for free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. for small orders, phone 1-800-835-8769. general description the max2470/max2471 are flexible, low-cost, high- reverse-isolation buffer amplifiers for applications with discrete and module-based vco designs. both feature differential 50 outputs for driving a single differential (balanced) load or two separate single-ended (unbal- anced) 50 loads. the max2470 offers a single-ended input and has two selectable frequency ranges of oper- ation: 10mhz to 500mhz and 10mhz to 200mhz. the max2471 offers a differential input and operates from 10mhz to 500mhz. the max2470/max2471 also feature high input impedance for maximum flexibility, enabling them to be used with a variety of oscillator topologies. high reverse isolation combined with low supply current make them ideal for applications requiring high perfor- mance with low power. these devices are also ideal for use as active baluns. the max2470 converts a single-ended input to a differ- ential output. the max2471 is useful as a differential buffer stage or to convert from a differential input to two single-ended outputs. the max2470 operates from a single +2.7v to +5.5v supply. at -5dbm output power, it consumes 5.5ma in the high-frequency range and only 3.6ma in the low-frequency r ange. the max2471 operates from a +2.7v to +5.5v single supply and consumes 5.5ma. both devices are available in ultra-small sot23-6 plas- tic packages, requiring minimal board space. applications cellular and pcs mobile phones ism-band applications active baluns general-purpose buffers/amplifiers features ? +2.7v to +5.5v supply range ? input frequency range high: 10mhz to 500mhz (max2470/2471) low: 10mhz to 200mhz (max2470) ? >14db power gain at 200mhz ? 64db typical reverse isolation at 200mhz ? low-distortion output drive ? ultra-small sot23-6 package ? high input impedance ? single-ended (max2470) or differential (max2471) inputs max2470/max2471 10mhz to 500mhz vco buffer amplifiers with differential outputs ________________________________________________________________ maxim integrated products 1 out bias v cc gnd out 50 w 50 w in hi/lo max2470 out bias v cc gnd out 50 w 50 w in in max2471 gnd hi/lo (in) out ( ) are for max2471 16 v cc 5 in out max2470 max2471 sot23-6 top view 2 34 typical operating circuits 19-4797; rev 0; 2/99 part max2470 eut-t max2471 eut-t -40? to +85? -40? to +85? temp. range pin- package 6 sot23-6 6 sot23-6 evaluation kit manual follows data sheet pin configuration ordering information sot top mark aaax aaay
f out = 200mhz, rhi/ lo = gnd no signal max2470/max2471 10mhz to 500mhz vco buffer amplifiers with differential outputs 2 _______________________________________________________________________________________ absolute maximum ratings dc electrical characteristics (typical operating circuit, v cc = +2.7v to +5.5v, t a = t min to t max , unless otherwise noted. typical values are at v cc = +3v, t a = +25?.) (note 1) ac electrical characteristics?ax2470 (v cc = +3v, hi/ lo = v cc , all outputs are differentially measured between out and out driving a 50 load through a 180 hybrid, t a = +25?, unless otherwise noted.) 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. v cc to gnd ..............................................................-0.3v to +7v in to gnd......-0.3v to (v cc + 0.3v) or 3.7v (whichever is lower) in to in ..................................................................-2.2v to +2.2v hi/ lo to gnd .............................................-0.3v to (v cc + 0.3v) continuous power dissipation sot23-6 (derate 8.7mw/? above +70?)...................696mw operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? lead temperature (soldering, 10sec ) ............................+300? vhi/ lo = gnd or v cc conditions ma 5.1 7.4 v 2.7 5.5 v cc supply voltage range ? -10 10 i in hi/ lo input bias current 3.0 4.5 v 2.0 v ih hi/ lo input level high v 0.6 v il hi/ lo input level low units min typ max symbol parameter hi/ lo = v cc hi/ lo = gnd hi/ lo = v cc conditions 14.9 mhz 10 200 f in 10 500 input frequency range (note 2) 14.9 13.8 14.1 units min typ max symbol parameter hi/ lo = v cc 5.5 hi/ lo = gnd 3.6 i cc supply current f in = 10mhz, hi/ lo = gnd r source = 50 v/v 16 a v voltage gain (note 4) 10.2 db 10.2 nf noise figure 8.9 13.3 15.3 hi/ lo = gnd db 9.9 13.4 15.0 is 21 i 2 gain (note 3) no signal p out = -5dbm, r load = 100 diff. no signal p out = -5dbm, r load = 100 diff. f in = 10mhz f in = 200mhz f in = 500mhz, t a = t min to t max f in = 10mhz f in = 200mhz f in = 200mhz, t a = t min to t max f out = 500mhz, hi/ lo = v cc f out = 200mhz, rhi/ lo = gnd
max2470/max2471 10mhz to 500mhz vco buffer amplifiers with differential outputs _______________________________________________________________________________________ 3 ac electrical characteristics?ax2471 (typical values are measured at v cc = +3v, t a = +25?, unless otherwise noted.) (note 8) ac electrical characteristics?ax2470 (continued) (v cc = +3v, hi/ lo = v cc , all outputs are differentially measured between out and out driving a 50 load through a 180 hybrid, t a = +25?, unless otherwise noted.) note 1: limits are 100% production tested at t a = +25?. limits over the entire operating temperature range are guaranteed by design and characterization but are not production tested. note 2: the part has been characterized over the specified frequency range. operation outside of this range is possible but not guaranteed. note 3: gain specified for p out = -5dbm. note 4: voltage gain measured with no input termination and no output load. note 5: output vswr is a single-ended measurement for each out and out . note 6: out to in isolation with out terminated with 50 . note 7: input terminated with 50 . note 8: unless otherwise noted: all inputs are differentially measured between in and in driven by a 50 load through a 180 hybrid; all outputs are differentially measured between out and out driving a 50 load through a 180 hybrid. 10mhz < f out < 500mhz, hi/ lo = v cc 1.5:1 conditions 10mhz < f out < 200mhz, hi/ lo = gnd 1.2:1 vswr out maximum output vswr (out, out ) (note 5) units min typ max symbol parameter 75 48 f in = 500mhz, hi/ lo = v cc 37 75 f in = 200mhz, hi/ lo = gnd db 45 isolation out to out (note 7) hi/ lo = v cc db 64 is 12 i 2 reverse isolation (note 6) f in = 200mhz, p out = -5dbm, hi/ lo = gnd dbc -30 harmonic suppression f in = 500mhz, p out = -5dbm, hi/ lo = v cc -26 f in = 100mhz f in = 500mhz f in = 100mhz f in = 200mhz hi/ lo = gnd f in = 10mhz f out = 500mhz, r source = 50 f in = 10mhz db is 21 i 2 gain (note 3) v/v 16 a v voltage gain (note 4) 8.4 f in = 200mhz conditions f in = 500mhz, t a = t min to t max 11.3 15.6 17.8 15.9 mhz 10 500 f in input frequency range (note 2) 16.9 units min typ max symbol parameter db nf noise figure 10mhz < f out < 500mhz 1.5:1 vswr out maximum output vswr (out, out ) (note 5) f in = 100mhz 74 f in = 500mhz 57 db is 12 i 2 reverse isolation f in = 500mhz 35 db isolation out to out (note 7) f in = 500mhz, p out = -5dbm -29 dbc harmonic suppression
max2470/max2471 10mhz to 500mhz vco buffer amplifiers with differential outputs 4 _______________________________________________________________________________________ typical operating characteristics (v cc = +3.0v, max2470 output and max2471 input and output measurements taken differentially, t a = +25?, unless otherwise noted.) 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 2.5 3.5 3.0 4.0 4.5 5.0 5.5 max2470 supply current vs. supply voltage (hi/lo = gnd) max2470/71-01 supply voltage (v) supply current (ma) -5dbm output power f in = 200mhz hi/lo = gnd t a = +85? t a = +25? t a = -40? 4.8 5.0 4.9 5.1 5.3 5.2 5.4 5.5 5.6 5.7 5.8 5.9 6.0 2.5 3.5 3.0 4.0 4.5 5.0 5.5 max2470 (hi/lo = v cc ) and max2471 supply current vs. supply voltage max2470/71-02 supply voltage (v) supply current (ma) t a = +25? -5dbm output power f in = 500mhz hi/lo = gnd (max2470) t a = -40? t a = +85? -16 -13 -14 -15 -12 -9 -10 -11 -8 -7 -5 -6 -4 -3 -1 -2 0 -30 -24 -26 -28 -20 -22 -16 -18 -12 -14 -10 max2470 output power vs. input power max2470/71-03 input power (dbm) output power (dbm) hi/lo = gnd f in = 200mhz hi/lo = v cc f in = 500mhz 8.0 10.0 9.0 14.0 13.0 12.0 11.0 15.0 16.0 0 100 50 150 200 max2470/71-04 frequency (mhz) is 21 i 2 (db) t a = -40? hi/lo = gnd max2470 transducer gain vs. frequency (hi/lo = gnd) t a = +25? t a = +85? 10.0 11.0 10.5 11.5 12.0 0 200 300 100 400 500 max2470 noise figure vs. frequency (hi/lo = v cc ) max2470/71-07 frequency (mhz) noise figure (db) hi/lo = v cc 9.0 10.0 14.0 13.0 12.0 11.0 15.0 17.0 16.0 0 200 100 300 400 500 max2470 transducer gain vs. frequency (hi/lo = v cc ) max2470/71-05 frequency (mhz) is 21 i 2 (db) t a = +85? t a = +25? t a = -40? hi/lo = v cc 9.5 10.0 11.0 10.5 11.5 12.0 0 100 50 150 200 max2470 noise figure vs. frequency (hi/lo = gnd) max2470/71-06 frequency (mhz) noise figure (db) hi/lo = gnd 10,000 1 0 150 200 50 100 350 500 max2470 real input impedance vs. frequency 10 100 1000 max2470/71-08 frequency (mhz) re [z in ] ( w ) 250 300 450 400 hi/lo = v cc -3000 -2000 -2500 -1000 -1500 -500 0 0 200 100 300 400 500 max2470 imaginary input impedance vs. frequency max2470/71-09 frequency (mhz) im [z in ] ( w ) hi/lo = v cc
max2470/max2471 10mhz to 500mhz vco buffer amplifiers with differential outputs _______________________________________________________________________________________ 5 1.00 1.25 1.50 0 200 100 300 400 500 max2470 output vswr vs. frequency max2470/71-10 frequency (mhz) output vswr hi/lo = v cc input terminated in 50 w single-ended measurement out out 20 40 30 70 60 50 80 90 0 200 100 300 400 500 max2470 output isolation vs. frequency max2470/71-11 frequency (mhz) output isolation (db) hi/lo = v cc single-ended measurement out to in out to in out to out input terminated in 50 w -14 -12 -10 -8 -6 -4 -2 0 2 -30 -24 -22 -28 -26 -20 -18 -16 -14 -12 -10 max2471 output power vs. input power max2470/71-12 input power (dbm) output power (dbm) f in = 200mhz f in = 500mhz typical operating characteristics (continued) (v cc = +3.0v, max2470 output and max2471 input and output measurements taken differentially, t a = +25? unless otherwise noted.) 14.0 14.5 15.0 15.5 16.0 16.5 17.0 17.5 0 150 200 50 100 250 300 350 400 450 500 max2471 differential transducer power gain vs. frequency max2470/71-13 frequency (mhz) transducer power gain (db) t a = +25? t a = +85? t a = -40? 7.25 7.50 7.75 8.00 8.25 8.50 0 150 200 50 100 250 300 350 400 450 500 max2471 noise figure vs. frequency max2470/71-14 frequency (mhz) noise figure (db) 1 10 100 1000 10,000 0 150 200 50 100 250 300 350 400 450 500 max2471 real input impedance vs. frequency max2470/71-15 frequency (mhz) re [z in ] ( w ) -1000 -500 0 500 0 200 100 300 400 500 max2471 imaginary input impedance vs. frequency max2470/71-16 frequency (mhz) im [z in ] ( w ) 1.00 1.25 1.50 0 200 100 300 400 500 max2471 output vswr vs. frequency max2470/71-17 frequency (mhz) output vswr input terminated single-ended measurement vswr out vswr out 20 30 60 50 40 80 70 90 0 200 300 100 400 500 max2471 output isolation vs. frequency max2470/71-18 frequency (mhz) output isolation (db) out to in input terminated in 50 w out to out single-ended measurement
_______________ detailed description bandwidth control circuitry the max2470 features a logic-controlled bias circuit which optimizes the performance for input frequencies from 10mhz to 500mhz (hi/ lo = v cc ) and 10mhz to 200mhz (hi/ lo = gnd). operating with hi/ lo = gnd significantly reduces power consumption. __________ applications information input considerations the max2470/max2471 offer high-impedance inputs, ideal for low-distortion buffering of a vco. for applica- tions with discrete transistor-based oscillator designs, simply ac-couple the oscillator directly to the inputs. the buffer? high input impedance results in minimal loading on the oscillator. for still higher real input impedance and reduced loading effects, match the inputs with a shunt-l matching circuit followed by a series blocking capacitor. for use with 50 vco mod- ules, terminate the buffer input(s) with a 50 shunt resistor followed by a series-blocking capacitor. this provides a very stable 50 termination and increases reverse isolation. for those applications needing both high gain and good input match, reactively match the buffer inputs to 50 with simple two-element matching circuits followed by a series blocking capacitor. output considerations the max2470 and max2471 incorporate fully differen- tial output stages capable of driving an ac-coupled 100 differential load or two ac-coupled 50 single- ended loads. this is ideal for applications that require the oscillator to drive two application circuits (e.g. mixer and pll) simultaneously. the high output-to-output iso- lation ensures minimal interaction between multiple load circuits. layout and power-supply bypassing a properly designed pc board is essential to any rf/ microwave circuit. be sure to use controlled impedance lines on all high-frequency inputs and outputs. bypass the power supply with decoupling capacitors as close to the v cc pins as possible. for long v cc lines (inductive), it may be necessary to add additional decoupling capaci- tors located further away from the device package. proper grounding of gnd is essential. if the pc board uses a topside rf ground, connect gnd directly to it. for a board where the ground plane is not on the com- ponent side, the best technique is to connect gnd to the board with a plated through-hole (via) to the ground plane close to the package. max2470/max2471 10mhz to 500mhz vco buffer amplifiers with differential outputs 6 _______________________________________________________________________________________ pin description differential noninverting buffer output. broadband 50 output. ac coupling is required. do not dc couple to this pin. out 1 pin 1 max2471 max2470 name 2 rf ground. connect to the ground plane as close as possible to the ic to minimize ground path inductance. gnd 2 3 bias and bandwidth control input. connect to v cc to set internal bias for higher band- width operation (10mhz to 500mhz). connect to gnd to set internal bias for lower band- width operation (10mhz to 200mhz) and to reduce overall current consumption. hi/ lo 4 differential inverting buffer output. broadband 50 output. ac coupling is required. do not dc couple to this pin . out 3 4 differential inverting buffer input. high impedance input to buffer amplifier. see setting the input impedance section. in 5 6 supply voltage input. +2.7v < v cc < +5.5v. v cc 6 differential noninverting buffer input. high impedance to buffer amplifier. see setting the input impedance section. in 5 function
max2470/max2471 10mhz to 500mhz vco buffer amplifiers with differential outputs _______________________________________________________________________________________ 7 chip information transistor count: 67 package information 6lsot.eps
max2470/max2471 10mhz to 500mhz vco buffer amplifiers with differential outputs 8 _______________________________________________________________________________________ notes
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