LTC6081IMS8-

FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ LTC6081/LTC6082 Precision Dual/Quad CMOS Rail-to-Rail Input/ Output Amplifiers DESCRIPTION The LTC®6081/LTC6082 are dual/quad low offset, low drift, low noise CMOS operational amplifiers with rail-to-rail input/output swing. The 70μV maximum offset, 1pA input bias current, 120dB open loop gain and 1.3μVP-P 0.1Hz to 10Hz noise make it perfect for precision signal conditioning. The LTC6081/ LTC6082 features 100dB CMRR and 98dB PSRR. Each amplifier consumes only 330μA of current on a 3V supply. The 10-lead DFN has an independent shutdown function that reduces each amplifier’s supply current to 1μA. LTC6081/LTC6082 is specified for power supply voltages of 3V and 5V from –40°C to 125°C. The dual LTC6081 is available in 8-lead MSOP and 10-lead DFN10 packages. The quad LTC6082 is available in 16-lead SSOP and DFN packages. , LTC, LT and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Maximum Offset Voltage: 70μV (25°C) Maximum Offset Drift: 0.8μV/°C Maximum Input Bias: 1pA (25°C) 40pA (TA ≤ 85°C) Open Loop Voltage Gain: 120dB Typ Gain Bandwidth Product: 3.6MHz CMRR: 100dB Min PSRR: 98dB Min 0.1Hz to 10Hz Noise: 1.3μVP-P Supply Current: 330μA Rail-to-Rail Inputs and Outputs Unity Gain Stable 2.7V to 5.5V Operation Voltage Dual LTC6081 in 8-Lead MSOP and 10-Lead DFN10 Packages; Quad LTC6082 in 16-Lead SSOP and DFN Packages APPLICATIONS ■ ■ ■ ■ ■ ■ Photodiode Amplifier Strain Gauge High Impedance Sensor Amplifier Microvolt Accuracy Threshold Detection Instrumentation Amplifiers Thermocouple Amplifiers TYPICAL APPLICATION Shock Sensor Amplifier (Accelerometer) 30 8.2pF 2M MURATA PKGS-00LD 770pF 0° SENSOR 1G 3.9pF 2M 3.9pF NUMBER OF AMPLIFIERS (OUT OF 100) V+ 0.1μF 25 20 15 10 5 0 –0.20 VOS Drift Histogram LTC6081MS8 TA = –40°C TO 125°C VS = 3V VCM = 0.5V + 1/2 LTC6081 – 1M V– 0.1μF 1M 10k 47pF VOUT = 109mV/g BW ~ 2.2kHz 60812 TA01 –0.10 0 0.10 VOSDRIFT (μV/°C) 0.20 0.30 60812 TA01b 60812f 1 LTC6081/LTC6082 ABSOLUTE MAXIMUM RATINGS (Note 1) Total Supply Voltage (V+ to V–) ...................................6V Input Voltage...................................................... V– to V+ Output Short Circuit Duration (Note 2) ............ Indefinite Operating Temperature Range (Note 3) LTC6081C, LTC6082C .......................... –40°C to 85°C LTC6081I, LTC6082I ............................ –40°C to 85°C LTC6081H, LTC6082H........................ –40°C to 125°C (H Temperature Range Not Available in DFN Package) Specified Temperature Range (Note 4) LTC6081C, LTC6082C .............................. 0°C to 70°C LTC6081I, LTC6082I ............................ –40°C to 85°C LTC6081H, LTC6082H........................ –40°C to 125°C Junction Temperature DFN Packages ................................................... 125°C All Other Packages ............................................ 150°C Storage Temperature Range DFN Packages .................................... –65°C to 125°C All Other Packages ............................. –65°C to 150°C Lead Temperature (Soldering, 10 Sec) .................. 300°C PIN CONFIGURATION TOP VIEW OUTA –INA +INA V– SHDN_A 1 2 3 4 5 A B 10 V + 9 OUTB 8 –INB 7 +INB 6 SHDN_B OUTA –INA +INA V– 1 2 3 4 TOP VIEW A B 8 7 6 5 V+ OUTB –INB +INB DD PACKAGE 10-LEAD (3mm × 3mm) PLASTIC DFN TJMAX = 125°C, θJA = 43°C/W UNDERSIDE METAL CONNECTED TO V– TOP VIEW OUTA –INA +INA V+ +INB –INB OUTB NC 1 2 3 4 5 6 7 8 B C A D MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 150°C, θJA = 200°C/W TOP VIEW 16 OUTD 15 –IND 14 +IND 13 V – 12 +INC 11 –INC 10 OUTC 9 NC OUTA –INA +INA V+ +INB –INB OUTB NC 1 2 3 4 5 6 7 8 B C A D 16 OUTD 15 –IND 14 +IND 13 V – 12 +INC 11 –INC 10 OUTC 9 NC DHC PACKAGE 16-LEAD (5mm × 3mm) PLASTIC DFN TJMAX = 125°C, θJA = 43°C/W UNDERSIDE METAL CONNECTED TO V– GN PACKAGE 16-LEAD PLASTIC SSOP TJMAX = 150°C, θJA = 110°C/W 60812f 2 LTC6081/LTC6082 ORDER INFORMATION LTC6081 C DD # TR PBF LEAD FREE DESIGNATOR PBF = Lead Free Blank = Lead Tin Lead Finish TAPE AND REEL TR = Tape and Reel Blank = Bulk NUMBER SIGN Required before Tape and Reel and Lead Free Orders PACKAGE TYPE DD = 10-Lead (3mm × 3mm) Plastic DFN DHC = 16-Lead (5mm × 3mm) Plastic DFN GN = 16-Lead Plastic SSOP MS8 = 8-Lead Plastic MSOP TEMPERATURE GRADE C = Commercial Temperature Range (0°C to 70°C) I = Industrial Temperature Range (–40°C to 85°C) H = High Temperature Range (–40°C to 125°C) (H grade not available for DD or DHC package) PRODUCT PART NUMBER LTC6081 (Precision Dual Amplifier) LTC6082 (Precision Quad Amplifier) Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ 60812f 3 LTC6081/LTC6082 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER VOS Offset Voltage CONDITIONS LTC6081MS8, LTC6082GN LTC6081MS8, LTC6082GN LTC6081DD, LTC6082DHC LTC6081DD, LTC6082DHC VCM = 0.5V, 2.5V VCM = 0.5V, 2.5V VCM = 0.5V, 2.5V VCM = 0.5V, 2.5V ● ● ● The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Test conditions are V+ = 3V, V– = 0V, VCM = 0.5V unless otherwise noted. C, I SUFFIXES MIN –70 –90 –70 –90 ±0.2 0.2 ● H SUFFIX MIN –70 –90 TYP MAX 70 90 UNITS μV μV μV μV μV/°C pA pA pA pA nV/√Hz μVP-P fA/√Hz V+ 3 7 95 86 93 86 98 96 –35 –350 105 100 105 100 110 1 V pF pF dB dB dB dB dB dB mV mV mV 40 360 110 15 15 120 mV mV mV dB mA mA 1 2.5 1.5 3.6 70 6 V/μs MHz MHz Deg μs 400 460 μA μA μA μA 2.7 –120 5.5 V dB TYP MAX 70 90 70 90 ±0.8 1 40 15 ΔVOS ⁄ΔT Input Offset Voltage Drift (Note 5) IB IOS en In Input Bias Current (Note 6) Input Offset Current ±0.2 0.2 0.1 ±0.8 1 500 100 0.1 ● Input Referred Noise Input Noise Current Density (Note 7) Input Common Mode Range Noise Density at f = 1kHz Integrated Noise From 0.1Hz to 10Hz 13 1.3 0.5 ● 13 1.3 0.5 V+ V– V– 3 7 CDIFF CCM CMRR Differential Input Capacitance Common Mode Input Capacitance Common Mode Rejection Ratio VCM = 0V to 1.5V VCM = 0V to 1.5V VCM = 0V to 3V VCM = 0V to 3V ● ● ● ● ● ● ● ● ● ● 95 88 93 88 98 96 –32 –320 105 100 105 100 110 1 PSRR VOUT Power Supply Rejection Ratio VS = 2.7V to 5.5V Output Voltage, High, Either Output Pin Output Voltage, Low, Either Output Pin (Referred to V–) No Load ISOURCE = 0.5mA ISOURCE = 5mA No Load ISINK = 0.5mA ISINK = 5mA RLOAD = 10k, 0.5V < VOUT < 2.5V Source Sink AV = 1 RL = 100k RL = 10k AV = 1, 1V Step No Load 1 33 300 110 17 17 1 ● 1 AVOL ISC SR GBW Φ0 tS IS Large-Signal Voltage Gain Output Short-Circuit Current Slew Rate Gain-Bandwidth Product (fTEST = 50kHz) Phase Margin Settling Time 0.1% Supply Current (Per Amplifier) Shutdown Current (Per Amplifier) 120 2.5 1.8 3.6 70 6 330 400 435 2 330 ● Shutdown, V⎯S⎯H⎯D⎯N ≤ 0.8V Guaranteed by the PSRR Test fs = 10kHz, RL = 10k 0.5 ● ● VS Supply Voltage Range Channel Separation 2.7 –120 5.5 60812f 4 LTC6081/LTC6082 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER Shutdown Logic THD tON tOFF Total Harmonic Distortion Turn-On Time Turn-Off Time ⎯S⎯H⎯D⎯N Pin Current CONDITIONS ⎯SHDN High ⎯⎯⎯ ⎯S⎯H⎯D⎯N Low f = 10kHz, V+ = 3V, VOUT = 1VP-P, RL = 10k V⎯S⎯H⎯D⎯N = 0.8V to 2V V⎯S⎯H⎯D⎯N = 2V to 0.8V V⎯S⎯H⎯D⎯N = 0V ● The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Test conditions are V+ = 3V, V– = 0V, VCM = 0.5V unless otherwise noted. C, I SUFFIXES MIN ● ● H SUFFIX MIN 2 TYP MAX 0.8 –90 10 2 2 UNITS V V dB μs μs μA TYP MAX 0.8 2 –90 10 2 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Test conditions are V+ = 5V, V– = 0V, VCM = 0.5V unless otherwise noted. C, I SUFFIXES SYMBOL PARAMETER VOS Offset Voltage CONDITIONS LTC6081MS8, LTC6082GN LTC6081MS8, LTC6082GN LTC6081DD, LTC6082DHC LTC6081DD, LTC6082DHC VCM = 0.5V VCM = 0.5V VCM = 0.5V VCM = 0.5V ● ● ● H SUFFIX MIN –70 –90 TYP MAX 70 90 UNITS μV μV μV μV μV/°C pA pA pA pA nV/√Hz μVP-P fA/√Hz V+ 3 7 100 94 86 98 96 –25 –220 110 110 95 110 1 V pF pF dB dB dB dB dB mV mV mV 32 240 110 120 mV mV mV dB MIN –70 –90 –70 –90 TYP MAX 70 90 70 90 ΔVOS ⁄ΔT Input Offset Voltage Drift (Note 8) IB IOS en In Input Bias Current ±0.2 0.2 ±0.8 ±0.2 0.2 ±0.8 ● 40 0.1 0.1 15 13 1.3 0.5 13 1.3 0.5 V+ 3 7 V– 500 100 Input Offset Current ● Input Referred Noise Input Noise Current Density (Note 7) Input Common Mode Range f = 1kHz 0.1Hz to 10Hz ● V– CDIFF CCM CMRR Differential Input Capacitance Common Mode Input Capacitance Common Mode Rejection Ratio VCM = 0V to 3.5V VCM = 0V to 3.5V VCM = 0V to 5V ● ● ● ● ● ● ● ● 100 95 86 98 96 –24 –200 110 110 95 110 1 PSRR VOUT Power Supply Rejection Ratio VS = 2.7V to 5.5V Output Voltage, High, Either Output Pin (Referred to V+) Output Voltage, Low, Either Output Pin (Referred to V–) No Load ISOURCE = 0.5mA ISOURCE = 5mA No Load ISINK = 0.5mA ISINK = 5mA RLOAD = 10k, 0.5V < VOUT < 4.5V 1 27 210 110 120 1 AVOL Large-Signal Voltage Gain 60812f 5 LTC6081/LTC6082 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER ISC SR GBW Φ0 tS IS Output Short-Circuit Current Slew Rate Gain-Bandwidth Product (fTEST = 50kHz) Phase Margin Settling Time 0.1% Supply Current (Per Amplifier) Shutdown Current (Per Amplifier) VS Supply Voltage Range Channel Separation Shutdown Logic THD tON tOFF Total Harmonic Distortion Turn-On Time Turn-Off Time ⎯S⎯H⎯D⎯N Pin Current CONDITIONS Source Sink AV = 1 RL = 100k RL = 10k AV = 1, 1V Step No Load ● ● ● ● The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Test conditions are V+ = 5V, V– = 0V, VCM = 0.5V unless otherwise noted. C, I SUFFIXES MIN 24 24 1 2.5 1.8 3.5 70 6 340 ● ● H SUFFIX MIN 21 21 1 2.5 1.5 3.5 70 6 TYP MAX UNITS mA mA V/μs MHz MHz Deg μs 425 490 μA μA μA 2.7 –120 3.5 5.5 V dB 1.2 –90 10 2 2 V V dB μs μs μA TYP MAX 425 465 6 340 Shutdown, V⎯S⎯H⎯D⎯N ≤ 1.2V Guaranteed by the PSRR Test fs = 10kHz, RL = 10k ⎯S⎯H⎯D⎯N High ⎯S⎯H⎯D⎯N Low f = 10kHz, V+ = 5V, VOUT = 2VP-P, RL = 10k V⎯S⎯H⎯D⎯N = 1.2V to 3.5V V⎯S⎯H⎯D⎯N = 3.5V to 1.2V V⎯S⎯H⎯D⎯N = 0V 2.7 –120 3.5 5.5 ● ● 1.2 –90 10 2 ● 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: A heat sink may be required to keep the junction temperature below the absolute maximum. This depends on the power supply voltage and how many amplifiers are shorted. Note 3: The LTC6081C/LTC6082C and LTC6081I/LTC6082I are guaranteed functional over the operating temperature range of –40°C to 85°C. The LTC6081H/LTC6082H are guaranteed functional over the operating temperature range of –40°C to 125°C. Note 4: The LTC6081C/LTC6082C are guaranteed to meet specified performance from 0°C to 70°C. The LTC6081C/LTC6082C 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 LTC6081I/LTC6082I are guaranteed to meet specified performance from –40°C to 85°C. The LTC6081H/LTC6082H are guaranteed to meet specified performance from –40°C to 125°C. Note 5: Input offset drift is computed from the limits of the VOS test divided by the temperature range. This is a conservative estimate of worst case drift. Consult the Typical Performance Characteristics section for more information on input offset drift. Note 6: IB guaranteed by the VS = 5V test. Note 7: Current noise is calculated from In = √2qIB, where q = 1.6 • 10–19 coulomb. Note 8: VOS drift is guaranteed by the VS = 3V test. 60812f 6 LTC6081/LTC6082 TYPICAL PERFORMANCE CHARACTERISTICS VOS Drift Histogram 30 NUMBER OF AMPS (OUT OF 100) 25 20 15 10 5 0 –0.20 NUMBER OF AMPS (OUT OF 100) LTC6081MS8 TA = –40°C TO 125°C VS = 3V VCM = 0.5V 25 VOS Drift Histogram LTC6081DFN TA = –40°C TO 125°C VS = 3V VCM = 0.5V VOS (μV) –0.20 –0.10 0 0.10 VOSDRIFT (μV/°C) 0.20 60812 G02 VOS vs Temperature 25 20 15 10 LTC6081MS8 VS = 3V VCM = 0.5V REPRESENTATIVE PARTS 20 15 5 0 –5 10 5 –10 –15 –0.10 0.10 VOSDRIFT (μV/°C) 0 0.20 0.30 60812 G01 0 –0.30 –20 –50 –30 –10 10 30 50 70 90 110 130 TEMPERATURE (°C) 60812 G03 VOS Histogram 18 16 NUMBER OF AMPS (OUT OF 100) 14 12 VOS (μV) 10 8 6 4 2 0 –9.5 –5.5 –1.5 2.5 VOS (μV) 6.5 10.5 60812 G04 VOS vs VCM 40 30 20 10 0 VS = 3V TA = 25°C REPRESENTATIVE PARTS 140 120 100 80 VOS (μV) 0 0.5 1.0 1.5 2.0 VCM (V) 2.5 3.0 60 40 20 0 –20 –40 VOS vs VCM VS = 5V TA = 25°C REPRESENTATIVE PARTS LTC6081MS8 TA = 25°C VS = 3V VCM = 0.5V –10 –20 –30 –40 0 1 2 VCM (V) 3 4 5 60812 G06 60812 G05 VOS vs Output Current 200 150 100 VOS (μV) 50 TA = 55°C 0 –50 –100 SOURCING CURRENT –6 –4 SINKING CURRENT 4 6 60812 G07 Warm-Up Drift vs Time 25 CHANGE IN OFFSET VOLTAGE (μV) TA = 25°C VCM = 0.5V NOISE VOLTAGE (nV/√Hz) VS = 5V 110 100 90 80 70 60 50 40 30 20 10 –5 0 5 10 15 20 25 30 35 40 45 50 55 60 TIME AFTER POWER UP (s) 60812 G08 Noise Voltage vs Frequency TA = 25°C VS = 5V VCM = 2.5V TA = 125°C TA = 25°C 20 15 10 VS = 3V 5 0 VS = 5V VCM = 0.5V VS = 3V VCM = 0.5V 1 10 100 1k FREQUENCY (Hz) 10k 100k 60812 G09 0 0 2 –2 OUTPUT CURRENT (mA) 60812f 7 LTC6081/LTC6082 TYPICAL PERFORMANCE CHARACTERISTICS Noise Voltage vs Frequency 300 280 260 240 220 200 180 160 140 120 100 80 60 40 20 0 1 10 VS = 3V TA = 25°C OUTPUT NOISE (500nV/DIV) 0.1Hz to 10Hz Output Voltage Noise TA = 25°C VS = 3V VCM = 0.5V OUTPUT NOISE (1μV/DIV) 5 10 15 20 25 30 35 40 45 50 TIME (s) 60812 G11 0.1Hz to 10Hz Output Voltage Noise TA = 25°C VS = 3V VCM = 2.5V NOISE VOLTAGE (nV/√Hz) PMOS INPUTS VCM = 0.5V NMOS INPUTS VCM = 2.5V 100 1k FREQUENCY (Hz) 10k 100k 60812 G10 0 0 5 10 15 20 25 30 35 40 45 50 TIME (s) 60812 G12 Input Bias Current vs Temperature 1000 VS = 5V VCM = 2.5V 40 30 20 10 IBIAS (pA) 0 –10 –20 1 –30 –40 0.1 20 40 60 80 100 TEMPERATURE (°C) 120 140 –50 IBIAS vs VCM LTC6081MS8 VS = 5V 500 400 300 200 TA = 70°C IBIAS (pA) 100 0 IBIAS vs VCM LTC6081MS8 VS = 5V TA = 125°C INPUT BIAS CURRENT (pA) 100 10 –100 –200 –300 –400 –500 TA = 85°C 0 60812 G13 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VCM (V) 60812 G14 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VCM (V) 60812 G15 Large Signal Transient Small Signal Transient 55 50 45 OVERSHOOT (%) 40 35 30 25 20 15 10 5 0 Overshoot vs CL TA = 25°C VS = 3V VCM = 0.5V AV = 1 0.5V/DIV GND 20mV/DIV GND AV = 10 TA = 25°C VS = ±1.5V RL = 10k CL = 100pF 200μs/DIV 60812 G16 TA = 25°C VS = ±1.5V RL = 10k CL = 100pF 20μs/DIV 60812 G17 10 100 1000 CAPACITIVE LOAD (pF) 10000 60812 G18 60812f 8 LTC6081/LTC6082 TYPICAL PERFORMANCE CHARACTERISTICS Supply Current vs Temperature 390 370 SUPPLY CURRENT (μA) 350 330 310 290 270 250 –40 –25 –10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) 60812 G19 Supply Current vs Time 1600 TA = 25°C NO BYPASS CAPACITOR 4 1000 Output Impedance vs Frequency VCM = 0.5V PER AMPLIFIER VS = 5V SUPPLY CURRENT OPAMP (μA) 1200 3 SUPPLY VOLTAGE OUTPUT IMPEDANCE (Ω) 100 AV = 100 10 AV = 10 1 AV = 1 0.1 VS = 3V VCM = 0.5V TA = 25°C 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M SUPPLY VOLTAGE (V) VS = 3V 800 2 400 SUPPLY CURRENT 0 0 100 200 300 400 TIME (μs) 60812 G20 1 0 500 0.01 100 60812 G21 Open Loop Gain 20 10 INPUT VOLTAGE (μV) INPUT VOLTAGE (μV) 0 –10 –20 RL = 2k –30 –40 0 0.5 1.0 1.5 2.0 OUTPUT VOLTAGE (V) 2.5 3.0 RL = 100k RL = 10k VS = 3V TA = 25°C 20 10 0 –10 –20 –30 –40 Open Loop Gain VS = 5V TA = 25°C 60 Open Loop Gain vs Frequency RL = 10k RL = 100k PHASE RL = 100k GAIN (dB) RL = 10k RL = 2k 20 270 180 90 PHASE (DEG) 0 –90 GAIN –20 VS = 5V VCM = 0.5V TA = 25°C 1k 10k 1M 100k FREQUENCY (Hz) 10M 40 0 –180 –270 –360 100M 60812 G24 –40 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 OUTPUT VOLTAGE (V) 60812 G23 60812 G22 Open Loop Gain vs Frequency 60 PHASE 40 0 PHASE (DEG) CMRR (dB) GAIN (dB) 20 –90 –180 GAIN –20 VS = 5V VCM = 0.5V TA = 25°C CL = 200pF 1k 10k 1M 100k FREQUENCY (Hz) 10M –270 –360 –450 100M 60812 G25 CMRR vs Frequency 180 90 120 100 80 60 40 20 0 –20 100 PSRR (dB) VS = 5V VCM = 0.5V TA = 25°C RL = 1k 120 100 80 60 40 20 0 PSRR vs Frequency VS = 5V VCM = 0.5V TA = 25°C RL = 10k RL = 100k 0 –40 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M –20 100 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 60812 G26 60812 G27 60812f 9 LTC6081/LTC6082 TYPICAL PERFORMANCE CHARACTERISTICS Channel Separation vs Frequency 0 –20 CHANNEL SEPARATION (dB) – 40 – 60 – 80 –100 –120 –140 100 OUTPUT VOLTAGE SWING (V) (REFERRED TO SUPPLY VOLTAGE) VS = 3V VCM = 0.5V RL = 10k +VS VS = 3V +VS –0.5 V = 0.5V CM +VS –1.0 +VS –1.5 +VS –2.0 –VS 2.0 –VS 1.5 –VS 1.0 –VS 0.5 –VS 0 0.01 TA = 125°C TA = 25°C TA = –55°C SINK DISTORTION (dBc) SOURCE Output Voltage Swing vs Load Current –20 –30 –40 –50 –60 –70 –80 –90 100 60789 G29 Distortion vs Frequency VS = 5V AV = 1 RL = 10k VOUT = 2VP-P 2ND 3RD 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 1 10 0.1 LOAD CURRENT (mA) –100 1 10 100 FREQUENCY (kHz) 1000 60812 G30 60812 G28 PIN FUNCTIONS OUT: Amplifier Output –IN: Inverting Input +IN: Noninverting Input V+: Positive Supply V–: Negative Supply ⎯S⎯H⎯D⎯N⎯_⎯A: Shutdown Pin of Amplifier A, active low and only valid for LTC6081DD. An internal current source pulls the pin to V+ when floating. ⎯S⎯H⎯D⎯N⎯_⎯B: Shutdown Pin of Amplifier B, active low and only valid for LTC6081DD. An internal current source pulls the pin to V+ when floating. NC: Not internally connected. Exposed Pad: Connected to V–. 60812f 10 LTC6081/LTC6082 APPLICATIONS INFORMATION Preserving Input Precision Preserving input accuracy of the LTC6081/LTC6082 requires that the application circuit and PC board layout do not introduce errors comparable or greater than the 5μV typical offset of the amplifiers. Temperature differentials across the input connections can generate thermocouple voltages of 10’s of microvolts so the connections to the input leads should be short, close together and away from heat dissipating components. Air current across the board can also generate temperature differentials. The extremely low input bias currents (0.1pA typical) allow high accuracy to be maintained with high impedance sources and feedback resistors. Leakage currents on the PC board can be higher than the input bias current. For example, 10GΩ of leakage between a 5V supply lead and an input lead will generate 500pA! Surround the input leads with a guard ring driven to the same potential as the input common mode voltage to avoid excessive leakage in high impedance applications. Capacitive Load LTC6081/LTC6082 can drive capactive load up to 200pF in unity gain. The capacitive load driving capability increases as the amplifier is used in higher gain configurations. A small series resistance between the output and the load further increases the amount of capacitance the amplifier can drive. ⎯S⎯H⎯D⎯N Pins Pins 5 and 6 are used for power shutdown on the LTC6081 in the DD package. If they are floating, internal current sources pull Pins 5 and 6 to V+ and the amplifiers operate normally. In shutdown, the amplifier output is high impedance, and each amplifier draws less than 2μA current. Rail-to-Rail Input The input stage of LTC6081/LTC6082 combines both PMOS and NMOS differential pairs, extending its input common mode voltage range to both positive and negative supply voltages. At high input common mode range, the NMOS pair is on. At low common mode range, the PMOS pair is on. The transition happens when the common voltage is between 1.3V and 0.9V below the positive supply. LTC6081 has better low frequency noise performance with PMOS input on due to its lower flicker noise (see Voltage Noise vs Frequency and 0.1Hz to 10Hz Input Voltage Noise in Typical Performance Characteristics). Thermal Hysteresis Figure 1 shows the input offset voltage hysteresis of the LTC6081IMS8 for 3 thermal cycles from –45°C to 90°C. The typical offset shift is ±4μV. The data was taken with the ICs in stress free sockets. Mounting to PC boards may cause additional hysteresis due to mechanical stress. The LTC6081 will meet offset voltage specifications in the electrical characteristics table even after 15μV of additional error from thermal hysteresis. 0.30 VOS CHANGE AFTER 3 THERMAL CYCLES VCM = 0.5V + 0.25 V = 3V 300 UNITS 0.20 0.15 0.10 0.5 0 PERCENTAGE OF UNITS –15 –12 –9 –6 –3 0 3 6 VOS CHANGE (μV) 9 12 15 60812 F01 Figure 1. VOS Thermal Hysteresis of LTC6081MS8 60812f 11 LTC6081/LTC6082 APPLICATIONS INFORMATION PC Board Layout Mechanical stress on a PC board and soldering-induced stress can cause the VOS and VOS drift to shift. The DD and DHC packages are more sensitive to stress. A simple way to reduce the stress-related shifts is to mount the IC near the short edge of the PC board, or in a corner. The board edge acts as a stress boundary, or a region where the flexure of the board is minimum. The package should always be mounted so that the leads absorb the stress and not the package. The package is generally aligned with the leads perpendicular to the long side of the PC board (see Figure 2). The most effective technique to relieve the PC board stress is to cut slots in the board around the op amp. These slots can be cut on three sides of the IC and the leads can exit on the fourth side. Figure 2 shows the layout of a LTC6081DD with slots at three sides. LONG DIMENSION SLOTS 60812 F02 Figure 2. Vertical Orientation of LTC6081DD with Slots 60812f 12 LTC6081/LTC6082 SIMPLIFIED SCHEMATIC Simplified Schematic of the Amplifier V+ R1 M10 M11 C1 R2 M8 I1 1μA V – – + I2 D4 V+ VBIAS M5 A1 V+ D7 M1 M2 V– D6 V– D5 A2 M6 M7 OUTPUT CONTROL D8 OUT +IN D3 V+ V+ D2 SHDN D1 V– V– –IN BIAS GENERATION NOTE: SHDN IS ONLY AVAILABLE IN THE DFN10 PACKAGE + – V– M3 M4 C2 M9 R3 R4 60812 SS 60812f 13 LTC6081/LTC6082 TYPICAL APPLICATIONS Low Side Current Sense 100k 15pF V+ VDD I LOAD – 1/2 LTC6081 VOUT = RSH • I • 101 eNOISE = 3μVP-P, RTI BW ~ 1kHz + RSH 1k 60812 TA03 Two Op-Amp Instrumentation Amplifier GAIN TRIM 1.96k 100k CMRR TRIM 976k 50k – VIN + V+ 0.1μF 1M 100k – 1/2 LTC6081 100k + – 1/2 LTC6081 VOUT = 1011 • VIN + V– 0.1μF 60812 TA04 60812f 14 LTC6081/LTC6082 TYPICAL APPLICATIONS Thermocouple Amplifier 5V 0.1μF 1M 1μF 5V LT1025 K R– 10k 100pF SENSOR: OMEGA 5TC-TT-K-30-36 K-TYPE THERMOCOUPLE 1M RESISTORS PROTECT CIRCUIT TO ±350V WITH NO PHASE REVERSAL OF AMPLIFIER OUTPUT 1pA MAX IBIAS TRANSLATES TO 0.05°C ERROR 20μV VOS → 0.5°C OFFSET 60812 TA05 + 1/2 LTC6081 1M – 2.49M VOUT = 10mV/°C 0°C TO 500°C Precision Nanoamp Bidirectional Current Source 100k VIN 100Ω + 1/4 LTC6082 – 1k GAIN TRIM 5k 97.6k 10-TURN 100k 0.1μF 2.5V 10mΩ 100Ω 0.01μF 1/4 LTC6082 100k 3.9pF 100k 0.1μF 1/4 LTC6082 IOUT = –1nA → 1nA FOR VIN = –10V → 10V TOTAL ERROR