general description the MAX3524 broadband amplifier is designed specifi- cally for cable television receiver and cable modem applications. the MAX3524 is a single-ended input, dif- ferential-output low-noise amplifier (lna) that offers 15db of gain. it operates from a +4.75v to +5.25v sin- gle supply from 44mhz to 880mhz. the MAX3524 includes an operational amplifier that is used to control an off-chip pin attenuator circuit at the input of the lna. the attenuator is typically used to regulate the input signal to a value that maintains high linearity for large signals. the MAX3524 is available in a 10-pin ?ax package with an exposed paddle (ep) and oper- ates in the extended temperature range (-40? to +85?). applications cable modem cable set-top box broadband amplifier catv infrastructure features single-ended input, differential output +4.75v to +5.25v single-supply operation broadband operation: 44mhz to 880mhz low noise figure: 4.2db high linearity: iip2 (42dbm), iip3(14dbm) voltage gain: 15db independent on-chip op amp MAX3524 low-noise, high-linearity broadband amplifier ________________________________________________________________ maxim integrated products 1 opin- r2 3k ? 10nf d2 cmdsh-3 d1 cmdsh-3 r1 3k ? from demod ic to control pin attenuator l1 = 0.5nh to 1nh l2 = 0.5nh to 1nh c l < 1.8pf output to tuner (differential drive) rfout+ rfin 1 2 rfgnd gnd *exposed paddle input: 44-880mhz 75 ? to 2k ? opout pin attenuator opin+ rfout- v cc r bias = 5.9 ? l bias = 680nh 0.1 f 0.1 f 10 f 0.1 f 0.1 f v cc = 5v 10 f v cc = 5v v cc op amp bias MAX3524 * 3 4 5 10 9 8 7 6 typical application circuit 19-1764; rev 1; 8/03 pin configuration appears at end of data sheet. ordering information part temp range pin-package MAX3524evb -40 c to +85 c 10 max-ep* *exposed paddle 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.
MAX3524 low-noise, high-linearity broadband amplifier 2 _______________________________________________________________________________________ absolute maximum ratings dc electrical characteristics ( typical application circuit , v cc = +4.75v to +5.25v, r bias = 5.9 ? , l bias = 680nh, t a = -40 c to +85 c, unless otherwise indicat- ed. typical values measured at v cc = +5.0v, t a = +25 c.) (notes 1, 2) ac electrical characteristics (MAX3524 ev kit as shown in figure 1 , v cc = +4.75v to +5.25v, p rfin = -20dbm, z s = 75 ? , r bias = 5.9 ? , l bias = 680nh, f in = 44mhz, z l = 50 ? || 2pf, t a = +25 c. typical values are at v cc = +5v, unless otherwise indicated.) (notes 2, 3) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. note 1: parameters are production tested at t a = +25 c and t a = +85 c. limits are guaranteed by design and characterization for t a = -40 c to +25 c. note 2: for optimum linearity, the dc resistance of l bias in series with r bias must be approximately 7.3 ? . note 3: guaranteed by design and characterization. note 4: gain is guaranteed over the operating frequency range, by design and characterization. insertion loss of balun is subtracted. production tested at 44mhz and 880mhz. note 5: corresponding voltage gain at r l = 3k ? , calculated as in figure 2. note 6: frequencies and input power levels: 275mhz, 325mhz, and -20dbm per tone. v cc to gnd ...........................................................-0.3v to +7.0v rfin ....................................................................................+2.0v p rfin ...................................................................................0dbm r bias (minimum) .......................................................................5 ? rfout+, rfout-, opin-, opin+, opout...-0.3v to (v cc + 0.3v) rfout+, rfout- short-circuit duration ...............................10s continuous power dissipation (t a = +70 c) 10-pin max (derate 10.3mw/ c above +70 c) .........825mw operating temperature range ...........................-40 c to +85 c storage temperature range .............................-65 c to +150 c junction temperature ......................................................+150 c lead temperature (soldering, 10s) .................................+300 c parameters conditions min typ max units supply supply voltage 4.75 5.25 v supply current 85 95 ma operational amplifier common-mode input range 0.5 3.0 v maximum output voltage i o = 20ma v cc - 0.5 v minimum output voltage i o = 20ma 0.5 v parameters conditions min typ max units operating frequency range 44 880 mhz t a = +25 c 8.0 9.8 11 power gain (note 4) t a = -40 c to +85 c 7.6 11.5 db voltage gain (note 5) r l = 3k ? 15 db noise figure (note 3) f rfin = 300mhz 4.2 4.9 db iip3 (notes 3, 6) 12 14 dbm iip2 (notes 3, 6) 40 42 dbm output-to-input isolation f rfin = 300mhz 40 60 db caution! esd sensitive device
MAX3524 low-noise, high-linearity broadband amplifier _______________________________________________________________________________________ 3 82 84 83 85 88 89 87 86 90 4.5 4.7 4.8 4.9 5.0 4.6 5.1 5.2 5.3 5.4 5.5 current vs. voltage MAX3524toc01 v cc (v) i cc (ma) t a = +25 c t a = +85 c t a = -40 c 6 7 8 9 10 11 12 40 240 140 340 440 540 640 740 840 940 power gain vs. frequency MAX3524 toc02 frequency (mhz) gain (db) t a = -45 c t a = +25 c t a = +85 c zs = 50 ? c l = 1.5pf 6 8 7 11 10 9 13 12 14 40 340 440 140 240 540 640 740 840 940 power gain vs. frequency MAX3524 toc03 frequency (mhz) gain (db) t a = -40 c t a = +25 c t a = +85 c zs = 75 ? c l = 1.5pf 6 7 8 9 10 11 12 40 240 140 340 440 540 640 740 840 940 power gain vs. frequency MAX3524 toc04 frequency (mhz) gain (db) t a = +25 c z s = 50 ? c l = 1.5pf v cc = 4.75, 5.00, 5.25 6 7 8 9 10 11 12 40 240 140 340 440 540 640 740 840 940 power gain vs. frequency MAX3524 toc05 frequency (mhz) gain (db) t a = +25 c z s = 75 ? c l = 1.5pf v cc = 4.75, 5.00, 5.25 0 1 2 3 4 5 6 40 240 140 340 440 540 640 740 840 940 noise figure vs. frequency MAX3524 toc06 frequency (mhz) noise figure (db) t a = +85 c t a = +25 c t a = -40 c 8 14 12 10 16 18 20 50 450 350 150 250 550 650 750 850 950 iip3 vs. frequency MAX3524 toc07 frequency (mhz) iip3 (dbm) t a = -40 c t a = +25 c t a = +85 c zs = 75 ? 30 35 40 45 50 55 60 100 300 200 400 500 600 700 800 900 1000 iip2 vs. frequency MAX3524 toc08 frequency (mhz) iip2 (dbm) t a = -40 c t a = +25 c t a = +85 c zs = 75 ? 4 10 8 6 12 14 16 40 440 340 140 240 540 640 740 840 940 1db compressed output power vs. frequency MAX3524toc09 frequency (mhz) p out (dbm) v cc = 5.25v v cc = 5.00v v cc = 4.75v typical operating characteristics (MAX3524 ev kit as shown in figure 1 , v cc = +5v, p rfin = -20dbm, z l = 50 ? || 2pf, r bias = 5.9 ? , l bias = 680nh, insertion loss of balun subtracted, t a = +25 c.)
MAX3524 low-noise, high-linearity broadband amplifier 4 _______________________________________________________________________________________ -80 -75 -70 -65 -60 -55 -50 -45 -40 20 70 120 170 220 psrr vs. frequency MAX3524toc11 frequency (mhz) psrr (db) typical operating characteristics (continued) (MAX3524 ev kit as shown in figure 1 , v cc = +5v, p rfin = -20dbm, z l = 50 ? || 2pf, r bias = 5.9 ? , l bias = 680nh, insertion loss of balun subtracted, t a = +25 c.) 0 50 100 150 200 250 300 350 400 40 240 440 640 840 resistance and capacitance vs. frequency MAX3524 toc12 frequency (mhz) resistance ( ? ) resistance z in = r ii c capacitance 1 1.5 2.0 2.5 capacitance (pf) pin description pin name function 1, 9 v cc supply voltage input. connect both pins together. bypass with a 10 f and 47pf capacitor to gnd. 2 rfin rf input of lna. requires dc blocking capacitor. 3 rfgnd bypass to gnd through 10nf capacitor. 4 opout operational amplifier output 5 opin- inverting input of operational amplifier 6 bias lna bias setting pin. for nominal bias, connect 5.9 ? resistor in series with 680nh to gnd (total dc resistance = resistance of r bias + dc resistance of the inductor = 7.3 ? ). the value of the resistor is adjusted to alter the current and therefore linearity of the lna. 7 opin+ noninverting input of operational amplifier 8 rfout- inverting output of lna 10 rfout+ noninverting output of lna slug gnd ground 0 1 2 3 4 5 6 0 1.0 0.5 1.5 2.0 2.5 3.0 3.5 4.0 op amp closed-loop voltage gain of 2 vs. frequency MAX3524 toc13 frequency (mhz) v gain (db) -80 -75 -70 -65 -60 -55 -50 -45 -40 40 240 440 640 840 isolation vs. frequency MAX3524toc10 frequency (mhz) isolation (db)
detailed description the MAX3524 is a broadband amplifier with a single- ended input and differential outputs, including an oper- ational amplifier that can be used to control an external attenuator circuit. figure 1 is the MAX3524 ev kit schematic. low-noise amplifier the low-noise amplifier operates from 44mhz to 880mhz and is designed specifically for cable tv and cable modem applications. the lna provides 15db of insertion voltage gain ( see figure 2) when driving a 3k ? load. at 300mhz, the noise figure is 4.2db, iip2 and iip3 are 42dbm and 14dbm, respectively. operational amplifier the operational amplifier is suitable for interfacing to a pin attenuator circuit which is typically employed at the input of the lna. the common-mode input range is 0.5v to 3v and the output voltage swing is 0.5v to v cc - 0.5v while sinking or sourcing 20ma. input bias current and input offset voltage are 1a and 1mv, respectively. the open-loop voltage gain is greater than 10,000. the gain bandwidth product is greater than 1mhz for a closed-loop voltage gain of one. MAX3524 low-noise, high-linearity broadband amplifier _______________________________________________________________________________________ 5 2v in 330 ? 30 ? 30 ? 75 ? z s rfin v cc (pin9) v1 0.06v1 1.8pf rfout- rfout+ a v = (v rfout + ) - (v rfout -) = 5.7 v in a v (db) = 20log 10 a v = 15db figure 2. lna equivalent circuit and open-circuit voltage gain calculation rf input to attenuator c11 0.1 f c10 0.1 f r9 100 ? r10 3k ? d1 d2 r7 10k ? v cc c12 0.1 f r2 r4 50k ? r3 50k ? r1 13.3 ? v cc c1 47pf v cc v cc rfin rfgnd op out op in r bias 5.81 ? l bias 0.1 f c2 2pf c15 0.1 f c15 0.1 f c14 47pf v cc rf output rf out- vcc2 rf out+ opin+ bias r8 3k ? d1, d2 small-signal schottky diodes, typically cmdsh-3 figure 1. MAX3524 ev kit schematic
MAX3524 applications information bias current the resistor, r bias , connected between bias and gnd controls the lna current. to make the current insensi- tive to temperature fluctuations, select a 1%, low tem- perature coefficient resistor for r bias . the current drawn by the lna is calculated using the following for- mula: i bias 0.58v / (r bias + dc resistance of l bias ) it is important to include the inductor resistance in the above equation as it is typically 1 ? to 2 ? . the MAX3524 ev kit uses a nominal inductor with dc resis- tance of 1.4 ? . higher values of r bias may be used to reduce supply current predominantly at the expense of linearity. circuit board layout and source impedance may require the value of i bias to be optimized for best linearity. input and output the lna input is single-ended. the rf input signal is coupled to rfin through a dc blocking capacitor. the lna outputs drive a differential load, such as a mixer, through dc blocking capacitors. the equivalent input lna impedance is 330 ? resistive in parallel with 1.8pf, as shown in figure 2. the approximate equivalent dif- ferential output impedance of the lna is 60 ? . to achieve s11 less than -6db, an insertion loss of greater than 1db must exist between the cable input and MAX3524. this loss typically comes from a diplexer and pin attenuator in a cable modem application. a shunt resistor may be added at the input of the lna to improve the return loss (s11). typically the return loss of the system is 2db better, as explained above. the s11 and noise-figure values for different shunt resistors are given in table 1. rf input power control using the operational amplifier in a cable system, the power level at the lna input is typically restricted to a maximum value to maintain lin- earity. this is accomplished by connecting a variable attenuator at the input of the lna and varying the atten- uation with the operational amplifier output. the opera- tional amplifier receives a dc control input that is proportional to lna output power. see typical application circuit . layout issues a properly designed pc board is essential to any rf/microwave circuit. use short interconnect and con- trolled impedance lines on all high-frequency inputs and outputs. use low inductance connections to ground on all gnd nodes and place decoupling capacitors close to all v cc connections. the ep is the ground for the MAX3524 and must be soldered to ground for proper operation. low-noise, high-linearity broadband amplifier 6 _______________________________________________________________________________________ r shunt ( ? ) ? s1 1 ? (lna) (db) noise figure (db) 450 -6 5 to 5.5 250 -8 5.5 to 6 125 -10 6 to 6.5 1 2 3 4 5 10 9 8 7 6 rfout+ v cc refout- opin+ opout rfgnd rfin v cc MAX3524 max top view bias opin- pin configuration chip information transistor count: 550 table 1. shunt-resistor noise-figure values
MAX3524 low-noise, high-linearity broadband amplifier maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 _____________________ 7 ? 2003 maxim integrated products printed usa is a registered trademark of maxim integrated products. 10lumax.eps package outline, 10l umax/usop 1 1 21-0061 i rev. document control no. approval proprietary information title: top view front view 1 0.498 ref 0.0196 ref s 6 side view bottom view 0 0 6 0.037 ref 0.0078 max 0.006 0.043 0.118 0.120 0.199 0.0275 0.118 0.0106 0.120 0.0197 bsc inches 1 10 l1 0.0035 0.007 e c b 0.187 0.0157 0.114 h l e2 dim 0.116 0.114 0.116 0.002 d2 e1 a1 d1 min -a 0.940 ref 0.500 bsc 0.090 0.177 4.75 2.89 0.40 0.200 0.270 5.05 0.70 3.00 millimeters 0.05 2.89 2.95 2.95 - min 3.00 3.05 0.15 3.05 max 1.10 10 0.60.1 0.60.1 ? 0.500.1 h 4x s e d2 d1 b a2 a e2 e1 l l1 c gage plane a2 0.030 0.037 0.75 0.95 a1 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 .)
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