LT1677_1

LT1677 Low Noise, Rail-to-Rail Precision Op Amp FEATURES ■ ■ DESCRIPTIO ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Rail-to-Rail Input and Output 100% Tested Low Voltage Noise: 3.2nV/√Hz Typ at 1kHz 4.5nV/√Hz Max at 1kHz Offset Voltage: 60µV Max Low VOS Drift: 0.2µV/°C Typ Low Input Bias Current: 20nA Max Wide Supply Range: 3V to ±18V High AVOL: 7V/µV Min, RL = 10k High CMRR: 109dB Min High PSRR: 108dB Min Gain Bandwidth Product: 7.2MHz Slew Rate: 2.5V/µs Operating Temperature Range: – 40°C to 85°C The LT ®1677 features the lowest noise performance available for a rail-to-rail operational amplifier: 3.2nV/√Hz wideband noise, 1/f corner frequency of 13Hz and 90nV peak-to-peak 0.1Hz to 10Hz noise. Low noise is combined with outstanding precision: 20µV offset voltage and 0.2µV/°C drift, 130dB common mode and power supply rejection and 7.2MHz gain bandwidth product. The common mode range exceeds the power supply by 100mV. The voltage gain of the LT1677 is extremely high, 19 million (typical) driving a 10k load. In the design, processing and testing of the device, particular attention has been paid to the optimization of the entire distribution of several key parameters. Consequently, the specifications have been spectacularly improved compared to competing rail-to-rail amplifiers. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. APPLICATIO S ■ ■ ■ ■ ■ ■ ■ Low Noise Signal Processing Microvolt Accuracy Threshold Detection Strain Gauge Amplifiers Tape Head Preamplifiers Direct Coupled Audio Gain Stages Infrared Detectors Battery-Powered Microphones TYPICAL APPLICATIO Distribution of Offset Voltage 25 3V Electret Microphone Amplifier 20 TA = 25°C VS = ±15V PERCENT OF UNITS 1.5V R1 10k AV = – 100 R3 1M 1.5V TO PA OR HEADPHONES 23Hz HIGHPASS + 3 – PANASONIC ELECTRET CONDENSER MICROPHONE WM-61 www.panasonic.com/pic (714) 373-7334 C1 0.68µF R2 10k 15 2 7 LT1677 4 –1.5V 6 10 5 1677 TA01 0 –40 –30 –20 –10 0 10 20 30 INPUT OFFSET VOLTAGE (µV) U 40 1677 TA02 U U 1677fa 1 LT1677 ABSOLUTE (Note 1) AXI U RATI GS PACKAGE/ORDER I FOR ATIO TOP VIEW VOS 1 TRIM –IN 2 +IN 3 –VS 4 N8 PACKAGE 8-LEAD PDIP VOS TRIM 7 +VS 8 6 OUT 5 NC S8 PACKAGE 8-LEAD PLASTIC SO Supply Voltage ...................................................... ± 22V Input Voltages (Note 2) ............ 0.3V Beyond Either Rail Differential Input Current (Note 2) ..................... ± 25mA Output Short-Circuit Duration (Note 3) ............ Indefinite Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec.)................. 300°C Operating Temperature Range LT1677C (Note 4) ............................. – 40°C to 85°C LT1677I ............................................. – 40°C to 85°C Specified Temperature Range LT1677C (Note 5) ............................. – 40°C to 85°C LT1677I ............................................. – 40°C to 85°C – + TJMAX = 150°C, θJA = 150°C/ W (N8) TJMAX = 150°C, θJA = 190°C/ W (S0-8) ORDER PART NUMBER LT1677CS8 LT1677IS8 LT1677CN8 LT1677IN8 S8 PART MARKING 1677 1677I 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. The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 3V, VCM = VO = 1.7V; VS = 5V, VCM = VO = 2.5V unless otherwise noted. SYMBOL VOS PARAMETER Input Offset Voltage (Note 11) CONDITIONS (Note 6) 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C VCM = VS + 0.1V VCM = VS – 0.2V, 0°C ≤ TA ≤ 70°C VCM = VS – 0.3V, – 40°C ≤ TA ≤ 85°C VCM = – 0.1V VCM = 0V, 0°C ≤ TA ≤ 70°C VCM = 0V, – 40°C ≤ TA ≤ 85°C ∆VOS ∆Temp ∆VOS ∆Time IB Average Input Offset Drift (Note 10) Long Term Input Voltage Stability Input Bias Current (Note 11) SO-8 N8 ● ● ● ● ● ● ● ● ELECTRICAL CHARACTERISTICS MIN TYP 35 55 75 150 180 200 1.5 1.8 2.0 0.40 0.20 0.3 ±2 ±3 ±7 0.19 0.19 0.25 MAX 90 150 210 400 550 650 5.0 6.0 6.5 2.0 1.5 UNITS µV µV µV µV µV µV mV mV mV µV/°C µV/°C µV/Mo 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C VCM = VS + 0.1V VCM = VS – 0.2V, 0°C ≤ TA ≤ 70°C VCM = VS – 0.3V, – 40°C ≤ TA ≤ 85°C VCM = – 0.1V VCM = 0V, 0°C ≤ TA ≤ 70°C VCM = 0V, – 40°C ≤ TA ≤ 85°C ● ● ● ● ● ● ● ● ● ● ● ● ± 20 ± 35 ± 50 0.40 0.60 0.75 – 1.2 –2.0 –2.3 – 0.41 – 0.45 – 0.47 4 5 8 6 10 15 20 25 30 15 20 40 30 40 65 100 150 160 IOS Input Offset Current (Note 11) 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C VCM = VS + 0.1V VCM = VS – 0.2V, 0°C ≤ TA ≤ 70°C VCM = VS – 0.3V, – 40°C ≤ TA ≤ 85°C VCM = – 0.1V VCM = 0V, 0°C ≤ TA ≤ 70°C VCM = 0V, – 40°C ≤ TA ≤ 85°C 2 U nA nA nA µA µA µA µA µA µA nA nA nA nA nA nA nA nA nA 1677fa W U U WW W LT1677 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 3V, VCM = VO = 1.7V; VS = 5V, VCM = VO = 2.5V unless otherwise noted. SYMBOL en PARAMETER Input Noise Voltage CONDITIONS (Note 6) 0.1Hz to 10Hz (Note 7) VCM = VS VCM = 0V fO = 10Hz VCM = VS, fO = 10Hz VCM = 0V, fO = 10Hz fO = 1kHz VCM = VS, fO = 1kHz VCM = 0V, fO = 1kHz in VCM Input Noise Current Density Input Voltage Range 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C Input Resistance Input Capacitance Common Mode Rejection Ratio (Note 11) V S = 3V VCM = – 0.1V to 3.1V VCM = 0V to 2.7V V S = 5V VCM = – 0.1V to 5.1V VCM = 0V to 4.7V PSRR AVOL Power Supply Rejection Ratio Large-Signal Voltage Gain VS = 2.7V to 40V, VCM = VO = 1.7V VS = 3.1V to 40V, VCM = VO = 1.7V VS = 3V, RL ≥ 10k, VO = 2.5V to 0.7V 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C VS = 3V, RL ≥ 2k, VO = 2.2V to 0.7V 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C VS = 3V, RL ≥ 600Ω, VO = 2.2V to 0.7V 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C VS = 5V, RL ≥ 10k, VO = 4.5V to 0.7V 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C VS = 5V, RL ≥ 2k, VO = 4.2V to 0.7V 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C VS = 5V, RL ≥ 600Ω, VO = 4.2V to 0.7V 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C 55 53 60 58 108 105 0.6 0.4 0.4 0.5 0.4 0.4 0.20 0.15 0.10 0.8 0.7 0.7 0.40 0.35 0.25 0.35 0.30 0.20 Common Mode ● ● ELECTRICAL CHARACTERISTICS MIN TYP 90 180 600 5.2 7 25 3.2 5.3 17 1.2 0.3 MAX UNITS nVP-P nVP-P nVP-P nV/√Hz nV/√Hz nV/√Hz Input Noise Voltage Density (Note 8) 4.5 nV/√Hz nV/√Hz nV/√Hz pA/√Hz pA/√Hz fO = 10Hz fO = 1kHz – 0.1 0 0 VS + 0.1V VS – 0.2V VS – 0.3V 2 4.2 68 67 73 72 125 120 4 3 3 1 0.9 0.8 0.43 0.40 0.35 5 4 4 0.9 0.8 0.6 0.67 0.60 0.45 V V V GΩ pF dB dB dB dB dB dB V/µV V/µV V/µV V/µV V/µV V/µV V/µV V/µV V/µV V/µV V/µV V/µV V/µV V/µV V/µV V/µV V/µV V/µV RIN CIN CMRR ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 1677fa 3 LT1677 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 3V, VCM = VO = 1.7V; VS = 5V, VCM = VO = 2.5V unless otherwise noted. SYMBOL VOL PARAMETER Output Voltage Swing Low (Note 11) CONDITIONS (Note 6) Above GND ISINK = 0.1mA 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C Above GND ISINK = 2.5mA 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C Above GND ISINK = 10mA 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C VOH Output Voltage Swing High (Note 11) Below VS ISOURCE = 0.1mA 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C Below VS ISOURCE = 2.5mA 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C Below VS ISOURCE = 10mA 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C ISC Output Short-Circuit Current (Note 3) VS = 3V 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C VS = 5V 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C SR Slew Rate (Note 13) AV = – 1 RL ≥ 10k, 0°C ≤ TA ≤ 70°C RL ≥ 10k, – 40°C ≤ TA ≤ 85°C fO = 100kHz fO = 100kHz, 0°C ≤ TA ≤ 70°C fO = 100kHz, – 40°C ≤ TA ≤ 85°C 2V Step 0.1%, AV = +1 2V Step 0.01%, AV = +1 IOUT = 0 AV = 100, f = 10kHz 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C ● ● ELECTRICAL CHARACTERISTICS MIN TYP 110 125 130 170 195 205 370 440 465 75 85 93 170 195 205 450 510 525 MAX 170 200 230 250 320 350 500 600 650 170 200 250 300 350 375 700 800 850 UNITS mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mA mA mA mA mA mA V/µs V/µs V/µs MHz MHz MHz µs µs Ω Ω ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 15 14 13 20 18 17 1.7 1.5 1.2 4.5 3.8 3.7 22 20 19 29 27 25 2.5 2.3 2.0 7.2 6.2 5.8 2.1 3.5 80 1 2.60 2.75 2.80 3.4 3.7 3.8 GBW Gain Bandwidth Product (Note 11) tS RO IS Settling Time Open-Loop Output Resistance Closed-Loop Output Resistance Supply Current (Note 12) mA mA mA 1677fa 4 LT1677 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = ± 15V, VCM = VO = 0V unless otherwise noted. SYMBOL VOS PARAMETER Input Offset Voltage 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C VCM = 15.1V VCM = 14.8V, 0°C ≤ TA ≤ 70°C VCM = 14.7V, – 40°C ≤ TA ≤ 85°C VCM = – 15.1V VCM = – 15V, 0°C ≤ TA ≤ 70°C VCM = – 15V, – 40°C ≤ TA ≤ 85°C ∆VOS ∆Temp ∆VOS ∆Time IB Average Input Offset Drift (Note 10) Long Term Input Voltage Stability Input Bias Current 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C VCM = 15.1V VCM = 14.8V, 0°C ≤ TA ≤ 70°C VCM = 14.7V, – 40°C ≤ TA ≤ 85°C VCM = – 15.1V VCM = – 15V, 0°C ≤ TA ≤ 70°C VCM = – 15V, – 40°C ≤ TA ≤ 85°C IOS Input Offset Current 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C VCM = 15.1V VCM = 14.8V, 0°C ≤ TA ≤ 70°C VCM = 14.7V, – 40°C ≤ TA ≤ 85°C VCM = – 15.1V VCM = – 15V, 0°C ≤ TA ≤ 70°C VCM = – 15V, – 40°C ≤ TA ≤ 85°C en Input Noise Voltage 0.1Hz to 10Hz (Note 7) VCM = 15V VCM = – 15V fO = 10Hz VCM = 15V, fO = 10Hz VCM = – 15V, fO = 10Hz fO = 1kHz VCM = 15V, fO = 1kHz VCM = – 15V, fO = 1kHz in VCM Input Noise Current Density Input Voltage Range 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C Input Resistance Input Capacitance Common Mode ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ELECTRICAL CHARACTERISTICS CONDITIONS (Note 6) MIN TYP 20 30 45 150 180 200 1.5 1.8 2.0 0.40 0.20 0.3 ±2 ±3 ±7 0.19 0.20 0.25 MAX 60 120 180 400 550 650 5.0 6.0 6.5 2.0 1.5 UNITS µV µV µV µV µV µV mV mV mV µV/°C µV/°C µV/Mo SO-8 N8 ± 20 ± 35 ± 50 0.40 0.60 0.75 nA nA nA µA µA µA µA µA µA – 1.2 –2.0 –2.3 – 0.42 – 0.46 – 0.48 3 5 8 5 8 12 20 25 30 90 180 600 5.2 7 25 3.2 5.3 17 1.2 0.3 4.5 15 20 40 25 35 60 105 160 170 nA nA nA nA nA nA nA nA nA nVP-P nVP-P nVP-P nV/√Hz nV/√Hz nV/√Hz nV/√Hz nV/√Hz nV/√Hz pA/√Hz pA/√Hz Input Noise Voltage Density fO = 10Hz fO = 1kHz – 15.1 – 15.0 – 15.0 15.1 14.8 14.7 2 4.2 V V V GΩ pF RIN CIN 1677fa 5 LT1677 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = ± 15V, VCM = VO = 0V unless otherwise noted. SYMBOL CMRR PARAMETER Common Mode Rejection Ratio CONDITIONS (Note 6) VCM = – 13.3V to 14V ● ELECTRICAL CHARACTERISTICS MIN 109 105 74 72 106 103 108 105 7 4 3 0.50 0.30 0.15 0.2 TYP 130 124 95 91 130 125 125 120 19 13 8 0.75 0.67 0.24 0.5 110 125 130 170 195 205 370 440 450 110 130 140 210 240 250 520 590 620 MAX UNITS dB dB dB dB dB dB dB dB V/µV V/µV V/µV V/µV V/µV V/µV V/µV VCM = – 15.1V to 15.1V VCM = – 15V to 14.7V PSRR Power Supply Rejection Ratio VS = ±1.7V to ± 18V ● ● VS = 2.7V to 40V VS = 3.1V to 40V AVOL Large-Signal Voltage Gain RL ≥ 10k, VO = ±14V 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C RL ≥ 2k, VO = ±13.5V 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C RL ≥ 600Ω, VO = ±10V VOL Output Voltage Swing Low Above – VS ISINK = 0.1mA 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C Above – VS ISINK = 2.5mA 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C Above – VS ISINK = 10mA 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C VOH Output Voltage Swing High Below +VS ISOURCE = 0.1mA 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C Below +VS ISOURCE = 2.5mA 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C Below +VS ISOURCE = 10mA 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C ISC Output Short-Circuit Current (Note 3) 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C Slew Rate RL ≥ 10k (Note 9) RL ≥ 10k (Note 9) 0°C ≤ TA ≤ 70°C RL ≥ 10k (Note 9) – 40°C ≤ TA ≤ 85°C fO = 100kHz fO = 100kHz, 0°C ≤ TA ≤ 70°C fO = 100kHz, – 40°C ≤ TA ≤ 85°C ● ● ● ● ● ● ● 170 200 230 250 320 350 500 600 650 170 200 250 300 350 375 700 800 850 mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mA mA mA V/µs V/µs V/µs MHz MHz MHz 1677fa ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 25 20 18 1.7 1.5 1.2 4.5 3.8 3.7 35 30 28 2.5 2.3 2.0 7.2 6.2 5.8 SR GBW Gain Bandwidth Product 6 LT1677 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = ± 15V, VCM = VO = 0V unless otherwise noted. SYMBOL THD tS RO IS PARAMETER Total Harmonic Distortion Settling Time Open-Loop Output Resistance Closed-Loop Output Resistance Supply Current 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C ● ● ELECTRICAL CHARACTERISTICS CONDITIONS (Note 6) RL = 2k, AV = 1, fO = 1kHz, VO = 10VP-P 10V Step 0.1%, AV = +1 10V Step 0.01%, AV = +1 IOUT = 0 AV = 100, f = 10kHz MIN TYP 0.0006 5 6 80 1 2.75 3.00 3.10 MAX UNITS % µs µs Ω Ω 3.5 3.9 4.0 mA mA mA 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 back-to-back diodes. Current limiting resistors are not used in order to achieve low noise. If differential input voltage exceeds ±1.4V, the input current should be limited to 25mA. If the common mode range exceeds either rail, the input current should be limited to 10mA. Note 3: A heat sink may be required to keep the junction temperature below absolute maximum. Note 4: The LT1677C and LT1677I are guaranteed functional over the Operating Temperature Range of – 40°C to 85°C. Note 5: The LT1677C is guaranteed to meet specified performance from 0°C to 70°C. The LT1677C is designed, characterized and expected to meet specified performance from – 40°C to 85°C but is not tested or QA sampled at these temperatures. The LT1677I is guaranteed to meet specified performance from – 40°C to 85°C. Note 6: Typical parameters are defined as the 60% yield of parameter distributions of individual amplifier; i.e., out of 100 LT1677s, typically 60 op amps will be better than the indicated specification. Note 7: See the test circuit and frequency response curve for 0.1Hz to 10Hz tester in the Applications Information section of the LT1677 data sheet. Note 8: Noise is 100% tested at ±15V supplies. Note 9: Slew rate is measured in AV = – 1; input signal is ±7.5V, output measured at ± 2.5V. Note 10: This parameter is not 100% tested. VS = 3V and 5V limits are guaranteed by correlation to VS = ±15V test. Note 11: VS = 5V limits are guaranteed by correlation to VS = 3V and VS = ±15V tests. Note 12: VS = 3V limits are guaranteed by correlation to VS = 5V and VS = ±15V tests. Note 13: Guaranteed by correlation to slew rate at VS = ± 15V and GBW at VS = 3V and VS = ± 15V tests. TYPICAL PERFOR A CE CHARACTERISTICS Voltage Noise vs Frequency 100 RMS VOLTAGE NOISE DENSITY (nV/√Hz) 1/f CORNER 10Hz VCM < – 14.5V 1/f CORNER 8.5Hz 10 VCM –13.5V TO 14.5V 1/f CORNER 13Hz VS = ± 15V TA = 25°C 1 10 100 FREQUENCY (Hz) 1000 1677 G01 VCM > 14.5V 1 0.1 VOLTAGE NOISE (20nV/DIV) VOLTAGE NOISE (20nV/DIV) 0 UW 0.1Hz to 10Hz Voltage Noise 0.01Hz to 1Hz Voltage Noise 0 2 4 6 TIME (SECONDS) 8 10 1677 G03 20 40 60 TIME (SECONDS) 80 100 1677 G04 1677fa 7 LT1677 TYPICAL PERFOR A CE CHARACTERISTICS Voltage Noise vs Temperature 7 RMS VOLTAGE NOISE DENSITY (nV/√Hz) RMS CURRENT NOISE DENSITY (pA/√Hz) VS = ±15V VCM = 0V 10Hz VCM < –13.5V 1/f CORNER 180Hz 1 VCM –13.5V TO 14.5V INPUT BIAS CURRENT (nA) 6 5 4 1kHz 3 2 –50 –25 50 25 0 75 TEMPERATURE (°C) Input Bias Current vs Temperature 600 VS = ± 15V INPUT BIAS CURRENT (nA) INPUT BIAS CURRENT (nA) 500 OFFSET VOLTAGE (mV) VCM = –14V CURRENT OUT OF DUT 400 300 VCM = 14.7V CURRENT INTO DUT 200 100 –50 –25 50 25 0 75 TEMPERATURE (°C) Warm-Up Drift 10 CHANGE IN OFFSET VOLTAGE (µV) VS = ± 15V TA = 25°C PERCENT OF UNITS (%) 8 SO PACKAGE 6 N PACKAGE 35 30 25 20 15 10 5 PERCENT OF UNITS (%) 4 2 0 0 1 3 2 TIME (MINUTES) 8 UW 100 1677 G08 Current Noise vs Frequency 10 VS = ± 15V TA = 25°C 10 Input Bias Current vs Temperature VS = ± 15V 9 VCM = 0V 8 7 6 5 4 3 2 1 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 125 1/f CORNER 90Hz 1/f CORNER 60Hz 0.1 10 VCM > 14.5V 10000 1677 G07 125 100 1000 FREQUENCY (Hz) 1677 G05 Input Bias Current Over the Common Mode Range 800 600 400 200 0 VCM = 14.3V –200 VCM = – 15.3V –400 –600 100 125 Offset Voltage Shift vs Common Mode 2.5 2.0 1.5 VOS IS REFERRED TO VCM = 0V 250 200 150 VS = ± 15V TA = 25°C OFFSET VOLTAGE (µV) VCM = – 13.6V VCM = 15.15V 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 100 50 0 –50 –100 INPUT BIAS CURRENT –800 0 4 –16 –12 –8 –4 8 12 COMMON MODE INPUT VOLTAGE (V) 16 –2.5 –1.0 V– 1.0 –150 VS = ± 1.5V TO ± 15V TA = 25°C –200 5 TYPICAL PARTS –250 2.0 –0.8 –0.4 V + 0.4 VCM – V + (V) 1677 G10 VCM – V – (V) 1677 G06 1677 G09 Distribution of Input Offset Voltage Drift (N8) 50 45 40 VS = ± 15V TA = – 40°C TO 85°C 167 PARTS (4 LOTS) 30 25 20 15 10 5 Distribution of Input Offset Voltage Drift (SO-8) VS = ± 15V TA = – 40°C TO 85°C 201 PARTS (5 LOTS) 4 5 1677 G02 0 –1.0 –0.6 –0.2 0.2 0.6 1.0 1.4 INPUT OFFSET VOLTAGE DRIFT (µV/°C) 1677 G13 0 –0.8 –0.4 0 0.4 0.8 1.2 1.6 2.0 INPUT OFFSET VOLTAGE DRIFT (µV/°C) 1677 G37 1677fa LT1677 TYPICAL PERFOR A CE CHARACTERISTICS VOS vs Temperature of Representative Units 140 120 100 80 60 40 20 0 –20 –40 –60 –80 –55 –35 –15 5 25 45 65 85 105 125 TEMPERATURE (°C) 1677 G11 OFFSET VOLTAGE CHANGE (µV) OFFSET VOLTAGE (mV) VOLTAGE OFFSET (µV) VS = ± 15V VCM = 0V SO-8 N8 Supply Current vs Supply Voltage 4 COMMON MODE REJECTION RATIO (dB) 140 120 100 80 60 40 20 0 1k 10k POWER SUPPLY REJECTION RATIO (dB) SUPPLY CURRENT (mA) TA = 125°C 3 TA = 25°C TA = – 55°C 2 1 0 ±5 ± 10 ± 15 SUPPLY VOLTAGE (V) Voltage Gain vs Frequency 180 OPEN LOOP VOLTAGE GAIN (V/µV) VS = ± 15V TA = 25°C 140 VOLTAGE GAIN (dB) 100 VCM = 0V VCM = VCC OVERSHOOT (%) 60 VCM = VEE 20 –20 0.01 1 10k 100 FREQUENCY (Hz) UW 1677 G15 Common Mode Range vs Temperature 2.5 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 –2.5 –1.0 V– 1.0 2.0 –0.8 –0.4 V+ 0.4 1677 G12 Long-Term Stability of Four Representative Units 250 200 5 4 3 2 1 0 –1 –2 –3 –4 –5 0 100 200 300 400 500 600 700 800 900 TIME (HOURS) 1677 G14 VS = ± 2.5V TO ± 15V 125°C 25°C –55°C –55°C 150 OFFSET VOLTAGE (µV) 100 50 0 VOS IS REFERRED 125°C TO VCM = 0V –50 25°C –100 –150 –200 –250 VCM – VS– (V) VCM – VS+ (V) Common Mode Rejection Ratio vs Frequency 160 VS = ± 15V TA = 25°C VCM = 0V Power Supply Rejection Ratio vs Frequency 160 140 120 100 NEGATIVE SUPPLY 80 POSITIVE SUPPLY 60 40 20 0 1 10 100 10k 1k FREQUENCY (Hz) 100k 1M VS = ± 15V TA = 25°C ± 20 100k 1M FREQUENCY (Hz) 10M 1677 G16 1677 G17 Voltage Gain vs Supply Voltage (Single Supply) 100 TA = 25°C RL TO GND VCM: VO = VS/2 RL = 10k Overshoot vs Load Capacitance 60 50 40 30 20 10 FALLING EDGE RISING EDGE VS = ±15V TA = 25°C RL = 10k TO 2k 10 1 RL = 2k 0.1 1M 100M 1677 G18 0 10 20 SUPPLY VOLTAGE (V) 30 1677 G19 0 10 100 CAPACITANCE (pF) 1000 1677 G21 1677fa 9 LT1677 TYPICAL PERFOR A CE CHARACTERISTICS PM, GBWP, SR vs Temperature PHASE MARGIN (DEG) GAIN BANDWIDTH PRODUCT, fO = 100kHz (MHz) 70 PHASE 60 GBW 50 8 7 6 VS = ± 15V CL = 15pF SLEW RATE (V/µs) 3 SLEW 2 1 –50 –25 50 25 0 75 TEMPERATURE (°C) Settling Time vs Output Step (Inverting) 12 10 SETTLING TIME (µs) VIN VOUT 10 SETTLING TIME (µs) VIN VOLTAGE GAIN (dB) 8 6 4 2 VS = ± 15V AV = – 1 TA = 25°C 0.1% OF FULL SCALE 0.01% OF FULL SCALE 8 6 4 0.1% OF 2 FULL SCALE 0 –10 –8 –6 –4 –2 0 2 4 OUTPUT STEP (V) 0.1% OF FULL SCALE 0.01% OF FULL SCALE 0.01% OF FULL SCALE 0.1% OF FULL SCALE 0 –10 –8 –6 –4 –2 0 2 4 OUTPUT STEP (V) 6 8 10 1677 G25 Gain, Phase Shift vs Frequency 50 40 100 VS = ± 15V VCM = 14.7V CL = 10pF 80 125°C 25°C – 55°C 60 40 GAIN 10 0 –10 0.1 1 10 FREQUENCY (MHz) PHASE 20 0 –20 100 1677 G35 Gain, Phase Shift vs Frequency 50 40 VOLTAGE GAIN (dB) 30 20 30 20 GAIN 10 0 PHASE OUTPUT VOLTAGE SWING (V) VOLTAGE GAIN (dB) –10 0.1 1 10 FREQUENCY (MHz) 10 + 2k – + – 0.01% OF FULL SCALE 5k 5k UW 100 1677 G22 Large-Signal Transient Response 50mV Small-Signal Transient Response 10V 0 5 4 – 10V – 50mV AVCL = – 1 VS = ± 15V 5µs/DIV AVCL = 1 VS = ± 15V CL = 15pF 0.5µs/DIV 125 Settling Time vs Output Step (Noninverting) 12 VS = ± 15V AV = 1 TA = 25°C 50 2k VOUT RL = 1k Gain, Phase Shift vs Frequency 100 VS = ± 15V VCM = 0V CL = 10pF 80 125°C 25°C – 55°C 60 40 GAIN 10 0 –10 PHASE 20 0 –20 100 1677 G34 40 30 20 PHASE SHIFT (DEG) 6 8 10 0.1 1 10 FREQUENCY (MHz) 1677 G26 Output Voltage Swing vs Load Current +VS – 0 VS = ± 15V –0.1 –0.2 –0.3 –0.4 –0.5 –0.6 –0.7 0.5 125°C 0.4 25°C 0.3 0.2 –55°C 0.1 –VS + 0 –10 –8 –6 –4 –2 0 2 4 6 8 ISOURCE ISINK OUTPUT CURRENT (mA) 10 –55°C 100 VS = ± 15V VCM = – 14V CL = 10pF 80 125°C 25°C – 55°C 60 40 20 0 PHASE SHIFT (DEG) PHASE SHIFT (DEG) 25°C 125°C –20 100 1677 G36 1677 G27 1677fa LT1677 TYPICAL PERFOR A CE CHARACTERISTICS Closed-Loop Output Impedance vs Frequency 100 SHORT-CIRCUIT CURRENT (mA) SINKING SOURCING 50 40 30 20 10 TOTAL HARMONIC DISTROTION + NOISE (%) OUTPUT IMPEDANCE (Ω) 10 1 AV = +100 0.1 AV = +1 0.01 0.001 10 100 10k 1k FREQUENCY (Hz) Total Harmonic Distortion and Noise vs Frequency for Inverting Gain TOTAL HARMONIC DISTORTION + NOISE (%) TOTAL HARMONIC DISTROTION + NOISE (%) 0.1 ZL = 2k/15pF VS = ± 15V VO = 10VP-P AV = –1, –10, – 100 MEASUREMENT BANDWIDTH = 10Hz TO 80kHz AV = – 100 0.001 0.1 0.01 ZL = 2k/15pF VS = ± 15V fO = 1kHz AV = +1, +10, +100 MEASUREMENT BANDWIDTH = 10Hz TO 22kHz AV = 100 AV = 10 TOTAL HARMONIC DISTORTION + NOISE (%) AV = – 10 AV = – 1 0.0001 20 100 1k FREQUENCY (Hz) 10k 20k 1677 G31 UW 100k 1677 G29 Output Short-Circuit Current vs Time VS = ± 15V Total Harmonic Distortion and Noise vs Frequency for Noninverting Gain 0.1 ZL = 2k/15pF VS = ±15V VO = 10VP-P AV = +1, +10, +100 MEASUREMENT BANDWIDTH = 10Hz TO 80kHz AV = 100 –55°C 25°C 125°C 0.01 –30 –35 –40 –45 –50 0 125°C –55°C 25°C 0.001 AV = 10 AV = 1 0.0001 20 100 1k FREQUENCY (Hz) 10k 20k 1677 G30 1M 3 2 4 1 TIME FROM OUTPUT SHORT TO GND (MIN) 1677 G28 Total Harmonic Distortion and Noise vs Output Amplitude for Noninverting Gain 1 1 Total Harmonic Distortion and Noise vs Output Amplitude for Inverting Gain ZL = 2k/15pF VS = ± 15V fO = 1kHz AV = –1, –10, –100 MEASUREMENT BANDWIDTH = 10Hz TO 22kHz AV = –100 AV = – 10 0.001 AV = – 1 0.1 0.01 0.01 0.001 AV = 1 0.0001 0.3 1 10 OUTPUT SWING (VP-P) 30 1677 G32 0.0001 0.3 1 10 OUTPUT SWING (VP-P) 30 1677 G33 1677fa 11 LT1677 APPLICATIO S I FOR ATIO General The LT1677 series devices may be inserted directly into OP-07, OP-27, OP-37 and sockets with or without removal of external compensation or nulling components. In addition, the LT1677 may be fitted to 741 sockets with the removal or modification of external nulling components. Rail-to-Rail Operation INPUT 3 Figure 2. Standard Adjustment 1k 15V 4.7k 4.7k 1 Offset Voltage Adjustment The input offset voltage of the LT1677 and its drift with temperature are permanently trimmed at wafer testing to a low level. However, if further adjustment of VOS is necessary, the use of a 10kΩ nulling potentiometer will not degrade drift with temperature. Trimming to a value other than zero creates a drift of (VOS / 300)µV/ °C, e.g., if VOS is adjusted to 300µV, the change in drift will be 1µV/ °C (Figure 2). Input = – 0.5V to 3.5V 3V 3V Figure 3. Improved Sensitivity Adjustment 2V 2V 1V 1V 0V – 0.5V 1577 F01a 0V – 0.5V 1577 F01b Figure 1. Voltage Follower with Input Exceeding the Supply Voltage (VS = 3V) 12 + 3 – 2 LT1677 4 + – To take full advantage of an input range that can exceed the supply, the LT1677 is designed to eliminate phase reversal. Referring to the photographs shown in Figure 1, the LT1677 is operating in the follower mode (AV = +1) at a single 3V supply. The output of the LT1677 clips cleanly and recovers with no phase reversal. This has the benefit of preventing lock-up in servo systems and minimizing distortion components. U The adjustment range with a 10kΩ pot is approximately ± 2.5mV. If less adjustment range is needed, the sensitivity and resolution of the nulling can be improved by using a smaller pot in conjunction with fixed resistors. The example has an approximate null range of ± 200µV (Figure 3). 10k 15V 1 2 8 7 6 OUTPUT LT1677 4 –15V 1677 F02 W UU 8 76 OUTPUT –15V 1677 F03 LT1677 Output 1677fa LT1677 APPLICATIO S I FOR ATIO Offset Voltage and Drift Thermocouple effects, caused by temperature gradients across dissimilar metals at the contacts to the input terminals, can exceed the inherent drift of the amplifier unless proper care is exercised. Air currents should be minimized, package leads should be short, the two input leads should be close together and maintained at the same temperature. The circuit shown to measure offset voltage is also used as the burn-in configuration for the LT1677, with the supply voltages increased to ± 20V (Figure 4). 50k* 15V 50k* –15V Figure 4. Test Circuit for Offset Voltage and Offset Voltage Drift with Temperature Unity-Gain Buffer Application When RF ≤ 100Ω and the input is driven with a fast, largesignal pulse (>1V), the output waveform will look as shown in the pulsed operation diagram (Figure 5). During the fast feedthrough-like portion of the output, the input protection diodes effectively short the output to the input and a current, limited only by the output short-circuit protection, will be drawn by the signal generator. With RF ≥ 500Ω, the output is capable of handling the current requirements (IL ≤ 20mA at 10V) and the amplifier stays in its active mode and a smooth transition will occur. RF LT1677 1677 F05 + 100Ω* 3 – 2 7 6 VOUT LT1677 4 VOUT = 1000VOS *RESISTORS MUST HAVE LOW THERMOELECTRIC POTENTIAL 1677 F04 OUTPUT Figure 5. Pulsed Operation U As with all operational amplifiers when RF > 2k, a pole will be created with RF and the amplifier’s input capacitance, creating additional phase shift and reducing the phase margin. A small capacitor (20pF to 50pF) in parallel with RF will eliminate this problem. Noise Testing The 0.1Hz to 10Hz peak-to-peak noise of the LT1677 is measured in the test circuit shown (Figure 6a). The frequency response of this noise tester (Figure 6b) indicates that the 0.1Hz corner is defined by only one zero. The test time to measure 0.1Hz to 10Hz noise should not exceed ten seconds, as this time limit acts as an additional zero to eliminate noise contributions from the frequency band below 0.1Hz. Measuring the typical 90nV peak-to-peak noise performance of the LT1677 requires special test precautions: 1. The device should be warmed up for at least five minutes. As the op amp warms up, its offset voltage changes typically 3µV due to its chip temperature increasing 10°C to 20°C from the moment the power supplies are turned on. In the ten-second measurement interval these temperature-induced effects can easily exceed tens of nanovolts. 2. For similar reasons, the device must be well shielded from air currents to eliminate the possibility of thermoelectric effects in excess of a few nanovolts, which would invalidate the measurements. 3. Sudden motion in the vicinity of the device can also “feedthrough” to increase the observed noise. Current noise is measured in the circuit shown in Figure 7 and calculated by the following formula: 2⎤ ⎡ 2 ⎢ eno − 130nV • 101 ⎥ ⎦ in = ⎣ 1MΩ 101 W UU ) ()( ( )( ) 1/ 2 – + 2.5V/µs The LT1677 achieves its low noise, in part, by operating the input stage at 100µA versus the typical 10µA of most other op amps. Voltage noise is inversely proportional while current noise is directly proportional to the square 1677fa 13 LT1677 APPLICATIO S I FOR ATIO 0.1µF 100k GAIN (dB) VOLTAGE GAIN = 50,000 *DEVICE UNDER TEST NOTE: ALL CAPACITOR VALUES ARE FOR NONPOLARIZED CAPACITORS ONLY 24.3k Figure 7 1000 R TOTAL NOISE DENSITY (nV/√Hz) R SOURCE RESISTANCE = 2R 100 10 RESISTOR NOISE ONLY 1 0.1 1 10 SOURCE RESISTANCE (kΩ) 100 1677 F08 Figure 8. Total Noise vs Source Resistance 14 + 500k – + – 10Ω * LT1677 2k 4.7µF + LT1001 – 100k 0.1µF Figure 6a. 0.1Hz to 10Hz Noise Test Circuit 100k 100Ω 500k LT1677 eno 1677 F07 VS = ± 15V TA = 25°C AT 1kHz AT 10Hz U 100 90 80 70 60 50 40 30 0.01 1677 F06a W UU 4.3k 22µF 2.2µF SCOPE ×1 RIN = 1M 110k 0.1 1 10 FREQUENCY (Hz) 100 1677 F06b Figure 6b. 0.1Hz to 10Hz Peak-to-Peak Noise Tester Frequency Response root of the input stage current. Therefore, the LT1677’s current noise will be relatively high. At low frequencies, the low 1/f current noise corner frequency (≈ 90Hz) minimizes current noise to some extent. In most practical applications, however, current noise will not limit system performance. This is illustrated in the Total Noise vs Source Resistance plot (Figure 8) where: Total Noise = [(op amp voltage noise)2 + (resistor noise)2 + (current noise RS)2]1/2 Three regions can be identified as a function of source resistance: (i) RS ≤ 400Ω. Voltage noise dominates (ii) 400Ω ≤ RS ≤ 50k at 1kHz Resistor noise dominates 400Ω ≤ RS ≤ 8k at 10Hz (iii) RS > 50k at 1kHz Current noise dominates RS > 8k at 10Hz } } Clearly the LT1677 should not be used in region (iii), where total system noise is at least six times higher than the voltage noise of the op amp, i.e., the low voltage noise specification is completely wasted. In this region the LT1792 or LT1793 is the best choice. 1677fa LT1677 APPLICATIO S I FOR ATIO Rail-to-Rail Input The LT1677 has the lowest voltage noise, offset voltage and highest gain when compared to any rail-to-rail op amp. The input common mode range for the LT1677 can exceed the supplies by at least 100mV. As the common mode voltage approaches the positive rail (+VS – 0.7V), the tail current for the input pair (Q1, Q2) is reduced, which prevents the input pair from saturating (refer to the Simplified Schematic). The voltage drop across the load resistors RC1, RC2 is reduced to less than 200mV, degrading the slew rate, bandwidth, voltage noise, offset voltage and input bias current (the cancellation is shut off). When the input common mode range goes below 1.5V above the negative rail, the NPN input pair (Q1, Q2) shuts off and the PNP input pair (Q8, Q9) turns on. The offset voltage, input bias current, voltage noise and bandwidth are also degraded. The graph of Offset Voltage Shift vs Common Mode shows where the knees occur by displaying the change in offset voltage. The change-over points are temperature dependent, see the graph Common Mode Range vs Temperature. INPUT VOLTAGE (50µV/DIV) RL = 600 RL = 1k RL = 10k INPUT VOLTAGE (5µV/DIV) – 15 – 10 – 5 0 5 10 15 OUTPUT VOLTAGE (V) TA = 25°C VS = ±15V RL CONNECTED TO 0V MEASURED ON TEKTRONIX 577 CURVE TRACER Figure 9. Voltage Gain Split Supply U Rail-to-Rail Output The rail-to-rail output swing is achieved by using transistor collectors (Q28, Q29) instead of customary class A-B emitter followers for the output stage. Referring to the Simplified Schematic, the output NPN transistor (Q29) sinks the current necessary to move the output in the negative direction. The change in Q29’s base emitter voltage is reflected directly to the gain node (collectors of Q20 and Q16). For large sinking currents, the delta VBE of Q29 can dominate the gain. Figure 9 shows the change in input voltage for a change in output voltage for different load resistors connected between the supplies. The gain is much higher for output voltages above ground (Q28 sources current) since the change in base emitter voltage of Q28 is attenuated by the gain in the PNP portion of the output stage. Therefore, for positive output swings (output sourcing current) there is hardly any change in input voltage for any load resistance. Highest gain and best linearity is achieved when the output is sourcing current, which is the case in single supply operation when the load is ground referenced. Figure 10 shows gains for both sinking and sourcing load currents for a worst-case load of 600Ω. RL TO 5V RL TO 0V 0 1 2 3 4 OUTPUT VOLTAGE (V) TA = 25°C VS = 5V RL = 600Ω MEASURED ON TEKTRONIX 577 CURVE TRACER 5 W UU Figure 10. Voltage Gain Single Supply 1677fa 15 LT1677 TYPICAL APPLICATIO S Microvolt Comparator with Hysteresis 3V 3V 10M 5% 15k 1% 15k 1% OUTPUT INPUT 1677 TA03 R2 5Ω *OMEGA SG-3/350LY11 350Ω, 1% ALL OTHER RESISTORS 1% R4 5.49k R4 ≅ 1000 AV = 2 • R* + R6 R2 + (R*/2) R6 TRIM R11 FOR BRIDGE BALANCE ( )( ) Precision High Side Current Sense SOURCE 3V < VS < 36V RIN 1k LOAD 16 + 3 – RLINE 0.1Ω 2 7 LT1677 4 6 ZETEX BC856B VOUT ROUT ROUT VOUT 20k ILOAD = RLINE RIN = 2V/AMP 1677 TA07 – POSITIVE FEEDBACK TO ONE OF THE NULLING TERMINALS CREATES APPROXIMATELY 5µV OF HYSTERESIS. OUTPUT CAN SINK 16mA INPUT OFFSET VOLTAGE IS TYPICALLY CHANGED LESS THAN 5µV DUE TO THE FEEDBACK + – 2 + 3 7 1 LT1677 4 6 U 3V Strain Gauge Amplifier R11 1k R10 232Ω R9 3.4Ω R* R8 7.5Ω R* R2 5Ω R3 5.49k 3V R7 22.1Ω R5 698Ω R* R* LT1677 R* VOUT FOR TEMP COMPENSATION R* OF GAIN R6 22.1Ω 1677 TA06 1677fa LT1677 TYPICAL APPLICATIO S 1.5V 2N3906 C1 10pF R1 1M 1.5V 7Hz POLE FOR SERVO C3 0.022µF 1.5V –1.5V + 3 – PANASONIC ELECTRET CONDENSER MICROPHONE WM-61 (714) 373-7334 + 3 – 2 7 LT1677 4 –1.5V C4 1µF R4 8k 6 2 + 3 – U 3V Super Electret Microphone Amplifier with DC Servo 1.5V 2N3906 16kHz ROLL OFF R3 1M R5 2k 2 7 LT1677 4 –1.5V 6 R2 80k C2 100pF 1.5V 7 20kHz ROLL OFF TO HEADPHONES LT1677 4 –1.5V 6 1677 TA05 1677fa 17 LT1677 W RC1A 6k Q35 SI PLIFIED SCHE ATIC RC2A 6k Q17 Q18 R2 50Ω R1 500Ω C1 40pF 100µA + Q4 R19 2k Q10 Q11 Q20 Q6 R20 2k Q7 C2 80pF + OUT Q12 Q5 Q27 C3 40pF Q23 R3 100Ω D4 Q3 100µA D1 D3 D2 160µA Q31 + –IN Q19 Q1A Q1B Q2A Q2B IA R9 200Ω 50µA 50µA IB Q22 Q30 Q26 R54 100Ω Q29 R23A 10k R8 200Ω Q13 ×2 IC ID Q21 Q24 Q8 Q9 Q15 Q14 Q16 Q25 R30 2k R26 100Ω Q38 R23B 10k R15 1k R14 1k R16 1k R25 1k R29 10Ω R13 100Ω R21 100Ω R24 100Ω IA, IB = 0µA VCM > 1.5V ABOVE –VS 200µA VCM < 1.5V ABOVE –VS IC = 200µA VCM < 0.7V BELOW +VS ID = 100µA VCM < 0.7V BELOW +VS 50µA VCM > 0.7V BELOW +VS 0µA VCM > 0.7V BELOW +VS 1677 SS + +IN C4 20pF –VS W Q28 + 18 +VS RC1B 1k C10 81pF PAD 8 200µA Q32 Q34 RC2B 1k R32 1.5k R34 2k PAD 1 1677fa LT1677 PACKAGE DESCRIPTIO U Dimensions in inches (millimeters) unless otherwise noted. 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 .300 – .325 (7.620 – 8.255) 2 3 4 .130 ± .005 (3.302 ± 0.127) .045 – .065 (1.143 – 1.651) .008 – .015 (0.203 – 0.381) .065 (1.651) TYP .120 (3.048) .020 MIN (0.508) MIN .018 ± .003 (0.457 ± 0.076) N8 1002 ( +.035 .325 –.015 8.255 +0.889 –0.381 ) .100 (2.54) BSC 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 S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) .189 – .197 (4.801 – 5.004) NOTE 3 8 7 6 5 .045 ±.005 .050 BSC .245 MIN .160 ±.005 .228 – .244 (5.791 – 6.197) .150 – .157 (3.810 – 3.988) NOTE 3 .030 ±.005 TYP RECOMMENDED SOLDER PAD LAYOUT .010 – .020 × 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) 0°– 8° TYP 1 2 3 4 .053 – .069 (1.346 – 1.752) .004 – .010 (0.101 – 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) .014 – .019 (0.355 – 0.483) TYP .050 (1.270) BSC SO8 0303 1677fa 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. 19 LT1677 TYPICAL APPLICATIO This 2-wire remote Geophone preamp operates on a current-loop principle and so has good noise immunity. Quiescent current is ≈ 10mA for a VOUT of 2.5V. Excitation will cause AC currents about this point of ~ ± 4mA for a VOUT of ~ ± 1V max. The op amp is configured for a voltage LINEAR TECHNOLOGY LM334Z 6mA V+ R V– R8 11Ω Q1 2N3904 12V 3V C LT1431CZ A R R6 4.99k R7 24.9k + C3 220µF R3 16.2k AV = R2 + R3||R4 R1 + RL ≅ 107 RELATED PARTS PART NUMBER LT1028/LT1128 LT1115 LT1124/LT1125 LT1126/LT1127 LT1226 LT1498/LT1499 LT1792 LT1793 LT1806 LT1881/LT1882 LT1884/LT1885 DESCRIPTION Ultralow Noise Precision Op Amps Ultralow Noise, Low distortion Audio Op Amp Dual/Quad Low Noise, High Speed Precision Op Amps Dual/Quad Decompensated Low Noise, High Speed Precision Op Amps Low Noise, Very High Speed Op Amp 10MHz, 5V/µs, Dual/Quad Rail-to-Rail Input and Output Op Amps Low Noise, Precision JFET Input Op Amp Low Noise, Picoampere Bias Current Op Amp Low Noise, 325MHz Rail-to-Rail Input and Output Op Amp Dual/Quad Rail-to-Rail Output Picoamp Input Precision Op Amps Dual/Quad Rail-to-Rail Output Picoamp Input Precision Op Amps COMMENTS Lowest Noise 0.85nV/√Hz 0.002% THD, Max Noise 1.2nV/√Hz Similar to LT1007 Similar to LT1037 1GHz, 2.6nV/√Hz, Gain of 25 Stable Precision C-LoadTM Stable 4.2nV/√Hz, 10fA/√Hz 6nV/√Hz, 1fA/√Hz, IB = 10pA Max 3.5nV/√Hz CLOAD to 1000pF, IB = 200pA Max 2.2MHz Bandwidth, 1.2V/µs SR C-Load is a trademark of Linear Technology Corporation. 1677fa 20 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com + GEOSPACE GS-20DX RL = 630Ω GEOPHONE www.geospacecorp.com/default.htm (713) 939-7093 – + 3 – U gain of ~107. Components R5 and Q1 convert the voltage into a current for transmission back to R10, which converts it into a voltage again. The LM334 and 2N3904 are not temperature compensated so the DC output contains temperature information. 2-Wire Remote Geophone Preamp R9 20Ω R4 14k R1 365Ω R2 100k 2 7 LT1677 4 C4 1000pF 1677 TA04 C2 0.1µF 6 R5 243Ω R10 250Ω VOUT 2.5V ± 1V LT 0306 REV A • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 2000