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l ow cost, high performance volt age feedback, 325 mhz amplifier ad8057/ad8058 rev. c information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. specifications subject to c hange without notice. no license is granted by implication or otherwise under any patent or patent rights of analog devices. trademarks and registered trademarks are the property of their respective owners. one technology way, p.o. box 9106, norwood, ma 02062 - 9106, u.s.a. tel: 781.329.4700 www.analog.com fax: 781.461.3113 ? 2010 analog devices, inc. all rights reserved. features low cost single (ad8057) and d ual (ad8058) high s peed 325 mhz , ? 3 db b andwidth (g = +1) 1000 v/ s slew rate gain f latness : 0.1 db to 28 mhz low n oise 7 nv/ hz low p ower 5.4 ma/ amplifier typical supply current @ 5 v low d istortion ? 85 dbc @ 5 mhz, r l = 1 k ? wide supply range from 3 v to 12 v small p ackaging ad8057 is a vailable in an 8 - lead soic and 5- lead sot - 23 ad8058 is a vailable in an 8 - lead soic and an 8 - lead msop applications imaging dvd/cd photodiode p reamp a nalog - to - digital d river professiona l cameras fi lters connection diagrams +in +v s ?v s ad8057 1 2 3 5 4 ?in v out (not to scale) 01064-001 figure 1. rt - 5 (sot - 23) 8 7 6 5 1 2 3 4 nc ?in +in nc +v s v out nc ?v s ad8057 (not to scale) nc = no connect 01064-002 figure 2. r- 8 (soic) out1 ?in1 +in1 ?v s +v s out2 ?in2 +in2 1 2 3 4 8 7 6 5 (not to scale) ad8058 01064-003 figure 3. rm - 8 (msop) and r - 8 (soic) general description the ad8057 (single) and ad8058 (dual) are very high perfor - mance amplifiers with a very low cost. the balance between cost and performance make them ideal for many applications. the ad8057 and ad8058 reduce the need to qualify a variety of specialty amplifiers. the ad8057 and ad8058 are voltage feedback amplifiers with the bandwidth and slew rate normally found in current feedback amplifiers. the ad8057 and ad8058 are low power amplifiers having low qu iescent current and a wide supply range from 3 v to 12 v. they have noise and distortion performance required for high end video systems as well as dc performance parameters rarely found in high speed amplifiers. the ad8057 and ad8058 are available in sta ndard soic packaging as well as tiny 5- lead sot - 23 (ad8057) and 8- lead msop (ad8058) packages. these amplifiers are available in the industrial temperature range of ?40c to +85c. frequency (mhz) 1 1000 10 gain (db) 100 5 4 ?5 3 2 1 0 ?1 ?2 ?3 ?4 g = +2 g = +10 g = +5 g = +1 01064-004 figure 4. small signal frequency response
ad8057/ad8058 rev. c | page 2 of 16 tabl e of contents features .............................................................................................. 1 applications ....................................................................................... 1 c onnection diagrams ....................................................................... 1 general description ......................................................................... 1 revision history ............................................................................... 2 specifications ..................................................................................... 3 absolute maximum ratings ............................................................ 5 maximum power dissipation ..................................................... 5 esd caution .................................................................................. 5 typical performance characteristics ..............................................6 test circuits ..................................................................................... 12 applications info rmation .............................................................. 13 driving capacitive loads .......................................................... 13 video filter .................................................................................. 13 different ial analog -to - digital driver ..................................... 14 layout .......................................................................................... 14 outline dimensions ....................................................................... 15 ordering guide .......................................................................... 16 revision history 10/10 rev. b to rev. c updated format .................................................................. universal change to third - order intercept parameter, table 1 ................. 3 changes to input common - mode voltage range parameter, table 2 ................................................................................................ 4 changes to figure 32 ...................................................................... 10 changes to figure 35 ...................................................................... 11 changes to figure 41 and figure 42 ............................................. 12 changes to figure 44 and figure 45 ............................................. 13 changes to ordering guide .......................................................... 16 8 /0 3 rev. a to rev. b renumbered figures and tpcs ........................................ universal changes to ordering guide ............................................................. 4 change to figure 8 ......................................................................... 12 update outlin e dimensions ......................................................... 14
ad8057/ad8058 rev. c | page 3 of 16 specifications @ t a = 25c, v s = 5 v, r l = 100 ?, r f = 0 ?, g ain = +1, unless otherwise noted. table 1 . parameter conditions min typ max unit dynamic performance C 3 db bandwidth g = +1, v o = 0.2 v p -p 325 mhz g = C 1, v o = 0.2 v p -p 95 mhz g = +1, v o = 2 v p -p 175 mhz bandwidth for 0.1 db flatness g = +1, v o = 0.2 v p -p 30 mhz slew rate g = +1, v o = 2 v s tep, r l = 2 k ? 850 v/s g = +1, v o = 4 v s tep, r l = 2 k ? 1150 v/s settling ti me to 0.1% g = +2, v o = 2 v s tep 30 ns noise/harmonic performance total harmonic distortion f c = 5 mhz, v o = 2 v p - p, r l = 1 k ? C 85 dbc f c = 20 mhz, v o = 2 v p - p, r l = 1 k ? C 62 dbc sfdr f = 5 mhz, v o = 2 v p - p, r l = 150 ? C 68 db third - or der intercept f = 5 mhz, v o = 2 v p -p ?35 dbm crosstalk, output to output f = 5 mhz, g = +2 ?60 db input voltage noise f = 100 khz 7 nv/ hz input current noise f = 100 khz 0.7 pa/ hz differential gain error ntsc, g = +2, r l = 150 ? 0.01 % n tsc, g = +2, r l = 1 k ? 0.02 % differential phase error ntsc, g = +2, r l = 150 ? 0.15 degrees ntsc, g = +2, r l = 1 k ? 0.01 degrees overload recovery v in = 200 mv p - p, g = +1 30 ns dc performance input offset voltage 1 5 mv t min to t max 2.5 mv input offset voltage drift 3 v/c input bias current 0.5 2.5 a t min to t max 3.0 a input offset current 0.75 a open - loop gain v o = 2.5 v, r l = 2 k ? 50 55 db v o = 2.5 v, r l = 150 ? 50 52 db input characteristics i nput resistance 10 m? input capacitance +input 2 pf input common - mode voltage range r l = 1 k ? ?4.0 +4.0 v common - mode rejection ratio v cm = 2.5 v 48 60 db output characteristics output voltage swing r l = 2 k ? ?4.0 +4.0 v r l = 150 ? 3.9 v capacitive load drive 30% o vershoot 30 pf power supply operating range 1.5 5.0 6 v quiescent current for ad8057 6.0 7.5 ma quiescent current for ad8058 14.0 15 ma power supply rejection ratio v s = 5 v to 1.5 v 54 59 db
ad8057/ad8058 rev. c | page 4 of 16 @ t a = 25c, v s = 5 v, r l = 100 ?, r f = 0 ?, g ain = +1, unless otherwise noted. table 2 . parameter conditions min typ max unit dynamic performance C 3 db bandwidth g = +1, v o = 0.2 v p -p 300 mhz g = +1, v o = 2 v p -p 155 mhz bandwidth for 0.1 db flat ness v o = 0.2 v p -p 28 mhz slew rate g = +1, v o = 2 v s tep, r l = 2 k ? 700 v/s settling time to 0.1% g = +2, v o = 2 v s tep 35 ns noise/harmonic performance total harmonic distortion f c = 5 mhz, v o = 2 v p - p, r l = 1 k ? C 75 dbc f c = 20 mh z, v o = 2 v p - p, r l = 1 k ? C 54 dbc crosstalk, output to output f = 5 mhz, g = +2 ?60 db input voltage noise f = 100 khz 7 nv/ hz input current noise f = 100 khz 0.7 pa/ hz differential gain error ntsc, g = +2, r l = 150 ? 0.05 % ntsc, g = +2 , r l = 1 k ? 0.05 % differential phase error ntsc, g = +2, r l = 150 ? 0.10 degrees ntsc, g = +2, r l = 1 k ? 0.02 degrees dc performance input offset voltage 1 5 mv t min to t max 2.5 mv input offset voltage drift 3 v/c input bias c urrent 0.5 2.5 a t min to t max 3.0 a input offset current 0.75 a open - loop gain v o = 1.5 v, r l = 2 k ? to m idsupply 50 55 db v o = 1.5 v, r l = 150 ? to m idsupply 45 52 db input characteristics input resistance 10 m? input capaci tance +input 2 pf input common - mode voltage range r l = 1 k ? 0.9 to 3.4 v common - mode rejection ratio v cm = 2.5 v 48 60 db output characteristics output voltage swing r l = 2 k ? 0.9 to 3.4 v r l = 150 ? 1.2 to 3.8 v capacitive load dri ve 30% o vershoot 30 pf power supply operating range 3 5.0 10 v quiescent current for ad8057 5.4 7. 0 ma quiescent current for ad8058 13.5 14 ma power supply rejection ratio 54 58 db
ad8057/ad8058 rev. c | page 5 of 16 absolute maximum rat ings table 3. parameter rating supply voltage (+v s to Cv s ) 12.6 v internal power dissipation 1 soic package (r) 0.8 w sot -23- 5 package (rt) 0.5 w msop package (rm) 0.6 w input voltage (common mode) v s differential input voltage 4.0 v output short - circuit duration observe power derating curves storage temperature range (r) ?65c to +125c operating temperature range (a grade) ?40c to +85c lead temperature (soldering 10sec) 300c 1 specification is for device in free air: 8- lead soic package: ja = 16 0c/w 5- lead sot - 23- 5 package: ja = 240c/w 8- lead msop package: ja = 200c/w stresses above those listed under absolute maximum ratings may cause permanent damage to the device. this is a stress rating only; functional operation of the device at these o r any other conditions above those indicated in the operational section of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. maximum power dissip ation the maximum power th at can be safely dissipated by the ad8057/ad8058 is limited by the associated rise in junction temperature. exceeding a junction temperature of 175c for an extended period can result in device failure. although the ad8057/ad8058 is internally short - circu it protected, this may not be sufficient t o guarantee that the maximum junction temper - ature (150c) is not exceeded under all conditions. to ensure proper operation, it is necessary to observe the maximum power derating curves. ambient temperature (c) 2.0 1.5 0 maximum power dissipation (w) ?50 ?40 ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 90 1.0 0.5 t j = 150c 8-lead soic 8-lead msop sot-23-5 01064-005 figure 5 . maximum power dissipation vs. ambient temperature esd caution
ad8057/ad8058 rev. c | page 6 of 16 typical performance characteristics load resistance ( ?) 4.5 4.0 0 100k 10k 10 100 output voltage (v) 1k 2.5 1.5 1.0 0.5 3.5 3.0 2.0 (+) output voltage abs (?) output 01064-006 figure 6 . output swing vs. load resistance ?40 ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 85 temperature (c) ?3.0 ?6.5 ?8.0 ?i supply (ma) ?3.5 ?6.0 ?7.0 ?7.5 ?4.5 ?5.5 ?4.0 ?5.0 ?i supply @ 1.5v ?i supply @ 5v 01064-007 figure 7. ?i supply vs. temperature temperature (c) 5.0 1.5 0 volts (v) 4.5 2.0 1.0 0.5 3.5 2.5 4.0 3.0 +5v swing r l = 150 ? +2.5v swing r l = 150 ? +1.5v swing r l = 150 ? ?40 ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 85 01064-008 figure 8 . positive output voltage swing vs. temperature temperature (c) 0 ?3.5 ?5.0 volts (v) ?0.5 ?3.0 ?4.0 ?4.5 ?1.5 ?2.5 ?1.0 ?2.0 ?40 ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 85 ?1.5v swing r l = 150 ? ?2.5v swing r l = 150 ? ?5v swing r l = 150 ? 01064-009 figure 9 . negative output voltage swing vs. temperature 6 ?2 ?6 v os (mv) ?4 2 0 4 v os @ 5v v os @ 1.5v ?40 ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 85 temperature (c) 01064-010 figure 10 . v os vs. temperature 3.5 1.5 0 a vol (mv/v) 0.5 2.5 2.0 3.0 1.0 a vol @ 5v a vol @ 2.5v ?40 ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 85 temperature (c) 01064-011 figure 11 . open - loop gain vs. temperature
ad8057/ad8058 rev. c | page 7 of 16 0 ?0.4 ?0.6 i b (a) ?0.5 ?0.2 ?0.3 ?0.1 ?0.8 ?0.7 temperature (c) ?40 ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 85 +i b @ 5v ?i b @ 5v ?i b @ 1.5v +i b @ 1.5v +i b @ 2.5v ?i b @ 2.5v 01064-012 figure 12 . input bias current vs. temperature 4 psrr (mv/v) 1 0 3 2 psrr @ 1.5v 5v ?40 ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 85 temperature (c) 01064-013 figure 13 . psrr vs. temperature frequency (mhz) 0 ?10 ?60 0.1 1000 1 10 100 psrr (db) ?20 ?30 ?50 ?40 ?psrr v s = 2.5v +psrr v s = 2.5v 01064-014 figure 14 . psrr vs. frequency 100mv 20mv/div ?100mv 4ns/div 01064-016 figure 15 . small signal step response g = +1, r l = 1 k ?, v s = 5 v, see figure 41 for test circuit 5v 1v/div ?5v 4ns/div 01064-017 figure 16 . large signal step response g = +1,rl = 1 k ?, v s = 5.0 v, see figure 41 f or test circuit 100mv 20mv/div 0v ?100mv 4ns/div 01064-019 figure 17 . small signal step response g = C 1, r l = 1 k ?, see figure 42 for test circuit
ad8057/ad8058 rev. c | page 8 of 16 5v 1v/div ?5v 4ns/div 01064-020 figure 18 . large signal step response g = C 1, r l = 1 k ? , see figure 42 for test circuit frequency (mhz) 1 1000 10 gain (db) 100 5 4 ?5 3 2 1 0 ?1 ?2 ?3 ?4 g = +2 g = +10 g = +5 g = +1 01064-021 figure 19 . small signal frequency response, v out = 0.2 v p -p frequency (mhz) 1 1000 10 gain (db) 100 5 4 ?5 3 2 1 0 ?1 ?2 ?3 ?4 g = +2 g = +10 g = +1 g = +5 01064-022 figure 20 . large signal frequency response, v out = 2 v p -p frequency (mhz) 1 1000 10 gain (db) 100 5 4 ?5 3 2 1 0 ?1 ?2 ?3 ?4 g = ?2 g = ?10 g = ?5 g = ?1 01064-023 figure 21 . large signal frequency resp onse frequency (mhz) 1 1000 10 gain (db) 100 0.5 0.4 ?0.5 0.3 0.2 0.1 0 ?0.1 ?0.2 ?0.3 ?0.4 v out = 0.2v g = +2 r l = 1.0k ? r f = 1.0k ? 01064-024 figure 22 . 0.1 db flatness g = +2 frequency (mhz) 1 1000 10 distortion (dbc) 100 ?50 ?60 ?110 ?70 ?80 ?90 ?100 thd second third 01064-025 figure 23 . distortion vs. frequency, r l = 150 ?
ad8057/ad8058 rev. c | page 9 of 16 v out (v p-p) ?40 ?50 ?80 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0 0 distortion (dbc) ?60 ?70 20mhz 5mhz 01064-026 figure 24 . distortion vs. v out @ 20 mhz, 5 mhz, r l = 150 ?, v s = 5.0 v v out (v p-p) 5.0 4.5 0 0 1 2 3 4 3.0 1.5 1.0 0.5 4.0 3.5 2.0 2.5 rise time and fall time (ns) rise time fall time 01064-027 figure 25 . rise time and fall time vs. v out , g = +1, r l = 1 k ?, r f = 0 ? v out (v p-p) 5 4 0 0 1 2 3 4 rise time and fall time (ns) 3 2 1 rise time fall time 01064-028 figure 26 . ri se time and fall time vs. v out , g = +2, r l = 100 ?, r f = 402 ? 0.4% 0.3% 0.2% 0.1% 0% ?0.1% ?0.2% ?0.3% ?0.4% 0 10 20 30 40 50 60 time (ns) v out = ?1v to + 1v or +1v to ?1v g = +2 r l = 100 ?/1k? 01064-029 figure 27 . settling time 500mv/ div 0v 20ns/div 2.5v v s = 2.5v r l = 1k ? g = +1 input signal output response 01064-030 figure 28 . input overload recovery, v s = 2.5 v 1v/div 0v 20ns/div 5.0v v s = 5.0v r l = 1k ? g = +1 input signal 5v output signal = 4.0v 01064-031 figure 29 . output overload recove ry, v s = 5.0 v
ad8057/ad8058 rev. c | page 10 of 16 frequency (mhz) 0 ?10 ?70 ?60 0.1 100 10 1 cmrr (db) ?20 ?30 ?50 ?40 01064-032 figure 30 . cmrr vs. frequency 200mv/ div 20ns/div 1.8v v s = 2.5v r1 = 1k ? g = +4 input signal = 0.6v output signal 1.7v 01064-033 figure 31 . output overload recovery, v s = 2.5 v 500mv/ div 20ns/div 4.5v v s = 5v r1 = 1k ? g = +4 01064-034 figure 32 . output overload recovery, v s = 5. 0 v frequency (mhz) 0 ?20 ?120 0.1 crosstalk (db) ?60 ?80 ?100 ?40 side b driven side a driven 1 10 100 01064-035 figure 33 . crosstalk (output -to- output) vs. frequency 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th differential gain (%) differential phase (degrees) 01064-036 v s = 5.0v r l = 150 ? 0.015 0.010 0.005 0 ?0.005 ?0.010 ?0.015 0.14 0.12 0.10 0.06 0.02 0.08 0.04 0 ?0.02 v s = 5.0v r l = 150 ? 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th differential gain (%) differential phase (degrees) 01064-037 v s = 5.0v r l = 1k ? 0.015 0.010 0.005 0 ?0.005 ?0.010 ?0.015 0.14 0.12 0.10 0.06 0.02 0.08 0.04 0 ?0.02 v s = 5.0v r l = 1k ? figure 34 . differential gain and differential phase one back terminated load (150 ?) (video op amps only)
ad8057/ad8058 rev. c | page 11 of 16 frequency (mhz) 180 135 ?90 0.01 phase (degrees) 45 0 ?45 90 80 60 40 20 0 ?20 open-loop gain (db) 0.1 1 10 100 1000 gain 01064-038 figure 35 . open - loop gain and phase vs. frequency 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th differential gain (%) differential phase (degrees) 01064-039 v s = +5v r l = 150 ? 0.01 0 ?0.01 ?0.02 ?0.03 ?0.04 ?0.05 0.14 0.12 0.10 0.06 0.02 0. 08 0. 04 0 ?0.02 v s = +5v r l = 150 ? figure 36 . differential gain and differential phase, r l = 150 ? 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th differential gain (%) differential phase (degrees) 01064-040 v s = +5v r l = 1k ? 0.01 0 ?0.01 ?0.02 ?0.03 ?0.04 ?0.05 0.14 0.12 0.10 0.06 0. 02 0. 08 0.04 0 ?0.02 v s = +5v r l = 1k ? figure 37 . differential gain and differential phase, r l = 1 k ? frequency (hz) 100 10 0.1 10 100 1k 10k 100k 1m 10m 100m v noise (nv/ hz) 1 01064-041 figure 38 . voltage noise vs. frequency frequency (hz) 100 10 0.1 10 100 1k 10k 100k 1m 10m 100m i noise (pa/ hz) 1 01064-042 figure 39 . current noise vs. frequency 100 10 z out (?) 1 0.1 1 frequenc y (mhz) 10 1000 100 0.1 01064-043 figure 40 . output impedan ce vs. frequency
ad8057/ad8058 rev. c | page 12 of 16 test circuits 0.01f 0.001f 4.7f 50? v in hp8130a pulse generator t r /t f = 1ns ad8057 ad8058 0.001f 0.01f 4.7f 1k? +v s ?v s v out 01064-015 figure 41 . test circuit, g = +1, r l = 1 k? 0.01f 0.001f 4.7f ?v s +v s v in 1k? 50? hp8130a pulse generator t r /t f = 1ns ad8057 ad8058 1k? 1k? v out 01064-018 0.001f 0.01f 4.7f figure 42 . test circuit, g = ?1, r l = 1 k ?
ad8057/ad8058 rev. c | page 13 of 16 applications informa tion driving capacitive l oads when driv ing a capac itive load, most op amps exhibit over shoot in their pulse response. figure 43 shows the relationship between the capacitive load that results in 30% overshoot and the closed - loop gain of an ad8058. it can be seen t hat, under the g ain = +2 condition, the device is stable with cap acitive loads of up to 69 pf. in general, to minimize peaking or to ensure device stability for larger values of capacitive loads, a small series resistor (r s ) can be added between the op am p output and the load capacitor (c l ) as shown in figure 44 . for the setup shown in figure 44 , the relationship between r s and c l was empirically derived and is shown in table 4 . closed-loop gain 500 400 0 5 1 2 3 4 c l (pf) 300 200 100 r s = 2.4 ? r s = 0 ? 01064-044 figure 43 . capacitive load drive vs. closed - loop gain ?2.5v r g r f r s c l v in = 200mv p-p ad8058 0.1f 10f 0.1f 10f +2.5v v out fet probe 01064-045 figure 44 . capacitive load drive circuit table 4 . recommended value for resistors r s , r f , r g vs. capacitive load, c l , which results in 30% overshoot gain r f r g c l (r s = 0 ?) c l (r s = 2.4 ?) 1 100 ? 11 pf 13 pf 2 100 ? 100 ? 51 pf 69 pf 3 100 ? 50 ? 104 pf 153 pf 4 100 ? 33.2 ? 186 pf 270 pf 5 100 ? 25 ? 245 pf 500 pf 10 100 ? 11 ? 870 pf 1580 pf 50ns/div 100mv ?100mv 200mv ?200mv +overshoot 29.0% 100mv/div 01064-046 figure 45 . typical pulse response with c l = 65 pf, gain = +2, and v s = 2.5 video filter some composite video signals that are derived from a digital source contain some clock feedthrough that can cause probl ems with downstream circuitry. this clock feedthrough is usually at 27 mhz, which is a standard clock frequency for both ntsc and pal video systems. a filter that passes the video band and rejects frequencies at 27 mhz can be used to remove these fre - quenc ies from the video signal. figure 46 shows a circuit that uses an ad8057 to create a single 5 v supply, 3 - pole sallen- key filter. this circuit uses a single rc pole in front of a standard 2 - pole active section. to shift the dc ope rating point to midsupply , ac coupling is provided by r4, r5, and c4. 2 3 0.1f + 10f ad8057 7 4 6 +5v +5v r4 10k? r5 10k? c4 0.1f r3 49.9 ? r2 499? c1 100pf r1 200? r f 1k? c2 680pf c3 36pf 01064-047 figure 46 . low- pass filter for video
ad8057/ad8058 rev. c | page 14 of 16 figure 47 shows a frequency sweep of this filter. the response is down 3 db at 5.7 mhz ; theref ore, it passes the video band with little attenuation. the rejection at 27 mhz is 42 db, which provides more than a factor of 100 in suppression of the clock components at this frequency. frequency (mhz) 0 10 ?10 ?90 ?70 ?80 ?60 100k 100m 10m 1m log magnitude (db) ?20 ?30 ?50 ?40 01064-048 figure 47 . video filter response differen tial analog - to - digital driver as system supply voltages are dropping, many adcs provide differential analog inputs to increase the dynamic range of the input signal while still operating on a low supply voltage. differential driving can also reduce second and other even - order distortion products. analog devices , inc., offers an assortment of 12 - and 14 - bit high speed converters that have differential inputs and can be run from a single 5 v supply. these include the ad9220, ad9221 , ad9223 , ad9224 , and ad9225 at 12 bits, and the ad9240 , ad9241 , and ad9243 at 14 bits. although these devices can operate over a range of common - mode voltages at their analog inputs, they work best when the common - mode voltage at the input is at the midsupply or 2.5 v. op amp arc hitectures that require upwards of 2 v of headroom at the output have significant problems when trying to drive such adcs while operating with a 5 v positive supply. the low headroom output design of the ad8057 and ad8058 make them ideal for driving these types of adcs. the ad8058 can be used to make a dc - coupled, single - ended - to - differential driver for one of these adcs. figure 48 is a schematic of such a circuit for driving an ad9225, 12 - bit, 25 msps adc. 2 3 0.1f 10f 0.1f 10f 0.1f 10f + 8 1 +5v 1k? ad8058 1k? 1k? 1k? 1k? 50? 50? 1k? 1k? 1k? 6 5 7 + ?5v 4 v in 0v vinb vina ad9225 +5v + ref +2.5v ad8058 01064-049 figure 48 . schematic circuit for driving ad9225 in this circuit, one of the op amps is configured in the inverting mode whereas the other is in the noninverting mode. however, to provide better bandwidth matching, each op amp is configured for a noise gain of +2. the inverting op amp is configured for a gain of ?1 and the noninverting op amp is configured for a gain of +2. each of these produces a noise gain of +2, which is deter - mined only by the inverse of the feedback ratio. the input signal to the n oninverting op amp is divided by two to normalize its level and make it equal to the inverting output. for 0 v input, the outputs of the op amps want to be at 2.5 v, which is the midsupply level of the adcs. this is accomplished by first taking the 2.5 v r efere nce output of the adc and divid ing it by two by a pair of 1 k ? resistors. the resulting 1.25 v is applied to the positive input of each op amp . this voltage is then multiplied by the gain of +2 of the op amps to provide a 2.5 v level at each output. the assumption for this circuit is that the input signal is bipolar with respect to ground and the circuit must be dc - coupled thereby implying the existence of a negat ive supply elsewhere in the sys tem. this circuit uses ? 5 v as the negative supply for the ad8058. tying the negative supply of the ad8058 t o ground causes a problem at the input of the noninverting op amp. the input common - mode voltage can only go to within 1 v of the negative rail. because this circuit requires that the positive inputs opera te with a 1.25 v bias, there is not enough room to swing this voltage in the negative direction. the inverting stage does not have this problem because its common - mode input voltage remains fixed at 1.25 v. if dc coupling is not required, various ac coupli ng techniques can be used to eliminate this problem. layout the ad8057 and ad8058 are high speed op amps for use in a board layout that follows standard high speed design rules. make a ll signal traces as short and direct as possible. in particular, keep t he parasitic capacitance on the inverting input of each device to a minimum to avoid excessive peaking and other undesirable performance. bypass t he power supplies very close to the power pins of the package with a 0.1 f capacitor in parallel with a large r ( approximately 10 f ) tantalum capacitor. connect t hese capacitors to a ground plane that either is on an inner layer or fills the area of the board that is not used for other signals.
ad8057/ad8058 rev. c | page 15 of 16 outline dimensions compliant to jedec standards mo-187-aa 0.80 0.60 0.40 8 0 4 8 1 5 pin 1 0.65 bsc seating plane 0.38 0.22 1.10 max 3.20 3.00 2.80 coplanarity 0.10 0.23 0.08 3.20 3.00 2.80 5.15 4.90 4.65 0.15 0.00 0.95 0.85 0.75 figure 49 . 8- lead mini small outline package [msop] (rm - 8) dimensions shown in millimeters controlling dimensions are in millimeters; inch dimensions (in parentheses) are rounded-off millimeter equi v alents for reference on ly and are not appropri a te for use in design. compliant t o jedec s t andards ms-012-a a 012407- a 0.25 (0.0098) 0.17 (0.0067) 1.27 (0.0500) 0.40 (0.0157) 0.50 (0.0196) 0.25 (0.0099) 45 8 0 1.75 (0.0688) 1.35 (0.0532) sea ting plane 0.25 (0.0098) 0.10 (0.0040) 4 1 8 5 5.00 (0.1968) 4.80 (0.1890) 4.00 (0.1574) 3.80 (0.1497) 1.27 (0.0500) bsc 6.20 (0.2441) 5.80 (0.2284) 0.51 (0.0201) 0.31 (0.0122) coplanarit y 0.10 figure 50 . 8- lead standard small outline package [soic] (r- 8) dimensions shown in millimeters and (inches) compliant to jedec standards mo-178-aa 121608- a 10 5 0 sea ting plane 1.90 bsc 0.95 bsc 0.20 bsc 5 1 2 3 4 3.00 2.90 2.80 3.00 2.80 2.60 1.70 1.60 1.50 1.30 1.15 0.90 0.15 max 0.05 min 1.45 max 0.95 min 0.20 max 0.08 min 0.50 max 0.35 min 0.55 0.45 0.35 figure 51 . 5- lead small o utline transistor package [sot - 23] (rt - 5) dimensions shown in millimeters
ad8057/ad8058 rev. c | page 16 of 16 ordering guide model 1 temperature range package description package option branding ad8057ar ?40c to +85c 8- lead narrow body soic r-8 ad8057arz ?40c to +85c 8- lead narrow bod y soic r-8 ad8057achips ?40c to +85c die waffle pak ad8057ar - reel ?40c to +85c 8- lead narrow body soic, 13 tape and reel r-8 ad8057ar - reel7 ?40c to +85c 8- lead narrow body soic, 7 tape and reel r-8 ad8057arz - reel ?40c to +85c 8- lead narr ow body soic, 13 tape and reel r-8 ad8057arz - reel7 ?40c to +85c 8- lead narrow body soic, 7 tape and reel r-8 ad8057art - r2 ?40c to +85c 5- lead sot - 23 rt -5 h7a ad8057art - reel7 ?40c to +85c 5- lead sot - 23 rt -5 h7a ad8057artz - r2 ?40c to +85c 5-l ead sot - 23 rt -5 h08 ad8057artz - reel ?40c to +85c 5- lead sot - 23 rt -5 h7a ad8057artz - reel7 ?40c to +85c 5- lead sot - 23 rt -5 h 08 ad8057ar - ebz ?40c to +85c 8- lead narrow body soic evaluation board ad8057art - ebz ?40c to +85c 5- lead sot - 23 evaluatio n board ad8058ar ?40c to +85c 8- lead narrow body soic r-8 ad8058arz ?40c to +85c 8- lead narrow body soic r-8 ad8058achips ?40c to +85c die waffle pak ad8058ar - reel ?40c to +85c 8- lead narrow body soic, 13 tape and reel r-8 ad8058arz - ree l ?40c to +85c 8- lead narrow body soic, 13 tape and reel r-8 ad8058ar - reel7 ?40c to +85c 8- lead narrow body soic, 7 tape and reel r-8 ad8058arz - reel7 ?40c to +85c 8- lead narrow body soic, 7 tape and reel r-8 ad8058arm ?40c to +85c 8- lead m sop rm -8 h8a ad8058arm - reel7 ?40c to +85c 8- lead msop rm -8 h8a ad8058armz - reel7 ?40c to +85c 8- lead msop rm -8 h8a ad8058armz ?40c to +85c 8- lead msop rm -8 h8a ad8058armz - reel ?40c to +85c 8- lead msop rm -8 h8a ad8058ar - ebz ?40c to +85c 8- lead narrow body soic evaluation board ad8058arm - ebz ?40c to +85c 8- lead msop evaluation board 1 z = rohs compliant part. ? 2010 analog devices, inc. all rights reserved. trademarks and registered trademarks are the property of their respective owners. d01064 -0- 10/10( c )

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