LT2078CS8

LT 2078/LT 2079 Micropower, Dual and Quad, Single Supply, Precision Op Amps FEATURES s s s s s s s s s s DESCRIPTION The LT ® 2078 is a micropower dual op amp in 8-pin small outline, standard surface mount package, and LT2079 is a micropower quad op amp offered in the standard 14-pin surface mount package. Both devices are optimized for single supply operation at 5V. ±15V specifications are also provided. Micropower performance of competing devices is achieved at the expense of seriously degrading precision, noise, speed and output drive specifications. The design effort of the LT2078/LT2079 was concentrated on reducing supply current without sacrificing other parameters. The offset voltage achieved is the lowest on any dual or quad nonchopper stabilized op amp––micropower or otherwise. Offset current, voltage and current noise, slew rate and gain bandwidth product are all two to ten times better than on previous micropower op amps. Both the LT2078/LT2079 can be operated from a single supply (as low as one lithium cell or two NiCd batteries). The input range goes below ground. The all NPN output stage swings to within a few millivolts of ground while sinking current––no power consuming pull-down resistors are needed. For applications requiring DIP packages refer to the LT1078/LT1079. , LTC and LT are registered trademarks of Linear Technology Corporation. s SO Package with Standard Pinout Supply Current per Amplifier: 50µA Max Offset Voltage: 70µV Max Offset Current: 250pA Max Voltage Noise: 0.6µVP-P, 0.1Hz to 10Hz Current Noise: 3pAP-P, 0.1Hz to 10Hz Offset Voltage Drift: 0.4µV/°C Gain Bandwidth Product: 200kHz Slew Rate: 0.07V/µs Single Supply Operation Input Voltage Range Includes Ground Output Swings to Ground while Sinking Current No Pull-Down Resistors Needed Output Sources and Sinks 5mA Load Current APPLICATIONS s s s s Battery or Solar-Powered Systems Portable Instrumentation Remote Sensor Amplifier Satellite Circuitry Micropower Sample-and-Hold Thermocouple Amplifier Micropower Filters TYPICAL APPLICATION Single Battery, Micropower, Gain = 100, Instrumentation Amplifier 10.1k 1M 1M 3V (Li-Ion) 8 7 OUT Distribution of Input Offset Voltage 800 700 VS = 5V, 0V 5000 OP AMPS TYPICAL PERFORMANCE INPUT OFFSET VOLTAGE = 40µV INPUT OFFSET CURRENT = 0.2nA TOTAL POWER DISSIPATION = 240µW COMMON MODE REJECTION = 110dB (AMPLIFIER LIMITED) GAIN BANDWIDTH PRODUCT = 200kHz OUTPUT NOISE = 85 µVP-P 0.1Hz TO 10Hz = 300 µVRMS OVER FULL BANDWIDTH INPUT RANGE = 0.03V TO 1.8V OUTPUT RANGE= 0.03V TO 2.3V (0.3mV ≤ VIN+ – VIN– ≤ 23mV) OUTPUTS SINK CURRENT—NO PULL-DOWN RESISTORS + + INVERTING 3 –INPUT NONINVERTING 5 +INPUT – A 1/2 LT2078 1 10.1k 6 NUMBER OF OP AMPS – 2 600 500 400 300 200 100 0 –120 –80 –40 40 80 0 INPUT OFFSET VOLTAGE (µV) 120 2078/79 • TA02 B 1/2 LT2078 4 LT2078/79 • TA01 U U U 1 LT2078/LT 2079 ABSOLUTE MAXIMUM RATINGS Supply Voltage ...................................................... ± 22V Differential Input Voltage ....................................... ± 30V Input Voltage ............... Equal to Positive Supply Voltage ............5V Below Negative Supply Voltage Output Short-Circuit Duration .......................... Indefinite Specified Temperature Range Commercial ............................................. 0°C to 70°C Industrial ............................................ – 40°C to 85°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C PACKAGE/ORDER INFORMATION TOP VIEW OUT A 1 –IN A 2 +IN A 3 V– 4 A B 8 7 6 5 V+ OUT B –IN B +IN B ORDER PART NUMBER LT2078ACS8 LT2078AIS8 LT2078CS8 LT2078IS8 PART MARKING 2078A 2078 2078AI 2078I S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 190°C/ W Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER VOS ∆VOS ∆Time IOS IB en Input Offset Voltage Long Term Input Offset Voltage Stability Input Offset Current Input Bias Current Input Noise Voltage Input Noise Voltage Density in Input Noise Current Input Noise Current Density Input Resistance Differential Mode Common Mode Input Voltage Range CMRR PSRR Common Mode Rejection Ratio VCM = 0V to 3.5V Power Supply Rejection Ratio VS = 2.3V to 12V LT2078 LT2079 VS = 5V, 0V, VCM = 0.1V, VO = 1.4V, TA = 25°C, unless otherwise noted. LT2078AC/LT2078AI LT2079AC/LT2079AI MIN TYP MAX 30 35 0.4 0.05 6 0.25 8 1.2 45 37 4.0 0.10 70 110 LT2078C/LT2078I LT2079C/LT2079I MIN TYP MAX 40 40 0.5 0.05 6 0.6 29 28 2.3 0.06 0.02 300 3.5 0 92 98 800 6 3.8 – 0.3 108 114 0.35 10 120 150 CONDITIONS (NOTE 1) 0.1Hz to 10Hz (Note 2) fO = 10Hz (Note 2) fO = 1000Hz (Note 2) 0.1Hz to 10Hz (Note 2) fO = 10Hz (Note 2) fO = 1000Hz (Note 3) 400 3.5 0 95 100 2 U U W WW U W TOP VIEW OUT A 1 –IN A 2 +IN A 3 V+ 4 +IN B 5 –IN B 6 OUT B 7 B C A D 14 OUT D 13 –IN D 12 +IN D 11 V – 10 +IN C 9 8 –IN C OUT C ORDER PART NUMBER LT2079AC LT2079AI LT2079C LT2079I S PACKAGE 14-LEAD PLASTIC SO TJMAX = 150°C, θJA = 150°C/ W UNITS µV µV µV/Mo nA nA µVP-P nV√Hz nV√Hz pAP-P pA√Hz pA√Hz MΩ GΩ V V dB dB 0.6 29 28 2.3 0.06 0.02 800 6 3.8 – 0.3 110 114 LT 2078/LT 2079 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER AVOL Large-Signal Voltage Gain Maximum Output Voltage Swing VS = 5V, 0V, VCM = 0.1V, VO = 1.4V, TA = 25°C, unless otherwise noted. LT2078AC/LT2078AI LT2079AC/LT2079AI MIN TYP MAX 200 150 1000 600 3.5 0.55 95 4.2 3.5 0.04 4.4 3.9 0.07 200 38 50 6 1.0 130 4.2 3.5 0.04 LT2078C/LT2078I LT2079C/LT2079I MIN TYP MAX 150 120 1000 600 3.5 0.55 95 4.4 3.9 0.07 200 39 110 2.3 2.2 2.3 55 6 1.0 130 CONDITIONS (NOTE 1) VO = 0.03V to 4V, No Load VO = 0.03V to 3.5V, RL = 50k Output Low, No Load Output Low, 2k to GND Output Low, ISINK = 100µA Output High, No Load Output High, 2k to GND UNITS V/mV V/mV mV mV mV V V V/µs kHz µA dB V SR GBW IS Slew Rate Gain Bandwidth Product Supply Current per Amplifier Channel Separation Minimum Supply Voltage AV = 1, VS = ± 2.5V fO ≤ 20kHz ∆VIN = 3V, RL = 10k, f ≤ 10Hz (Note 4) 110 2.2 VS = 5V, 0V, VCM = 0.1V, VO = 1.4V, – 40°C ≤ TA ≤ 85°C for I grades, unless otherwise noted. SYMBOL PARAMETER VOS ∆VOS ∆T IOS IB CMRR PSRR AVOL Input Offset Voltage Input Offset Voltage Drift (Note 5) Input Offset Current Input Bias Current Common Mode Rejection Ratio VCM = 0.05V to 3.2V Power Supply Rejection Ratio Large-Signal Voltage Gain Maximum Output Voltage Swing VS = 3.1V to 12V VO = 0.05V to 4V, No Load VO = 0.05V to 3.5V, RL = 50k Output Low, No Load Output Low, ISINK = 100µA Output High, No Load Output High, 2k to GND IS Supply Current per Amplifier CONDITIONS LT2078 LT2079 LT2078 LT2079 q q q q q q q q q q q q q q q LT2078AI/LT2079AI MIN TYP MAX 70 80 0.4 0.6 0.07 7 90 96 110 80 106 110 600 400 4.5 125 3.9 3.0 4.2 3.7 43 60 8 170 250 280 1.8 3.0 0.70 10 LT2078I/LT2079I MIN TYP MAX 95 100 0.5 0.6 0.1 7 86 92 80 60 104 110 600 400 4.5 125 3.9 3.0 4.2 3.7 45 70 8 170 370 400 2.5 3.5 1.0 12 UNITS µV µV µV/°C µV/°C nA nA dB dB V/mV V/mV mV mV V V µA VS = 5V, 0V, VCM = 0.1V, VO = 1.4V, 0°C ≤ TA ≤ 70°C, unless otherwise noted (Note 6). SYMBOL PARAMETER VOS ∆VOS ∆T IOS IB CMRR PSRR Input Offset Voltage Input Offset Voltage Drift (Note 5) Input Offset Current Input Bias Current Common Mode Rejection Ratio VCM = 0V to 3.4V Power Supply Rejection Ratio VS = 2.6V to 12V CONDITIONS LT2078 LT2079 LT2078 LT2079 q q q q q q q q LT2078AC/LT2079AC MIN TYP MAX 50 60 0.4 0.5 0.06 6 92 98 108 112 150 180 1.8 3.0 0.35 9 LT2078C/LT2079C MIN TYP MAX 60 70 0.5 0.6 0.06 6 88 95 106 112 240 270 2.5 3.5 0.50 11 UNITS µV µV µV/°C µV/°C nA nA dB dB 3 LT2078/LT 2079 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER AVOL Large-Signal Voltage Gain Maximum Output Voltage Swing CONDITIONS VS = 5V, 0V, VCM = 0.1V, VO = 1.4V, 0°C ≤ TA ≤ 70°C, unless otherwise noted. LT2078AC/LT2079AC MIN TYP MAX q q q q q q q LT2078C/LT2079C MIN TYP MAX 110 80 750 500 4.0 105 4.1 3.3 4.3 3.8 42 63 7 150 UNITS V/mV V/mV mV mV V V µA VO = 0.05V to 4V, No Load VO = 0.05V to 3.5V, RL = 50k Output Low, No Load Output Low, ISINK = 100µA Output High, No Load Output High, 2k to GND 150 110 750 500 4.0 105 7 150 4.1 3.3 4.3 3.8 40 55 IS Supply Current per Amplifier VS = ± 15V, TA = 25°C, unless otherwise noted. LT2078AC/LT2078AI LT2079AC/LT2079AI MIN TYP MAX 50 60 0.05 6 13.5 –15.0 98 100 1000 400 ± 13.0 ± 11.0 0.06 VS = 5V, 0V to ±18V VO = ±10V, RL = 50k VO = ±10V, RL = 2k RL = 50k RL = 2k 13.8 –15.3 114 114 5000 1100 ± 14.0 ± 13.2 0.10 46 65 250 350 0.25 8 13.5 –15.0 95 98 1000 300 ± 13.0 ± 11.0 0.06 LT2078C/LT2078I LT2079C/LT2079I MIN TYP MAX 70 80 0.05 6 13.8 –15.3 114 114 5000 1100 ±14.0 ± 13.2 0.10 47 75 350 450 0.35 10 SYMBOL PARAMETER VOS IOS IB Input Offset Voltage Input Offset Current Input Bias Current Input Voltage Range CMRR PSRR AVOL VOUT SR IS CONDITIONS LT2078 LT2079 UNITS µV µV nA nA V V dB dB V/mV V/mV V V V/µs µA Common Mode Rejection Ratio VCM = 13.5V, –15V Power Supply Rejection Ratio Large-Signal Voltage Gain Maximum Output Voltage Swing Slew Rate Supply Current per Amplifier VS = ± 15V, – 40°C ≤ TA ≤ 85°C for I grades, unless otherwise noted. SYMBOL PARAMETER VOS ∆VOS ∆T IOS IB AVOL CMRR PSRR Input Offset Voltage Input Offset Voltage Drift (Note 5) Input Offset Current Input Bias Current Large-Signal Voltage Gain VO = ± 10V, RL = 5k VS = 5V, 0V to ± 18V CONDITIONS LT2078 LT2079 LT2078 LT2079 q q q q q q q q q q q LT2078AI/LT2079AI MIN TYP MAX 90 100 0.5 0.6 0.07 7 200 92 96 ±11.0 700 110 110 ±13.5 52 80 430 500 1.8 3.0 0.70 10 LT2078I/LT2079I MIN TYP MAX 120 130 0.6 0.7 0.1 7 150 88 92 ±11.0 700 110 110 ±13.5 54 95 600 700 2.5 3.8 1.0 12 UNITS µV µV µV/°C µV/°C nA nA V/mV dB dB V µA Common Mode Rejection Ratio VCM = 13V, –14.9V Power Supply Rejection Ratio Maximum Output Voltage Swing RL = 5k IS Supply Current per Amplifier 4 LT 2078/LT 2079 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER VOS ∆VOS ∆T IOS IB AVOL CMRR PSRR Input Offset Voltage Input Offset Voltage Drift (Note 5) Input Offset Current Input Bias Current Large-Signal Voltage Gain Common Mode Rejection Ratio Power Supply Rejection Ratio Maximum Output Voltage Swing IS Supply Current per Amplifier VO = ± 10V, RL = 5k VCM = 13V, –15V VS = 5V, 0V to ± 18V RL = 5k CONDITIONS LT2078 LT2079 LT2078 LT2079 VS = ± 15V, 0°C ≤ TA ≤ 70°C, unless otherwise noted (Note 6). LT2078AC/LT2079AC MIN TYP MAX q q q q q q q q q q q LT2078C/LT2079C MIN TYP MAX 90 100 0.6 0.7 0.06 6 250 92 95 ± 11.0 1200 112 112 ± 13.6 50 85 460 540 2.5 3.8 0.50 11 UNITS µV µV µV/°C µV/°C nA nA V/mV dB dB V µA 70 80 0.5 0.6 0.06 6 300 95 98 ± 11.0 1200 112 112 ± 13.6 49 330 410 1.8 3.0 0.35 9 73 The q denotes specifications which apply over the full operating temperature range. Note 1: Typical parameters are defined as the 60% yield of parameter distributions of individual amplifiers, i.e., out of 100 LT2079s (or 100 LT2078s) typically 240 op amps (or 120) will be better than the indicated specification. Note 2: This parameter is tested on a sample basis only. All noise parameters are tested with VS = ± 2.5V, VO = 0V. Note 3: This parameter is guaranteed by design and is not tested. Note 4: Power supply rejection ratio is measured at the minimum supply voltage. The op amps actually work at 1.8V supply but with a typical offset skew of –300µV. Note 5: This parameter is not 100% tested. Note 6: The LT2078C/LT2079C are designed, characterized and expected to meet the industrial temperature limits, but are not tested at – 40°C and 85°C. I-grade parts are guaranteed. TYPICAL PERFORMANCE CHARACTERISTICS Distribution of Offset Voltage Drift with Temperature 25 VS = 5V, 0V VCM = 0.1V 80 LT2078'S 25 LT2079'S = 260 OP AMPS OFFSET CURRENT (pA) INPUT BIAS CURRENT (nA) 20 PERCENT OF UNITS (%) 15 BIAS CURRENT (nA) 10 5 0 –2 0 1 –1 2 OFFSET VOLTAGE DRIFT WITH TEMPERATURE (µV/°C) LT2078/79 • TPC01 UW Input Bias and Offset Currents vs Temperature 100 VS = 5V, 0V TO ±15V IOS Input Bias Current vs Common Mode Voltage 0 VS = 5V, 0V –2 –4 –6 –8 –10 –12 –1 0 1 2 3 COMMON MODE VOLTAGE (V) 4 TA = 125°C TA = – 55°C TA = 25°C 50 0 –5 IB –6 –7 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 125 LT2078/79 • TPC02 LT2078/79 • TPC03 5 LT2078/LT 2079 TYPICAL PERFORMANCE CHARACTERISTICS 0.1Hz to 10Hz Noise TA = 25°C VS = ± 2.5V NOISE VOLTAGE (0.4µV/DIV) NOISE VOLTAGE (0.4µV/DIV) CHANNEL A VOLTAGE NOISE DENSITY (nV/√Hz) CURRENT NOISE DENSITY (fA/√Hz) CHANNEL B 0 2 6 4 TIME (SEC) 10Hz Voltage Noise Distribution 35 OFFSET VOLTAGE CHANGE (µV) 30 TA = 25°C VS = ±2.5V 10 5 0 –5 CHANGE IN OFFSET VOLTAGE (µV) PERCENT OF UNITS 25 20 15 10 5 0 25 35 30 VOLTAGE NOISE DENSITY (nV/√Hz) 40 Minimum Supply Voltage 100 0 –100 –200 –300 –400 70°C 25°C NONFUNCTIONAL V – = 0V –0.1V ≤ VCM ≤ 0.4V 125°C 1000 INPUT OFFSET VOLTAGE (µV) 100 ISINK = 100µA ISINK = 10µA VS = 5V, 0V OUTPUT VOLTAGE SWING (V) SATURATION VOLTAGE (mV) 0°C –500 0 2 3 1 POSITIVE SUPPLY VOLTAGE (V) LT2078/79 • TPC10 6 UW 8 LT2078/79 • TPC04 LT2078/79 • TPC07 0.01Hz to 10Hz Noise 1000 Noise Spectrum TA = 25°C VS = ± 2.5V (AT VS = ±15V VOLTAGE NOISE IS 4% LESS CURRENT NOISE IS UNCHANGED) TA = 25°C VS = ± 2.5V 300 CURRENT NOISE 0.4µV CHANNEL A 100 VOLTAGE NOISE 30 1/f CORNER 0.7Hz 10 0.1 1 100 10 FREQUENCY (Hz) 1000 CHANNEL B 10 0 20 60 40 TIME (SEC) 80 100 LT2078/79 • TPC05 LT2078/79 • TPC06 Long Term Stability of Two Representative Units (LT2078) 15 TA = 25°C, VS = 5V, 0V VCM = 0.1V 1A 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0 1 2 3 TIME (MONTHS) 4 5 Warm-Up Drift TA = 25°C VS = ±15V WARM UP DRIFT AT VS = 5V, 0V IS IMMEASURABLY LOW 2B 1B –10 –15 2A LT2079 LT2078 0 1 2 3 LT2078/79 • TPC09 TIME AFTER POWER-ON (MINUTES) LT2078/79 • TPC08 Output Saturation vs Temperature vs Sink Current V+ ISINK = 2mA ISINK = 1mA Output Voltage Swing vs Load Current 125°C V+ – 1 V+ – 2 –55°C 25°C –55°C 10 ISINK = 1µA NO LOAD RL = 5k TO GND V– + 2 125°C V– + 1 25°C –55°C V– 0.1 1 10 0.01 SOURCING OR SINKING LOAD CURRENT (mA) LT2078/79 • TPC11.5 1 –50 –25 0 25 50 75 TEMPERATURE (°C) 100 125 LT2078/79 • TPC11 LT 2078/LT 2079 TYPICAL PERFORMANCE CHARACTERISTICS Gain, Phase vs Frequency 30 PHASE MARGIN 58° 20 100 5V, 0V 10 PHASE MARGIN 46° 140 160 5V, 0V ±15V 180 200 80 60 40 20 0 VS = 5V, 0V VOLTAGE GAIN (V/V) VOLTAGE GAIN (dB) VOLTAGE GAIN (dB) 0 –10 10 30 100 300 FREQUENCY (kHz) 1000 Slew Rate, Gain Bandwidth Product and Phase Margin vs Temperature SLEW RATE (V/ µs) 0.12 0.10 0.08 0.06 0.04 SLEW = ± 15V 80 60 40 20 0 1 10 100 1k 10k FREQUENCY (Hz) 100k 1M TA = 25°C VS = ±2.5V VIN = 3VP-P RL = 10k OVERSHOOT (%) φM = ± 15V φM = 5V, 0V 65 55 45 CHANNEL SEPARATION (dB) SLEW = 5V, 0V GAIN BANDWIDTH PRODUCT (kHz) 240 220 200 180 GBW = ± 15V GBW = 5V, 0V fO = 20kHz 50 25 0 75 TEMPERATURE (°C) 100 125 160 –50 –25 Undistorted Output Swing vs Frequency PEAK-TO-PEAK OUTPUT SWING, VS = ± 15V (V) 30 COMMON MODE REJECTION RATIO (dB) POWER SUPPLY REJECTION RATIO (dB) VS = ±15V RL ≥ 100k VS = 5V, 0V RL ≥ 100k VS = 5V, 0V RL ≥ 1k 20 10 TA = 25°C LOAD RL, TO GND 0 0.01 1 10 FREQUENCY (kHz) UW ±15V VS = ±15V RL = 30k Voltage Gain vs Frequency 140 120 100 VS = ±15V TA = 25°C 10M Voltage Gain vs Load Resistance VS = ±15V VS = 5V, 0V 125°C 25°C –55°C 120 PHASE SHIFT (DEG) 1M –55°C 25°C 125°C –20 0.01 0.1 1 10 100 1k 10k 100k 1M FREQUENCY (Hz) LT2078/79 • TPC13 100k 100 1k 10k 100k LOAD RESISTANCE TO GROUND (Ω) 1M LTC2078/79 TPC12 LT2078/79 • TPC14 Channel Separation vs Frequency 120 100 120 100 80 60 Capacitive Load Handling TA = 25°C VS = 5V, 0V 75 PHASE MARGIN (DEG) PEAK-TO-PEAK OUTPUT SWING, VS = 5V, 0V (V) AV = 1 AV = 5 40 20 0 10 100 1000 CAPACITIVE LOAD (pF) 10000 LT2078/79 • TPC17 AV = 10 LT2078/79 • TPC15 LT2078/79 • TPC16 Common Mode Rejection Ratio vs Frequency 120 100 VS = ±15V 80 VS = 5V, 0V 60 40 20 0 10 100 1k 10k FREQUENCY (Hz) 100k 1M TA = 25°C Power Supply Rejection Ratio vs Frequency 120 100 80 60 40 20 0 0.1 NEGATIVE SUPPLY 5 4 3 2 1 0 100 LT2078/79 • TPC18 POSITIVE SUPPLY TA = 25°C VS = ± 2.5V + 1VP-P SINE WAVE 1 10 100 1k 10k FREQUENCY (Hz) 100k 1M LT2078/79 • TPC19 LT2078/79 • TPC20 7 LT2078/LT 2079 TYPICAL PERFORMANCE CHARACTERISTICS Supply Current vs Temperature 55 SUPPLY CURRENT PER AMPLIFIER (µA) 50 COMMON MODE RANGE (V) OUTPUT IMPEDANCE (Ω) VS = ±15V 45 40 35 30 25 –50 –25 VS = 5V, 0V 50 25 75 0 TEMPERATURE (°C) Small-Signal Transient Response VS = 5V, 0V 20mV/DIV 20mV/DIV 0V 0V 20mV/DIV AV = 1 10µs/DIV CL = 15pF INPUT 50mV TO 150mV Large-Signal Transient Response VS = 5V, 0V 1V/DIV 5V/DIV AV = 1, NO LOAD 50µs/DIV INPUT PULSE 0V TO 3.8V LT2078/79 • TPC27 8 UW 100 LT2078/79 • TPC21 LT2078/79 • TPC24 Common Mode Range vs Temperature V+ V+ – 1 V+ – 2 V– + 1 V– V– – 1 –50 –25 V + = 2.5V TO 18V V – = 0V TO –18V Closed-Loop Output Impedance 1k AV = 100 AV = 10 10 AV = 1 1 100 0.1 125 0 25 50 75 TEMPERATURE (°C) 100 125 10 100 1k 10k FREQUENCY (Hz) 100k LT2078/79 • TPC23 LT2078/79 • TPC22 Small-Signal Transient Response VS = ± 2.5V Small-Signal Transient Response VS = ± 15V 0V AV = 1 CL = 15pF 10µs/DIV LT2078/79 • TPC25 AV = 1 CL = 15pF 10µs/DIV LT2078/79 • TPC26 Large-Signal Transient Response VS = ± 15V 0V 0V AV = 1 NO LOAD 100µs/DIV LT2078/79 • TPC28 LT 2078/LT 2079 SI PLIFIED SCHEMATIC W 2.2k Q16 Q39 Q9 C2 175pF Q7 Q8 Q10 Q17 Q20 Q34 6.2k 6.2k 1.35k 10k Q38 30Ω 4A 5.35k Q23 V+ Q45 Q51 Q55 Q43 700k V– LT2078/79 • SIMPLIFIED SCHEM IN – IN + W 1/2 LT2078, 1/4 LT2079 V+ 10k 10k 5.6k 1.3k 3.6k Q54 1 1 5k Q53 2 Q47 11.5k 12.5k Q5 Q6 Q14 Q15 Q32 Q52 Q46 Q3 Q4 Q24 Q29 Q37 Q30 1 3 Q25 3k Q35 Q26 C4 4pF 2.9k 30Ω OUT Q44 V + V– Q40 Q41 Q12 4 Q11 1 8.6k C1 50pF Q27 600Ω Q1 Q21 Q2 Q22 Q28 V+ C5 2.5pF 150k C3 40pF Q19 Q50 Q31 Q36 J1 Q33 Q42 Q48 Q49 600Ω Q18 9.1k 700k 9 LT2078/LT 2079 APPLICATIONS INFORMATION The LT2078/LT2079 devices are fully specified with V + = 5V, V – = 0V, VCM = 0.1V. This set of operating conditions appears to be the most representative for battery powered micropower circuits. Offset voltage is internally trimmed to a minimum value at these supply voltages. When 9V or 3V batteries or ± 2.5V dual supplies are used, bias and offset current changes will be minimal. Offset voltage changes will be just a few microvolts as given by the PSRR and CMRR specifications. For example, if PSRR = 114dB (=2µV/V), at 9V the offset voltage change will be 8µV. Similarly, VS = ± 2.5V, VCM = 0V is equivalent to a common mode voltage change of 2.4V or a VOS change of 7µV if CMRR = 110dB (3µV/V). A full set of specifications is also provided at ± 15V supply voltages for comparison with other devices and for completeness. Single Supply Operation The LT2078/LT2079 is quite tolerant of power supply bypassing. In some applications requiring faster settling time the positive supply pin of the LT2078/LT2079 should be bypassed with a small capacitor (about 0.1µF). The same is true for the negative supply pin when using split supplies. The LT2078/LT2079 are fully specified for single supply operation, i.e., when the negative supply is 0V. Input common mode range goes below ground and the output swings within a few millivolts of ground while sinking current. All competing micropower op amps either cannot swing to within 600mV of ground (OP-20, OP-220, OP420) or need a pull-down resistor connected to the output to swing to ground (OP-90, OP-290, OP-490, HA5141/42/ 44). This difference is critical because in many applications these competing devices cannot be operated as micropower op amps and swing to ground simultaneously. 5V R – 1mV 99R 100mV + LT2078/79 • F02a Figure 1a. Gain 100 Amplifier 10 U W U U As an example, consider the instrumentation amplifier shown on the front page. When the common mode signal is low and the output is high, amplifier A has to sink current. When the common mode signal is high and the output low, amplifier B has to sink current. The competing devices require a 12k pull-down resistor at the output of amplifier A and a 15k at the output of B to handle the specified signals. (The LT2078 does not need pull-down resistors.) When the common mode input is high and the output is high these pull-down resistors draw 300µA (150µA each), which is excessive for micropower applications. The instrumentation amplifier is by no means the only application requiring current sinking capability. In seven of the nine single supply applications shown in this data sheet the op amps have to be able to sink current. In two of the applications the first amplifier has to sink only the 6nA input bias current of the second op amp. The competing devices, however, cannot even sink 6nA without a pull-down resistor Since the output of the LT2078/LT2079 cannot go exactly to ground, but can only approach ground to within a few millivolts, care should be exercised to ensure that the output is not saturated. For example, a 1mV input signal will cause the amplifier to set up in its linear region in the gain 100 configuration shown in Figure 1, but is not enough to make the amplifier function properly in the voltage follower mode. Single supply operation can also create difficulties at the input. The driving signal can fall below 0V — inadvertently or on a transient basis. If the input is more than a few hundred millivolts below ground, two distinct problems can occur on previous single supply designs, such as the LM124, LM158, OP-20, OP-21, OP-220, OP-221, OP-420 (1 and 2), OP-90/290/490 (2 only): 5V – 1mV + OUTPUT SATURATION ≈ 3.5mV LT2078/79 • F02b Figure 1b. Voltage Follower LT 2078/LT 2079 APPLICATIONS INFORMATION 1. When the input is more than a diode drop below ground, unlimited current will flow from the substrate (V – terminal) to the input. This can destroy the unit. On the LT2078/LT2079, resistors in series with the input protect the devices even when the input is 5V below ground. 2. When the input is more than 400mV below ground (at 25°C), the input stage saturates and phase reversal occurs at the output. This can cause lockup in servo systems. Due to a unique phase reversal protection circuitry, the LT2078/LT2079 output does not reverse, as illustrated in Figure 2, even when the inputs are at –1V. Distortion There are two main contributors of distortion in op amps: distortion caused by nonlinear common mode rejection and output crossover distortion as the output transitions from sourcing to sinking current. The common mode rejection of the LT2078/LT2079 is very good, typically 108dB. Therefore, as long as the input operates in the normal common mode range, there will be very little common mode induced distortion. If the op amp is operating inverting there is no common mode induced distortion. Crossover distortion will increase as the output load resistance decreases. For the lowest distortion the LT2078/ LT2079 should be operated with the output always sourcing current, this is usually accomplished by putting a resistor from the output to V –. In an inverting configuration with no load, the output will source and sink current through the feedback resistor. High value feedback resistors will reduce crossover distortion and maintain micropower operation. Matching Specifications In many applications the performance of a system depends on the matching between two op amps, rather than Table 1 PARAMETER VOS Match, ∆VOS LT2078AC/LT2079AC/LT2078AI/LT2079AI 50% YIELD 98% YIELD 30 110 40 150 0.5 1.2 6 8 0.12 0.4 120 100 117 105 LT2078C/LT2079C/LT2078I/LT2079I 50% YIELD 98% YIELD 50 190 50 250 0.6 1.8 6 10 0.15 0.5 117 97 117 102 UNITS µV µV µV/°C nA nA dB dB LT2078 LT2079 Temperature Coefficient ∆VOS Average Noninverting IB Match of Noninverting IB CMRR Match PSRR Match 4V 4V 2V 2V 0V 0V 6VP-P INPUT –1V TO 5V 1ms/DIV LT2078/79 • F01a 1ms/DIV OP-90 EXHIBITS OUTPUT PHASE REVERSAL LT2078/79 • F01b Figure 2. Voltage Follower with Input Exceeding the Negative Common Mode Range (VS = 5V, 0V) U W U U 4V 2V 0V 1ms/DIV LT2078/LT2079 NO PHASE REVERSAL LT2078/79 • F01C 11 LT2078/LT 2079 APPLICATIONS INFORMATION the individual characteristics of the two devices, the two and three op amp instrumentation amplifier configurations shown in this data sheet are examples. Matching characteristics are not 100% tested on the LT2078/LT2079. Some specifications are guaranteed by definition. For example, 70µV maximum offset voltage implies that mismatch cannot be more than 140µV. 95dB (= 17.5µV/V) CMRR means that worst-case CMRR match is 89dB (= 35µV/V). However, Table 1 can be used to estimate the expected matching performance at VS = 5V, 0V between the two sides of the LT2078, and between amplifiers A and D, and between amplifiers B and C of the LT2079. Comparator Applications The single supply operation of the LT2078/LT2079 and its ability to swing close to ground while sinking current lends itself to use as a precision comparator with TTL compatible output. 4 OUTPUT (V) OUTPUT (V) INPUT (mV) 200µs/DIV LT2078/79 • F03 2 0 INPUT (mV) 0 –100 VS = 5V, 0V Figure 3. Comparator Rise Response Time to 10mV, 5mV, 2mV Overdrives TYPICAL APPLICATIONS Micropower, 10ppm/°C, ± 5V Reference 2M LT1034BC-1.2 220k 5VOUT 120k 3 1M 9V + – 8 1 1M 6 1/2 LT2078 2 4 –9V 510k 1% – 1/2 LT2078 7 –5.000VOUT LT2078/79 • TA03 510k 5 + 160k 1% 20k SUPPLY CURRENT = 9V BATTERY = 115µA –9V BATTERY = 85 µA OUTPUT NOISE = 36µVP-P, 0.1Hz TO 10Hz THE LT2078 CONTRIBUTES LESS THAN 3% OF THE TOTAL OUTPUT NOISE AND DRIFT WITH TIME AND TEMPERATURE. THE ACCURACY OF THE –5V OUTPUT DEPENDS ON THE MATCHING OF THE TWO 1M RESISTORS 12 U W U U U 4 2 0 100 0 VS = 5V, 0V 200µs/DIV LT2078/79 • F04 Figure 4. Comparator Fall Response Time to 10mV, 5mV, 2mV Overdrives Gain of 10 Difference Amplifier 10M 3V 1M –IN 1M +IN – 1/2 LT2078 OUTPUT 0.0035V TO 2.4V LT2078/79 • TA04 + 10M BANDWIDTH= 20kHz OUTPUT OFFSET= 0.7mV OUTPUT NOISE= 80 µVP-P (0.1Hz TO 10Hz) 260 µVRMS OVER FULL BANDWIDTH THE USEFULNESS OF DIFFERENCE AMPLIFIERS IS LIMITED BY THE FACT THAT THE INPUT RESISTANCE IS EQUAL TO THE SOURCE RESISTANCE. THE PICOAMPERE OFFSET CURRENT AND LOW CURRENT NOISE OF THE LT2078 ALLOWS THE USE OF 1M SOURCE RESISTORS WITHOUT DEGRADATION IN PERFORMANCE. IN ADDITION, WITH MEGOHM RESISTORS MICROPOWER OPERATION CAN BE MAINTAINED LT 2078/LT 2079 TYPICAL APPLICATIONS Picoampere Input Current, Triple Op Amp Instrumentation Amplifier with Bias Current Cancellation –IN 3 + 1/4 LT2079 1 R2 1M R1 1M RG 200k 9 R3 9.1M +IN 10M –IN 2 – 2R 20M 6 – 1/4 LT2079 7 R1 1M 10 R2 1M +IN 5 + 9V 4 14 R 10M 2R 20M 12 + – 1/4 LT2079 13 11 GAIN = 1 + 2R1 R3 = 100 FOR VALUES SHOWN RG R2 INPUT BIAS CURRENT TYPICALLY < 150pA INPUT RESISTANCE = 3R = 30M FOR VALUES SHOWN NEGATIVE COMMON MODE LIMIT = (IB)(2R) + 20mV ≈ 140mV GAIN BANDWIDTH PRODUCT = 1.8MHz Half-Wave Rectifier 2M 3V 2M INPUT 1M – 1/2 LT2078 OUTPUT + VOMIN = 6mV NO DISTORTION TO 100Hz 1.8V –1.8V 1.8V 0V LT2078/79 • TA07 1.11k 10k 3V TO 18V 2 – + 4 1 6 1 1/4 LT2079 3 11 IN ERROR DUE TO SWITCH ON RESISTANCE, LEAKAGE CURRENT, NOISE AND TRANSIENTS ARE ELIMINATED U 85V, –100V Common Mode Range Instrumentation Amplifier (AV = 10) 1M 9V 10M 2 10M – + 8 1 100k 6 1/2 LT2078 3 4 –9V – 1/2 LT2078 7 OUTPUT 8V TO –9V LT2078/79 • TA06 – 1/4 LT2079 8 OUTPUT 4mV TO 8.2V LT2078/79 • TA05 100k 5 + 1M + R3 9.1M BANDWIDTH =2kHz OUTPUT OFFSET =8mV OUTPUT NOISE =0.8mV P-P (0.1Hz TO 10Hz) =1.4mV RMS OVER FULL BANDWIDTH (DOMINATED BY RESISTOR NOISE) INPUT RESISTANCE =10M ( ) Absolute Value Circuit (Full-Wave Rectifier) 200k 5V 200k INPUT 2 3.5V 0V 1 1N4148 4 6 5 – + 8 1/2 LT2078 3.5V 3 + 1/2 LT2078 7 OUTPUT – LT2078/79 • TA08 –3.5V VOMIN = 4mV NO DISTORTION TO 100Hz Programmable Gain Amplifier (Single Supply) 100k 1M 3V TO 18V 11 13 A 2 4 9 12 – 1/4 LT2079 14 OUT – 1/4 LT2079 7 9 3B + 5 LT2078/79 • TA09 + – 1/4 LT2079 88 C CD4016B 13 5 6 7 GAIN PIN 13 1000 HIGH 100 LOW 10 LOW 10 + CD4016B PIN 5 LOW HIGH LOW PIN 6 LOW LOW HIGH 13 LT2078/LT 2079 TYPICAL APPLICATIONS Single Supply, Micropower, Second Order Lowpass Filter with 60Hz Notch 0.02µF 27.6k 0.1% IN 27.6k 0.1% 5V 8 1 6 2.64M 0.1% 2.64M 0.1% 2000pF 0.5% 120k 5% 100pF fC = 40Hz Q = 30 1000pF 0.5% 1000pF 0.5% LT2078/79 • TA10 Y INPUT (5mV TO 50V) 505k 0.1% 9V 1/4 LT2079 7 30k 5% 30k 5% 14 1/4 LT2079 12 10k GAIN 11 –1.5V TO –9V X INPUT (5mV TO 50V) 505k 0.1% 220pF 499k 0.5% 1/4 LT2079 1 30k 5% INPUT 510k 9V 1M 680k 1N914 1000pF 510k Q6 2N4393 VSET VOUT VIN 14 + 5 – 6 4 7 1M Q5 1/4 LT2079 11 –9V BIPOLAR SYMMETRY IS EXCELLENT VSET BECAUSE ONE DEVICE, Q2, * 1% FILM SETS BOTH LIMITS ** RATIO MATCH 0.05% SUPPLY CURRENT ≈ 240µA Q2, Q3, Q4, Q5 CA3096 TRANSISTOR ARRAY BANDWIDTH = 150kHz + + 1M 1N914 1/4 LT2079 10 510k 12 – – Q1 2N4393 + 3 – + 3 Micropower Dead Zone Generator Q4 1M** 1M** 2 1M* Q2 1 1/4 LT2079 1M* GAIN 200k 8 1M** 13 1M** Q3 470k VSET DEAD ZONE CONTROL INPUT 0.4V TO 5V 9 + – 2 Q2 Q4 10 – 9 1/4 LT2079 8 + + 5 – – 6 4 U – 1/2 LT2078 7 3 0.01µF 2 + – 5.1M 1% 1/2 LT2078 4 5 + OUTPUT TYPICAL OFFSET ≈ 600µV 1.35M 0.1% Micropower Multiplier/Divider 505k 0.1% Z INPUT (5mV TO 50V) 220pF Q1 Q3 220pF 13 Q1,Q2, Q3, Q4 = MAT-04 TYPICAL LINEARITY = 0.01% OF FULL-SCALE OUTPUT (X)(Y) OUTPUT = , POSITIVE INPUTS ONLY (Z) X + Y+ Z + OUT 500k OUT POSITIVE SUPPLY CURRENT = 165µA + 500k NEGATIVE SUPPLY CURRENT = 165µA + BANDWIDTH (< 3VP-P SIGNAL): X AND Y INPUTS = 10kHz Z INPUT = 4kHz OUTPUT (5mV TO 8V) lt2078/79 • TA11 1/4 LT2079 14 VOUT LT2078/79 • TA12 LT 2078/LT 2079 TYPICAL APPLICATIONS Lead-Acid Low-Battery Detector with System Shutdown BATTERY OUTPUT 2M 1% 2M 1% 910k 5% 3 12V PACKAGE DESCRIPTION 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 0.014 – 0.019 (0.355 – 0.483) *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 0.016 – 0.050 0.406 – 1.270 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 0.053 – 0.069 (1.346 – 1.752) 0° – 8° TYP 0.016 – 0.050 0.406 – 1.270 0.014 – 0.019 (0.355 – 0.483) *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 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. U U + 1/2 LT2078 1 LO = BATTERY LOW (IF VS < 10.90V) 2 – 5 + – 8 7 LO = SYSTEM SHUTDOWN (IF VS < 10.05V) 1/2 LT2078 255k 1% 280k 1% LT1004-1.2 LT2078/79 • TA13 6 4 TOTAL SUPPLY CURRENT = 105µA Dimensions in inches (millimeters) unless otherwise noted. S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 8 0.189 – 0.197* (4.801 – 5.004) 7 6 5 0.053 – 0.069 (1.346 – 1.752) 0°– 8° TYP 0.228 – 0.244 (5.791 – 6.197) 0.004 – 0.010 (0.101 – 0.254) 0.150 – 0.157** (3.810 – 3.988) 0.050 (1.270) BSC 1 2 3 4 SO8 0695 S Package 14-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 0.337 – 0.344* (8.560 – 8.738) 14 13 12 11 10 9 8 0.004 – 0.010 (0.101 – 0.254) 0.150 – 0.157** (3.810 – 3.988) 0.050 (1.270) TYP 0.228 – 0.244 (5.791 – 6.197) S14 0695 1 2 3 4 5 6 7 15 LT2078/LT 2079 TYPICAL APPLICATION Platinum RTD Signal Conditioner with Curvature Correction 3V (LITHIUM) 13k* 12.3k* 10k* 2 50k 5°C TRIM 1k** 1k** 43.2k** 1µF 5k 220°C TRIM LT1004-1.2 1 RP 1k AT 0°C 1µF 1.21M* (SELECT AT 110°C) LT2078/79 • TA14 RELATED PARTS PART NUMBER DESCRIPTION LT1178/LT1179 Dual/Quad 17µA Max, Single Supply Precision Op Amps LT1211/LT1212 14MHz, 7V/µs Single Supply Dual and Quad Precision Op Amps COMMENTS 70µV VOS Max and 2.5µV/°C Drift Max, 85kHz GBW, 0.04V/µs Slew Rate, Input/Output Common Mode Includes Ground 275µV VOS Max, 6µV/°C Drift Max Input Voltage Range Includes Ground LT1490/LT1491 Dual/ Quad Micropower Rail-to-Rail Input and Output Op Amps Single Supply Input Range: –0.4V to 44V, Micropower 50µA Amplifier, Rail-to-Rail Input and Output, 200kHz GBW LT2178/LT2179 Dual/Quad 17µA Max, Single Supply Precision Op Amps SO-8 and 14-Lead Standard Pinout, 70µV VOS Max, 85kHz GBW 16 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 q FAX: (408) 434-0507 q TELEX: 499-3977 + RP = ROSEMOUNT 118MF ** = TRW MAR-6 0.1% * = 1% METAL FILM 1k** 5 – U 8 + – 3 1/2 LT2078 4 6 1/2 LT2078 7 0.02V TO 2.2VOUT = 2°C TO 220°C ± 0.1°C LT/GP 1096 7K • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 1996