LT1881

LT1881/LT1882 Dual and Quad Rail-to-Rail Output, Picoamp Input Precision Op Amps FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Offset Voltage: 50μV Maximum (LT1881A) Input Bias Current: 200pA Maximum (LT1881A) Offset Voltage Drift: 0.8μV/°C Maximum Rail-to-Rail Output Swing Supply Range: 2.7V to 36V Operates with Single or Split Supplies Open-Loop Voltage Gain: 1 Million Minimum 1mA Maximum Supply Current Per Amplifier Stable at AV = 1, CL = 1000pF Standard Pinouts The LT®1881 and LT1882 op amps bring high accuracy input performance to amplifiers with rail-to-rail output swing. Input bias currents and capacitive load driving capabilities are superior to the similar LT1884 and LT1885 amplifiers, at the cost of a slight loss in speed. Input offset voltage is trimmed to less than 50μV and the low drift maintains this accuracy over the operating temperature range. Input bias currents are an ultralow 200pA maximum. The amplifiers work on any total power supply voltage between 2.7V and 36V (fully specified from 5V to ± 15V). Output voltage swings to within 40mV of the negative supply and 220mV of the positive supply make these amplifiers good choices for low voltage single supply operation. Capacitive loads up to 1000pF can be driven directly in unity-gain follower applications. The dual LT1881 and LT1881A are available with standard pinouts in S8 and PDIP packages. The quad LT1882 is in a 14-pin SO package. For a higher speed device with similar DC specifications, see the LT1884/LT1885. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. APPLICATIO S ■ ■ ■ ■ ■ Thermocouple Amplifiers Bridge Transducer Conditioners Instrumentation Amplifiers Battery-Powered Systems Photo Current Amplifiers TYPICAL APPLICATIO 5V 16-Bit Voltage Output DAC on ± 5V Supply 26 24 22 20 18 16 14 12 10 8 6 4 2 0 VS = ± 15V TC VOS Distribution, Industrial Grade 5V + LT1881 – LT1634 4.096V R1 –5V RCOM REF ROFS 33pF 5V DAC PERCENT OF UNITS (%) 1.65k 40 N8 (1 LOT) 144 S8 (2 LOTS) 184 TOTAL PARTS – LT1881 1 –0.9–0.8–0.7–0.6–0.5–0.4–0.3–0.2–0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 INPUT OFFSET VOLTAGE DRIFT (μV/°C) 1881/2 TA01a LTC®1597 + –5V VOUT – 4.096V TO 4.096V 1881/2 TA01 U 18812fa U U 1 LT1881/LT1882 ABSOLUTE AXI U RATI GS Supply Voltage (V + to V –) ....................................... 40V Differential Input Voltage (Note 2) ......................... ± 10V Input Voltage .................................................... V + to V – Input Current (Note 2) ........................................ ± 10mA Output Short-Circuit Duration (Note 3) ............ Indefinite PACKAGE/ORDER I FOR ATIO TOP VIEW OUT A 1 –IN A 2 +IN A 3 V– 4 N8 PACKAGE 8-LEAD PDIP A B 8 7 6 5 V+ OUT B –IN B +IN B ORDER PART NUMBER LT1881CN8 LT1881IN8 LT1881CS8 LT1881IS8 LT1881ACN8 LT1881AIN8 LT1881ACS8 LT1881AIS8 S8 PART MARKING 1881 1881I 1881A 1881AI OUT A 1 –IN A 2 +IN A 3 V+ 4 +IN B 5 –IN B 6 OUT B 7 S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 130°C/W (N8) TJMAX = 150°C, θJA = 190°C/W (S8) Consult LTC marketing for parts specified with wider operating temperature ranges. The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Single supply operation VS = 5V, 0V; VCM = VS/2 unless otherwise noted. (Note 5) SYMBOL VOS PARAMETER Input Offset Voltage (LT1881A) 0°C < TA < 70°C – 40°C < TA < 85°C Input Offset Voltage (LT1881/LT1882) 0°C < TA < 70°C – 40°C < TA < 85°C ΔVOS/ΔT Input Offset Voltage Drift (Note 6) Input Offset Current (LT1881A) 0°C < TA < 70°C – 40°C < TA < 85°C Input Offset Current (LT1881/LT1882) 0°C < TA < 70°C – 40°C < TA < 85°C ● ● ● ● ● ● ● ● ● ● ELECTRICAL CHARACTERISTICS CONDITIONS 0°C < TA < 70°C – 40°C < TA < 85°C ΔVOS/ΔTIME Long-Term Input Offset Voltage Stability IOS 2 U U W WW U W (Note 1) Operating Temperature Range (Note 4) .. – 40°C to 85°C Specified Temperature Range (Note 5) ... – 40°C to 85°C Maximum Junction Temperature .......................... 150°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C TOP VIEW 14 OUT D A D 13 –IN D 12 +IN D 11 V – B C 10 +IN C 9 8 –IN C OUT C ORDER PART NUMBER LT1882CS LT1882IS S PACKAGE 14-LEAD PLASTIC SO TJMAX = 150°C, θJA = 150°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/ MIN TYP 25 MAX 50 85 110 80 125 150 0.8 0.8 200 250 300 500 600 700 UNITS μV μV μV μV μV μV μV/°C μV/°C μV/month pA pA pA pA pA pA 18812fa 30 0.3 0.3 0.3 100 150 LT1881/LT1882 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Single supply operation VS = 5V, 0V; VCM = VS/2 unless otherwise noted. (Note 5) SYMBOL IB PARAMETER Input Bias Current (LT1881A) 0°C < TA < 70°C – 40°C < TA < 85°C Input Bias Current (LT1881/LT1882) 0°C < TA < 70°C – 40°C < TA < 85°C Input Noise Voltage en in RIN CIN VCM CMRR PSRR Input Noise Voltage Density Input Noise Current Density Input Resistance Input Capacitance Input Voltage Range ● ● ● ● ● ELECTRICAL CHARACTERISTICS CONDITIONS MIN TYP 100 MAX 200 250 300 500 600 700 UNITS pA pA pA pA pA pA μVP-P nV/√Hz pA/√Hz MΩ GΩ pF 150 0.1Hz to 10Hz f = 1kHz f = 1kHz Differential Mode Common Mode ● ● ● 0.5 14 0.03 20 100 2 + 1.0 V – + 1.2 106 104 106 106 500 350 300 250 250 200 128 V– V+ – 1.0 V + – 1.2 V V dB dB dB dB Common Mode Rejection Ratio Power Supply Rejection Ratio 1V < VCM < 4V 1.2V < VCM < 3.8V V – = 0V, VCM = 1.5V 0°C < TA < 85°C, 2.7V < V + < 32V TA = –40°C, 3V < V + < 32V RL = 10k; 1V < VOUT < 4V ● ● ● ● 132 132 2.4 1600 800 400 20 25 70 270 120 130 180 360 40 50 150 600 220 230 300 600 0.85 1.2 0.9 1.4 1.0 1.5 2.7 Minimum Operating Supply Voltage AVOL Large-Signal Voltage Gain V V/mV V/mV V/mV V/mV V/mV V/mV mV mV mV mV mV mV mV mV mA mA mA mA mA mA mA mA MHz dB μs 18812fa RL = 2k; 1V < VOUT < 4V ● RL = 1k; 1V < VOUT < 4V ● VOL Output Voltage Swing Low No Load ISINK = 100μA ISINK = 1mA ISINK = 5mA No Load ISOURCE = 100μA ISOURCE = 1mA ISOURCE = 5mA VS = 3V, 0V ● ● ● ● ● ● ● ● VOH Output Voltage Swing High (Referred to V +) IS Supply Current Per Amplifier 0.45 ● 0.65 0.65 0.70 30 30 1.0 120 30 VS = 5V, 0V ● 0.5 0.5 ● ● ● VS = 12V, 0V ISC GBW tS Short-Circuit Current Gain Bandwidth Product Channel Separation Settling Time VOUT Short to GND VOUT Short to V + f = 20kHz f = 1kHz 0.01%, VOUT = 1.5V to 3.5V, AV = –1, RL = 2k 15 15 0.35 3 LT1881/LT1882 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Single supply operation VS = 5V, 0V; VCM = VS/2 unless otherwise noted. (Note 5) SYMBOL SR + SR – FPBW ΔVOS PARAMETER Slew Rate Positive Slew Rate Negative Full-Power Bandwidth Offset Voltage Match (LT1881A) CONDITIONS AV = – 1 ● ELECTRICAL CHARACTERISTICS MIN 0.15 0.12 0.11 0.08 8.75 6.35 TYP 0.35 0.18 14 30 MAX UNITS V/μs V/μs V/μs V/μs kHz kHz AV = – 1 ● VOUT = 4VP-P (Note 10) (Note 7) 0°C < TA < 70°C – 40°C < TA < 85°C (Note 7) 0°C < TA < 70°C – 40°C < TA < 85°C (Notes 6, 7) (Notes 7, 8) 0°C < TA < 70°C – 40°C < TA < 85°C (Notes 7, 8) 0°C < TA < 70°C – 40°C < TA < 85°C (Notes 7, 9) V – = 0V, VCM = 1.5V 0°C < TA < 85°C, 2.7V < V + < 32V TA = –40°C, 3V < V + < 32V ● ● ● 70 125 160 125 175 235 1.2 300 400 500 700 900 1000 μV μV μV μV μV μV μV/°C pA pA pA pA pA pA dB dB dB Offset Voltage Match (LT1881/LT1882) 35 ● ● ● ● ● Offset Voltage Match Drift ΔIB+ Noninverting Bias Current Match (LT1881A) Noninverting Bias Current Match (LT1881/LT1882) ΔCMRR ΔPSRR Common Mode Rejection Match Power Supply Rejection Match (Notes 7, 9) 0.4 200 250 ● ● ● ● 102 104 104 125 126 126 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Split supply operation VS = ± 15V, VCM = 0V unless otherwise noted. (Note 5) SYMBOL VOS PARAMETER Input Offset Voltage (LT1881A) 0°C < TA < 70°C – 40°C < TA < 85°C Input Offset Voltage (LT1881/LT1882) 0°C < TA < 70°C – 40°C < TA < 85°C ΔVOS/ΔT Input Offset Voltage Drift (Note 6) Input Offset Current (LT1881A) 0°C < TA < 70°C – 40°C < TA < 85°C Input Offset Current (LT1881/LT1882) 0°C < TA < 70°C – 40°C < TA < 85°C ● ● ● ● ● ● ● ● ● ● CONDITIONS MIN TYP 25 MAX 50 85 110 80 125 150 0.8 0.8 200 250 300 500 600 700 UNITS μV μV μV μV μV μV μV/°C μV/°C μV/month pA pA pA pA pA pA 30 0°C < TA < 70°C – 40°C < TA < 85°C 0.3 0.3 0.3 150 ΔVOS/ΔTIME Long-Term Input Offset Voltage Stability IOS 150 18812fa 4 LT1881/LT1882 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Split supply operation VS = ± 15V, VCM = 0V unless otherwise noted. (Note 5) SYMBOL IB PARAMETER Input Bias Current (LT1881A) 0°C < TA < 70°C – 40°C < TA < 85°C Input Bias Current (LT1881/LT1882) 0°C < TA < 70°C – 40°C < TA < 85°C Input Noise Voltage en in RIN CIN VCM CMRR +PSRR –PSRR AVOL Input Noise Voltage Density Input Noise Current Density Input Resistance Input Capacitance Input Voltage Range ● ● ● ● ● ELECTRICAL CHARACTERISTICS CONDITIONS MIN TYP 150 MAX 200 250 300 500 600 700 UNITS pA pA pA pA pA pA μVP-P nV/√Hz pA/√Hz MΩ GΩ pF 150 0.1Hz to 10Hz f = 1kHz f = 1kHz Differential Mode Common Mode ● ● ● 0.5 14 0.03 20 100 2 + 1.0 V – + 1.2 114 110 106 1000 700 175 125 90 65 130 132 132 ± 1.2 1600 420 230 20 25 70 270 160 160 180 360 0.5 ● V– V+ – 1.0 V + – 1.2 V V dB dB dB Common Mode Rejection Ratio Positive Power Supply Rejection Ratio Negative Power Supply Rejection Ratio Minimum Operating Supply Voltage Large-Signal Voltage Gain –13.5V < VCM < 13.5V V– V+ = – 15V, VCM = 15V, VCM = 0V; 1.5V < V + < 18V < – 18V = 0V; –1.5V < V – ● ● ● ● ±1.35 V V/mV V/mV V/mV V/mV V/mV V/mV RL = 10k; –13.5V < VOUT < 13.5V ● RL = 2k; –13.5V < VOUT < 13.5V ● RL = 1k; –12V < VOUT < 12V ● VOL Output Voltage Swing Low (Referred to VEE) No Load ISINK = 100μA ISINK = 1mA ISINK = 5mA No Load ISOURCE = 100μA ISOURCE = 1mA ISOURCE = 5mA VS = ± 15V VOUT Short to V – ● ● ● ● ● ● ● ● 40 50 150 600 220 230 300 600 1.1 1.6 mV mV mV mV mV mV mV mV mA mA mA mA mA mA MHz dB μs V/μs V/μs 18812fa VOH Output Voltage Swing High (Referred to VCC) IS ISC Supply Current Per Amplifier Short-Circuit Current 0.85 40 40 30 30 0.85 120 35 ● 20 15 20 15 0.4 VOUT Short to V + ● GBW tS SR + Gain Bandwidth Product Channel Separation Settling Time Slew Rate Positive f = 20kHz f = 1kHz 0.01%, VOUT = – 5V to 5V, AV = – 1, RL = 2k AV = – 1 ● 0.21 0.18 0.4 5 LT1881/LT1882 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Split supply operation VS = ± 15V, VCM = 0V unless otherwise noted. (Note 5) SYMBOL SR – FPBW ΔVOS PARAMETER Slew Rate Negative Full-Power Bandwidth Offset Voltage Match (LT1881/LT1882) CONDITIONS AV = – 1 ● ELECTRICAL CHARACTERISTICS MIN 0.13 0.1 1.47 1.13 TYP 0.20 2.25 42 MAX UNITS V/μs V/μs kHz kHz VOUT = 28VP-P (Note 10) (Note 5) 0°C < TA < 70°C – 40°C < TA < 85°C 0°C < TA < 70°C – 40°C < TA < 85°C ● ● ● 125 175 235 70 125 160 1.1 700 900 1000 300 400 500 μV μV μV μV μV μV μV/°C pA pA pA pA pA pA dB dB dB Offset Voltage Match (LT1881A) ● ● ● ● ● 35 Offset Voltage Match Drift ΔIB+ Noninverting Bias Current Match (LT1881/LT1882) Noninverting Bias Current Match (LT1881A) ΔCMRR Δ+PSRR Δ –PSRR Common Mode Rejection Match Positive Power Supply Rejection Match Negative Power Supply Rejection Match (Notes 6, 7) (Notes 7, 8) 0°C < TA < 70°C – 40°C < TA < 85°C 0°C < TA < 70°C – 40°C < TA < 85°C (Notes 7, 9) V – = – 15V, VCM = 0V, 1.5V < V + < 18V, (Notes 7, 9) V + = 15V, VCM = 0V, – 1.5V < V – < – 18V, (Notes 7, 9) 0.4 240 200 ● ● ● ● ● 110 108 104 125 130 130 Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The inputs are protected by internal resistors and back-to-back diodes. If the differential input voltage exceeds ±0.7V, the input current should be limited externally to less than 10mA. Note 3: A heat sink may be required to keep the junction temperature below absolute maximum. Note 4: The LT1881C, LT1882C, LT1881I and LT1882I are guaranteed functional over the operating temperature range of – 40°C to 85°C. Note 5: The LT1881C and LT1882C are designed, characterized and expected to meet specified performance from – 40°C to 85°C but are not tested or QA sampled at these temperatures. The LT1881I and LT1882I are guaranteed to meet specified performance from – 40°C to 85°C. Note 6: This parameter is not 100% tested. Note 7: Matching parameters are the difference between amplifiers A and B in the LT1881; and between amplifiers A and D and B and C in the LT1882. Note 8: This parameter is the difference between the two noninverting input bias currents. Note 9: ΔCMRR and ΔPSRR are defined as follows: CMRR and PSRR are measured in μV/V on each amplifier. The difference is calculated in μV/V and then converted to dB. Note 10: Full power bandwidth is calculated from the slew rate: FPBW = SR/2πVP. 18812fa 6 LT1881/LT1882 TYPICAL PERFOR A CE CHARACTERISTICS Supply Current per Amplifier vs Supply Voltage 0.45 0.40 0.35 AV = – 1 RISING 0.45 0.40 0.35 SLEW RATE (V/μs) SLEW RATE (V/μs) 0.30 0.25 0.20 0.15 0.10 0.05 0 0 4 8 12 16 20 24 28 32 TOTAL SUPPLY VOLTAGE (V) 36 FALLING 0.30 0.25 0.20 0.15 0.10 0.05 0 0 4 8 12 16 20 24 28 32 TOTAL SUPPLY VOLTAGE (V) 36 FALLING SLEW RATE (V/μs) Settling Time vs Output Step 10 8 6 VS = ± 15V AV = –1 10 8 6 GAIN BANDWIDTH PRODUCT (kHz) OUTPUT STEP (V) OUTPUT STEP (V) 4 2 0 –2 –4 –6 –8 –10 0.1% 0.01% 0.1% 0.01% 0 5 10 15 20 25 30 35 40 45 50 55 60 65 SETTLING TIME (μs) 1881/2 G04 Phase Margin vs Supply Voltage 60 58 10 PHASE MARGIN (DEG) 56 54 –55°C GAIN (dB) 125°C 52 50 125°C GAIN (dB) 48 46 –40 –40 0 4 8 12 16 20 24 28 32 TOTAL SUPPLY VOLTAGE (V) UW 1881/2 G02 1881/2 G07 Slew Rate vs Supply Voltage 0.5 AV = – 1 RISING 0.4 Slew Rate vs Temperature AV = – 1 RISING VS = ± 15V VS = ± 5V VS = ± 15V FALLING 0.2 VS = ± 5V 0.3 0.1 0 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 1881/2 G03 1881/2 G02 Settling Time vs Output Step 900 VS = ± 15V AV = 1 850 Gain Bandwidth Product vs Supply Voltage 4 2 0 –2 –4 –6 –8 –10 125°C 800 750 700 650 600 25°C –55°C 0.1% 0.01% 0.1% 0.01% 0 5 10 15 20 25 30 35 40 45 50 55 60 65 SETTLING TIME (μs) 1881/2 G05 0 4 8 12 16 20 24 28 32 TOTAL SUPPLY VOLTAGE (V) 36 1881/2 G06 Gain vs Frequency, AV = – 1 10 Gain vs Frequency, AV = 1 0 0 –10 –10 VS = ± 2.5V –20 VS = ± 15V –20 VS = ± 2.5V –30 VS = ± 15V –30 36 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 1881/2 G08 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 1881/2 G09 18812fa 7 LT1881/LT1882 TYPICAL PERFOR A CE CHARACTERISTICS Gain vs Frequency with CLOAD, AV = 1 10 VS = ± 15V 0 1500pF 1000pF 0 10 VS = ± 15V 1800pF GAIN (dB) GAIN (dB) –10 –20 0pF –30 –40 1k 10k 100k 1M FREQUENCY (Hz) Large Signal Response, AV = – 1 TIME (50μs/DIV) 1881/2 G12 TIME (50μs/DIV) VOUT (20mV/DIV) VOUT (5V/DIV) VOUT (5V/DIV) Small Signal Response, AV = – 1, CL = 1000pF VOUT (20mV/DIV) VOUT (20mV/DIV) TIME (2μs/DIV) 1881/2 G15 TIME (2μs/DIV) VOUT (20mV/DIV) 8 UW Gain vs Frequency with CLOAD, AV = – 1 500pF –10 1000pF –20 500pF –30 0pF 10M 100M 1881/2 G10 –40 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 1881/2 G11 Large Signal Response, AV = 1 Small Signal Response, AV = – 1, No Load 1881/2 G13 TIME (2μs/DIV) 1881/2 G14 Small Signal Response, AV = 1, RL = 2k Small Signal Response, AV = 1, CL = 500pF 1881/2 G16 TIME (2μs/DIV) 1881/2 G17 18812fa LT1881/LT1882 TYPICAL PERFOR A CE CHARACTERISTICS LT1881 VOS Distribution, TA = 25°C 26 24 22 20 18 16 14 12 10 8 6 4 2 0 VS = ± 15V 40 N8 (1 LOT) 144 S8 (2 LOTS) 184 TOTAL PARTS 200 150 VS = ± 15V 0 OFFSET VOLTAGE DRIFT (μV) PERCENT OF UNITS (%) VOLTAGE OFFSET (μV) –60 –40 –20 0 20 40 OUTPUT OFFSET VOLTAGE (μV) LT1881 Input Bias Current vs Common Mode Voltage 1000 800 600 400 IBIAS (pA) 150 100 INPUT BIAS CURRENT (pA) INPUT COMMON MODE RANGE (V) VS = ± 15V 200 0 200 400 600 800 1000 –20 –15 –10 –5 0 5 VCM (V) 10 LT1881 Input Common Mode Voltage vs Temperature 5 INPUT COMMON MODE VOLTAGE (V) 4 3 2 1 0 –1 –2 –3 –4 –5 –50 V –25 0 25 50 75 TEMPERATURE (°C) 100 125 –+0 OUTPUT VOLTAGE SWING (V) V+ – 0.5 RL = 2k V+ – 1.0 AV = –1 TA = 25°C V – + 1.0 OUTPUT SATURATION VOLTAGE (V) VS = ± 5V UW 60 1881/2 G18 LT1881IS8 Voltage Offset vs Temperature 5 Warm-Up Drift vs Time 100 50 0 –50 N8 VS = 5V –5 –10 –15 N8 VS = ± 15V –20 –25 –30 S8 VS = 5V, ± 15V –100 –150 –200 –55 –35 –15 5 25 45 65 85 105 125 TEMPERATURE (°C) 1881/2 G19 0 20 40 60 80 100 120 TIME AFTER POWER UP (s) 140 1881/2 G20 LT1881 Input Bias Current vs Temperature V+ – 0 VS = ± 15V +IBIAS 50 0 –IBIAS –50 –100 –150 –40 V+ – 0.5 V+ – 1.0 V+ – 1.5 LT1881 Input Common Mode Range vs Supply Voltage ΔVOS < 1mV 85°C –40°C 25°C V – + 1.5 V – + 1.0 V – + 0.5 V– + 0 0 2 –40°C 25°C 85°C 4 6 8 10 12 SUPPLY VOLTAGE (± V) 14 1881/2 G23 15 20 –20 0 20 40 60 TEMPERATURE (°C) 80 1881/2 G22 16 1881/2 G21 LT1881 Output Voltage Swing vs Supply Voltage V+ – 0 RL = 10k 1 LT1881 Output Saturation Voltage vs Load Current (Output High) VS = ± 15V VOD = 30mV TA = 25°C 0.1 TA = 85°C TA = – 40°C V – + 0.5 RL = 2k RL = 10k 0 2 4 6 8 10 12 14 16 18 20 SUPPLY VOLTAGE (± V) 1881/2 G25 0.01 0.001 0.01 0.1 1 SOURCING LOAD CURRENT (mA) 10 1881/2 G26 1881/2 G24 18812fa 9 LT1881/LT1882 TYPICAL PERFOR A CE CHARACTERISTICS LT1881 Output Saturation Voltage vs Load Current (Output Low) 1 OUTPUT SATURATION VOLTAGE (V) VS = ± 15V VOD = 30mV 0.1 TA = 25°C TA = 85°C OUTPUT SHORT-CIRCUIT CURRENT (mA) TA = – 40°C 0.01 0.001 0.001 0.1 1 0.01 SINKING LOAD CURRENT (mA) LT1881 Open-Loop Gain vs Frequency 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 –10 –20 0.1 70 VS = ± 15V 60 50 LOOP GAIN (dB) LOOP GAIN (dB) 40 30 20 10 0 –10 –20 LOOP GAIN PHASE 100 PHASE (DEG) CHANNEL SEPARATION (dB) 1 10 100 1k 10k 100k 1M 10M 100M FREQUENCY (Hz) 1881/2 G30 Gain Bandwidth Product vs Temperature 900 VS = ± 15V GAIN BANDWIDTH PRODUCT (KHz) 850 10 800 750 700 650 600 550 –50 VS = ± 2.5V OUTPUT IMPEDANCE (Ω) 100 PSSR (dB) –25 0 25 50 TEMPERATURE (°C) 10 UW 10 1881/2 G27 LT1881 Output Short-Circuit Current vs Temperature 60 56 52 48 44 40 36 32 28 24 20 16 12 8 4 0 – 55 –35 –15 LT1881 Output Voltage vs Large Input Voltage VIN GND SINKING VOUT SOURCING AV = 1 VS = ± 2.5V VIN = ± 5V RIN = 10k 1881 G29.tif GND 5 25 45 65 85 105 125 TEMPERATURE (°C) 1881/2 G28 LT1881 Open-Loop Gain and Phase vs Frequency 175 VS = ± 5V 150 120 –40 –60 –80 –100 –120 –140 –20 LT1881 Channel Separation vs Frequency VS = ± 15V AV = 10 75 50 25 0 –25 –50 10k 100k 1M FREQUENCY (Hz) –100 10M 1881/2 G31 –30 1k 10 100 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 1881/2 G32 Output Impedance vs Frequency VS = ± 2.5V AV = 100 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 –10 LT1881 PSRR vs Frequency VS = ± 15V 1 AV = 10 0.1 AV = 1 –PSSR +PSSR 0.01 75 100 0.001 100 1k 10k FREQUENCY (Hz) 100k 1881/2 G34 1 10 100 1k 10k FREQUENCY (Hz) 100k 1M 1881/2 G33 1881/2 G35 18812fa LT1881/LT1882 TYPICAL PERFOR A CE CHARACTERISTICS Common Mode Rejection Ratio vs Frequency 120 100 80 CMRR (dB) 60 40 20 0 0.1 1 10 100 1k 10k FREQUENCY (Hz) 100k 1M 0 5 10 15 1s/DIV 20 25 30 NOISE VOLTAGE DENSITY (nV/VHz) NOISE VOLTAGE (0.2μV/DIV) LT1881 Noise Current Density vs Frequency 180 TOTAL INPUT REFERRED NOISE (nV/√Hz) NOISE CURRENT DENSITY (fA/√Hz) 160 140 120 100 80 60 40 20 0 1 10 100 FREQUENCY (Hz) VS = ±15V OVERSHOOT (%) LT1881 Series Output Resistance vs Capacitive Load 120 35 PEAK-TO-PEAK OUTPUT VOLTAGE (V) SERIES OUTPUT RESISTANCE (Ω) 100 80 60 40 20 0 0 AV = 1 TA = 25°C VS = ± 2.5V THD + NOISE (%) VS = ± 15V 2000 4000 6000 8000 CAPACITIVE LOAD (pF) UW 1881/2 G36 1881/2 G39 1881/2 G42 LT1881 0.1Hz to 10Hz Noise 50 45 40 35 30 25 20 15 10 5 0 1 LT1881 Noise Voltage vs Frequency VS = ± 5V AV = 1 10 100 FREQUENCY (Hz) 1k 1881/2 G38 1881/2 G37 LT1881A Total Noise vs Source Resistance 1000 30 25 100 20 LT1881 Overshoot vs Capacitive Load VS = ±15V RL = 10k AV = 1 15 AV = – 1 10 5 10 1 1000 1 10 100 1k RS (Ω) 10k 100k 1M 0 10 100 1k CAPACITIVE LOAD (pF) 10k 1881/2 G41 1881/2 G36 LT1881 Undistorted Output Swing vs Frequency 10 30 1 25 20 15 10 5 0 AV = –1 TA = 25°C VS = ± 2.5V AV = –1 TA = 25°C VS = ± 15V LT1881 THD + Noise vs Frequency VS = ±15V VIN = 2VP-P 0.1 0.01 AV = – 1 0.001 AV = 1 10000 1 10 FREQUENCY (kHz) 100 1881/2 G43 0.0001 10 100 1k 10k FREQUENCY (Hz) 100k 1881/2 G44 18812fa 11 LT1881/LT1882 TYPICAL PERFOR A CE CHARACTERISTICS LT1881 Total Harmonic Distortion + Noise vs Output Voltage Amplitude AV = – 1 VS = ± 2.5V 1 THD + NOISE (%) f = 1kHz RF = RG = 10k CHANGE IN INPUT OFFSET VOLTAGE (20μV/DIV) 10 AV = – 1 VS = ±15V 0.1 AV = 2 VS = ± 2.5V AV = 2 VS = ±15V 0.1 1 10 OUTPUT VOLTAGE AMPLITUDE (VP-P) 100 0.01 0.001 10m LT1881 Settling Time/ Output Step 0.01% GND 0.5mV/DIV AV = 1 VS = ± 15V 20μs/DIV LT1881 Gain vs Temperature 5.0 4.5 4.0 3.5 GAIN (V/μV) 3.0 2.5 2.0 1.5 1.0 0.5 0 –50 –25 0 25 50 75 TEMPERATURE (°C) 100 125 0.1 RL = 2k 0V TO 10V 0V TO –10V RL = 10k GAIN (V/μV) VS = ± 5V 10.0 12 UW LT1881 Open-Loop Gain RL = 2k RL = 10k RL = 50k OUTPUT VOLTAGE (5V/DIV) VS = ± 15V 1881 G46.tif 1881/2 G45 LT1881 Settling Time/ Output Step 0.01% 0.5mV/DIV 10V 10V GND 1881 G47.tif AV = 1 VS = ± 15V 50μs/DIV 1881 G48.tif LT1881 Gain vs Load Resistance +AVOL (0V TO 10V) – AVOL (0V TO –10V) 1.0 VS = ±15V 0 5 10 15 20 25 LOAD RESISTANCE (kΩ) 1881/2 G50 30 1881/2 G49 18812fa LT1881/LT1882 APPLICATIO S I FOR ATIO The LT1881 dual and LT1882 quad op amps feature exceptional input precision with rail-to-rail output swing. The amplifiers are similar to the LT1884 and LT1885 devices. The LT1881 and LT1882 offer superior capacitive load driving capabilities over the LT1884 and LT1885 in low voltage gain configurations. Offset voltages are trimmed to less than 50μV and input bias currents are less than 200pA on the “A” grade devices. Obtaining beneficial advantage of these precision input characteristics depends upon proper applications circuit design and board layout. Preserving Input Precision Preserving the input voltage accuracy of the LT1881/ LT1882 requires that the applications circuit and PC board layout do not introduce errors comparable to or greater than the 30μV offset. Temperature differentials across the input connections can generate thermocouple voltages of 10’s of microvolts. PC board layouts should keep connections to the amplifier’s input pins close together and away from heat dissipating components. Air currents across the board can also generate temperature differentials. The extremely low input bias currents, 150pA, allow high accuracy to be maintained with high impedance sources and feedback networks. The LT1881/LT1882’s low input bias currents are obtained by using a cancellation circuit on-chip. This causes the resulting IBIAS + and IBIAS – to be uncorrelated, as implied by the IOS specification being greater than the IBIAS. The user should not try to balance the input resistances in each input lead, as is commonly recommended with most amplifiers. The impedance at either input should be kept as small as possible to minimize total circuit error. U PC board layout is important to insure that leakage currents do not corrupt the low IBIAS of the amplifier. In high precision, high impedance circuits, the input pins should be surrounded by a guard ring of PC board interconnect, with the guard driven to the same common mode voltage as the amplifier inputs. Input Common Mode Range The LT1881 and LT1882 outputs are able to swing nearly to each power supply rail, but the input stage is limited to operating between V – +1V and V + –1V. Exceeding this common mode range will cause the gain to drop to zero; however, no phase reversal will occur. Input Protection The inverting and noninverting input pins of the LT1881 and LT1882 have limited on-chip protection. ESD protection is provided to prevent damage during handling. The input transistors have voltage clamping and limiting resistors to protect against input differentials up to 10V. Short transients above this level will also be tolerated. If the input pins can see a sustained differential voltage above 10V, external limiting resistors should be used to prevent damage to the amplifier. A 1k resistor in each input lead will provide protection against a 30V differential voltage. Capacitive Loads The LT1881 and LT1882 can drive capacitive loads up to 1000pF in unity-gain. The capacitive load driving increases as the amplifier is used in higher gain configurations. Capacitive load driving may be increased by decoupling the capacitance from the output with a small resistance. 18812fa W U U 13 LT1881/LT1882 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 14 U N8 Package 8-Lead PDIP (Narrow 0.300) (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 .020 (3.048) MIN (0.508) MIN .018 ± .003 (0.457 ± 0.076) N8 1002 .100 (2.54) BSC 18812fa LT1881/LT1882 PACKAGE DESCRIPTIO U S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) .045 ±.005 .050 BSC 8 .189 – .197 (4.801 – 5.004) NOTE 3 7 6 5 .160 ±.005 .228 – .244 (5.791 – 6.197) .150 – .157 (3.810 – 3.988) NOTE 3 1 2 3 4 .053 – .069 (1.346 – 1.752) 0°– 8° TYP .004 – .010 (0.101 – 0.254) .014 – .019 (0.355 – 0.483) TYP .050 (1.270) BSC SO8 0303 .245 MIN .030 ±.005 TYP RECOMMENDED SOLDER PAD LAYOUT .010 – .020 × 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN INCHES (MILLIMETERS) 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) S Package 14-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) .045 ±.005 .050 BSC N 14 13 .337 – .344 (8.560 – 8.738) NOTE 3 12 11 10 9 8 .245 MIN N .160 ±.005 .228 – .244 (5.791 – 6.197) 1 2 3 N/2 N/2 .150 – .157 (3.810 – 3.988) NOTE 3 .030 ±.005 TYP RECOMMENDED SOLDER PAD LAYOUT 1 .010 – .020 × 45° (0.254 – 0.508) 2 3 4 5 6 7 .053 – .069 (1.346 – 1.752) 0° – 8° TYP .008 – .010 (0.203 – 0.254) .004 – .010 (0.101 – 0.254) .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN .014 – .019 (0.355 – 0.483) TYP .050 (1.270) BSC S14 0502 INCHES (MILLIMETERS) 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) 18812fa 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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 15 LT1881/LT1882 TYPICAL APPLICATIO – 10k 0.1% 10k 0.1% A1 1/2 LT1881 + RELATED PARTS PART NUMBER LT1112/LT1114 LT1167 LT1677 LT1793 LT1880 LT1884/LT1885 LTC2050 DESCRIPTION Dual/Quad Picoamp Input Op Amp Gain Programmable Instrumentation Amp Low Noise, Rail-to-Rail Precision Op Amp Low Noise JFET Op Amp SOT-23 Picoamp Input Precision Op Amp Dual/Quad Picoamp Input Op Amp Zero Drift Op Amp in SOT-23 COMMENTS VOS = 60μV Max Gain Error = 0.08% Max en = 3.2nV/√Hz IB = 10pA Max 150μV Max VOS, – 40°C to 85°C Operation Guaranteed, SOT-23 Package 3 Times Faster than LT1881/LT1882 VOS = 3μV Max, Rail-to-Rail Output 16 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com U –50°C to 600°C Digital Thermometer Operates on 3.3V VCC = 3.3V RF 1k R1 4k R2 4k VCC – RT VCC R3 1k A2 1/2 LT1881 VREF +IN –IN GND LTC1287 VCC CLK DOUT 1μF + V V = CC + 1.588mV/°C 2 CS/SHDN RT: OMEGA F4132 1000Ω RTD R1, R2, R3, RF: USE BI 698-3 2k × 8 RESISTOR NETWORK 1881/2 TA02 18812fa LT 0407 REV A • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 2000