LT1881/LT1882 Dual and Quad Rail-to-Rail Output, Picoamp Input Precision Op Amps U FEATURES DESCRIPTIO ■ 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. ■ ■ ■ ■ ■ ■ ■ ■ ■ 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 U APPLICATIO S ■ ■ ■ ■ ■ Thermocouple Amplifiers Bridge Transducer Conditioners Instrumentation Amplifiers Battery-Powered Systems Photo Current Amplifiers 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. U TYPICAL APPLICATIO 16-Bit Voltage Output DAC on ±5V Supply TC VOS Distribution, Industrial Grade 5V 5V PERCENT OF UNITS (%) 1.65k + LT1881 – LT1634 4.096V –5V R1 RCOM REF ROFS 33pF 5V DAC – LT1881 LTC®1597 + VOUT – 4.096V TO 4.096V 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 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 –5V 1881/2 TA01 18812fa 1 LT1881/LT1882 W W U W ABSOLUTE AXI U RATI GS (Note 1) 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 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 U W U PACKAGE/ORDER I FOR ATIO ORDER PART NUMBER TOP VIEW OUT A 1 8 V+ –IN A 2 7 OUT B 6 –IN B +IN A 3 A B V– 4 5 N8 PACKAGE 8-LEAD PDIP S8 PACKAGE 8-LEAD PLASTIC SO LT1881CN8 LT1881IN8 LT1881CS8 LT1881IS8 LT1881ACN8 LT1881AIN8 LT1881ACS8 LT1881AIS8 +IN B TJMAX = 150°C, θJA = 130°C/W (N8) TJMAX = 150°C, θJA = 190°C/W (S8) ORDER PART NUMBER TOP VIEW 14 OUT D OUT A 1 –IN A 2 A D 12 +IN D +IN A 3 V+ 4 +IN B 5 13 –IN D LT1882CS LT1882IS 11 V – B C 10 +IN C –IN B 6 9 –IN C OUT B 7 8 OUT C S PACKAGE 14-LEAD PLASTIC SO TJMAX = 150°C, θJA = 150°C/W S8 PART MARKING 1881 1881I 1881A 1881AI 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 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 PARAMETER VOS Input Offset Voltage (LT1881A) CONDITIONS MIN 0°C < TA < 70°C – 40°C < TA < 85°C ● ● 0°C < TA < 70°C – 40°C < TA < 85°C ● ● 0°C < TA < 70°C – 40°C < TA < 85°C ● ● Input Offset Voltage (LT1881/LT1882) ΔVOS/ΔT Input Offset Voltage Drift (Note 6) ΔVOS/ΔTIME Long-Term Input Offset Voltage Stability IOS TYP MAX UNITS 25 50 85 110 μV μV μV 30 80 125 150 μV μV μV 0.3 0.3 0.8 0.8 μV/°C μV/°C μV/month 0.3 Input Offset Current (LT1881A) 0°C < TA < 70°C – 40°C < TA < 85°C ● ● 0°C < TA < 70°C – 40°C < TA < 85°C ● ● Input Offset Current (LT1881/LT1882) 100 200 250 300 pA pA pA 150 500 600 700 pA pA pA 18812fa 2 LT1881/LT1882 ELECTRICAL CHARACTERISTICS 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 PARAMETER IB Input Bias Current (LT1881A) CONDITIONS MIN 0°C < TA < 70°C – 40°C < TA < 85°C ● ● 0°C < TA < 70°C – 40°C < TA < 85°C ● ● Input Bias Current (LT1881/LT1882) Input Noise Voltage 0.1Hz to 10Hz TYP MAX UNITS 100 200 250 300 pA pA pA 150 500 600 700 pA pA pA μVP-P 0.5 en Input Noise Voltage Density f = 1kHz 14 nV/√Hz in Input Noise Current Density f = 1kHz 0.03 pA/√Hz RIN Input Resistance Differential Mode Common Mode 20 100 MΩ GΩ CIN Input Capacitance VCM CMRR PSRR ● Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Large-Signal Voltage Gain 2 V– 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 pF V+ ● + 1.0 V – + 1.2 106 104 128 ● dB dB 106 106 132 132 dB dB ● ● Minimum Operating Supply Voltage AVOL ● ● RL = 10k; 1V < VOUT < 4V – 1.0 V + – 1.2 2.4 2.7 V V V 500 350 1600 ● V/mV V/mV 300 250 800 ● V/mV V/mV 250 200 400 ● V/mV V/mV RL = 2k; 1V < VOUT < 4V RL = 1k; 1V < VOUT < 4V VOL Output Voltage Swing Low No Load ISINK = 100μA ISINK = 1mA ISINK = 5mA ● ● ● ● 20 25 70 270 40 50 150 600 mV mV mV mV VOH Output Voltage Swing High (Referred to V +) No Load ISOURCE = 100μA ISOURCE = 1mA ISOURCE = 5mA ● ● ● ● 120 130 180 360 220 230 300 600 mV mV mV mV IS Supply Current Per Amplifier VS = 3V, 0V 0.45 0.65 0.85 1.2 mA mA 0.5 0.65 0.9 1.4 mA mA 0.5 0.70 1.0 1.5 mA mA 15 15 30 30 mA mA 0.35 1.0 MHz ● VS = 5V, 0V ● VS = 12V, 0V ● ● ● ISC Short-Circuit Current VOUT Short to GND VOUT Short to V + GBW Gain Bandwidth Product f = 20kHz Channel Separation f = 1kHz 120 dB Settling Time 0.01%, VOUT = 1.5V to 3.5V, AV = –1, RL = 2k 30 μs tS 18812fa 3 LT1881/LT1882 ELECTRICAL CHARACTERISTICS 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 PARAMETER CONDITIONS MIN TYP SR + Slew Rate Positive AV = – 1 0.35 ● 0.15 0.12 V/μs V/μs 0.11 0.08 0.18 ● V/μs V/μs VOUT = 4VP-P (Note 10) 8.75 6.35 14 ● kHz kHz (Note 7) 0°C < TA < 70°C – 40°C < TA < 85°C ● ● (Note 7) 0°C < TA < 70°C – 40°C < TA < 85°C ● ● Offset Voltage Match Drift (Notes 6, 7) ● Noninverting Bias Current Match (LT1881A) (Notes 7, 8) 0°C < TA < 70°C – 40°C < TA < 85°C ● ● Noninverting Bias Current Match (LT1881/LT1882) (Notes 7, 8) 0°C < TA < 70°C – 40°C < TA < 85°C ● ● ΔCMRR Common Mode Rejection Match (Notes 7, 9) ● 102 125 dB ΔPSRR Power Supply Rejection Match (Notes 7, 9) V – = 0V, VCM = 1.5V 0°C < TA < 85°C, 2.7V < V + < 32V TA = –40°C, 3V < V + < 32V ● 104 104 126 126 dB dB SR – FPBW ΔVOS Slew Rate Negative Full-Power Bandwidth Offset Voltage Match (LT1881A) Offset Voltage Match (LT1881/LT1882) ΔIB+ AV = – 1 MAX UNITS 30 70 125 160 μV μV μV 35 125 175 235 μV μV μV 0.4 1.2 μV/°C 200 300 400 500 pA pA pA 250 700 900 1000 pA pA pA 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 PARAMETER VOS Input Offset Voltage (LT1881A) CONDITIONS MIN 0°C < TA < 70°C – 40°C < TA < 85°C ● ● 0°C < TA < 70°C – 40°C < TA < 85°C ● ● 0°C < TA < 70°C – 40°C < TA < 85°C ● ● Input Offset Voltage (LT1881/LT1882) ΔVOS/ΔT Input Offset Voltage Drift (Note 6) ΔVOS/ΔTIME Long-Term Input Offset Voltage Stability IOS TYP MAX UNITS 25 50 85 110 μV μV μV 30 80 125 150 μV μV μV 0.3 0.3 0.8 0.8 μV/°C μV/°C μV/month 0.3 Input Offset Current (LT1881A) 0°C < TA < 70°C – 40°C < TA < 85°C ● ● 0°C < TA < 70°C – 40°C < TA < 85°C ● ● Input Offset Current (LT1881/LT1882) 150 200 250 300 pA pA pA 150 500 600 700 pA pA pA 18812fa 4 LT1881/LT1882 ELECTRICAL CHARACTERISTICS 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 PARAMETER IB Input Bias Current (LT1881A) CONDITIONS MIN 0°C < TA < 70°C – 40°C < TA < 85°C ● ● 0°C < TA < 70°C – 40°C < TA < 85°C ● ● Input Bias Current (LT1881/LT1882) Input Noise Voltage 0.1Hz to 10Hz TYP MAX UNITS 150 200 250 300 pA pA pA 150 500 600 700 pA pA pA μVP-P 0.5 en Input Noise Voltage Density f = 1kHz 14 nV/√Hz in Input Noise Current Density f = 1kHz 0.03 pA/√Hz RIN Input Resistance Differential Mode Common Mode 20 100 MΩ GΩ CIN Input Capacitance VCM CMRR +PSRR –PSRR ● ● ● Input Voltage Range Common Mode Rejection Ratio –13.5V < VCM < 13.5V Positive Power Supply Rejection Ratio V– Negative Power Supply Rejection Ratio V+ = 15V, VCM Large-Signal Voltage Gain + 1.0 V – + 1.2 ● 114 130 dB 132 dB < 18V ● 110 = 0V; –1.5V < V – < –18V ● 106 = –15V, VCM pF V+ ● = 0V; 1.5V < V + RL = 10k; –13.5V < VOUT < 13.5V – 1.0 V + – 1.2 132 ±1.2 ● Minimum Operating Supply Voltage AVOL 2 V– V V dB ±1.35 V 1000 700 1600 ● V/mV V/mV 175 125 420 ● V/mV V/mV 90 65 230 ● V/mV V/mV 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 ● ● ● ● 20 25 70 270 40 50 150 600 mV mV mV mV VOH Output Voltage Swing High (Referred to VCC) No Load ISOURCE = 100μA ISOURCE = 1mA ISOURCE = 5mA ● ● ● ● 160 160 180 360 220 230 300 600 mV mV mV mV IS Supply Current Per Amplifier VS = ±15V 0.5 0.85 1.1 1.6 mA mA ● 20 15 40 40 mA mA ● 20 15 30 30 mA mA 0.4 0.85 MHz ● ISC Short-Circuit Current VOUT Short to V – VOUT Short to V + GBW Gain Bandwidth Product f = 20kHz Channel Separation f = 1kHz 120 dB tS Settling Time 0.01%, VOUT = – 5V to 5V, AV = –1, RL = 2k 35 μs SR + Slew Rate Positive AV = – 1 0.4 V/μs V/μs ● 0.21 0.18 18812fa 5 LT1881/LT1882 ELECTRICAL CHARACTERISTICS 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 PARAMETER CONDITIONS SR – Slew Rate Negative AV = – 1 FPBW ΔVOS MIN TYP 0.13 0.1 0.20 ● V/μs V/μs VOUT = 28VP-P (Note 10) 1.47 1.13 2.25 ● kHz kHz (Note 5) 0°C < TA < 70°C – 40°C < TA < 85°C ● ● 0°C < TA < 70°C – 40°C < TA < 85°C ● ● Offset Voltage Match Drift (Notes 6, 7) ● Noninverting Bias Current Match (LT1881/LT1882) (Notes 7, 8) 0°C < TA < 70°C – 40°C < TA < 85°C ● ● 0°C < TA < 70°C – 40°C < TA < 85°C ● ● Full-Power Bandwidth Offset Voltage Match (LT1881/LT1882) Offset Voltage Match (LT1881A) ΔIB+ Noninverting Bias Current Match (LT1881A) MAX UNITS 42 125 175 235 μV μV μV 35 70 125 160 μV μV μV μV/°C 0.4 1.1 240 700 900 1000 pA pA pA 200 300 400 500 pA pA pA ΔCMRR Common Mode Rejection Match (Notes 7, 9) ● 110 125 dB Δ+PSRR Positive Power Supply Rejection Match V – = – 15V, VCM = 0V, 1.5V < V + < 18V, (Notes 7, 9) ● 108 130 dB Δ –PSRR Negative Power Supply Rejection Match V + = 15V, VCM = 0V, – 1.5V < V – < – 18V, (Notes 7, 9) ● 104 130 dB 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 U W TYPICAL PERFOR A CE CHARACTERISTICS Supply Current per Amplifier vs Supply Voltage Slew Rate vs Supply Voltage 0.45 0.45 AV = –1 0.40 RISING AV = –1 RISING FALLING 0.20 0.15 0.30 0.25 0.15 0.10 0.05 0.05 4 8 12 16 20 24 28 32 TOTAL SUPPLY VOLTAGE (V) FALLING 0.20 0.10 0 0 4 8 12 16 20 24 28 32 TOTAL SUPPLY VOLTAGE (V) 1881/2 G02 0 –2 –4 0.1% 0.01% 4 0.01% 0 –2 0.1% 0.01% –4 –6 –8 –8 –10 0 5 10 15 20 25 30 35 40 45 50 55 60 65 SETTLING TIME (μs) 0.1% 2 –6 –10 1881/2 G03 GAIN BANDWIDTH PRODUCT (kHz) 2 25 50 75 100 125 150 TEMPERATURE (°C) 900 6 0.01% 0 Gain Bandwidth Product vs Supply Voltage VS = ±15V AV = 1 8 OUTPUT STEP (V) OUTPUT STEP (V) 0.1% VS = ±5V 0.2 0 –50 –25 36 10 VS = ±15V AV = –1 4 VS = ±15V FALLING Settling Time vs Output Step 10 6 0.3 1881/2 G02 Settling Time vs Output Step 8 VS = ±5V 0.1 0 36 SLEW RATE (V/μs) SLEW RATE (V/μs) 0.25 VS = ±15V RISING 0.4 0.35 0.30 850 125°C 800 25°C 750 –55°C 700 650 600 0 5 10 15 20 25 30 35 40 45 50 55 60 65 SETTLING TIME (μs) 1881/2 G04 0 4 8 12 16 20 24 28 32 TOTAL SUPPLY VOLTAGE (V) 1881/2 G05 Phase Margin vs Supply Voltage 36 1881/2 G06 Gain vs Frequency, AV = –1 60 Gain vs Frequency, AV = 1 10 10 0 0 –10 –10 58 –55°C 125°C 54 125°C 52 GAIN (dB) 56 GAIN (dB) PHASE MARGIN (DEG) SLEW RATE (V/μs) 0.5 AV = –1 0.40 0.35 0 Slew Rate vs Temperature –20 VS = ±2.5V 50 VS = ±2.5V VS = ±15V –20 VS = ±15V –30 –30 48 46 0 4 8 12 16 20 24 28 32 TOTAL SUPPLY VOLTAGE (V) 36 1881/2 G07 –40 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 1881/2 G08 –40 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 1881/2 G09 18812fa 7 LT1881/LT1882 U W TYPICAL PERFOR A CE CHARACTERISTICS Gain vs Frequency with CLOAD, AV = 1 Gain vs Frequency with CLOAD, AV = –1 10 10 VS = ±15V VS = ±15V 0 0 1500pF 1800pF –10 GAIN (dB) GAIN (dB) 1000pF 500pF –20 –10 1000pF –20 500pF 0pF –30 –40 –30 1k 10k 100k 1M FREQUENCY (Hz) 10M –40 100M 0pF 1k 10k 100k 1M FREQUENCY (Hz) 1881/2 G10 VOUT (20mV/DIV) TIME (50μs/DIV) 1881/2 G12 1881/2 G15 TIME (2μs/DIV) 1881/2 G13 Small Signal Response, AV = 1, RL = 2k VOUT (20mV/DIV) VOUT (20mV/DIV) Small Signal Response, AV = –1, CL = 1000pF TIME (2μs/DIV) Small Signal Response, AV = –1, No Load Large Signal Response, AV = 1 1881/2 G14 Small Signal Response, AV = 1, CL = 500pF VOUT (20mV/DIV) VOUT (5V/DIV) TIME (50μs/DIV) 100M 1881/2 G11 VOUT (5V/DIV) Large Signal Response, AV = –1 10M TIME (2μs/DIV) 1881/2 G16 TIME (2μs/DIV) 1881/2 G17 18812fa 8 LT1881/LT1882 U W TYPICAL PERFOR A CE CHARACTERISTICS 200 150 40 N8 (1 LOT) 144 S8 (2 LOTS) 184 TOTAL PARTS 5 VS = ±15V 0 OFFSET VOLTAGE DRIFT (μV) VS = ±15V 100 50 0 –50 –100 –60 –40 –20 0 20 40 OUTPUT OFFSET VOLTAGE (μV) –200 –55 –35 –15 60 –15 N8 VS = ±15V –30 5 25 45 65 85 105 125 TEMPERATURE (°C) INPUT COMMON MODE RANGE (V) INPUT BIAS CURRENT (pA) 0 200 400 600 140 V+ – 0 100 200 40 60 80 100 120 TIME AFTER POWER UP (s) LT1881 Input Common Mode Range vs Supply Voltage VS = ±15V VS = ±15V 400 20 0 1881/2 G20 150 600 S8 VS = 5V, ±15V –20 LT1881 Input Bias Current vs Temperature 1000 +IBIAS 50 0 –IBIAS –50 –100 800 ΔVOS < 1mV V+ – 0.5 85°C V+ – 1.0 V+ – 1.5 –40°C 25°C V – + 1.5 –40°C 25°C V – + 1.0 V – + 0.5 85°C 1000 –20 –15 –10 –5 0 5 VCM (V) 10 15 20 –150 –40 –20 0 20 40 60 TEMPERATURE (°C) LT1881 Input Common Mode Voltage vs Temperature OUTPUT VOLTAGE SWING (V) 2 1 VS = ±5V –1 –2 –3 V+ – 0.5 RL = 2k V+ – 1.0 AV = –1 TA = 25°C V – + 1.0 RL = 2k V – + 0.5 RL = 10k –4 V –25 0 25 50 75 TEMPERATURE (°C) 100 125 1881/2 G24 4 6 8 10 12 SUPPLY VOLTAGE (±V) 14 16 1 RL = 10k 3 2 LT1881 Output Saturation Voltage vs Load Current (Output High) V+ – 0 4 –5 –50 0 1881/2 G23 LT1881 Output Voltage Swing vs Supply Voltage 5 0 80 V– + 0 1881/2 G22 1881/2 G21 INPUT COMMON MODE VOLTAGE (V) –10 1881/2 G19 LT1881 Input Bias Current vs Common Mode Voltage 800 N8 VS = 5V –5 –25 –150 1881/2 G18 IBIAS (pA) Warm-Up Drift vs Time –+0 0 2 4 6 8 10 12 14 16 18 20 SUPPLY VOLTAGE (±V) 1881/2 G25 OUTPUT SATURATION VOLTAGE (V) 26 24 22 20 18 16 14 12 10 8 6 4 2 0 LT1881IS8 Voltage Offset vs Temperature VOLTAGE OFFSET (μV) PERCENT OF UNITS (%) LT1881 VOS Distribution, TA = 25°C VS = ±15V VOD = 30mV TA = 85°C TA = 25°C 0.1 0.01 0.001 TA = –40°C 0.01 0.1 1 SOURCING LOAD CURRENT (mA) 10 1881/2 G26 18812fa 9 LT1881/LT1882 U W TYPICAL PERFOR A CE CHARACTERISTICS LT1881 Output Saturation Voltage vs Load Current (Output Low) 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 TA = 85°C 0.1 TA = 25°C TA = –40°C 0.01 0.001 0.001 0.1 1 0.01 SINKING LOAD CURRENT (mA) 10 AV = 1 VS = ±2.5V VIN = ±5V RIN = 10k 5 25 45 65 85 105 125 TEMPERATURE (°C) LT1881 Open-Loop Gain and Phase vs Frequency 70 VS = ±15V 175 VS = ±5V LOOP GAIN (dB) 60 120 40 100 30 75 PHASE 20 50 10 25 LOOP GAIN 0 –10 –25 –20 –50 –30 1k –20 10k 100k 1M FREQUENCY (Hz) –100 10M –40 –60 –80 –100 –120 –140 10 Output Impedance vs Frequency VS = ±15V VS = ± 2.5V 850 AV = 100 650 1 PSSR (dB) OUTPUT IMPEDANCE (Ω) 700 AV = 10 0.1 AV = 1 0.01 600 550 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 1881/2 G33 10k 100k 1M FREQUENCY (Hz) 0.001 100 1k 10k FREQUENCY (Hz) 100k 1881/2 G34 10M 100M LT1881 PSRR vs Frequency 10 VS = ± 2.5V 1k 1881/2 G32 100 900 800 100 1881/2 G31 Gain Bandwidth Product vs Temperature 750 VS = ±15V AV = 10 150 50 0 10 100 1k 10k 100k 1M 10M100M FREQUENCY (Hz) 1881 G29.tif LT1881 Channel Separation vs Frequency PHASE (DEG) LOOP GAIN (dB) GND SOURCING 1881/2 G30 GAIN BANDWIDTH PRODUCT (KHz) VOUT 1881/2 G28 LT1881 Open-Loop Gain vs Frequency 1 GND SINKING 1881/2 G27 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 –10 –20 0.1 VIN CHANNEL SEPARATION (dB) VS = ±15V VOD = 30mV OUTPUT SHORT-CIRCUIT CURRENT (mA) OUTPUT SATURATION VOLTAGE (V) 1 LT1881 Output Voltage vs Large Input Voltage 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 –10 VS = ±15V –PSSR +PSSR 1 10 100 1k 10k FREQUENCY (Hz) 100k 1M 1881/2 G35 18812fa 10 LT1881/LT1882 U W TYPICAL PERFOR A CE CHARACTERISTICS Common Mode Rejection Ratio vs Frequency LT1881 Noise Voltage vs Frequency LT1881 0.1Hz to 10Hz Noise 120 NOISE VOLTAGE (0.2μV/DIV) 100 80 CMRR (dB) NOISE VOLTAGE DENSITY (nV/VHz) 50 60 40 20 0 0.1 1 10 100 1k 10k FREQUENCY (Hz) 100k 0 1M 5 10 15 1s/DIV 20 LT1881 Noise Current Density vs Frequency 100 80 60 40 20 10 100 FREQUENCY (Hz) 10 10 100 1k RS (Ω) 10k 100k 20 0 2000 4000 6000 8000 CAPACITIVE LOAD (pF) 10000 1881/2 G42 AV = –1 10 LT1881 Undistorted Output Swing vs Frequency 100 1k CAPACITIVE LOAD (pF) 10k LT1881 THD + Noise vs Frequency 10 30 1 AV = –1 TA = 25°C VS = ±15V 25 20 15 AV = –1 TA = 25°C VS = ±2.5V 10 5 VS = ±15V VIN = 2VP-P 0.1 0.01 AV = –1 0.001 AV = 1 0 0 AV = 1 15 1881/2 G41 THD + NOISE (%) 40 20 1881/2 G36 PEAK-TO-PEAK OUTPUT VOLTAGE (V) 60 1k VS = ±15V RL = 10k 0 10 1M 35 VS = ±15V 10 100 FREQUENCY (Hz) 5 1 120 80 5 LT1881 Overshoot vs Capacitive Load 100 1000 VS = ±2.5V 10 25 LT1881 Series Output Resistance vs Capacitive Load AV = 1 TA = 25°C 15 30 1881/2 G39 100 20 1881/2 G38 1 0 1 25 1 OVERSHOOT (%) 120 TOTAL INPUT REFERRED NOISE (nV/√Hz) NOISE CURRENT DENSITY (fA/√Hz) 140 30 0 30 1000 160 35 LT1881A Total Noise vs Source Resistance 180 VS = ±15V 40 1881/2 G37 1881/2 G36 SERIES OUTPUT RESISTANCE (Ω) 25 VS = ±5V AV = 1 45 1 10 FREQUENCY (kHz) 100 1881/2 G43 0.0001 10 100 1k 10k FREQUENCY (Hz) 100k 1881/2 G44 18812fa 11 LT1881/LT1882 U W TYPICAL PERFOR A CE CHARACTERISTICS LT1881 Total Harmonic Distortion + Noise vs Output Voltage Amplitude LT1881 Open-Loop Gain CHANGE IN INPUT OFFSET VOLTAGE (20μV/DIV) 10 f = 1kHz RF = RG = 10k AV = –1 VS = ±2.5V THD + NOISE (%) 1 AV = –1 VS = ±15V 0.1 AV = 2 VS = ±2.5V 0.01 RL = 10k RL = 2k RL = 50k OUTPUT VOLTAGE (5V/DIV) 0.001 10m 1881 G46.tif VS = ±15V AV = 2 VS = ±15V 0.1 1 10 OUTPUT VOLTAGE AMPLITUDE (VP-P) 100 1881/2 G45 LT1881 Settling Time/ Output Step 0.01% LT1881 Settling Time/ Output Step 0.01% 0.5mV/DIV 10V 10V GND GND 0.5mV/DIV AV = 1 VS = ±15V 20μs/DIV AV = 1 VS = ±15V 1881 G47.tif LT1881 Gain vs Temperature 1881 G48.tif LT1881 Gain vs Load Resistance 5.0 4.5 50μs/DIV 10.0 VS = ±5V +AVOL (0V TO 10V) 4.0 – AVOL (0V TO –10V) 3.0 GAIN (V/μV) GAIN (V/μV) 3.5 RL = 10k 2.5 2.0 0V TO 10V 0V TO –10V 1.5 1.0 1.0 RL = 2k VS = ±15V 0.5 0 –50 –25 0 25 50 75 TEMPERATURE (°C) 100 125 1881/2 G49 0.1 0 5 10 15 20 25 LOAD RESISTANCE (kΩ) 30 1881/2 G50 18812fa 12 LT1881/LT1882 U W U U 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. 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 13 LT1881/LT1882 U PACKAGE DESCRIPTIO N8 Package 8-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) .400* (10.160) MAX 8 7 6 5 1 2 3 4 .255 ± .015* (6.477 ± 0.381) .300 – .325 (7.620 – 8.255) .008 – .015 (0.203 – 0.381) ( +.035 .325 –.015 8.255 +0.889 –0.381 ) .045 – .065 (1.143 – 1.651) .130 ± .005 (3.302 ± 0.127) .065 (1.651) TYP .100 (2.54) BSC .120 .020 (3.048) MIN (0.508) MIN .018 ± .003 (0.457 ± 0.076) N8 1002 NOTE: 1. DIMENSIONS ARE INCHES MILLIMETERS *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm) 18812fa 14 LT1881/LT1882 U PACKAGE DESCRIPTIO S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) .189 – .197 (4.801 – 5.004) NOTE 3 .045 ±.005 .050 BSC 7 8 .245 MIN 5 6 .160 ±.005 .150 – .157 (3.810 – 3.988) NOTE 3 .228 – .244 (5.791 – 6.197) .030 ±.005 TYP 1 RECOMMENDED SOLDER PAD LAYOUT .010 – .020 × 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) 3 2 4 .053 – .069 (1.346 – 1.752) .004 – .010 (0.101 – 0.254) 0°– 8° TYP .016 – .050 (0.406 – 1.270) .050 (1.270) BSC .014 – .019 (0.355 – 0.483) TYP 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) SO8 0303 S Package 14-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) .337 – .344 (8.560 – 8.738) NOTE 3 .045 ±.005 .050 BSC 14 N 12 11 10 9 8 N .245 MIN .160 ±.005 .150 – .157 (3.810 – 3.988) NOTE 3 .228 – .244 (5.791 – 6.197) 1 .030 ±.005 TYP 13 2 3 N/2 N/2 RECOMMENDED SOLDER PAD LAYOUT 1 .010 – .020 × 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) 2 3 4 5 6 .053 – .069 (1.346 – 1.752) .004 – .010 (0.101 – 0.254) 0° – 8° TYP .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN .014 – .019 (0.355 – 0.483) TYP 7 .050 (1.270) BSC 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) S14 0502 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 U TYPICAL APPLICATIO –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 VCC +IN CLK + –IN GND – 10k 0.1% A1 1/2 LT1881 + 10k 0.1% LTC1287 1μF DOUT CS/SHDN V V = CC + 1.588mV/°C 2 RT: OMEGA F4132 1000Ω RTD R1, R2, R3, RF: USE BI 698-3 2k × 8 RESISTOR NETWORK 1881/2 TA02 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1112/LT1114 Dual/Quad Picoamp Input Op Amp VOS = 60μV Max LT1167 Gain Programmable Instrumentation Amp Gain Error = 0.08% Max LT1677 Low Noise, Rail-to-Rail Precision Op Amp en = 3.2nV/√Hz LT1793 Low Noise JFET Op Amp IB = 10pA Max LT1880 SOT-23 Picoamp Input Precision Op Amp 150μV Max VOS, – 40°C to 85°C Operation Guaranteed, SOT-23 Package LT1884/LT1885 Dual/Quad Picoamp Input Op Amp 3 Times Faster than LT1881/LT1882 LTC2050 Zero Drift Op Amp in SOT-23 VOS = 3μV Max, Rail-to-Rail Output 18812fa 16 Linear Technology Corporation LT 0407 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com © LINEAR TECHNOLOGY CORPORATION 2000