factory for application assistance. if amp saw filter l1 if + if C l2 c3 supply decoupling v cc 5527 f14 figure 14. bandpass if matching for differential if architectures standard evaluation board layout discrete if evaluation board layout
15 LT5527 5527f 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 represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. u package descriptio uf package 16-lead plastic qfn (4mm 4mm) (reference ltc dwg # 05-08-1692) 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 16 15 1 2 bottom viewexposed 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 C 0.05 (uf) qfn 09-04 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 0.25 45 chamfer
16 LT5527 5527f ? linear technology corporation 2005 lt/tp 0305 500 ?printed in the usa linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com related parts part number description comments infrastructure lt5511 high linearity upconverting mixer rf output to 3ghz, 17dbm iip3, integrated lo buffer lt5512 dc-3ghz high signal level downconverting mixer dc to 3ghz, 17dbm iip3, integrated lo buffer lt5514 ultralow distortion, if amplifier/adc driver 850mhz bandwidth, 47dbm oip3 at 100mhz, 10.5db to 33db gain control range with digitally controlled gain lt5515 1.5ghz to 2.5ghz direct conversion quadrature 20dbm iip3, integrated lo quadrature generator demodulator lt5516 0.8ghz to 1.5ghz direct conversion quadrature 21.5dbm iip3, integrated lo quadrature generator demodulator lt5517 40mhz to 900mhz quadrature demodulator 21dbm iip3, integrated lo quadrature generator lt5519 0.7ghz to 1.4ghz high linearity upconverting mixer 17.1dbm iip3 at 1ghz, integrated rf output transformer with 50 ? matching, single-ended lo and rf ports operation lt5520 1.3ghz to 2.3ghz high linearity upconverting mixer 15.9dbm iip3 at 1.9ghz, integrated rf output transformer with 50 ? matching, single-ended lo and rf ports operation lt5521 10mhz to 3700mhz high linearity 24.2dbm iip3 at 1.95ghz, nf = 12.5db, 3.15v to 5.25v supply, single-ended upconverting mixer lo port operation lt5522 400mhz to 2.7ghz high signal level 4.5v to 5.25v supply, 25dbm iip3 at 900mhz, nf = 12.5db, 50 ? single-ended rf downconverting mixer and lo ports lt5524 low power, low distortion adc driver with digitally 450mhz bandwidth, 40dbm oip3, 4.5db to 27db gain control programmable gain lt5525 high linearity, low power downconverting mixer single-ended 50 ? rf and lo ports, 17.6dbm iip3 at 1900mhz, i cc = 28ma lt5526 high linearity, low power downconverting mixer 3v to 5.3v supply, 16.5dbm iip3, 100khz to 2ghz rf, nf = 11db, i cc = 28ma, C65dbm lo-rf leakage lt5528 1.5ghz to 2.4ghz high linearity direct i/q 21.8dbm oip3 at 2ghz, C159dbm/hz noise floor, 50 ? interface at all ports modulator rf power detectors lt5504 800mhz to 2.7ghz rf measuring receiver 80db dynamic range, temperature compensated, 2.7v to 5.25v supply ltc ? 5505 rf power detectors with >40db dynamic range 300mhz to 3ghz, temperature compensated, 2.7v to 6v supply ltc5507 100khz to 1000mhz rf power detector 100khz to 1ghz, temperature compensated, 2.7v to 6v supply ltc5508 300mhz to 7ghz rf power detector 44db dynamic range, temperature compensated, sc70 package ltc5509 300mhz to 3ghz rf power detector 36db dynamic range, low power consumption, sc70 package ltc5530 300mhz to 7ghz precision rf power detector precision v out offset control, shutdown, adjustable gain ltc5531 300mhz to 7ghz precision rf power detector precision v out offset control, shutdown, adjustable offset ltc5532 300mhz to 7ghz precision rf power detector precision v out offset control, adjustable gain and offset lt5534 50mhz to 3ghz rf power detector with 60db 1db output variation over temperature, 38ns response time dynamic range ltc5536 precision 600mhz to 7ghz rf detector 25ns response time, comparator reference input, latch enable input, with fast compatator output C26dbm to +12dbm input range low voltage rf building block lt5546 500mhz quadrature demodulator with vga and 17mhz baseband bandwidth, 40mhz to 500mhz if, 1.8v to 5.25v supply, C7db to 17mhz baseband bandwidth 56db linear power gain wide bandwidth adcs ltc1749 12-bit, 80msps 500mhz bw s/h, 71.8db snr ltc1750 14-bit, 80msps 500mhz bw s/h, 75.5db snr

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