LTC1151

LTC1151 Dual ±15V Zero-Drift Operational Amplifier FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Maximum Offset Voltage Drift: 0.05µV/°C High Voltage Operation: ±18V No External Components Required Maximum Offset Voltage: 5µV Low Noise: 1.5µVP-P (0.1Hz to 10Hz) Minimum Voltage Gain: 125dB Minimum CMRR: 106dB Minimum PSRR: 110dB Low Supply Current: 0.9mA/Amplifier Single Supply Operation: 4.75V to 36V Input Common Mode Range Includes Ground Typical Overload Recovery Time: 20ms Available in 8-Lead N8 and 16-Lead SW Packages The LTC®1151 is a high voltage, high performance dual zero-drift operational amplifier. The two sample-and-hold capacitors per amplifier required externally by other chopper 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 µ V, drift of 0.01µV/°C, 0.1Hz to 10Hz input noise voltage of 1.5µVP-P, and a typical voltage gain of 140dB. It has a slew rate of 3V/µs 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. , LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. APPLICATIO S ■ ■ ■ ■ ■ ■ Strain Gauge Amplifiers Instrumentation Amplifiers Electronic Scales Medical Instrumentation Thermocouple Amplifiers High Resolution Data Acquisition TYPICAL APPLICATIO ±15V Dual Thermocouple Amplifier 51Ω 100Ω* 240k 15V 60 50 NOISE VOLTAGE (nV/√Hz) 0.1µF 6 15V VIN K 7 LT1025 3 VO GND 4 R– 5 470k –15V TYPE K 2 0.1µF 1 0.1µF – 8 7 OUTPUT A 100mV/°C 40 30 20 10 0 1 10 – + 2k 5 1/2 LTC1151 + 240k 51Ω 100Ω* – – + 2k 3 1/2 LTC1151 4 OUTPUT B 100mV/°C + 0.1µF TYPE K * FULL SCALE TRIM: TRIM FOR 10.0V OUTPUT WITH THERMOCOUPLE AT 100°C –15V 1151 TA01 U Noise Spectrum 100 1k FREQUENCY (Hz) 10k 1151 TA02 U U 1151fa 1 LTC1151 ABSOLUTE (Note 1) AXI U RATI GS Operating Temperature Range LTC1151C .............................................. 0°C to 70°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................. 300°C Total Supply Voltage (V + to V –) ............................. 36V Input Voltage (Note 2) .......... (V + + 0.3V) to (V – – 0.3V) Output Short Circuit Duration ......................... Indefinite Burn-In Voltage ...................................................... 36V PACKAGE/ORDER I FOR ATIO TOP VIEW OUT A 1 –IN A 2 +IN A 3 V– 4 8 7 6 5 V+ OUT B –IN B +IN B ORDER PART NUMBER LTC1151CN8 N8 PACKAGE 8-LEAD PLASTIC DIP TJMAX = 110°C, θJA = 130°C/ W Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS PARAMETER Input Offset Voltage Average Input Offset Drift Long Term Offset Voltage Drift Input Offset Current Input Bias Current Input Noise Voltage Input Noise Current Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Large-Signal Voltage Gain TA = 25°C CONDITIONS TA = 25°C (Note 3) (Note 3) The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = ±15V, unless otherwise specified. MIN ● TA = 25°C ● RS = 100Ω, 0.1Hz to 10Hz RS = 100Ω, 0.1Hz to 1Hz f = 10Hz (Note 4) Positive Negative VCM = V – to 12V VS = ± 2.375V to ±16V RL = 10k, VOUT = ± 10V ● ● ● ● ● 2 U U W WW U W TOP VIEW NC NC OUT A –IN A +IN A V– NC NC 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 NC NC V+ OUT B –IN B +IN B NC NC ORDER PART NUMBER LTC1151CSW SW PACKAGE 16-LEAD PLASTIC SO (WIDE) TJMAX = 110°C, θJA = 200°C/ W LTC1151C TYP ± 0.5 ± 0.01 50 ± 20 MAX ±5 ± 0.05 ± 200 ± 0.5 ±100 ± 0.5 UNITS µV µV/°C nV/√mo pA nA pA nA µVP-P µVP-P fA/√Hz V V dB dB dB ● ±15 1.5 0.5 2.2 12 –15 106 110 125 13.2 –15.3 130 130 140 1151fa LTC1151 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = ±15V, unless otherwise specified. PARAMETER Maximum Output Voltage Swing CONDITIONS RL = 10k, TA = 25°C RL = 10k RL = 100k RL = 10k, CL = 50pF No Load, TA = 25°C No Load ● ELECTRICAL CHARACTERISTICS MIN LTC1151C TYP MAX UNITS V V V V/µs MHz ±13.5 ±14.50 +10.5/–13.5 ±14.95 2.5 2 0.9 1.5 2.0 Slew Rate Gain-Bandwidth Product Supply Current per Amplifier Internal Sampling Frequency ● mA mA Hz 1000 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 5V, unless otherwise specified. Input Offset Voltage Average Input Offset Drift Long Term Offset Voltage Drift Input Offset Current Input Bias Current Input Noise Voltage Input Noise Current Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Large-Signal Voltage Gain Maximum Output Voltage Swing Slew Rate Gain Bandwidth Product Supply Current per Amplifier Internal Sampling Frequency Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Connecting any terminal to voltages greater than V + or less than V – may cause destructive latch-up. It is recommended that no sources operating from external supplies be applied prior to power-up of the LTC1151. No Load, TA = 25°C ● TA = 25°C (Note 3) (Note 3) TA = 25°C TA = 25°C RS = 100Ω, 0.1Hz to 10Hz RS = 100Ω, 0.1Hz to 1Hz f = 10Hz (Note 4) Positive Negative VCM = 0V to 2.7V VS = ± 2.375V to ± 16V RL = 10k, VOUT = 0.3V to 4.5V RL = 10k to GND RL = 100k to GND RL = 10k, CL = 50pF ● ● ● ± 0.05 ± 0.01 50 ±10 ±5 2.0 0.7 1.3 2.7 0 110 110 115 130 140 4.85 4.97 1.5 1.5 0.5 750 3.2 – 0.3 ±5 ± 0.05 100 50 µV µV/ °C nV/ √mo pA pA µVP-P µVP-P fA/√Hz V V dB dB dB V V V/µs MHz 1.0 1.5 mA mA Hz Note 3: These parameters are guaranteed by design. Thermocouple effects preclude measurement of these voltage levels in high speed automatic test systems. VOS is measured to a limit determined by test equipment capability. Note 4: Current Noise is calculated from the formula: IN = √(2q • Ib) where q = 1.6 × 10 –19 Coulomb. 1151fa 3 LTC1151 TYPICAL PERFOR A CE CHARACTERISTICS Supply Current vs Supply Voltage 2.5 TA = 25°C TOTAL SUPPLY CURRENT (mA) COMMON MODE RANGE (V) 2.0 TOTAL SUPPLY CURRENT (mA) 1.5 1.0 0.5 0 4 8 12 16 20 24 28 32 TOTAL SUPPLY VOLTAGE (V) 36 Output Short-Circuit Current vs Supply Voltage 6 30 SHORT-CIRCUIT OUTPUT CURRENT (mA) 4 2 0 –3 –6 –9 –12 –15 4 TA = 25°C 25 OUTPUT VOLTAGE (VP-P) VOUT = V – ISOURCE CMRR (dB) VOUT = V + ISINK 8 12 16 20 24 28 32 36 TOTAL SUPPLY VOLTAGE, V + TO V – (V) 1151 G04 Gain and Phase vs Frequency 100 80 GAIN (dB) VS = ±15V CL = 100pF PHASE GAIN 60 40 60 40 45 0 GAIN 45 0 PSRR (dB) GAIN (dB) 20 –45 0 10 100 1k 10k 100k FREQUENCY (Hz) 1M 10M 1151 G07 4 UW 1151 G01 Supply Current vs Temperature 2.00 15 Common Mode Input Voltage Range vs Supply Voltage TA = 25°C 10 5 0 –5 –10 VS = ±15V 1.75 1.50 1.25 0 10 20 40 50 TEMPERATURE (˚C) 30 60 70 –15 0 ± 2.5 ± 5.0 ± 7.5 ±10.0 ± 12.5 ± 15.0 1151 G03 SUPPLY VOLTAGE (V) 1151 G02 Undistorted Output Swing vs Frequency 160 140 120 CMRR vs Frequency VS = ±15V 20 15 10 5 100 80 60 40 VS = ±15V RL = 10k 1k 10k 100k FREQUENCY (Hz) 1M 1151 G05 20 0 1 10 100 1k FREQUENCY (Hz) 10k 100k 1151 G06 0 100 Gain and Phase vs Frequency 100 135 80 90 PHASE (DEG) PSRR vs Frequency 160 135 90 PHASE (DEG) 140 120 100 80 60 40 –45 20 0 NEGATIVE SUPPLY POSITIVE SUPPLY VS = ± 15V VS = ± 2.5V CL = 100pF PHASE 20 0 10 100 1k 10k 100k FREQUENCY (Hz) 1M 10M 1151 G08 1 10 100 1k FREQUENCY (Hz) 10k 100k 1151 G09 1151fa LTC1151 TYPICAL PERFOR A CE CHARACTERISTICS Input Bias Current Magnitude vs Temperature 1000 VCM = 0 VS = ±15V INPUT BIAS CURRENT (pA) INPUT BIAS CURRENT (pA) INPUT BIAS CURRENT (pA) 100 10 1 –50 –25 25 50 75 0 TEMPERATURE (°C) 0.1Hz to 10Hz Noise VS = ±15V TA = 25°C 1µV 1s Small-Signal Transient Response 5V/DIV 50mV/DIV 2V/DIV 2ms/DIV VS = ±15V, AV = 1 CL = 100pF, RL = 10k 1151 G14 VS = ±15V, AV = 1 CL = 100pF, RL = 10k 2ms/DIV 1151 G15 2V/DIV UW 1151 G10 Input Bias Current Magnitude vs Supply Voltage 18 15 12 9 6 3 0 TA = 25°C VCM = 0V Input Bias Current vs Input Common Mode Voltage 60 45 30 –IB 15 0 –15 +IB –30 –45 VS = ±15V TA = 25°C 100 125 0 ±2 ± 4 ± 6 ± 8 ± 10 ± 12 ± 14 ± 16 SUPPLY VOLTAGE (V) 1151 G11 –60 –15 –5 5 10 –10 0 INPUT COMMON MODE VOLTAGE (V) 15 1151 G12 10s 1151 G13 Large-Signal Transient Response Negative Overload Recovery 5 0 0 2ms/DIV VS = ±15V, AV = –100 NOTE: POSITIVE OVERLOAD RECOVERY IS TYPICALLY 3ms. 1151 G16 1151fa 5 LTC1151 TEST CIRCUITS Offset Voltage Test Circuit 1M V+ 7 6 OUTPUT RL 1k 2 – + LTC1151 3 4 V – 1151 TC01 DC-10Hz Noise Test Circuit 100pF 100k 5V 2 10Ω 3 5V 2 6 800k 3 – + 7 – 8 1 800k 0.04µF 800k 6 – 1/2 LT1057 7 OUTPUT LTC1151 4 –5V 1/2 LT1057 +4 –5V 5 + 0.02µF 0.01µF 1151 TC02 1151fa 6 LTC1151 APPLICATI 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 degrade 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 LTC1151’s ultra low drift is to be fully utilized. Any connection of dissimilar metals forms a thermoelectric junction producing 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. S I FOR ATIO ACHIEVING PICOAMPERE/MICROVOLT PERFORMANCE U 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 amplifier’s 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 unnecessary 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. 1151fa W U UO 7 LTC1151 APPLICATI S I FOR ATIO 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 Tin Oxide Carbon Composition Metal Film Wire Wound Evenohm, Manganin THERMAL EMF/°C GRADIENT >1mV/°C ∼ 450µV/°C ∼ 20µV/°C ∼ 2µV/°C PACKAGE-INDUCED OFFSET VOLTAGE Package-induced thermal EMF effects are another important 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, NOMINALLY UNNECESSARY RESISTOR USED TO THERMALLY BALANCE OTHER INPUT RESISTOR RESISTOR LEAD, SOLDER, COPPER TRACE JUNCTION Figure 1. Extra Resistors Cancel Thermal EMF 8 U they are outside the LTC1151’s 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 correction 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. LEAD WIRE/SOLDER COPPER TRACE JUNCTION W U UO + LTC1151 OUTPUT – 1151 F01 1151fa LTC1151 TYPICAL APPLICATI 1M UO –IN S High Voltage Instrumentation Amplifier 1k V+ 1M 2 0.1µF 1 1k 6 – + 8 1/2 LTC1151 3 – 1/2 LTC1151 7 VOUT +IN 5 + 4 V– GAIN = 1000V/V OUTPUT OFFSET < 5mA 0.1µF 1151 TA03 1151fa 9 LTC1151 PACKAGE DESCRIPTIO .300 – .325 (7.620 – 8.255) .008 – .015 (0.203 – 0.381) ( +.035 .325 –.015 8.255 +0.889 –0.381 ) INCHES MILLIMETERS *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm) NOTE: 1. DIMENSIONS ARE 10 U N8 Package 8-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) .400* (10.160) MAX 8 7 6 5 .255 ± .015* (6.477 ± 0.381) 1 2 3 4 .130 ± .005 (3.302 ± 0.127) .045 – .065 (1.143 – 1.651) .065 (1.651) TYP .120 (3.048) .020 MIN (0.508) MIN .018 ± .003 (0.457 ± 0.076) N8 1002 .100 (2.54) BSC 1151fa LTC1151 PACKAGE DESCRIPTIO .030 ±.005 TYP N .420 MIN 1 2 3 RECOMMENDED SOLDER PAD LAYOUT 1 .291 – .299 (7.391 – 7.595) NOTE 4 .010 – .029 × 45° (0.254 – 0.737) 0° – 8° TYP .005 (0.127) RAD MIN .009 – .013 (0.229 – 0.330) NOTE 3 .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN INCHES (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. 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 4. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) U SW Package 16-Lead Plastic Small Outline (Wide .300 Inch) (Reference LTC DWG # 05-08-1620) .050 BSC .045 ±.005 .398 – .413 (10.109 – 10.490) NOTE 4 16 15 14 13 12 11 10 9 N .325 ±.005 NOTE 3 .394 – .419 (10.007 – 10.643) N/2 N/2 2 3 4 5 6 7 8 .093 – .104 (2.362 – 2.642) .037 – .045 (0.940 – 1.143) .050 (1.270) BSC .004 – .012 (0.102 – 0.305) .014 – .019 (0.356 – 0.482) TYP S16 (WIDE) 0502 1151fa 11 LTC1151 TYPICAL APPLICATI 1/2 LTC1151 –15V RELATED PARTS PART NUMBER LTC1049 LTC1050 LTC1051/LTC1053 LTC1150 LTC1152 LT1677 LT1884/LT1885 LTC2053 LTC2054/LTC2055 DESCRIPTION Low Power Zero-Drift Op Amp Precision Zero-Drift Op Amp Precision Zero-Drift Op Amp ±15V Zero-Drift Op Amp Low Noise Rail-toRail Input and Output Rail-to-Rail Output Precision Op Amp Zero-Drift Instrumentation Amp Single/Dual Zero-Drift Op Amp COMMENTS Low Supply Current 200µA Single Supply Operation 4.75V to 16V, Noise Tested and Guaranteed Dual/Quad High Voltage Operation ±18V VOS = 90µV, VS = 2.7V to 44V Precision Op Amp VOS = 50µV, IB = 400pA, VS = 2.7V to 40V Single Supply, 2.7V to ±5V, SOT-23/MS8/GN 16 Package Rail-to-Rail, MS8, 116dB, Two Resistors Set Gain 150µA per Amplifier (Max), SOT-23/MS8 Package Rail-to-Rail Input and Output Zero-Drift Op Amp Single Zero-Drift Op Amp with Rail-to-Rail Input and Output and Shutdown LTC2050/LTC2051/LTC2052 Single/Dual/Quad Zero-Drift Op Amp 12 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● – + UO 15V S Bridge Amplifier with Active Common-Mode Suppression 15V 350Ω TRIM TO SET BRIDGE OPERATING CURRENT 49.9k 0.1µF – 350Ω STRAIN GAUGE 1/2 LTC1151 + 499Ω VOUT AV = 100 0.1µF 390Ω –15V 1151 TA04 1151fa LT 1105 REV A • PRINTED IN USA www.linear.com © LINEAR TECHNOLOGY CORPORATION 1993