1 LTC1151 dual 15v zero-drift operational amplifier 15v 15v + 15v 0.1 m f 6 5 8 1/2
LTC1151 7 output a
100mv/? 1151 ta01 240k 51 w 100 w * 0.1 m f 2k lt1025 15v 470k v in k v o r gnd 7 3 + + type k 0.1 m f 2 3 4 1/2
LTC1151 1 output b
100mv/? 240k 51 w 100 w * 0.1 m f 2k + 5 4 type k * full scale trim: trim for 10.0v output
with thermocouple at 100? u a o pp l ic at i ty p i ca l d u escriptio s f ea t u re the LTC1151 is a high voltage, high performance dual zero-drift operational amplifier. the two sample-and-hold capacitors per amplifier required externally by other chop- per amplifiers are integrated on-chip. the LTC1151 also incorporates proprietary high voltage cmos structures which allow operation at up to 36v total supply voltage. the LTC1151 has a typical offset voltage of 0.5 m v, drift of 0.01 m v/ c, 0.1hz to 10hz input noise voltage of 1.5 m v p-p , and a typical voltage gain of 140db. it has a slew rate of 3v/ m s and a gain-bandwidth product of 2.5mhz with a supply current of 0.9ma per amplifier. overload recovery times from positive and negative saturation are 3ms and 20ms, respectively. the LTC1151 is available in a standard 8-lead plastic dip package as well as a 16-lead wide body so. the LTC1151 is pin compatible with industry-standard dual op amps and runs from standard 15v supplies, allowing it to plug in to most standard bipolar op amp sockets while offering significant improvement in dc performance. u s a o pp l ic at i n strain gauge amplifiers n instrumentation amplifiers n electronic scales n medical instrumentation n thermocouple amplifiers n high resolution data acquisition n maximum offset voltage drift: 0.05 m v/ c n high voltage operation: 18v n no external components required n maximum offset voltage: 5 m v n low noise: 1.5 m v p-p (0.1hz to 10hz) n minimum voltage gain: 125db n minimum cmrr: 106db n minimum psrr: 110db n low supply current: 0.9ma/amplifier n single supply operation: 4.75v to 36v n input common-mode range includes ground n typical overload recovery time: 20ms noise spectrum 15v dual thermocouple amplifier frequency (hz) 10 noise voltage (nv/ ? hz) 20 30 40 60 1 100 1k 10k 1151 ta02 0 10 50
LTC1151 2 total supply voltage (v + to v C ) ............................. 36v input voltage (note 2) .......... (v + + 0.3v) to (v C C 0.3v) output short circuit duration ......................... indefinite burn-in voltage ...................................................... 36v (note 1) a u g w a w u w a r b s o lu t exi t i s operating temperature range LTC1151c............................................... 0 c to 70 c storage temperature range ................ C 65 c to 150 c lead temperature (soldering, 10 sec)................. 300 c wu u package / o rder i for atio t jmax = 110 c, q ja = 130 c/w order part number order part number t jmax = 110 c, q ja = 200 c/w LTC1151cs LTC1151cn8 1
2
3
4 8
7
6
5
top view out a
?n a
+in a
v v +
out b
?n b
+in b n8 package
8-lead plastic dip e lectr ic al c c hara terist ics v s = 15v, t a = operating temperature range, unless otherwise specified. LTC1151c parameter conditions min typ max units input offset voltage t a = 25 c (note 3) 0.5 5 m v average input offset drift (note 3) l 0.01 0.05 m v/ c long term offset voltage drift 50 nv/ ? mo input offset current t a = 25 c 20 200 pa l 0.5 na input bias current t a = 25 c 15 100 pa l 0.5 na input noise voltage r s = 100 w , 0.1hz to 10hz 1.5 m v p-p r s = 100 w , 0.1hz to 1hz 0.5 m v p-p input noise current f = 10hz (note 4) 2.2 fa/ ? hz input voltage range positive l 12 13.2 v negative l C15 C15.3 v common-mode rejection ratio v cm = v C to 12v l 106 130 db power supply rejection ratio v s = 2.375v to 16v l 110 130 db large-signal voltage gain r l = 10k, v out = 10v l 125 140 db nc
nc
out a
?n a
+in a
v
nc
nc nc
nc
v +
out b
?n b
+in b
nc
nc top view s package
16-lead plastic sol 1
2
3
4
5
6
7
8 16
15
14
13
12
11
10
9
3 LTC1151 e lectr ic al c c hara terist ics v s = 15v, t a = operating temperature range, unless otherwise specified. LTC1151c parameter conditions min typ max units maximum output voltage swing r l = 10k, t a = 25 c 13.5 14.50 v r l = 10k l +10.5/C13.5 v r l = 100k 14.95 v slew rate r l = 10k, c l = 50pf 2.5 v/ m s gain-bandwidth product 2 mhz supply current per amplifier no load, t a = 25 c 0.9 1.5 ma no load l 2.0 ma internal sampling frequency 1000 hz input offset voltage t a = 25 c (note 3) 0.05 5 m v average input offset drift (note 3) l 0.01 0.05 m v/ c long term offset voltage drift 50 nv/ ? mo input offset current t a = 25 c 10 100 pa input bias current t a = 25 c 550 pa input noise voltage r s = 100 w , 0.1hz to 10hz 2.0 m v p-p r s = 100 w , 0.1hz to 1hz 0.7 m v p-p input noise current f = 10hz (note 4) 1.3 fa/ ? hz input voltage range positive 2.7 3.2 v negative 0 C 0.3 v common-mode rejection ratio v cm = 0v to 2.7v 110 db power supply rejection ratio v s = 2.375v to 16v l 110 130 db large-signal voltage gain r l = 10k, v out = 0.3v to 4.5v l 115 140 db maximum output voltage swing r l = 10k to gnd 4.85 v r l = 100k to gnd 4.97 v slew rate r l = 10k, c l = 50pf 1.5 v/ m s gain bandwidth product 1.5 mhz supply current per amplifier no load, t a = 25 c 0.5 1.0 ma l 1.5 ma internal sampling frequency 750 hz the denotes the specifications which apply over the full operating temperature range. note 1: absolute maximum ratings are those values beyond which life of the device may be impaired. note 2: connecting any terminal to voltages greater than v + or less than v C may cause destructive latch-up. it is recommended that no sources operating from external supplies be applied prior to power-up of the LTC1151. note 3: these parameters are guaranteed by design. thermocouple effects preclude measurement of these voltage levels in high speed automatic test systems. v os is measured to a limit determined by test equipment capability. note 4: current noise is calculated from the formula: i n = ? (2q ? i b ) where q = 1.6 10 C19 coulomb. v s = 5v, t a = operating temperature range, unless otherwise specified.
LTC1151 4 cc hara terist ics uw a t y p i ca lper f o r c e supply current vs supply voltage common-mode input voltage range vs supply voltage cmrr vs frequency output short-circuit current vs supply voltage gain and phase vs frequency psrr vs frequency total supply voltage (v) 4 0 total supply current (ma) 1.0 2.5 12 20 24 1151 g01 0.5 2.0 1.5 816 28 32 36 t a = 25? supply voltage (v) 0 ?5 common-mode range (v) ?0 ? 0 5 10 15 2.5 5.0 10.0 7.5 1151 g03 15.0 12.5 t a = 25? frequency (hz) 40 cmrr (db) 60 100 140 160 1 10k 100k 1k 1151 g06 0 10 120 80 20 100 v s = ?5v total supply voltage, v + to v (v) 4 ?5 short-circuit output current (ma) ?2 ? ? 0 4 6 12 20 28 36 1151 g04 2 ? 8162432 t a = 25? v out = v
i source v out = v +
i sink frequency (hz) 10 0 gain (db) 20 40 60 1151 g07 80 100 100 1k 10k 100k 1m 10m phase (deg) 135
90
45
0
?5 phase gain v s = ?5v
c l = 100pf 80 psrr (db) 100 120 140 160 1 100 1k 10k 1151 g09 60 10 20 40 100k 0 positive
supply negative
supply frequency (hz) v s = 15v frequency (hz) 10 0 gain (db) 20 40 60 1151 g08 80 100 100 1k 10k 100k 1m 10m phase (deg) 135
90
45
0
?5 phase gain v s = 2.5v
c l = 100pf gain and phase vs frequency frequency (hz) 20 output voltage (v p-p ) 25 30 100 10k 100k 1m 1151 g05 15 1k 5 10 0 v s = 15v
r l = 10k
undistorted output swing vs frequency supply current vs temperature temperature (?c) 0
1.75 2.00 40 1151 g02 1.50 10 30 70 1.25 total supply current (ma) 20 50 60 v s = 15v
5 LTC1151 0.1hz to 10hz noise negative overload recovery input bias current magnitude vs supply voltage large-signal transient response input common-mode voltage (v) ?5 ?0 input bias current (pa) ? 5 1151 g12 15 ?0 0 10 ?5 ?0 ?5 0 15 30 45 60 ? b +i b v s = 15v
t a = 25? input bias current vs input common-mode voltage temperature (?) ?0 1 input bias current (pa) 10 100 1000 ?5 0 125 1151 g10 25 50 75 100 v cm = 0
v s = ?5v cc hara terist ics uw a t y p i ca lper f o r c e input bias current magnitude vs temperature supply voltage (v) 0 0 input bias current (pa) 3 6 9 12 15 1151 g11 18 ? ? ? ? ?0 12 ?4 ?6 t a = 25?
v cm = 0v 1s 10s 1 m v 1151 g13 v s = ?5v
t a = 25? small-signal transient response v s = 15v, a v = 1 c l = 100pf, r l = 10k v s = 15v, a v = 1 c l = 100pf, r l = 10k 2ms/div 2ms/div 2ms/div v s = 15v, a v = C100 note: positive overload recovery is typically 3ms. 5 2v/div 0 0 2v/div 50mv/div 1151 g14 1151 g15 5v/div 1151 g16
LTC1151 6 test circuits offset voltage test circuit dc-10hz noise test circuit u s a o pp l ic at i wu u i for atio achieving picoampere/microvolt performance picoamperes in order to realize the picoampere level of accuracy of the LTC1151 proper care must be exercised. leakage currents in circuitry external to the amplifier can significantly de- grade performance. high quality insulation should be used (e.g., teflon); cleaning of all insulating surfaces to remove fluxes and other residues will probably be necessary, particularly for high temperature performance. surface coating may be necessary to provide a moisture barrier in high humidity environments. board leakage can be minimized by encircling the input connections with a guard ring operated at a potential close to that of the inputs: in inverting configurations the guard ring should be tied to ground; in noninverting connections to the inverting input. guarding both sides of the printed circuit board is required. bulk leakage reduction depends on the guard ring width. microvolts thermocouple effects must be considered if the LTC1151s ultra low drift is to be fully utilized. any connection of dissimilar metals forms a thermoelectric junction produc- ing an electric potential which varies with temperature (seebeck effect). as temperature sensors, thermocouples exploit this phenomenon to produce useful information. in low drift amplifier circuits the effect is a primary source of error. connectors, switches, relay contacts, sockets, resistors, solder, and even copper wire are all candidates for thermal emf generation. junctions of copper wire from different manufacturers can generate thermal emfs of 200nv/ c; four times the maximum drift specification of the LTC1151. minimizing thermal emf-induced errors is possible if judicious attention is given to circuit board layout and component selection. it is good practice to minimize the number of junctions in the amplifiers input signal path. avoid connectors, sockets, switches, and relays where possible. in instances where this is not possible, attempt to balance the number and type of junctions so that differential cancellation occurs. doing this may involve deliberately introducing junctions to offset unavoidable junctions. figure 1 is an example of the introduction of an unneces- sary resistor to promote differential thermal balance. maintaining compensating junctions in close physical proximity will keep them at the same temperature and reduce thermal emf errors. when connectors, switches, relays and/or sockets are necessary they should be selected for low thermal emf activity. the same techniques of thermally balancing and coupling the matching junctions are effective in reducing the thermal emf errors of these components. 3 27 4 6 1m 1k v + v output r l 1151 tc01 + LTC1151 100pf 100k output 1151 tc02 + 5v 7 6 4 3 2 ?v LTC1151 10 w + 7 5 6 0.02 m f 800k + 3 2 800k 800k 0.04 m f 0.01 m f 1/2
lt1057 5v 8 1 4 ?v 1/2
lt1057
7 LTC1151 u s a o pp l ic at i wu u i for atio lead wire/solder
copper trace junction nominally unnecessary
resistor used to
thermally balance
other input resistor output resistor lead, solder,
copper trace junction 1151 f01 + LTC1151 figure 1. extra resistors cancel thermal emf resistors are another source of thermal emf errors. table 1 shows the thermal emf generated for different resistors. the temperature gradient across the resistor is important, not the ambient temperature. there are two junctions formed at each end of the resistor and if these junctions are at the same temperature, their thermal emfs will cancel each other. the thermal emf numbers are approximate and vary with resistor value. high values give higher thermal emf. table 1. resistor thermal emf resistor type thermal emf/ c gradient tin oxide > 1mv/ c carbon composition ~ 450 m v/ c metal film ~ 20 m v/ c wire wound evenohm, manganin ~ 2 m v/ c package-induced offset voltage package-induced thermal emf effects are another impor- tant source of errors. they arise at the junctions formed when wire or printed circuit traces contact a package lead. like all the previously mentioned thermal emf effects, they are outside the LTC1151s offset nulling loop and cannot be cancelled. the input offset voltage specification of the LTC1151 is actually set by the package-induced warm-up drift rather than by the circuit itself. the thermal time constant ranges from 0.5 to 3 minutes, depending on package type. aliasing like all sampled data systems, the LTC1151 exhibits aliasing behavior at input frequencies near the sampling frequency. the LTC1151 includes a high frequency cor- rection loop which minimizes this effect. as a result, aliasing is not a problem for many applications. for a complete discussion of the correction circuitry and aliasing behavior, please refer to the ltc1051/ltc1053 data sheet. low supply operation the minimum supply for proper operation of the LTC1151 is typically 4.0v ( 2.0v). in single supply applications, psrr is guaranteed down to 4.7v ( 2.35v) to ensure proper operation at minimum ttl supply voltage of 4.75v. u s a o pp l ic at i ty p i ca l +in out v 5 7 4 6 3 2 8 1 1k 1m 1k 1m 1151 ta03 gain = 1000v/v
output offset < 5ma + 1/2
LTC1151 + 1/2
LTC1151 v ?n 0.1 m f 0.1 m f v + high voltage instrumentation amplifier 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 circuits as described herein will not infringe on existing patent rights.
LTC1151 8 linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7487 (408) 432-1900 l fax : (408) 434-0507 l telex : 499-3977 ? linear technology corporation 1993 lt/gp 0193 10k rev 0 u s a o pp l ic at i ty p i ca l bridge amplifier with active common-mode suppression dimensions in inches (millimeters) unless otherwise noted. u package d e sc r i pti o s package, 16-lead sol n8 package, 8-lead plastic dip note:
pin 1 ident, notch on top and cavities on the bottom of packages are the manufacturing options.
the part may be supplied with or without any of the options. see note 0.398 ?0.413
(10.109 ?10.490) 16 15 14 13 12 11 10 9 1 23 4 5 6 78 0.394 ?0.419
(10.007 ?10.643) 0.037 ?0.045
(0.940 ?1.143) 0.004 ?0.012
(0.102 ?0.305) 0.093 ?0.104
(2.362 ?2.642) 0.050
(1.270)
typ 0.014 ?0.019
(0.356 ?0.482)
typ 0??8?typ see note 0.005
(0.127)
rad min 0.009 ?0.013
(0.229 ?0.330) 0.016 ?0.050
(0.406 ?1.270) 0.291 ?0.299
(7.391 ?7.595) 45 0.010 ?0.029
(0.254 ?0.737) 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 15v 15v 350 w
strain
gauge + 499 w 1/2
LTC1151 1151 ta04 + 1/2
LTC1151 15v 0.1 m f 0.1 m f 15v 49.9k 390 w v out
a v = 100 350 w trim to set
bridge operating
current
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