View LT6600-10_1567089.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

LT6600-10 1 6600f , ltc and lt are registered trademarks of linear technology corporation. features descriptio u applicatio s u typical applicatio u n programmable differential gain via two external resistors n adjustable output common mode voltage n operates and specified with 3v, 5v, 5v supplies n 0.5db ripple 4th order lowpass filter with 10mhz cutoff n 82db s/n with 3v supply and 2v p-p output n low distortion, 2v p-p , 800 w load 1mhz: 88dbc 2nd, 97dbc 3rd 5mhz: 74dbc 2nd, 77dbc 3rd n fully differential inputs and outputs n so-8 package n compatible with popular differential amplifier pinouts very low noise, differential amplifier and 10mhz lowpass filter n high speed adc antialiasing and dac smoothing in networking or cellular base station applications n high speed test and measurement equipment n medical imaging n drop-in replacement for differential amplifiers the lt ? 6600-10 combines a fully differential amplifier with a 4th order 10mhz lowpass filter approximating a chebyshev frequency response. most differential amplifi- ers require many precision external components to tailor gain and bandwidth. in contrast, with the LT6600-10, two external resistors program differential gain, and the filters 10mhz cutoff frequency and passband ripple are internally set. the LT6600-10 also provides the necessary level shifting to set its output common mode voltage to accom- modate the reference voltage requirements of a/ds. using a proprietary internal architecture, the LT6600-10 integrates an antialiasing filter and a differential amplifier/ driver without compromising distortion or low noise performance. at unity gain the measured in band signal-to-noise ratio is an impressive 82db. at higher gains the input referred noise decreases so the part can process smaller input differential signals without signifi- cantly degrading the output signal-to-noise ratio. the LT6600-10 also features low voltage operation. the differential design provides outstanding performance for a 2v p-p signal level while the part operates with a single 3v supply. for similar devices with other cutoff frequencies, refer to the lt6600-20 and lt6600-2.5. + + r in 402 r in 402 0.01 f 0.1 f 49.9 49.9 18pf 5v 5v + v mid v ocm v in v cm a in v + v d out LT6600-10 ltc1748 3 4 1 7 2 8 5 6 6600 ta01a gain = 402 /r in 1 f frequency (mhz) 0 frequency (db) 4 8 12 16 20 24 28 32 6600 ta01b ?0 0 ?0 ?0 ?0 ?0 ?0 ?0 ?0 ?0 ?00 ?10 input is a 4.7mhz sinewave 2v p-p f sample = 66mhz an 8192 point fft spectrum
LT6600-10 2 6600f parameter conditions min typ max units filter gain, v s = 3v v in = 2v p-p , f in = dc to 260khz C 0.4 0 0.5 db v in = 2v p-p , f in = 1mhz (gain relative to 260khz) l C 0.1 0 0.1 db v in = 2v p-p , f in = 5mhz (gain relative to 260khz) l C 0.4 C 0.1 0.3 db v in = 2v p-p , f in = 8mhz (gain relative to 260khz) l C 0.3 0.1 1 db v in = 2v p-p , f in = 10mhz (gain relative to 260khz) l C0.2 0.3 1.7 db v in = 2v p-p , f in = 30mhz (gain relative to 260khz) l C28 C25 db v in = 2v p-p , f in = 50mhz (gain relative to 260khz) l C44 db filter gain, v s = 5v v in = 2v p-p , f in = dc to 260khz C 0.5 0 0.5 db v in = 2v p-p , f in = 1mhz (gain relative to 260khz) l C 0.1 0 0.1 db v in = 2v p-p , f in = 5mhz (gain relative to 260khz) l C 0.4 C 0.1 0.3 db v in = 2v p-p , f in = 8mhz (gain relative to 260khz) l C 0.4 0.1 0.9 db v in = 2v p-p , f in = 10mhz (gain relative to 260khz) l C 0.3 0.2 1.4 db v in = 2v p-p , f in = 30mhz (gain relative to 260khz) l C28 C25 db v in = 2v p-p , f in = 50mhz (gain relative to 260khz) l C44 db filter gain, v s = 5v v in = 2v p-p , f in = dc to 260khz C 0.6 C 0.1 0.4 db filter gain, r in = 100 w , v s = 3v, 5v, 5v v in = 2v p-p , f in = dc to 260khz 11.4 12 12.6 db filter gain temperature coefficient (note 2) f in = 260khz, v in = 2v p-p 780 ppm/c noise noise bw = 10khz to 10mhz, r in = 402 w 56 m v rms distortion (note 4) 1mhz, 2v p-p , r l = 800 w 2nd harmonic 88 dbc 3rd harmonic 97 dbc 5mhz, 2v p-p , r l = 800 w 2nd harmonic 74 dbc 3rd harmonic 77 dbc differential output swing measured between pins 4 and 5 v s = 5v l 3.85 5.0 v p-p diff pin 7 shorted to pin 2 v s = 3v l 3.85 4.9 v p-p diff input bias current average of pin 1 and pin 8 l C85 C40 m a total supply voltage ................................................ 11v operating temperature range (note 6) ...C40 c to 85 c specified temperature range (note 7) ....C40 c to 85 c junction temperature ........................................... 150 c storage temperature range ................. C 65 c to 150 c lead temperature (soldering, 10 sec).................. 300 c order part number s8 part marking t jmax = 150 c, q ja = 100 c/w 660010 600i10 absolute axi u rati gs w ww u package/order i for atio uu w (note 1) electrical characteristics consult ltc marketing for parts specified with wider operating temperature ranges. the l denotes specifications that apply over the full operating temperature range, otherwise specifications are at t a = 25 c. unless otherwise specified v s = 5v (v + = 5v, v C = 0v), r in = 402 w , and r load = 1k. lt6600cs8-10 lt6600is8-10 top view in + v mid v out in v ocm v + out + s8 package 8-lead plastic so 1 2 3 4 8 7 6 5
LT6600-10 3 6600f note 1: absolute maximum ratings are those values beyond which the life of a device may be impaired. note 2: this is the temperature coefficient of the internal feedback resistors assuming a temperature independent external resistor (r in ). note 3: the input common mode voltage is the average of the voltages applied to the external resistors (r in ). specification guaranteed for r in 3 100 w . note 4: distortion is measured differentially using a differential stimulus, the input common mode voltage, the voltage at pin 2, and the voltage at pin 7 are equal to one half of the total power supply voltage. parameter conditions min typ max units input referred differential offset r in = 402 w v s = 3v l 520 mv v s = 5v l 10 30 mv v s = 5v l 835 mv r in = 100 w v s = 3v l 513 mv v s = 5v l 522 mv v s = 5v l 530 mv differential offset drift 10 m v/ c input common mode voltage (note 3) differential input = 500mv p-p ,v s = 3v l 0.0 1.5 v r in = 100 w v s = 5v l 0.0 3.0 v v s = 5v l C2.5 1.0 v output common mode voltage (note 5) differential output = 2v p-p ,v s = 3v l 1.0 1.5 v pin 7 at midsupply v s = 5v l 1.5 3.0 v v s = 5v l C1.0 2.0 v output common mode offset v s = 3v l C35 5 40 mv (with respect to pin 2) v s = 5v l C40 0 40 mv v s = 5v l C55 C5 35 mv common mode rejection ratio 61 db voltage at v mid (pin 7) v s = 5 l 2.46 2.51 2.55 v v s = 3 1.5 v v mid input resistance l 4.3 5.5 7.7 k w v ocm bias current v ocm = v mid = v s /2 v s = 5v l C15 C3 m a v s = 3v l C10 C3 m a power supply current v s = 3v, v s = 5 35 39 ma v s = 3v, v s = 5 l 43 ma v s = 5v l 36 46 ma electrical characteristics note 5: output common mode voltage is the average of the voltages at pins 4 and 5. the output common mode voltage is equal to the voltage applied to pin 2. note 6: the lt6600c is guaranteed functional over the operating temperature range C40 c to 85 c. note 7: the lt6600c is guaranteed to meet 0 c to 70 c specifications and is designed, characterized and expected to meet the extended temperature limits, but is not tested at C40 c and 85 c. the lt6600i is guaranteed to meet specified performance from C40 c to 85 c. the l denotes specifications that apply over the full operating temperature range, otherwise specifications are at t a = 25 c. unless otherwise specified v s = 5v (v + = 5v, v C = 0v), r in = 402 w , and r load = 1k.
LT6600-10 4 6600f typical perfor a ce characteristics uw amplitude response frequency (hz) 100k ?0 ?0 ?0 0 10 1m 10m 100m 6600 g01 ?0 ?0 ?0 ?0 ?0 gain 20log diffout diffin () v s = 5v gain = 1 frequency (mhz) 0.5 ? gain (db) group delay (ns) ? ? ? ? 1 ? 14.9 6600 g02 ? ? 0 ? 10 15 25 30 35 45 20 50 55 60 40 5.3 10.1 v s = 5v gain = 1 t a = 25 c frequency (mhz) 0.5 2 gain (db) group delay (ns) 3 5 6 7 12 9 14.9 6600 g03 4 10 11 8 10 15 25 30 35 45 20 50 55 60 40 5.3 10.1 v s = 5v gain = 4 t a = 25 c passband gain and group delay passband gain and group delay frequency (hz) 100k 0.1 output impedance ( ) 1 10 100 1m 10m 100m 6600 g04 frequency (hz) 10k 60 cmrr (db) 65 70 75 80 100k 1m 10m 6600 g05 55 50 40 35 45 v s = 5v gain = 1 v in = 1v p-p t a = 25 c output impedance vs frequency (out + or out C ) common mode rejection ratio power supply rejection ratio distortion vs frequency v in = 2v p-p , v s = 3v, r l = 800 w at each output, t a = 25 c frequency (mhz) 0.1 ?00 distortion (db) ?0 ?0 ?0 ?0 ?0 110 6600 g07 ?0 differential input, 2nd harmonic differential input, 3rd harmonic single-ended input, 2nd harmonic single-ended input, 3rd harmonic frequency (mhz) 0.1 ?00 distortion (db) ?0 ?0 ?0 ?0 ?0 110 6600 g08 ?0 differential input, 2nd harmonic differential input, 3rd harmonic single-ended input, 2nd harmonic single-ended input, 3rd harmonic distortion vs frequency v in = 2v p-p , v s = 5v, r l = 800 w at each output, t a = 25 c frequency (hz) 20 psrr (db) 30 50 60 80 90 1k 100k 1m 100m 6600 g06 10 10k 10m 70 40 0 v s = 3v v in = 200mv p-p t a = 25 c v + to diffout
LT6600-10 5 6600f typical perfor a ce characteristics uw distortion vs signal level v s = 3v, r l = 800 w at each output, t a = 25 c input level (v p-p ) 0 ?00 distortion (db) ?0 ?0 ?0 ?0 ?0 ?0 1234 6600 g09 5 2nd harmonic, 5mhz input 3rd harmonic, 5mhz input 2nd harmonic, 1mhz input 3rd harmonic, 1mhz input input level (v p-p ) 0 ?0 ?0 ?0 4 6600 g10 ?0 ?0 123 5 ?0 ?00 ?10 distortion (db) 2nd harmonic, 5mhz input 3rd harmonic, 5mhz input 2nd harmonic, 1mhz input 3rd harmonic, 1mhz input input common mode voltage relative to pin 7 (v) ? ?00 distortion component (db) ?0 ?0 ?0 ?0 ?0 ? ? 0 1 6600 g11 23 ?0 2nd harmonic, v s = 3v 3rd harmonic, v s = 3v 2nd harmonic, v s = 5v 3rd harmonic, v s = 5v distortion vs signal level v s = 5v, r l = 800 w at each output, t a = 25 c distortion vs input common mode level, 2v p-p , 1mhz input, 1x gain, r l = 800 w at each output, t a = 25 c distortion vs input common mode level, 0.5v p-p , 1mhz input, 4x gain, r l = 800 w at each output, t a = 25 c input common mode voltage relative to pin 7 (v) ? ?00 distortion component (db) ?0 ?0 ?0 ?0 ?0 ? ? 0 1 6600 g12 23 ?0 2nd harmonic, v s = 3v 3rd harmonic, v s = 3v 2nd harmonic, v s = 5v 3rd harmonic, v s = 5v transient response, differential gain = 1 v out + 50mv/div differential input 200mv/div 100ns/div 6600 g13 total supply voltage (v) 2 power supply current (ma) 32 36 10 6600 g14 28 24 4 6 8 3 5 7 9 40 30 34 26 38 t a = 85 c t a = 25 c t a = ?0 c power supply current vs power supply voltage output common mode voltage (v) ? ?00 distortion component (db) ?0 ?0 ?0 ?0 ?0 ?.5 0 0.5 1 6600 g15 1.5 2 ?0 2nd harmonic, v s = 3v 3rd harmonic, v s = 3v 2nd harmonic, v s = 5v 3rd harmonic, v s = 5v 2nd harmonic, v s = 5v 3rd harmonic, v s = 5v distortion vs output common mode, 2v p-p 1mhz input, 1x gain, t a = 25 c
LT6600-10 6 6600f in C and in + (pins 1, 8): input pins. signals can be applied to either or both input pins through identical external resistors, r in . the dc gain from differential inputs to the differential outputs is 402 w /r in . v ocm (pin 2): is the dc common mode reference voltage for the 2nd filter stage. its value programs the common mode voltage of the differential output of the filter. pin 2 is a high impedance input, which can be driven from an external voltage reference, or pin 2 can be tied to pin 7 on the pc board. pin 2 should be bypassed with a 0.01 m f ceramic capacitor unless it is connected to a ground plane. v + and v C (pins 3, 6): power supply pins . for a single 3.3v or 5v supply (pin 6 grounded) a quality 0.1 m f ceramic bypass capacitor is required from the positive supply pin (pin 3) to the negative supply pin (pin 6). the bypass should be as close as possible to the ic. for dual supply applications, bypass pin 3 to ground and pin 6 to ground with a quality 0.1 m f ceramic capacitor. out + and out C (pins 4, 5): output pins . pins 4 and 5 are the filter differential outputs. each pin can drive a 100 w and/or 50pf load to ac ground. v mid (pin 7): the v mid pin is internally biased at mid- supply, see block diagram. for single supply operation the v mid pin should be bypassed with a quality 0.01 m f ceramic capacitor to pin 6. for dual supply operation, pin 7 can be bypassed or connected to a high quality dc ground. a ground plane should be used. a poor ground will increase noise and distortion. pin 7 sets the output common mode voltage of the 1st stage of the filter. it has a 5.5k w impedance, and it can be overridden with an external low impedance voltage source. block diagra w uu u pi fu ctio s + + v ocm + + v ocm 402 402 200 200 200 200 1 2 3 4 v + v 11k 11k 8 7 6 5 op amp proprietary lowpass filter stage v in v in + r in r in 6600 bd in + v ocm v + out + out v v mid in
LT6600-10 7 6600f interfacing to the LT6600-10 the LT6600-10 requires 2 equal external resistors, r in , to set the differential gain to 402 w /r in . the inputs to the filter are the voltages v in + and v in C presented to these external components, figure 1. the difference between v in + and v in C is the differential input voltage. the average of v in + and v in C is the common mode input voltage. similarly, the voltages v out + and v out C appearing at pins 4 and 5 of the LT6600-10 are the filter outputs. the difference between v out + and v out C is the differential output voltage. the average of v out + and v out C is the common mode output voltage. figure 1 illustrates the LT6600-10 operating with a single 3.3v supply and unity passband gain; the input signal is dc coupled. the common mode input voltage is 0.5v and the differential input voltage is 2v p-p . the common mode output voltage is 1.65v and the differential output voltage applicatio s i for atio wu uu is 2v p-p for frequencies below 10mhz. the common mode output voltage is determined by the voltage at pin 2. since pin 2 is shorted to pin 7, the output common mode is the mid-supply voltage. in addition, the common mode input voltage can be equal to the mid-supply voltage of pin 7 (refer to the distortion vs input common mode level graphs in the typical performance characteristics). figure 2 shows how to ac couple signals into the LT6600-10. in this instance, the input is a single-ended signal. ac coupling allows the processing of single-ended or differential signals with arbitrary common mode levels. the 0.1 m f coupling capacitor and the 402 w gain setting resistor form a high pass filter, attenuating signals below 4khz. larger values of coupling capacitors will propor- tionally reduce this highpass 3db frequency. in figure 3 the LT6600-10 is providing 12db of gain. the gain resistor has an optional 62pf in parallel to improve + 402 402 0.01 f 0.1 f 3.3v + v in v in + 3 4 1 7 2 8 5 6 6600 f01 v out + v out v t 3 2 1 v in + v in v t 3 2 1 v out + LT6600-10 v out 0 0 + 402 402 0.01 f 0.1 f 0.1 f 0.1 f 3.3v + v in + 3 4 1 7 2 8 5 6 6600 f02 v out + v out v 3 2 2 1 v t 1 0 0 ? v in + LT6600-10 v out + v out + 100 100 0.1 f 0.01 f 0.01 f 5v + v in v in + 3 4 1 7 2 8 5 6 6600 f03 v out + v out 62pf 62pf + 2v v t 3 2 1 0 v in + v in v t 3 2 1 0 v out + v out LT6600-10 500mv p-p (diff) figure 1 figure 2 figure 3
LT6600-10 8 6600f applicatio s i for atio wu u u the passband flatness near 10mhz. the common mode output voltage is set to 2v. use figure 4 to determine the interface between the LT6600-10 and a current output dac. the gain, or trans- impedance, is defined as a = v out /i in w . to compute the transimpedance, use the following equation: a r rr = + w 402 1 12 by setting r1 + r2 = 402 w , the gain equation reduces to a = r1 w . the voltage at the pins of the dac is determined by r1, r2, the voltage on pin 7 and the dac output current (i in + or i in C ). consider figure 4 with r1 = 49.9 w and r2 = 348 w . the voltage at pin 7 is 1.65v. the voltage at the dac pins is given by: vv r rr i rr rr mv i dac pin in in = ++ + + =+w 7 1 1 2 402 12 12 103 43 6 . i in is i in C or i in + .the transimpedance in this example is 50.4 w . figure 5 is a laboratory setup that can be used to charac- terize the LT6600-10 using single-ended instruments with 50 w source impedance and 50 w input impedance. for a unity gain configuration the LT6600-10 requires a 402 w source resistance yet the network analyzer output is calibrated for a 50 w load resistance. the 1:1 transformer, 53.6 w and 388 w resistors satisfy the two constraints above. the transformer converts the single-ended source into a differential stimulus. similarly, the output the LT6600-10 will have lower distortion with larger load resistance yet the analyzer input is typically 50 w . the 4:1 turns (16:1 impedance) transformer and the two 402 w resistors of figure 5, present the output of the LT6600-10 with a 1600 w differential load, or the equivalent of 800 w to ground at each output. the impedance seen by the network analyzer input is still 50 w , reducing reflections in the cabling between the transformer and analyzer input. figure 5 + 0.1 f 0.01 f 3.3v + LT6600-10 3 4 v out + i in + i in v out 1 7 2 8 5 6 6600 f04 current output dac r1 r1 r2 r2 figure 4 evaluating the LT6600-10 the low impedance levels and high frequency operation of the LT6600-10 require some attention to the matching networks between the LT6600-10 and other devices. the previous examples assume an ideal (0 w ) source imped- ance and a large (1k w ) load resistance. among practical examples where impedance must be considered is the evaluation of the LT6600-10 with a network analyzer. + 0.1 f 0.1 f 2.5v 2.5v + LT6600-10 3 4 1 7 2 8 5 6 6600 f05 402 402 network analyzer input 50 coilcraft ttwb-16a 4:1 network analyzer source coilcraft ttwb-1010 1:1 50 53.6 388 388 differential and common mode voltage ranges the differential amplifiers inside the LT6600-10 contain circuitry to limit the maximum peak-to-peak differential voltage through the filter. this limiting function prevents excessive power dissipation in the internal circuitry and provides output short-circuit protection. the limiting function begins to take effect at output signal levels above 2v p-p and it becomes noticeable above 3.5v p-p . this is illustrated in figure 6; the ltc6600-10 was configured with unity passband gain and the input of the filter was driven with a 1mhz signal. because this voltage limiting takes place well before the output stage of the filter reaches the supply rails, the input/output behavior of the ic shown in figure 6 is relatively independent of the power supply voltage.
LT6600-10 9 6600f applicatio s i for atio wu u u the two amplifiers inside the LT6600-10 have indepen- dent control of their output common mode voltage (see the block diagram section). the following guidelines will optimize the performance of the filter for single supply operation. pin 7 must be bypassed to an ac ground with a 0.01 m f or higher capacitor. pin 7 can be driven from a low imped- ance source, provided it remains at least 1.5v above v C and at least 1.5v below v + . an internal resistor divider sets the voltage of pin 7. while the internal 11k resistors are well matched, their absolute value can vary by 20%. this should be taken into consideration when connecting an external resistor network to alter the voltage of pin 7. pin 2 can be shorted to pin 7 for simplicity. if a different common mode output voltage is required, connect pin 2 to a voltage source or resistor network. for 3v and 3.3v supplies the voltage at pin 2 must be less than or equal to the mid supply level. for example, voltage (pin 2) 1.65v on a single 3.3v supply. for power supply voltages higher than 3.3v the voltage at pin 2 can be set above mid supply. the voltage on pin 2 should not be more than 1v below the voltage on pin 7. the voltage on pin 2 should not be more than 2v above the voltage on pin 7. pin 2 is a high impedance input. the LT6600-10 was designed to process a variety of input signals including signals centered around the mid-supply voltage and signals that swing between ground and a positive voltage in a single supply system (figure 1). the range of allowable input common mode voltage (the average of v in + and v in C in figure 1) is determined by the power supply level and gain setting (see electrical characteristics). common mode dc currents in applications like figure 1 and figure 3 where the LT6600-10 not only provides lowpass filtering but also level shifts the common mode voltage of the input signal, dc currents will be generated through the dc path be- tween input and output terminals. minimize these currents to decrease power dissipation and distortion. consider the application in figure 3. pin 7 sets the output common mode voltage of the 1st differential amplifier inside the LT6600-10 (see the block diagram section) at 2.5v. since the input common mode voltage is near 0v, there will be approximately a total of 2.5v drop across the series combination of the internal 402 w feedback resistor and the external 100 w input resistor. the resulting 5ma common mode dc current in each input path, must be absorbed by the sources v in + and v in C . pin 2 sets the common mode output voltage of the 2nd differential amplifier inside the LT6600-10, and therefore sets the common mode output voltage of the filter. since in the example, figure 3, pin 2 differs from pin 7 by 0.5v, an additional 2.5ma (1.25ma per side) of dc current will flow in the resistors coupling the 1st differential amplifier output stage to filter output. thus, a total of 12.5ma is used to translate the common mode voltages. a simple modification to figure 3 will reduce the dc common mode currents by 36%. if pin 7 is shorted to pin 2 the common mode output voltage of both op amp stages will be 2v and the resulting dc current will be 8ma. of course, by ac coupling the inputs of figure 3, the common mode dc current can be reduced to 2.5ma. noise the noise performance of the LT6600-10 can be evaluated with the circuit of figure 7. given the low noise output of the LT6600-10 and the 6db attenuation of the transformer coupling network, it will be necessary to measure the noise floor of the spectrum analyzer and subtract the instrument noise from the filter noise measurement. figure 6 1mhz input level (v p-p ) 0 20 0 ?0 ?0 ?0 ?0 100 120 35 6600 f06 12 46 output level (dbv) 3rd harmonic 85 c 1db passband gain compression points 1mhz 25 c 1mhz 85 c 3rd harmonic 25 c 2nd harmonic 25 c 2nd harmonic 85 c
LT6600-10 10 6600f noise and gives a true measure of the s/n achievable in the system. conversely, if each output is measured individu- ally and the noise power added together, the resulting calculated noise level will be higher than the true differen- tial noise. power dissipation the LT6600-10 amplifiers combine high speed with large- signal currents in a small package. there is a need to ensure that the diess junction temperature does not exceed 150 c. the LT6600-10 package has pin 6 fused to the lead frame to enhance thermal conduction when connecting to a ground plane or a large metal trace. metal trace and plated through-holes can be used to spread the heat generated by the device to the backside of the pc board. for example, on a 3/32" fr-4 board with 2oz copper, a total of 660 square millimeters connected to pin 6 of the LT6600-10 (330 square millimeters on each side of the pc board) will result in a thermal resistance, q ja , of about 85 c/w. without extra metal trace connected to the applicatio s i for atio wu u u example: with the ic removed and the 25 w resistors grounded, measure the total integrated noise (e s ) of the spectrum analyzer from 10khz to 10mhz. with the ic inserted, the signal source (v in ) disconnected, and the input resistors grounded, measure the total integrated noise out of the filter (e o ). with the signal source con- nected, set the frequency to 1mhz and adjust the ampli- tude until v in measures 100mv p-p . measure the output amplitude, v out , and compute the passband gain a = v out /v in . now compute the input referred integrated noise (e in ) as: e ee a in os = ()() 22 table 1 lists the typical input referred integrated noise for various values of r in . figure 8 is plot of the noise spectral density as a function of frequency for an LT6600-10 with r in = 402 w using the fixture of figure 7 (the instrument noise has been sub- tracted from the results). table 1. noise performance input referred passband integrated noise input referred gain (v/v) r in 10khz to 10mhz noise dbm/hz 4 100 w 24 m v rms C149 2 200 w 34 m v rms C146 1 402 w 56 m v rms C142 the noise at each output is comprised of a differential component and a common mode component. using a transformer or combiner to convert the differential out- puts to single-ended signal rejects the common mode figure 7 + 0.1 f 0.1 f 2.5v 2.5v + LT6600-10 3 4 1 7 2 8 5 6 r in r in 25 25 6600 f07 spectrum analyzer input 50 v in coilcraft ttwb-1010 1:1 figure 8 frequency (mhz) 0.1 spectral density (nv rms / hz) integrated noise ( v rms ) 35 30 25 20 15 10 5 0 140 120 100 80 60 40 20 0 1.0 10 100 6600 f08 spectral density integrated noise table 2. LT6600-10 so-8 package thermal resistance copper area topside backside board area thermal resistance (mm 2 ) (mm 2 ) (mm 2 ) (junction-to-ambient) 1100 1100 2500 65 c/w 330 330 2500 85 c/w 35 35 2500 95 c/w 35 0 2500 100 c/w 0 0 2500 105 c/w
LT6600-10 11 6600f u package descriptio 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. s8 package 8-lead plastic small outline (narrow .150 inch) (reference ltc dwg # 05-08-1610) v C pin to provide a heat sink, the thermal resistance will be around 105 c/w. table 2 can be used as a guide when considering thermal resistance. junction temperature, t j , is calculated from the ambient temperature, t a , and power dissipation, p d . the power dissipation is the product of supply voltage, v s , and supply current, i s . therefore, the junction temperature is given by: t j = t a + (p d ? q ja ) = t a + (v s ? i s ? q ja ) where the supply current, i s , is a function of signal level, load impedance, temperature and common mode volt- ages. for a given supply voltage, the worst-case power dissi- pation occurs when the differential input signal is maxi- mum, the common mode currents are maximum (see applications information regarding common mode dc currents), the load impedance is small and the ambient temperature is maximum. to compute the junction tem- perature, measure the supply current under these worst- case conditions, estimate the thermal resistance from table 2, then apply the equation for t j . for example, using the circuit in figure 3 with dc differential input voltage of 250mv, a differential output voltage of 1v, no load resis- tance and an ambient temperature of 85 c, the supply current (current into pin 3) measures 48.9ma. assuming a pc board layout with a 35mm 2 copper trace, the q ja is 100 c/w. the resulting junction temperature is: t j = t a + (p d ? q ja ) = 85 + (5 ? 0.0489 ? 100) = 109 c when using higher supply voltages or when driving small impedances, more copper may be necessary to keep t j below 150 c. applicatio s i for atio wu u u .016 ?.050 (0.406 ?1.270) .010 ?.020 (0.254 ?0.508) 45 0 ?8 typ .008 ?.010 (0.203 ?0.254) so8 0303 .053 ?.069 (1.346 ?1.752) .014 ?.019 (0.355 ?0.483) typ .004 ?.010 (0.101 ?0.254) .050 (1.270) bsc 1 2 3 4 .150 ?.157 (3.810 ?3.988) note 3 8 7 6 5 .189 ?.197 (4.801 ?5.004) note 3 .228 ?.244 (5.791 ?6.197) .245 min .160 .005 recommended solder pad layout .045 .005 .050 bsc .030 .005 typ inches (millimeters) note: 1. dimensions in 2. drawing not to scale 3. these dimensions do not include mold flash or protrusions. mold flash or protrusions shall not exceed .006" (0.15mm)
LT6600-10 12 6600f linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 l fax: (408) 434-0507 l www.linear.com ? linear technology corporation 2002 lt/tp 0403 2k ? printed in usa a wcdma transmit filter (10mhz lowpass filter with a 28mhz notch) + 100 27pf r q 301 100 1 h 33pf 33pf 0.1 f 0.1 f v + v + 3 4 1 7 2 8 5 6 v out + v out LT6600-10 v out + v out 6600 ta03a v in v in + gain = 12db inductors are coilcraft 1008ps-102m 1 h frequency (hz) 200k ?8 gain (db) ? 2 12 22 1m 10m 100m 6600 ta03b ?8 ?8 ?8 ?8 ?8 ?8 related parts part number description comments ltc ? 1565-31 650khz linear phase lowpass filter continuous time, so8 package, fully differential ltc1566-1 low noise, 2.3mhz lowpass filter continuous time, so8 package, fully differential lt1567 very low noise, high frequency filter building block 1.4nv/ ? hz op amp, msop package, differential output lt1568 very low noise, 4th order building block lowpass and bandpass filter designs up to 10mhz, differential outputs ltc6600-2.5 very low noise, differential amplifier adjustable output common mode voltage and 2.5mhz lowpass filter ltc6600-20 very low noise, differential amplifier adjustable output common mode voltage and 20mhz lowpass filter amplitude response + r c r r r 0.1 f 0.1 f v + v + 3 4 1 7 2 8 5 6 v out + v out LT6600-10 v out + v out 6600 ta02a v in v in + c = 1 2 ?r ?10mhz gain = , maximum gain = 4 402 2r 5th order, 10mhz lowpass filter frequency (hz) 100k ?0 gain (db) ?0 ?0 0 10 1m 10m 100m 6600 ta02b ?0 ?0 ?0 ?0 ?0 differential gain = 1 r = 200 c = 82pf amplitude response transient response 5th order, 10mhz lowpass filter differential gain = 1 v out + 50mv/div differential input 200mv/div 100ns/div 6600 ta02c typical applicatio s u

▲Up To Search▲

Price & Availability of LT6600-10

	To Download LT6600-10 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .