LT1678/LT1679 1678/LT1679 SO-14 LT1677 LT1679 LT1678CS8 LT1678IS8 1678I

Dual/Quad Low Noise, Rail-to-Rail, Precision Op Amps U FEATURES s s s s s s s s s s s s s DESCRIPTIO Rail-to-Rail Input and

LT1678/LT1679 LT1678/LT1679 Dual/Quad Low Noise, Rail-to-Rail, Precision Op Amps U FEATURES s s s s s s s s s s s s s DESCRIPTIO Rail-to-Rail Input and Output 100% Tested Low Voltage Noise: 3.9nV/Hz Typ at 1kHz 5.5nV/Hz Max at 1kHz Single Supply Operation from 2.5V to 36V Offset Voltage: 100µV Max Low Input Bias Current: 20nA Max High AVOL: 3V/µV Min, RL = 10k High CMRR: 100dB Min High PSRR: 106dB Min Gain Bandwidth Product: 20MHz Operating Temperature Range: 40°C to 85°C Matching Specifications No Phase Inversion 8-Lead SO and 14-Lead SO Packages The LT ®1678/LT1679 1678/LT1679 are dual/quad rail-to-rail op amps offering both low noise and precision: 3.9nV/Hz wideband noise, 1/f corner frequency of 4Hz and 90nV peak-to-peak 0.1Hz to 10Hz noise are combined with outstanding precision: 100µV maximum offset voltage, greater than 100dB common mode and power supply rejection and 20MHz gain bandwidth product. The LT1678/LT1679 LT1678/LT1679 bring precision as well as low noise to single supply applications as low as 3V. The input range exceeds the power supply by 100mV with no phase inversion while the output can swing to within 170mV of either rail. The LT1678/LT1679 LT1678/LT1679 are offered in the SO-8 and SO-14 SO-14 packages. A full set of matching specifications are also provided, facilitating their use in matching dependent applications such as a two op amp instrumentation amplifier design. The LT1678/LT1679 LT1678/LT1679 are specified for supply voltages of ±15V, single 5V as well as single 3V. For a single amplifier with similiar performance, see the LT1677 LT1677 data sheet. U APPLICATIO S s s s s s Strain Gauge Amplifiers Portable Microphones Battery-Powered Rail-to-Rail Instrumentation Low Noise Signal Processing Microvolt Accuracy Threshold Detection Infrared Detectors , LTC and LT are registered trademarks of Linear Technology Corporation. U s TYPICAL APPLICATIO Instrumentation Amplifier with Shield Driver 2 0.1Hz to 10Hz Voltage Noise + 1 1/4 LT1679 LT1679 1k VS = ±2.5V RF 3.4k + 8 10 + 15V 5 GUARD INPUT 30k 9 1/4 LT1679 LT1679 RG 100 6 4 + 1/4 LT1679 LT1679 RG 100 11 15V 7 OUTPUT 30k VOLTAGE NOISE (50nV/DIV) 3 GUARD GAIN = 1000 13 12 1/4 LT1679 LT1679 + 14 0 RF 3.4k 16789 TA01 2 4 6 TIME (sec) 8 10 16789 TA01b 1k 16789f 1 LT1678/LT1679 LT1678/LT1679 W W W AXI U U ABSOLUTE RATI GS (Note 1) Supply Voltage . ±18V 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 (Note 4) . 40°C to 85°C Specified Temperature Range (Note 5) . 40°C to 85°C U U W PACKAGE/ORDER I FOR ATIO ORDER PART NUMBER TOP VIEW 8 V+ OUT A 1 IN A 2 +IN A 3 7 A B V 4 OUT B 6 IN B 5 LT1678CS8 LT1678CS8 LT1678IS8 LT1678IS8 +IN B S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, JA = 190°C/ W 14 OUT D OUT A 1 IN A 2 A D V+ 4 11 V B C 10 +IN C IN B 6 9 IN C OUT B 7 1678 1678I 1678I LT1679CS LT1679CS LT1679IS LT1679IS 13 IN D 12 +IN D +IN A 3 +IN B 5 S8 PART MARKING ORDER PART NUMBER TOP VIEW 8 OUT C S PACKAGE 14-LEAD 14-LEAD PLASTIC SO TJMAX = 150°C, JA = 160°C/ W Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The q 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 PARAMETER CONDITIONS (Note 6) VOS Input Offset Voltage (Note 11) 0°C TA 70°C 40°C TA 85°C TYP MAX UNITS q q 35 55 75 100 270 350 µV µV µV VS =5V, VCM = VS + 0.1V VS =5V, VCM = VS 0.3V, 0°C TA 70°C VS =5V, VCM = VS 0.3V, 40°C TA 85°C q q 150 180 200 550 750 1000 µV µV µV VS =5V, VCM = 0.1V VS =5V, VCM = 0V, 0°C TA 70°C VS =5V, VCM = 0V, 40°C TA 85°C VOS Temp IB q q 1.5 1.8 2.0 30 45 50 mV mV mV q 0.40 3 µV/°C q q ±2 ±3 ±7 ±20 ±35 ±50 nA nA nA 0.19 0.19 0.25 0.40 0.60 0.75 µA µA µA Average Input Offset Drift (Note 10) Input Bias Current (Note 11) 0°C TA 70°C 40°C TA 85°C MIN VS = 5V, VCM = VS + 0.1V q VS = 5V, VCM = VS 0.3V, 0°C TA 70°C VS = 5V, VCM = VS 0.3V, 40°C TA 85°C q VS = 5V, VCM = 0.1V VS = 5V, VCM = 0V, 0°C TA 70°C VS = 5V, VCM = 0V, 40°C TA 85°C q q 5 8.4 10 0.41 0.45 0.47 µA µA µA 16789f 2 LT1678/LT1679 LT1678/LT1679 ELECTRICAL CHARACTERISTICS The q 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 PARAMETER CONDITIONS (Note 6) IOS Input Offset Current (Note 11) 0°C TA 70°C 40°C TA 85°C TYP MAX q q 4 5 8 25 35 55 nA nA nA VS = 5V, VCM = VS + 0.1V q VS = 5V, VCM = VS 0.3V, 0°C TA 70°C VS = 5V, VCM = VS 0.3V, 40°C TA 85°C q 6 10 15 30 40 65 nA nA nA 0.1 0.1 0.15 1.6 2.0 2.4 µA µA µA VS = 5V, VCM = 0.1V VS = 5V, VCM = 0V, 0°C TA 70°C VS = 5V, VCM = 0V, 40°C TA 85°C en MIN q q Input Noise Voltage 0.1Hz to 10Hz (Note 7) VCM = VS VCM = 0V Input Noise Voltage Density (Note 8) fO = 10Hz VCM = VS, fO = 10Hz VCM = 0V, fO = 10Hz 4.4 6.6 19 fO = 1kHz VCM = VS, fO = 1kHz VCM = 0V, fO = 1kHz 3.9 5.3 9 fO = 10Hz fO = 1kHz 1.2 0.3 in Input Noise Current Density VCM 90 180 1600 Input Voltage Range q RIN Input Resistance CIN Common Mode Rejection Ratio Common Mode nVP-P nVP-P nVP-P nV/Hz nV/Hz nV/Hz 5.5 nV/Hz nV/Hz nV/Hz pA/Hz pA/Hz VS + 0.1V VS 0.3V 2 Input Capacitance CMRR 0.1 0 UNITS V V G 125 120 dB dB 0.6 0.3 3 2 V/µV V/µV q q 0.5 0.4 0.4 3 0.9 0.8 V/µV V/µV V/µV q q 0.20 0.15 0.10 0.43 0.40 0.35 V/µV V/µV V/µV q q 1 0.6 0.3 3.8 2 2 V/µV V/µV V/µV VS = 5V, RL = 2k, VO = 4.2V to 0.7V 0°C TA 70°C 40°C TA 85°C q q 0.7 0.6 0.5 3.5 3.2 3.0 V/µV V/µV V/µV VS = 5V, RL = 600, VO = 4.2V to 0.7V 0°C TA 70°C 40°C TA 85°C Output Voltage Swing Low (Note 11) 100 98 VS = 5V, RL = 10k, VO = 4.5V to 0.7V O°C < TA < 70°C 40 < TA < 85°C VOL q VS = 3V, RL = 600, VO = 2.2V to 0.7V 0°C TA 70°C 40°C TA 85°C Large-Signal Voltage Gain q dB dB VS = 3V, RL = 2k, VO = 2.2V to 0.7V 0°C TA 70°C 40°C TA 85°C AVOL Power Supply Rejection Ratio pF 120 120 q PSRR 4.2 98 92 q q 0.6 0.5 0.4 3.0 2.8 2.5 V/µV V/µV V/µV Above GND ISINK = 0.1mA 0°C TA 70°C 40°C TA 85°C q q VS = 5V, VCM = 1.9V to 3.9V VS = 5V, VCM = 1.9V to 3.9V VS = 2.7V to 36V, VCM = VO = 1.7V VS = 3.1V to 36V, VCM = VO = 1.7V VS = 3V, RL = 10k, VO = 2.5V to 0.7V 80 125 130 170 200 250 mV mV mV 16789f 3 LT1678/LT1679 LT1678/LT1679 ELECTRICAL CHARACTERISTICS The q 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 PARAMETER CONDITIONS (Note 6) VOL Output Voltage Swing Low (Note 11) Above GND ISINK = 2.5mA 0°C TA 70°C 40°C TA 85°C Output Short-Circuit Current (Note 3) UNITS q q 170 195 205 250 320 350 mV mV mV q q 370 440 465 600 720 770 mV mV mV Below VS ISOURCE = 0.1mA 0°C TA 70°C 40°C TA 85°C q q 75 85 93 150 200 250 mV mV mV q q 110 195 205 250 350 375 mV mV mV Below VS ISOURCE = 10mA 0°C TA 70°C 40°C TA 85°C ISC MAX Below VS ISOURCE = 2.5mA 0°C TA 70°C 40°C TA 85°C Output Voltage Swing High (Note 11) TYP Above GND ISINK = 10mA 0°C TA 70°C 40°C TA 85°C VOH MIN q q 170 200 230 400 500 550 mV mV mV VS = 3V q 15 13 22 19 mA mA q 18 14 29 25 mA mA AV = 1, RL = 10k RL = 10k, 0°C TA 70°C RL = 10k, 40°C TA 85°C q q 4 3.5 3 6 5.8 5.5 V/µs V/µs V/µs fO = 100kHz fO = 100kHz q 13 12.5 20 19 MHz MHz VS = 5V SR GBW Slew Rate (Note 13) Gain Bandwidth Product (Note 11) tS Settling Time 2V Step 0.1%, AV = +1 2V Step 0.01%, AV = +1 1.4 2.4 µs µs RO Open-Loop Output Resistance Closed-Loop Output Resistance IOUT = 0 AV = 100, f = 10kHz 100 1 IS Supply Current per Amplifier (Note 12) q VOS IB+ CMRR PSRR Offset Voltage Match (Notes 11, 15) Noninverting Bias Current Match (Notes 11, 15) 2 2.5 3.4 3.8 mA mA 0°C TA 70°C 40°C TA 85°C q q 35 55 75 150 400 525 µV µV µV 0°C TA 70°C 40°C TA 85°C q q ±2 ±3 ±7 ±30 ±55 ±75 nA nA nA Common Mode Rejection Match (Notes 11, 14, 15) VS = 5V, VCM = 1.9V to 3.9V q Power Supply Rejection Match (Notes 11, 14, 15) VS = 2.7V to 36V, VCM = VO = 1.7V VS = 3.1V to 36V, VCM = VO = 1.7V 94 88 110 110 dB dB q 96 94 120 120 dB dB 16789f 4 LT1678/LT1679 LT1678/LT1679 ELECTRICAL CHARACTERISTICS The q 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 PARAMETER VOS CONDITIONS (Note 6) TYP MAX UNITS Input Offset Voltage q q 20 30 45 150 350 420 µV µV µV q 0.40 3 0°C TA 70°C 40°C TA 85°C q q ±2 ±3 ±7 ±20 ±35 ±50 nA nA nA 0°C TA 70°C 40°C TA 85°C q q 3 5 8 25 35 55 nA nA nA 0°C TA 70°C 40°C TA 85°C VOS Temp Average Input Offset Drift (Note 10) IB MIN Input Bias Current IOS en Input Offset Current Input Noise Voltage 0.1Hz to 10Hz (Note 7) VCM = 15V VCM = 15V 90 180 1600 Input Noise Voltage Density fO = 10Hz VCM = 15V, fO = 10Hz VCM = 15V, fO = 10Hz 4.4 6.6 19 fO = 1kHz VCM = 15V, fO = 1kHz VCM = 15V, fO = 1kHz 3.9 5.3 9 fO = 10Hz fO = 1kHz 1.2 0.3 in Input Noise Current Density VCM Input Voltage Range (Note 16) RIN Input Resistance CIN Input Capacitance CMRR Common Mode Rejection Ratio q 13.3 Common Mode µV/°C nVP-P nVP-P nVP-P nV/Hz nV/Hz nV/Hz 5.5 nV/Hz nV/Hz nV/Hz pA/Hz pA/Hz 14 V 2 4.2 pF q AVOL Power Supply Rejection Ratio Large-Signal Voltage Gain 100 96 130 124 dB dB q PSRR VCM = 13.3V to 14V G 106 100 130 125 dB dB RL = 10k, VO = ±14V 0°C TA 70°C 40°C TA 85°C q q 3 2 1 7 6 4 V/µV V/µV V/µV RL = 2k, VO = ±13.5V 0°C TA 70°C 40°C TA 85°C q q 0.8 0.5 0.4 1.7 1.4 1.1 V/µV V/µV V/µV VS = ±1.7V to ±18V 16789f 5 LT1678/LT1679 LT1678/LT1679 ELECTRICAL CHARACTERISTICS The q 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 PARAMETER CONDITIONS (Note 6) VOL Output Voltage Swing Low Above VS ISINK = 0.1mA 0°C TA 70°C 40°C TA 85°C UNITS q q 110 125 130 200 230 260 mV mV mV q q 170 195 205 280 350 380 mV mV mV q q 370 440 450 600 700 750 mV mV mV Below +VS ISOURCE = 0.1mA 0°C TA 70°C 40°C TA 85°C q q 80 90 100 150 200 250 mV mV mV Below +VS ISOURCE = 2.5mA 0°C TA 70°C 40°C TA 85°C q q 110 120 120 200 300 350 mV mV mV Below +VS ISOURCE = 10mA 0°C TA 70°C 40°C TA 85°C ISC MAX Above VS ISINK = 10mA 0°C TA 70°C 40°C TA 85°C Output Voltage Swing High TYP Above VS ISINK = 2.5mA 0°C TA 70°C 40°C TA 85°C VOH MIN q q 200 250 250 450 500 550 mV mV mV q SR GBW Output Short-Circuit Current (Note 3) Slew Rate Gain Bandwidth Product 20 15 35 28 mA mA RL = 10k (Note 9) RL = 10k (Note 9) 0°C TA 70°C RL = 10k (Note 9) 40°C TA 85°C q q 4 3.5 3 6 5.8 5.5 V/µs V/µs V/µs fO = 100kHz fO = 100kHz q 13 12.5 20 19 MHz MHz THD Total Harmonic Distortion RL = 2k, AV = 1, fO = 1kHz, VO = 20VP-P 20VP-P 0.00025 % tS Settling Time 10V Step 0.1%, AV = +1 10V Step 0.01%, AV = +1 2.7 3.9 µs µs RO Open-Loop Output Resistance Closed-Loop Output Resistance IOUT = 0 AV = 100, f = 10kHz 100 1 IS Supply Current per Amplifier 2.5 3 q Channel Separation VOS IB+ CMRR PSRR Offset Voltage Match (Note 15) Noninverting Bias Current Match (Note 15) f = 10Hz, VO = ±10V, RL = 10k 3.5 4.5 132 mA mA dB 0°C TA 70°C 40°C TA 85°C q q 5 30 45 225 525 630 µV µV µV 0°C TA 70°C 40°C TA 85°C q q ±2 ±3 ±7 ±30 ±55 ±75 nA nA nA Common Mode Rejection Match (Notes 14, 15) VCM = 13.3V to 14V q Power Supply Rejection Match (Notes 14, 15) 96 92 120 115 dB dB VS = ±1.7V to ±18V q 100 96 123 120 dB dB 16789f 6 LT1678/LT1679 LT1678/LT1679 ELECTRICAL CHARACTERISTICS Note 1: Absolute Maximum Ratings are those values beyond which the life of the device may be impaired. 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 LT1678C/LT1679C LT1678C/LT1679C and LT1678I/LT1679I LT1678I/LT1679I are guaranteed functional over the Operating Temperature Range of 40°C to 85°C. Note 5: The LT1678C/LT1679C LT1678C/LT1679C are guaranteed to meet specified performance from 0°C to 70°C. The LT1678C/LT1679C LT1678C/LT1679C are 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 LT1678I/ LT1678I/ LT1679I LT1679I are 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 LT1678/LT1679s, typically 60 op amps will be better than the indicated specification. Note 7: See the test circuit and frequency response curve for 0.1Hz to10Hz tester in the Applications Information section. 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. 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. Note 14: CMRR and PSRR are defined as follows: 1. CMRR and PSRR are measured in µV/V on the individual amplifiers. 2. The difference is calculated between the matching sides in µV/V. 3. The result is converted to dB. Note 15: Matching parameters are the difference between amplifiers A and B on the LT1678 LT1678 and between amplifiers A and D and B and C in the LT1679 LT1679. Note 16: Input range guaranteed by the common mode rejection ratio test. U W TYPICAL PERFOR A CE CHARACTERISTICS VS = 5V, 0V VCM = 0V 100 10 FREQUENCY (Hz) 1000 16789 G01 VOLTAGE NOISE (50nV/DIV) VCM = 14.5V 1 VS = 5V, 0V VOLTAGE NOISE (50nV/DIV) NOISE VOLTAGE (nV/Hz) VS = ±15V TA = 25°C 10 1 0.1 0.01Hz to 1Hz Voltage Noise 0.1Hz to 10Hz Voltage Noise Voltage Noise vs Frequency 100 0 2 4 6 TIME (sec) 8 10 16789 G02 0 20 40 60 TIME (sec) 80 100 16789 G03 16789f 7 LT1678/LT1679 LT1678/LT1679 U W TYPICAL PERFOR A CE CHARACTERISTICS Voltage Noise vs Temperature Input Bias Current vs Temperature Current Noise vs Frequency 10 VS = ±15V VCM = 0V NOISE VOLTAGE (pA/Hz) 5 10Hz 4 1kHz 3 2 16 VS = ±15V TA = 25°C 14 VCM = 0V 1 VCM = 14.5V 8 6 4 2 0 4 100 125 0.1 1 FREQUENCY (kHz) VCM = 14V CURRENT OUT OF DUT 800 600 400 0 50 25 25 0 50 75 TEMPERATURE (°C) 4 400 3 500 300 VCM = 13.5V 100 VCM = 14.5V INPUT BIAS CURRENT 100 VCM = 14.1V 300 100 0 0 1 100 2 200 100 125 4 VCM = 15.2V 0 8 4 16 12 8 4 12 COMMON MODE INPUT VOLTAGE (V) 16 5 1.0 6 4 2 VS = 5V, 0V VCM = 0V 100 VOLTAGE OFFSET (µV) PERCENT OF UNITS (%) SO PACKAGE 20 15 0 2 3 4 TIME (min) 16789 G10 0 100 10 200 5 1 500 200 VS = 5V, 0V TA = 40°C TO 85°C 25 111 PARTS (2 LOTS) 8 400 VOS vs Temperature of Representive Units Distribution of Input Offset Voltage Drift (SO-8) VS = ±15V TA = 25°C 0 V 1.0 2.0 0.8 0.4 V 0.4 VCM VS (V) VCM VS+ (V) 300 16789 G09 30 10 VS = ±1.5V TO ±15V TA = 25°C 5 TYPICAL PARTS 16789 G08 Warm-Up Drift vs Time 200 1 3 900 300 VOS IS REFERRED TO VCM = 0V 2 500 16789 G07 0 500 700 VCM = 14.7V CURRENT INTO DUT 200 5 OFFSET VOLTAGE (µV) 1000 125 Offset Voltage Shift vs Common Mode VS = ±15V TA = 25°C 700 INPUT BIAS CURRENT (nA) 1200 100 16789 G06 Input Bias Current Over the Common Mode Range 900 VS = ±15V 50 25 75 0 TEMPERATURE (°C) 16789 G05 Input Bias Current vs Temperature 1400 6 50 25 10 OFFSET VOLTAGE (mV) 50 25 0 75 TEMPERATURE (°C) 25 0.1 0.01 16789 G04 INPUT BIAS CURRENT (nA) 10 2 1 50 CHANGE IN OFFSET VOLTAGE (µV) VS = ±15V VCM = 0V 12 INPUT BIAS CURRENT (nA) RMS VOLTAGE NOISE DENSITY (nV/Hz) 6 3.0 1.0 2.0 3.0 2.0 1.0 0 INPUT OFFSET VOLTAGE DRIFT (µV/°C) 16789 G11 300 55 35 15 5 25 45 65 85 105 125 TEMPERATURE (°C) 16789 G12 16789f 8 LT1678/LT1679 LT1678/LT1679 U W TYPICAL PERFOR A CE CHARACTERISTICS Common Mode Range vs Temperature 500 400 3 300 2 200 25°C 55°C 1 100 55°C 125°C 0 0 25°C 1 100 VOS IS REFERRED TO VCM = 0V 2 3 200 OFFSET VOLTAGE (µV) OFFSET VOLTAGE (mV) 4 300 125°C 400 4 5 1.0 500 V 1.0 2.0 0.8 0.4 V 0.4 VCM VS (V) VCM VS+ (V) 160 4.0 3.5 3.0 TA = 125°C 2.5 TA = 25°C 2.0 TA = 55°C 1.5 1.0 0 ±5 ±10 ±15 SUPPLY VOLTAGE (V) COMMON MODE REJECTION RATIO (dB) VS = ±2.5V TO ±15V SUPPLY CURRENT PER AMPLIFIER (mA) 5 Common Mode Rejection Ratio vs Frequency Supply Current vs Supply Voltage 140 VS = ±15V TA = 25°C VCM = 0V 120 100 80 60 40 20 0 10k ±20 100k 1M FREQUENCY (Hz) 16789 G14 16789 G15 16789 G09 Power Supply Rejection Ratio vs Frequency VS = ±15V TA = 25°C 120 100 NEGATIVE SUPPLY 80 60 POSITIVE SUPPLY 40 20 0 0.001 VS = ±15V RL = 2k TO 10k 50 AV = 1 TA = 25°C RL = 10k RL = 2k 1 TA = 25°C RL TO GND VCM = VO = VS/2 0.1 0.01 0.1 1 10 FREQUENCY (kHz) 100 0 1000 10 20 SUPPLY VOLTAGE (V) Phase Margin, Gain Bandwidth Product and Slew Rate vs Temperature PHASE MARGIN (DEG) 20 SLEW RATE (V/µs) 8 15 VS = ±15V CL = 15pF AV = 1 RF = RG = 1k 60 30 50 GAIN BANDWIDTH PRODUCT 25 10 6 +SR SR 4 55 35 15 5 25 45 65 85 105 125 TEMPERATURE (°C) GAIN BANDWIDTH PRODUCT, fO = 100kHz (MHz) 40 PHASE MARGIN 30 RISING EDGE 20 FALLING EDGE 10 0 30 10 100 CAPACITIVE LOAD (pF) 1000 16789 G18 Small Signal Transient Response Large Signal Transient Response 90 80 40 16789 G17 16789 G16 70 % Overshoot vs Capacitive Load 60 OVERSHOOT (%) 140 Voltage Gain vs Supply Voltage 10 OPEN LOOP VOLTAGE GAIN (V/µV) POWER SUPPLY REJECTION RATIO (dB) 160 10M 50mV 10V 0V 10V 50mV AVCL = 1 VS = ±15V AVCL = 1 VS = ±15V CL = 15pF 5µs/DIV 16789 G20 0.5µs/DIV 16789 G21 16789 G19 16789f 9 LT1678/LT1679 LT1678/LT1679 U W TYPICAL PERFOR A CE CHARACTERISTICS Settling Time vs Output Step (Inverting) VOUT 3 0.01% OF FULL SCALE 0.01% OF FULL SCALE 2 1 0.1% OF FULL SCALE 0.1% OF FULL SCALE 0 10 8 6 4 2 0 2 4 OUTPUT STEP (V) 6 8 VIN VOUT + RL = 1k 4 0.01% OF FULL SCALE 3 0.01% OF FULL SCALE 2 0 10 8 6 10 4 2 0 2 4 OUTPUT STEP (V) Gain, Phase Shift vs Frequency 20 40 TA = 55°C 10 TA = 125°C 0 10 20 GAIN 0 TA = 25°C 0.1 40 20 20 TA = 25°C TA = 25°C GAIN AV = 1 0.01 0.001 10k 1k FREQUENCY (Hz) 0 100k 1M 16789 G28 VS = ±15V 20 100 VS TA = 55°C TA = 125°C TA = 25°C 0.2 0.3 0.8 0.7 TA = 125°C 0.6 0.5 TA = 25°C 0.4 0.3 0.2 TA = 55°C 0.1 1 10 FREQUENCY (MHz) 20 100 1 10 FREQUENCY (MHz) 0.1 0 TA = 55°C 0.1 +VS 0 10 8 6 4 2 0 2 4 6 OUTPUT CURRENT (mA) 16789 G26 ZL = 2k/15pF VS = ±15V VO = 20VP-P 20VP-P AV = 1, 10, 100 MEASUREMENT BANDWIDTH 0.01 = 10Hz TO 80kHz AV = 100 0.001 AV = 10 AV = 1 100 1k FREQUENCY (Hz) 10k 10 Total Harmonic Distortion and Noise vs Frequency for Noninverting Gain 0.1 0.0001 20 8 16789 G27 TOTAL HARMONIC DISTORTION + NOISE (%) AV = 100 100 40 TA = 125°C 10 10 TOTAL HARMONIC DISTORTION + NOISE (%) OUTPUT IMPEDANCE () 10 10 TA = 55°C 0.1 Total Harmonic Distortion and Noise vs Frequency for Noninverting Gain VS = ±15V 0.1 0 Output Voltage Swing vs Load Current PHASE TA = 55°C Closed-Loop Output Impedance vs Frequency 1 20 GAIN 16789 G24 60 16789 G25 100 10 10 30 0 20 100 1 10 FREQUENCY (MHz) VOLTAGE GAIN (dB) VOLTAGE GAIN (dB) 60 TA = 125°C 40 TA = 125°C 10 PHASE SHIFT (DEG) TA = 55°C TA = 25°C TA = 25°C TA = 125°C 60 0 100 VS = ±15V VCM = 14V 80 CL = 10pF 50 PHASE SHIFT (DEG) PHASE 30 20 Gain, Phase Shift vs Frequency 100 VS = ±15V VCM = 14.7V 80 CL = 10pF 40 8 30 16789 G23 16789 G22 50 6 TA = 55°C TA = 25°C 0.1% OF FULL SCALE 0.1% OF 1 FULL SCALE PHASE 40 2k 100 VS = ±15V VCM = 0V CL = 10pF 80 PHASE SHIFT (DEG) 4 2k OUTPUT VOLTAGE SWING (V) VIN + SETTLING TIME (µs) VS = ±15V AV = 1 5 TA = 25°C 5k 5k Gain, Phase Shift vs Frequency 50 VOLTAGE GAIN (dB) 5 VS = ±15V AV = 1 TA = 25°C 6 SETTLING TIME (µs) 6 Settling Time vs Output Step (Noninverting) 50k 16789 G29 0.1 ZL = 2k/15pF VS = ±15V VO = 20VP-P 20VP-P AV = 1, 10, 100 MEASUREMENT BANDWIDTH 0.01 = 10Hz TO 80kHz AV = 100 0.001 AV = 10 AV = 1 0.0001 20 100 1k FREQUENCY (Hz) 10k 50k 16789 G30 16789f 10 LT1678/LT1679 LT1678/LT1679 U W U U APPLICATIO S I FOR ATIO Rail-to-Rail Operation To take full advantage of an input range that can exceed the supply, the LT1678/LT1679 LT1678/LT1679 are designed to eliminate phase reversal. Referring to the photographs shown in Figure 1, the LT1678/LT1679 LT1678/LT1679 are operating in the follower mode (AV = +1) at a single 3V supply. The output of the LT1678/LT1679 LT1678/LT1679 clips cleanly and recovers with no phase reversal. This has the benefit of preventing lock-up in servo systems and minimizing distortion components. input and a current, limited only by the output short-circuit protection, will be drawn by the signal generator. With RF 500, 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. 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. RF Input = 0.5V to 3.5V 6V/µs 3 + INPUT VOLTAGE (V) OUTPUT 2 LT1678 LT1678 16789 F02 Figure 2. Pulsed Operation 1 Noise Testing 0 0.5 50µs/DIV 16789 F01a LT1678 LT1678 Output OUTPUT VOLTAGE (V) 3 2 The 0.1Hz to 10Hz peak-to-peak noise of the LT1678/ LT1678/ LT1679 LT1679 are measured in the test circuit shown (Figure 3). The frequency response of this noise tester (Figure 4) 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 LT1678/LT1679 LT1678/LT1679 requires special test precautions: 1 0 0.5 50µs/DIV 16789 F01b Figure 1. Voltage Follower with Input Exceeding the Supply Voltage (VS = 3V) Unity-Gain Buffer Application When RF 100 and the input is driven with a fast, largesignal pulse (>1V), the output waveform will look as shown in the pulsed operation diagram (Figure 2). During the fast feedthrough-like portion of the output, the input protection diodes effectively short the output to the 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. 16789f 11 LT1678/LT1679 LT1678/LT1679 U W U U APPLICATIO S I FOR ATIO 100 0.1µF 90 100k 2k * LT1678 LT1678 + 4.3k 22µF SCOPE ×1 RIN = 1M LT1001 LT1001 + 4.7µF VOLTAGE GAIN = 50,000 2.2µF GAIN (dB) 10 80 24.3k 60 50 110k 40 100k *DEVICE UNDER TEST NOTE: ALL CAPACITOR VALUES ARE FOR NONPOLARIZED CAPACITORS ONLY 70 30 0.01 0.1µF 16789 F03 0.1 1 10 FREQUENCY (Hz) 100 16789 F04 Figure 4. 0.1Hz to 10Hz Peak-to-Peak Noise Tester Frequency Response Figure 3. 0.1Hz to 10Hz Noise Test Circuit 3. Sudden motion in the vicinity of the device can also "feedthrough" to increase the observed noise. Total Noise = [(op amp voltage noise)2 + (resistor noise)2 + (current noise RS)2]1/2 Current noise is measured in the circuit shown in Figure 5 and calculated by the following formula: Three regions can be identified as a function of source resistance: 1/ 2 (i) RS 400. Voltage noise dominates (ii) 400 RS 50k at 1kHz Resistor Noise 400 RS 8k at 10Hz Dominates 2 2 eno - 130nV · 101 in = 1M 101 ) ( ) ( ( )( ) (iii) RS > 50k at 1kHz Current Noise RS > 8k at 10Hz Dominates 100k 500k LT1678 LT1678 eno + 500k 100 16789 F05 Figure 5. Clearly the LT1678/LT1679 LT1678/LT1679 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 LT1113 LT1113 or LT1169 LT1169 are better choices. 1000 VS = ±15V TA = 25°C The LT1678/LT1679 LT1678/LT1679 achieve their 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 root of the input stage current. Therefore, the LT1678/LT1679 LT1678/LT1679's current noise will be relatively high. At low frequencies, the low 1/f current noise corner frequency ( 200Hz) 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 6) where: TOTAL NOISE DENSITY (nV/Hz) R R SOURCE RESISTANCE = 2R 100 AT 1kHz AT 10Hz 10 RESISTOR NOISE ONLY 1 0.1 1 10 SOURCE RESISTANCE (k) 100 16789 F06 Figure 6. Total Noise vs Source Resistance 16789f 12 LT1678/LT1679 LT1678/LT1679 U W U U APPLICATIO S I FOR ATIO Rail-to-Rail Input Rail-to-Rail Output The input common mode range for the LT1678/LT1679 LT1678/LT1679 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). The rail-to-rail output swing is achieved by using transistor collectors (Q28, Q29 referring to the Simplified Schematic) instead of customary class A-B emitter followers for the output stage. 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 7 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 are achieved when the output is sourcing current, which is the case in single supply operation when the load is ground referenced. Figure 8 shows gains for both sinking and sourcing load currents for a worst-case load of 600. 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. RL = 600 RL = 1k INPUT VOLTAGE (50µV/DIV) RL TO 0V RL = 10k INPUT VOLTAGE (10µV/DIV) RL TO 5V TA = 25°C VS = ±15V RL CONNECTED TO 0V MEASURED ON TEKTRONIX 577 CURVE TRACER 15 10 5 0 5 10 15 OUTPUT VOLTAGE (V) 0 16789 F07 Figure 7. Voltage Gain Split Supply VOLTAGE GAIN SINGLE SUPPLY VS = 5V RL = 600 MEASURED ON TEKTRONIX 577 CURVE TRACER 1 2 3 OUTPUT VOLTAGE (V) 4 5 16789 F08 Figure 8. Voltage Gain Single Supply 16789f 13 Q13 ×2 IA Q21 R21 100 R24 100 Q24 Q8 R8 200 Q9 D2 D3 IB D1 D4 R9 200 Q1A Q3 Q1B Q12 100µA IC C10 81pF Q2A Q10 Q2B RC2 6k Q6 Q4 ID 50µA Q11 Q7 IA, IB = 0µA VCM > 1.5V ABOVE VS IC = 200µA VCM < 0.7V BELOW +VS ID = 100µA VCM < 0.7V BELOW +VS 200µA VCM < 1.5V ABOVE VS 50µA VCM > 0.7V BELOW +VS 0µA VCM > 0.7V BELOW +VS R13 100 +IN IN Q5 RC1 6k Q17 Q15 50µA Q18 R15 1k Q19 R19 2k R14 1k Q14 Q22 100µA 200µA R16 1k Q16 160µA Q20 R20 2k + R25 1k Q25 Q23 C2 80pF R2 50 Q32 R30 2k Q30 Q31 R32 1.5k R26 Q38 100 Q26 R1 500 C1 40pF R3 100 + Q35 Q34 C3 40pF Q27 R34 2k R54 100 16789 SS R23B 10k R29 10 Q29 Q28 VS C4 20pF R23A 10k + + OUT SI PLIFIED SCHE ATIC W W 14 + +VS LT1678/LT1679 LT1678/LT1679 16789f LT1678/LT1679 LT1678/LT1679 U PACKAGE DESCRIPTIO S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference 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) 3 2 4 .053 .069 (1.346 1.752) .008 .010 (0.203 0.254) .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 .150 Inch) (Reference 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 16789f 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 LT1678/LT1679 LT1678/LT1679 U TYPICAL APPLICATIO Bridge Reversal Eliminates 1/f Noise and Offset Drift of a Low Noise, Non-autozeroed, Bipolar Amplifier. Circuit Gives 14nV Noise Level or 19 Effective Bits Over a 10mV Span VREF 3 4 VREF 7V 1 5,6,7,8 LT1461-5 LT1461-5 2 10µF 0.1µF 5V 100k 1 + 350 350 350 0.047µF VREF 100k 3 REF+ 1k 0.1% 100 IN+ 1µF 100 0.1% 350 10 1/2 LT1678 LT1678 1k 0.1% LTC2440 LTC2440 100 IN 1µF 0.047µF REF 10 1/2 LT1678 LT1678 + 4 5,6,7,8 2 1 2X SILICONIX Si9801 2 2 1 2s 16789 TA02 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1028/LT1128 LT1028/LT1128 Ultralow Noise Precision Op Amps Lowest Noise 0.85nV/Hz LT1115 LT1115 Ultralow Noise, Low distortion Audio Op Amp 0.002% THD, Max Noise 1.2nV/Hz LT1124/LT1125 LT1124/LT1125 Dual/Quad Low Noise, High Speed Precision Op Amps Similar to LT1007 LT1007 LT1126/LT1127 LT1126/LT1127 Dual/Quad Decompensated Low Noise, High Speed Precision Op Amps Similar to LT1037 LT1037 LT1226 LT1226 Low Noise, Very High Speed Op Amp 1GHz, 2.6nV/Hz, Gain of 25 Stable LT1498/LT1499 LT1498/LT1499 10MHz, 5V/µs, Dual/Quad Rail-to-Rail Input and Output Op Amps Precision C-LoadTM Stable LT1677 LT1677 Single Version of LT1678/LT1679 LT1678/LT1679 Rail-to-Rail 3.2nV/Hz LT1792 LT1792 Low Noise, Precision JFET Input Op Amp 4.2nV/Hz, 10fA/Hz LT1793 LT1793 Low Noise, Picoampere Bias Current Op Amp 6nV/Hz, 1fA/Hz, IB = 10pA Max LT1806 LT1806 Low Noise, 325MHz Rail-to-Rail Input and Output Op Amp 3.5nV/Hz LT1881/LT1882 LT1881/LT1882 Dual/Quad Rail-to-Rail Output Picoamp Input Precision Op Amps CLOAD to 1000pF, IB = 200pA Max LT1884/LT1885 LT1884/LT1885 Dual/Quad Rail-to-Rail Output Picoamp Input Precision Op Amps 2.2MHz Bandwidth, 1.2V/µs SR C-Load is a trademark of Linear Technology Corporation. 16789f 16 Linear Technology Corporation LT/TP 0104 1K · PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 q FAX: (408) 434-0507 q www.linear.com © LINEAR TECHNOLOGY CORPORATION 2003