LT1253/lt1254 1 low cost dual and quad video amplifiers the LT1253 is a low cost dual current feedback amplifier for video applications. the lt1254 is a quad version of the LT1253. the amplifiers are completely isolated except for the power supply pins and therefore have excellent isola- tion, over 94db at 5mhz. dual and quad amplifiers signifi- cantly reduce costs compared with singles; the number of insertions is reduced and fewer supply bypass capacitors are required. in addition, these duals and quads cost less per amplifier than single video amplifiers. the LT1253/lt1254 amplifiers are ideal for driving low impedance loads such as cables and filters. the wide bandwidth and high slew rate of these amplifiers make driving rgb signals between pcs and workstations easy. the excellent linearity of these amplifiers makes them ideal for composite video. the LT1253 is available in 8-pin dips and the s8 surface mount package. the lt1254 is available in 14-pin dips and the s14 surface mount package. both parts have the industry standard dual and quad op amp pin out. for higher performance, see the lt1229/lt1230. n low cost n current feedback amplifiers n differential gain: 0.03%, r l = 150 w , v s = 5v n differential phase: 0.28 , r l = 150 w , v s = 5v n flat to 30mhz, 0.1db n 90mhz bandwidth on 5v n wide supply range: 2v(4v) to 14v(28v) n low power: 60mw per amplifier at 5v s f ea t u re d u escriptio n rgb cable drivers n composite video cable drivers n gain blocks in if stages u s a o pp l ic at i u a o pp l ic at i ty p i ca l transient response v s = 5v a v = 2 r l = 150 w v o = 1v LT1253/54 ? ta02 v in v out r g
620 w r f
620 w 75 w 75 w
cable 75 w + 1/2 LT1253 LT1253/54 ?ta01 a v = 1 + r f
r g at amplifier output.
6db less at v out . bw = 90mhz 5v ?v
2 LT1253/lt1254 a u g w a w u w a r b s o lu t exi t i s storage temperature range ................ C 65 c to 150 c junction temperature (note 2) ............................ 150 c lead temperature (soldering, 10 sec)................. 300 c total supply voltage (v + to v C ) ............................. 28v input current ..................................................... 15ma output short-circuit duration (note 1) ........ continuous operating temperature range LT1253c, lt1254c................................. 0 c to 70 c wu u package / o rder i for atio order part number order part number lt1254cn lt1254cs s8 part marking 1253 LT1253cn8 LT1253cs8 n package
14-lead plastic dip + v d 14 13 12 11 10 9 8 7 6 5 4 3 2 1 out a in a +in a +in b in b out b out c v in d out d top view a +in d +in c in c c b s package
14-lead plastic soic t jmax = 150 c, q ja = 100 c/ w (n) t jmax = 150 c, q ja = 150 c/ w (s) 8 7 6 5 4 3 2 1 + in a +in a v top view n8 package
8-lead plastic dip
out a out b v in b +in b a b s8 package
8-lead plastic soic symbol parameter conditions min typ max units v os input offset voltage 515 mv +i b noninverting bias current 115 m a Ci b inverting bias current 20 100 m a a vol large-signal voltage gain v s = 5v, v o = 2v, r l = 150 w 560 1500 v/v psrr power supply rejection ratio v s = 3v to 12v 60 70 db cmrr common-mode rejection ratio v s = 5v, v cm = 2v 55 65 db v out maximum output voltage swing v s = 12v, r l = 500 w 7.0 10.5 v v s = 5v, r l = 150 w 2.5 3.7 v i out maximum output current 30 55 ma i s supply current per amplifier 6 11 ma r in input resistance 110 m w c in input capacitance 3pf power supply range dual 2 12 v single 4 24 v channel separation f = 10mhz 88 db sr input slew rate a v = 1 125 v/ m s output slew rate a v = 2 250 v/ m s electrical characteristics 0 c t a 70 c, v s = 5v to 12v, unless otherwise noted. t jmax = 150 c, q ja = 70 c/ w (n) t jmax = 150 c, q ja = 100 c/ w (s)
LT1253/lt1254 3 symbol parameter conditions min typ max units t r small-signal rise time v s = 12v, a v = 2 3.5 ns rise and fall time v s = 5v, a v = 2, v out = 1v p-p 5.8 ns t p propagation delay v s = 5v, a v = 2 3.5 ns note 1: a heat sink may be required to keep the junction temperature below absolute maximum when the output is shorted indefinitely. note 2: t j is calculated from the ambient temperature t a and power dissipation p d according to the following formulas: LT1253cn8: t j = t a + (p d 100 c/w) LT1253cs8: t j = t a + (p d 150 c/w) lt1254cn: t j = t a + (p d 70 c/w) lt1254cs: t j = t a + (p d 100 c/w) typical ac perfor a ce wu small signal small signal small signal v s a v r l r f r g C 3db bw (mhz) C 0.1db bw (mhz) peaking (db) 12 1 1000 1100 none 270 51 3.4 12 1 150 1000 none 204 48 1.3 12 C 1 1000 750 150 110 59 0.1 12 C 1 150 768 768 89 50 0.1 12 2 1000 715 715 179 76 0.3 12 2 150 715 715 117 62 0 12 5 1000 680 180 106 42 0 12 5 150 680 180 90 47 0 12 10 1000 620 68.1 89 49 0.1 12 10 150 620 68.1 80 46 0.1 5 1 1000 787 none 218 53 1.5 5 1 150 787 none 158 91 0.1 5 C 1 1000 715 715 76 28 0.1 5 C 1 150 715 715 70 30 0.1 5 2 1000 620 620 117 58 0.1 5 2 150 620 620 92 52 0.1 5 5 1000 620 150 82 36 0 5 5 150 620 150 72 34 0 5 10 1000 562 61.9 70 35 0 5 10 150 562 61.9 65 28 0 bandwidth differential differential v s a v r l r f r g gain phase 12 2 1000 750 750 0.01% 0.03 12 2 150 750 750 0.01% 0.12 5 2 1000 750 750 0.03% 0.18 5 2 150 750 750 0.03% 0.28 ntsc video (note 1) electrical characteristics 0 c t a 70 c, v s = 5v to 12v, unless otherwise noted. note 1: differential gain and phase are measured using a tektronix tsg 120 yc/ntsc signal generator and a tektronix 1780r video measurement set. the resolution of this equipment is 0.1% and 0.1 . ten identical amplifier stages were cascaded giving an effective resolution of 0.01% and 0.01 .
4 LT1253/lt1254 cc hara terist ics uw a t y p i ca lper f o r c e supply current vs supply voltage supply voltage (?) supply current (ma) 12 LT1253/54 ?tpc01 4 0816 0 10 5 1 2 3 4 6 7 8 9 2 6 10 14 18 55? 25? 125? 175? output saturation voltage vs temperature temperature (?) output saturation voltage (v) v + 50 25 75 125 LT1253/54 ?tpc02
v 0 1.0 ?.0 0.5 0.5 ?5 50 100 r l =
2v v s ?2v input common-mode limit vs temperature temperature (?) common-mode range (v) 2.0 v + 50 25 75 125 LT1253/54 ?tpc03
v 0 1.0 1.0 2.0 0.5 1.5 1.5 0.5 25 50 100 v + = 2v to 12v v = 2v to ?2v settling time (ns) output step (v) 60 LT1253/54 ?tpc04 20 0 40 80 100 ?0 10 0 ? ? ? ? 2 4 6 8 noninverting inverting v s = ?2v
r f = r g = 1k inverting noninverting settling time to 10mv vs output step 2nd and 3rd harmonic distortion vs frequency frequency (mhz) 1 ?0 distortion (dbc) ?0 ?0 ?0 ?0 ?0 10 100 LT1253/54 ?tpc05 v s = ?2v
v o = 2v p-p
r l = 100 w
r f = 750 w
a v = 10db 2nd 3rd power supply rejection vs frequency frequency (hz) power supply rejection (db) 40 80 10k 1m 10m 100m LT1253/54 ?tpc06 0 100k v s = ?2v
r l = 100 w
r f = r g = 750 w negative 20 60 positive spot noise voltage and current vs frequency frequency (hz) 10 1 10 100 1k 100k LT1253/54 ?tpc07 100 10k spot noise (nv/ ? hz or pa/ ? hz) ? n e n +i n output impedance vs frequency frequency (hz) output impedance ( w ) 0.1 100 10k 1m 10m 100m LT1253/54 ?tpc08 0.001 100k 0.01 10 v s = ?2v 1.0 r f = r g = 2k r f = r g = 750 w output short-circuit current vs temperature temperature (?) ?5 output short-circuit current (ma) 40 60 100 150 LT1253/54 ?tpc09 0 50 25 50 75 125 175 30 70 50
LT1253/lt1254 5 cc hara terist ics uw a t y p i ca lper f o r c e 12v frequency response 5v frequency response 12v frequency response 5v frequency response frequency (hz) 1m 6 gain (db) 7 8 9 10m 100m 1g LT1253/54 ?tpc12 5 4 3 2 v s = ?2v
a v = 2
r l = 150 w
r f = 715 w
r g = 715 w
120 100 ?0 ?0 ?0 140 160 180 ?0 phase (deg) 0 phase gain 10 11 12 200 frequency (hz) 1m 6 gain (db) 7 8 9 10m 100m 1g LT1253/54 ?tpc13 5 4 3 2 v s = 5v
a v = 2
r l = 150 w
r f = 620 w
r g = 620 w
120 100 ?0 ?0 ?0 140 160 180
?0 phase (deg) 0 phase gain 10 11 12 200 frequency (hz) 1m 20 gain (db) 21 22 23 10m 100m 1g LT1253/54 ?tpc14 19 18 17 16 v s = ?2v
a v = 10
r l = 150 w
r f = 620 w
r g = 68.1 w
120 100 ?0 ?0 ?0 140 160 180 ?0 phase (deg) 0 phase gain 24 25 26 200 frequency (hz) 1m 20 gain (db) 21 22 23 10m 100m 1g LT1253/54 ?tpc15 19 18 17 16 v s = 5v
a v = 10
r l = 150 w
r f = 562 w
r g = 61.9 w
120 100 ?0 ?0 ?0 140 160 180 ?0 phase (deg) 0 phase gain 24 25 26 200 12v frequency response 5v frequency response frequency (hz) 1m ? gain (db) 0 1 2 3 10m 100m 1g LT1253/54 ?tpc11 ? ? ? ? 4 v s = 5v
a v = 1
r l = 150 w
r f = 787 w 120 100 ?0 ?0 ?0 140 160 180 ?0 phase (deg) 0 phase gain 5 200 frequency (hz) 1m ? gain (db) 0 1 2 3 10m 100m 1g LT1253/54 ?tpc10 ? ? ? ? 4 v s = 12v
a v = 1
r l = 150 w
r f = 1k 120 100 ?0 ?0 ?0 140 160 180 ?0 phase (deg) 0 phase gain 200 5
6 LT1253/lt1254 transient response LT1253/54 ? tpc16 transient response v s = 5v a v = 1 r l = 150 w LT1253/54 ? tpc17 r f = 562 w r g = 61.9 w v o = 1.5v v s = 5v a v = 10 r l = 150 w r f = 787 w v o = 1v power dissipation the LT1253/lt1254 amplifiers combine high speed and large output current drive into very small packages. be- cause these amplifiers work over a very wide supply range, it is possible to exceed the maximum junction temperature under certain conditions. to insure that the LT1253/ lt1254 are used properly, we must calculate the worst case power dissipation, define the maximum ambient temperature, select the appropriate package and then calculate the maximum junction temperature. the worst case amplifier power dissipation is the total of the quiescent current times the total power supply voltage plus the power in the ic due to the load. the quiescent supply current of the LT1253/lt1254 has a strong nega- tive temperature coefficient. the supply current of each amplifier at 150 c is less than 7ma and typically is only 4.5ma. the power in the ic due to the load is a function of the output voltage, the supply voltage and load resistance. the worst case occurs when the output voltage is at half supply, if it can go that far, or its maximum value if it cannot reach half supply. for example, lets calculate the worst case power dissipa- tion in a video cable driver operating on a 12v supply that delivers a maximum of 2v into 150 w . p dmax = 2 v s i smax + (v s C v omax ) v omax /r l p dmax = 2 12v 7ma + (12v C 2v) 2v/150 = 0.168 + 0.133 = 0.301 watt per amp now if that is the dual LT1253, the total power in the package is twice that, or 0.602w. we now must calculate how much the die temperature will rise above the ambient. the total power dissipation times the thermal resistance of the package gives the amount of temperature rise. for the above example, if we use the s8 surface mount package, the thermal resistance is 150 c/w junction to ambient in still air. temperature rise = p dmax r q ja = 0.602w 150 c/w = 90.3 c the maximum junction temperature allowed in the plastic package is 150 c. therefore the maximum ambient al- lowed is the maximum junction temperature less the temperature rise. maximum ambient = 150 c C 90.3 c = 59.7 c note that this is less than the maximum of 70 c that is specified in the absolute maximum data listing. in order to use this package at the maximum ambient we must lower the supply voltage or reduce the output swing. applicatio s i for atio w uu u cc hara terist ics uw a t y p i ca lper f o r c e
LT1253/lt1254 7 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. as a guideline to help in the selection of the LT1253/ lt1254, the following table describes the maximum sup- ply voltage that can be used with each part based on the following assumptions: 1. the maximum ambient is 70 c. 2. the load is a double-terminated video cable, 150 w . 3. the maximum output voltage is 2v (peak or dc). applicatio s i for atio w uu u max power at max t a LT1253cn8 v s < 14 (abs max) 0.800w LT1253cs8 v s < 10.6 0.533w lt1254cn v s < 11.4 1.143w lt1254cs v s < 7.6 0.727w si plified sche atic ww one amplifier LT1253/54 ?ss +in ?n v out v + v n8 package 8-lead plastic dip package descriptio u dimensions in inches (millimeters) unless otherwise noted. n8 0392 0.045 ?0.015
(1.143 ?0.381) 0.100 ?0.010
(2.540 ?0.254) 0.065
(1.651)
typ 0.045 ?0.065
(1.143 ?1.651) 0.130 ?0.005
(3.302 ?0.127) 0.020
(0.508)
min 0.018 ?0.003
(0.457 ?0.076) 0.125
(3.175)
min
0.009 ?0.015
(0.229 ?0.381) 0.300 ?0.320
(7.620 ?8.128) 0.325 +0.025
0.015 +0.635
0.381 8.255 () 12 3 4 87 6 5 0.250 ?0.010
(6.350 ?0.254)
0.400
(10.160)
max
8 LT1253/lt1254 linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7487 (408) 432-1900 l fax : (408) 434-0507 l telex : 499-3977 n package 14-lead plastic dip n14 0392 0.015
(0.380)
min 0.125
(3.175)
min 0.130 ?0.005
(3.302 ?0.127) 0.045 ?0.065
(1.143 ?1.651) 0.065
(1.651)
typ 0.018 ?0.003
(0.457 ?0.076) 0.100 ?0.010
(2.540 ?0.254) 0.075 ?0.015
(1.905 ?0.381) 0.260 ?0.010
(6.604 ?0.254) 0.770
(19.558)
max 3 1 2 4 5 6 7 8 9 10 11 12 13 14 0.009 ?0.015
(0.229 ?0.381) 0.300 ?0.325
(7.620 ?8.255) 0.325 +0.025
0.015 +0.635
0.381 8.255 () s8 package 8-lead soic package descriptio u dimensions in inches (millimeters) unless otherwise noted. 1 2 3 4 0.150 ?0.157
(3.810 ?3.988) 8 7 6 5 0.189 ?0.197
(4.801 ?5.004) 0.228 ?0.244
(5.791 ?6.197) 0.010 ?0.020
(0.254 ?0.508) 0.016 ?0.050
0.406 ?1.270 45 0 8?typ 0.008 ?0.010
(0.203 ?0.254) so8 0392 0.053 ?0.069
(1.346 ?1.752) 0.014 ?0.019
(0.355 ?0.483) 0.004 ?0.010
(0.101 ?0.254) 0.050
(1.270)
bsc s package 14-lead soic 1 2 3 4 0.150 ?0.157
(3.810 ?3.988) 14 13 0.337 ?0.344
(8.560 ?8.738) 0.228 ?0.244
(5.791 ?6.197) 12 11 10 9 5 6 7 8 0.010 ?0.020
(0.254 ?0.508) 0.016 ?0.050
0.406 ?1.270 45 0??8?typ 0.008 ?0.010
(0.203 ?0.254) so14 0392 0.053 ?0.069
(1.346 ?1.752) 0.014 ?0.019
(0.355 ?0.483) 0.004 ?0.010
(0.101 ?0.254) 0.050
(1.270)
typ ? linear technology corporation 1993 lt/gp 0193 10k rev 0
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