LT 2078/LT 2079 Micropower, Dual and Quad, Single Supply, Precision Op Amps U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO DESCRIPTION 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 SO Package with Standard Pinout U APPLICATIO S APPLICATIONS ■ ■ ■ ■ Battery or Solar-Powered Systems Portable Instrumentation Remote Sensor Amplifier Satellite Circuitry Micropower Sample-and-Hold Thermocouple Amplifier Micropower Filters 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. U APPLICATION TYPICAL APPLICATIO Single Battery, Micropower, Gain = 100, Instrumentation Amplifier 1M 2 INVERTING 3 –INPUT – A 1/2 LT2078 1 10.1k 6 + NONINVERTING 5 +INPUT 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 – 1M 800 3V (Li-Ion) 8 700 B 1/2 LT2078 + 4 7 OUT LT2078/79 • TA01 OUTPUT NOISE = 85µVP-P 0.1Hz TO 10Hz = 300µVRMS 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 NUMBER OF OP AMPS 10.1k Distribution of Input Offset Voltage VS = 5V, 0V 5000 OP AMPS 600 500 400 300 200 100 0 –120 –80 –40 40 80 0 INPUT OFFSET VOLTAGE (µV) 120 2078/79 • TA02 20789fa 1 LT2078/LT 2079 W W U W ABSOLUTE MAXIMUM RATINGS (Note 1) 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 W U U PACKAGE/ORDER INFORMATION ORDER PART NUMBER TOP VIEW OUT A 1 –IN A 2 A +IN A 3 V– 4 B 8 V+ 7 OUT B 6 –IN B 5 +IN B S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 190°C/ W 14 OUT D OUT A 1 LT2078ACS8 LT2078AIS8 LT2078CS8 LT2078IS8 –IN A 2 PART MARKING OUT B 7 2078A 2078 2078AI 2078I ORDER PART NUMBER TOP VIEW A D V+ 4 LT2079ACS LT2079AIS LT2079CS LT2079IS 11 V – 10 +IN C +IN B 5 –IN B 6 13 –IN D 12 +IN D +IN A 3 B C 9 –IN C 8 OUT C S PACKAGE 14-LEAD PLASTIC SO TJMAX = 150°C, θJA = 150°C/ W Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER VS = 5V, 0V, VCM = 0.1V, VO = 1.4V, TA = 25°C, unless otherwise noted. CONDITIONS (NOTE 2) LT2078AC/LT2078AI LT2079AC/LT2079AI MIN TYP MAX LT2078C/LT2078I LT2079C/LT2079I MIN TYP MAX 30 35 40 40 70 110 120 150 µV µV VOS Input Offset Voltage ∆VOS ∆Time Long Term Input Offset Voltage Stability 0.4 IOS Input Offset Current 0.05 0.25 0.05 0.35 nA IB Input Bias Current 6 8 6 10 nA en Input Noise Voltage 0.1Hz to 10Hz (Note 3) 0.6 1.2 0.6 µVP-P Input Noise Voltage Density fO = 10Hz (Note 3) fO = 1000Hz (Note 3) 29 28 45 37 29 28 nV√Hz nV√Hz Input Noise Current 0.1Hz to 10Hz (Note 3) 2.3 4.0 2.3 pAP-P Input Noise Current Density fO = 10Hz (Note 3) fO = 1000Hz 0.06 0.02 0.10 0.06 0.02 pA√Hz pA√Hz Input Resistance Differential Mode Common Mode (Note 4) in LT2078 LT2079 UNITS µV/Mo 0.5 400 800 6 300 800 6 MΩ GΩ Input Voltage Range 3.5 0 3.8 – 0.3 3.5 0 3.8 – 0.3 V V CMRR Common Mode Rejection Ratio VCM = 0V to 3.5V 95 110 92 108 dB PSRR Power Supply Rejection Ratio 100 114 98 114 dB VS = 2.3V to 12V 20789fa 2 LT 2078/LT 2079 ELECTRICAL CHARACTERISTICS CONDITIONS (NOTE 1) LT2078AC/LT2078AI LT2079AC/LT2079AI MIN TYP MAX LT2078C/LT2078I LT2079C/LT2079I MIN TYP MAX Large-Signal Voltage Gain VO = 0.03V to 4V, No Load VO = 0.03V to 3.5V, RL = 50k 200 150 1000 600 150 120 1000 600 Maximum Output Voltage Swing Output Low, No Load Output Low, 2k to GND Output Low, ISINK = 100µA Output High, No Load Output High, 2k to GND 4.2 3.5 3.5 0.55 95 4.4 3.9 4.2 3.5 3.5 0.55 95 4.4 3.9 0.04 0.07 0.04 0.07 V/µs 200 kHz SYMBOL PARAMETER AVOL VS = 5V, 0V, VCM = 0.1V, VO = 1.4V, TA = 25°C, unless otherwise noted. SR Slew Rate AV = 1, VS = ± 2.5V GBW Gain Bandwidth Product fO ≤ 20kHz 200 IS Supply Current per Amplifier Channel Separation ∆VIN = 3V, RL = 10k, f ≤ 10Hz 110 Minimum Supply Voltage (Note 5) 2.2 38 6 1.2 130 50 39 UNITS V/mV V/mV 6 1.2 130 mV mV mV V V µA 55 110 2.3 2.2 dB 2.3 V The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 5V, 0V, VCM = 0.1V, VO = 1.4V, – 40°C ≤ TA ≤ 85°C for I grades, unless otherwise noted. SYMBOL PARAMETER CONDITIONS LT2078AI/LT2079AI MIN TYP MAX LT2078I/LT2079I MIN TYP MAX UNITS VOS Input Offset Voltage LT2078 LT2079 ● ● 70 80 250 280 95 100 370 400 µV µV ∆VOS ∆T Input Offset Voltage Drift (Note 6) LT2078 LT2079 ● ● 0.4 0.6 1.8 3.0 0.5 0.6 2.5 3.5 µV/°C µV/°C IOS Input Offset Current ● 0.07 0.70 0.1 1.0 nA IB Input Bias Current ● 7 10 7 12 nA CMRR ● 90 106 86 104 dB PSRR Common Mode Rejection Ratio VCM = 0.05V to 3.2V Power Supply Rejection Ratio VS = 3.1V to 12V ● 96 110 92 110 dB AVOL Large-Signal Voltage Gain VO = 0.05V to 4V, No Load VO = 0.05V to 3.5V, RL = 50k ● ● 110 80 600 400 80 60 600 400 V/mV V/mV Maximum Output Voltage Swing Output Low, No Load Output Low, ISINK = 100µA ● ● Output High, No Load Output High, 2k to GND ● ● IS Supply Current per Amplifier 4.5 125 3.9 3.0 4.2 3.7 43 ● 8 170 4.5 125 3.9 3.0 60 8 170 mV mV 4.2 3.7 45 V V µA 70 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 5V, 0V, VCM = 0.1V, VO = 1.4V, 0°C ≤ TA ≤ 70°C, unless otherwise noted (Note 7) SYMBOL PARAMETER CONDITIONS LT2078AC/LT2079AC MIN TYP MAX LT2078C/LT2079C MIN TYP MAX UNITS VOS Input Offset Voltage LT2078 LT2079 ● ● 50 60 150 180 60 70 240 270 µV µV ∆VOS ∆T Input Offset Voltage Drift (Note 6) LT2078 LT2079 ● ● 0.4 0.5 1.8 3.0 0.5 0.6 2.5 3.5 µV/°C µV/°C IOS Input Offset Current ● 0.06 0.35 0.06 0.50 nA IB Input Bias Current ● 6 9 6 11 nA CMRR Common Mode Rejection Ratio VCM = 0V to 3.4V Power Supply Rejection Ratio VS = 2.6V to 12V ● 92 108 88 106 dB ● 98 112 95 112 dB PSRR 20789fa 3 LT2078/LT 2079 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 5V, 0V, VCM = 0.1V, VO = 1.4V, 0°C ≤ TA ≤ 70°C, unless otherwise noted. SYMBOL PARAMETER AVOL IS CONDITIONS Large-Signal Voltage Gain VO = 0.05V to 4V, No Load VO = 0.05V to 3.5V, RL = 50k ● ● Maximum Output Voltage Swing Output Low, No Load Output Low, ISINK = 100µA ● ● Output High, No Load Output High, 2k to GND ● ● Supply Current per Amplifier LT2078AC/LT2079AC MIN TYP MAX LT2078C/LT2079C MIN TYP MAX 150 110 110 80 750 500 4.0 105 4.1 3.3 4.3 3.8 40 ● 7 150 750 500 4.0 105 4.1 3.3 55 UNITS V/mV V/mV 7 150 mV mV 4.3 3.8 42 V V µA 63 VS = ±15V, TA = 25°C, unless otherwise noted. SYMBOL PARAMETER VOS Input Offset Voltage IOS Input Offset Current IB Input Bias Current CONDITIONS LT2078AC/LT2078AI LT2079AC/LT2079AI MIN TYP MAX LT2078C/LT2078I LT2079C/LT2079I MIN TYP MAX 50 60 250 350 70 80 350 450 µV µV 0.05 0.25 0.05 0.35 nA 6 8 6 10 nA LT2078 LT2079 Input Voltage Range UNITS 13.5 –15.0 13.8 –15.3 13.5 –15.0 13.8 –15.3 V V 98 114 95 114 dB CMRR Common Mode Rejection Ratio VCM = 13.5V, –15V PSRR Power Supply Rejection Ratio VS = 5V, 0V to ±18V 100 114 98 114 dB AVOL Large-Signal Voltage Gain VO = ±10V, RL = 50k VO = ±10V, RL = 2k 1000 400 5000 1100 1000 300 5000 1100 V/mV V/mV VOUT Maximum Output Voltage Swing RL = 50k RL = 2k ±13.0 ±11.0 ±14.0 ±13.2 ±13.0 ±11.0 ±14.0 ±13.2 V V SR Slew Rate 0.06 0.10 0.06 0.10 V/µs IS Supply Current per Amplifier 46 65 47 µA 75 The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = ±15V, – 40°C ≤ TA ≤ 85°C for I grades, unless otherwise noted. SYMBOL PARAMETER CONDITIONS LT2078AI/LT2079AI MIN TYP MAX LT2078I/LT2079I MIN TYP MAX UNITS VOS Input Offset Voltage LT2078 LT2079 ● ● 90 100 430 500 120 130 600 700 µV µV ∆VOS ∆T Input Offset Voltage Drift (Note 6) LT2078 LT2079 ● ● 0.5 0.6 1.8 3.0 0.6 0.7 2.5 3.8 µV/°C µV/°C IOS Input Offset Current ● 0.07 0.70 0.1 1.0 nA IB Input Bias Current 7 10 7 12 AVOL Large-Signal Voltage Gain VO = ±10V, RL = 5k ● 200 700 150 700 V/mV CMRR Common Mode Rejection Ratio VCM = 13V, –14.9V ● 92 110 88 110 dB PSRR Power Supply Rejection Ratio ● 96 110 92 110 dB Maximum Output Voltage Swing RL = 5k ● ±11.0 ±13.5 ±11.0 ±13.5 V Supply Current per Amplifier ● IS ● VS = 5V, 0V to ±18V 52 80 54 95 nA µA 20789fa 4 LT 2078/LT 2079 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = ±15V, 0°C ≤ TA ≤ 70°C, unless otherwise noted (Note 7). SYMBOL PARAMETER CONDITIONS LT2078AC/LT2079AC MIN TYP MAX LT2078C/LT2079C MIN TYP MAX UNITS VOS Input Offset Voltage LT2078 LT2079 ● ● 70 80 330 410 90 100 460 540 µV µV ∆VOS ∆T Input Offset Voltage Drift (Note 6) LT2078 LT2079 ● ● 0.5 0.6 1.8 3.0 0.6 0.7 2.5 3.8 µV/°C µV/°C IOS Input Offset Current ● 0.06 0.35 0.06 0.50 nA IB Input Bias Current ● 6 9 6 11 nA AVOL Large-Signal Voltage Gain VO = ±10V, RL = 5k ● 300 1200 250 1200 V/mV CMRR Common Mode Rejection Ratio VCM = 13V, –15V ● 95 112 92 112 dB PSRR Power Supply Rejection Ratio VS = 5V, 0V to ±18V ● 98 112 95 112 dB Maximum Output Voltage Swing RL = 5k ● ±11.0 ±13.6 ±11.0 ±13.6 V IS Supply Current per Amplifier 49 ● Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: 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 3: This parameter is tested on a sample basis only. All noise parameters are tested with VS = ±2.5V, VO = 0V. 73 50 µA 85 Note 4: This parameter is guaranteed by design and is not tested. Note 5: 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 6: This parameter is not 100% tested. Note 7: 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. U W TYPICAL PERFORMANCE CHARACTERISTICS 15 10 5 0 –2 0 1 –1 2 OFFSET VOLTAGE DRIFT WITH TEMPERATURE (µV/°C) LT2078/79 • TPC01 100 –5 Input Bias Current vs Common Mode Voltage 0 VS = 5V, 0V TO ±15V 50 VS = 5V, 0V –2 IOS INPUT BIAS CURRENT (nA) PERCENT OF UNITS (%) 20 VS = 5V, 0V VCM = 0.1V 80 LT2078'S 25 LT2079'S = 260 OP AMPS OFFSET CURRENT (pA) 25 Input Bias and Offset Currents vs Temperature BIAS CURRENT (nA) Distribution of Offset Voltage Drift with Temperature 0 IB –6 –7 –50 –25 TA = 125°C TA = –55°C –4 TA = 25°C –6 –8 –10 50 0 75 25 TEMPERATURE (°C) 100 125 LT2078/79 • TPC02 –12 –1 0 1 2 3 COMMON MODE VOLTAGE (V) 4 LT2078/79 • TPC03 20789fa 5 LT2078/LT 2079 U W TYPICAL PERFORMANCE CHARACTERISTICS 0.01Hz to 10Hz Noise 0.1Hz to 10Hz Noise Noise Spectrum 1000 CHANNEL B VOLTAGE NOISE DENSITY (nV/√Hz) CURRENT NOISE DENSITY (fA/√Hz) TA = 25°C VS = ±2.5V CHANNEL A NOISE VOLTAGE (0.4µV/DIV) NOISE VOLTAGE (0.4µV/DIV) TA = 25°C VS = ±2.5V CHANNEL A 0.4µV 300 CURRENT NOISE 100 VOLTAGE NOISE 30 1/f CORNER 0.7Hz CHANNEL B 0 2 6 4 TIME (SEC) 8 0 10 20 60 40 TIME (SEC) 80 LT2078/79 • TPC04 Long Term Stability of Two Representative Units (LT2078) OFFSET VOLTAGE CHANGE (µV) 20 15 10 5 0 25 TA = 25°C, VS = 5V, 0V VCM = 0.1V 10 1A 5 0 2B –5 1B –10 2A –15 35 30 VOLTAGE NOISE DENSITY (nV/√Hz) 1 2 3 TIME (MONTHS) 4 0°C 25°C –55°C NONFUNCTIONAL SATURATION VOLTAGE (mV) 70°C LT2078/79 • TPC10 LT2078 0.1 1 0 2 LT2078/79 • TPC09 Output Voltage Swing vs Load Current 125°C ISINK = 1mA 100 ISINK = 100µA ISINK = 10µA VS = 5V, 0V 10 ISINK = 1µA NO LOAD 1 –50 –25 3 V+ RL = 5k TO GND 2 3 1 POSITIVE SUPPLY VOLTAGE (V) LT2079 0.2 TIME AFTER POWER-ON (MINUTES) –400 0 0.3 ISINK = 2mA –100 –300 0.4 5 1000 125°C –200 0.5 Output Saturation vs Temperature vs Sink Current V – = 0V –0.1V ≤ VCM ≤ 0.4V 0 0.6 LT2078/79 • TPC08 Minimum Supply Voltage 100 TA = 25°C VS = ±15V WARM UP DRIFT AT VS = 5V, 0V IS IMMEASURABLY LOW 0.7 0 0 40 LT2078/79 • TPC07 INPUT OFFSET VOLTAGE (µV) Warm-Up Drift 0 25 50 75 TEMPERATURE (°C) 100 125 LT2078/79 • TPC11 OUTPUT VOLTAGE SWING (V) PERCENT OF UNITS 25 1000 0.8 CHANGE IN OFFSET VOLTAGE (µV) 35 TA = 25°C VS = ±2.5V 100 10 FREQUENCY (Hz) LT2078/79 • TPC06 15 30 1 LT2078/79 • TPC05 10Hz Voltage Noise Distribution –500 10 0.1 100 TA = 25°C VS = ±2.5V (AT VS = ±15V VOLTAGE NOISE IS 4% LESS CURRENT NOISE IS UNCHANGED) V+ – 1 25°C –55°C V+ – 2 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 20789fa 6 LT 2078/LT 2079 U W TYPICAL PERFORMANCE CHARACTERISTICS Gain, Phase vs Frequency 10M 5V, 0V 120 100 140 PHASE MARGIN 46° 10 160 5V, 0V 180 ±15V 200 0 PHASE SHIFT (DEG) ±15V 120 VS = ±15V VS = 5V, 0V TA = 25°C VS = ±15V 80 VS = 5V, 0V 60 25°C 125°C VOLTAGE GAIN (V/V) 20 100 VOLTAGE GAIN (dB) PHASE MARGIN 58° VOLTAGE GAIN (dB) Voltage Gain vs Load Resistance Voltage Gain vs Frequency 140 30 40 –55°C –55°C 1M 25°C 125°C 20 0 –20 0.01 0.1 –10 10 100 300 FREQUENCY (kHz) 30 1000 0.06 65 φM = ±15V 0.04 55 45 φM = 5V, 0V GBW = ±15V 220 GBW = 5V, 0V 100 100 80 80 60 40 TA = 25°C VS = ±2.5V VIN = 3VP-P RL = 10k 20 fO = 20kHz 160 –50 –25 100 125 1 10 100 1k 10k FREQUENCY (Hz) VS = ±15V RL = 30k 3 10 2 TA = 25°C LOAD RL, TO GND 0 0.01 1 1 10 FREQUENCY (kHz) 100k 0 100 LT2078/79 • TPC18 AV = 10 100 1000 CAPACITIVE LOAD (pF) 10 1M 10000 LT2078/79 • TPC17 Power Supply Rejection Ratio vs Frequency 120 120 COMMON MODE REJECTION RATIO (dB) 4 PEAK-TO-PEAK OUTPUT SWING, VS = 5V, 0V (V) 5 VS = 5V, 0V RL ≥ 100k VS = 5V, 0V RL ≥ 1k AV = 5 40 Common Mode Rejection Ratio vs Frequency VS = ±15V RL ≥ 100k 20 60 LT2078/79 • TPC16 Undistorted Output Swing vs Frequency 30 AV = 1 0 0 50 25 0 75 TEMPERATURE (°C) LT2078/79 • TPC15 PEAK-TO-PEAK OUTPUT SWING, VS = ±15V (V) TA = 25°C VS = 5V, 0V 20 TA = 25°C POWER SUPPLY REJECTION RATIO (dB) 200 180 120 OVERSHOOT (%) 75 SLEW = 5V, 0V CHANNEL SEPARATION (dB) SLEW RATE (V/µs) 240 Capacitive Load Handling Channel Separation vs Frequency SLEW = ±15V 0.08 1M LT2078/79 • TPC14 120 PHASE MARGIN (DEG) GAIN BANDWIDTH PRODUCT (kHz) Slew Rate, Gain Bandwidth Product and Phase Margin vs Temperature 0.10 1k 10k 100k LOAD RESISTANCE TO GROUND (Ω) LT2078/79 • TPC13 LTC2078/79 TPC12 0.12 100k 100 10 100 1k 10k 100k 1M FREQUENCY (Hz) 1 100 VS = ±15V 80 VS = 5V, 0V 60 40 20 0 10 100 1k 10k FREQUENCY (Hz) 100k 1M LT2078/79 • TPC19 100 80 NEGATIVE SUPPLY 60 POSITIVE SUPPLY 40 20 0 0.1 TA = 25°C VS = ±2.5V + 1VP-P SINE WAVE 1 10 100 1k 10k FREQUENCY (Hz) 100k 1M LT2078/79 • TPC20 20789fa 7 LT2078/LT 2079 U W TYPICAL PERFORMANCE CHARACTERISTICS Common Mode Range vs Temperature 50 V+ – 1 VS = ±15V 45 40 VS = 5V, 0V 35 30 Closed-Loop Output Impedance V + = 2.5V TO 18V V – = 0V TO –18V 1k OUTPUT IMPEDANCE (Ω) 55 V+ COMMON MODE RANGE (V) V+ – 2 V– + 1 V– AV = 100 100 AV = 10 10 AV = 1 1 0.1 25 –50 –25 50 25 75 0 TEMPERATURE (°C) 100 125 V– – 1 –50 –25 0 25 50 75 TEMPERATURE (°C) LT2078/79 • TPC21 100 1k 10k FREQUENCY (Hz) 0V Small-Signal Transient Response VS = ± 15V 0V AV = 1 CL = 15pF LT2078/79 • TPC24 10µs/DIV 0V AV = 1 CL = 15pF 10µs/DIV LT2078/79 • TPC25 LT2078/79 • TPC26 Large-Signal Transient Response VS = ± 15V 5V/DIV 1V/DIV Large-Signal Transient Response VS = 5V, 0V 100k LT2078/79 • TPC23 Small-Signal Transient Response VS = ± 2.5V 20mV/DIV 20mV/DIV 10 125 LT2078/79 • TPC22 Small-Signal Transient Response VS = 5V, 0V AV = 1 10µs/DIV CL = 15pF INPUT 50mV TO 150mV 100 20mV/DIV SUPPLY CURRENT PER AMPLIFIER (µA) Supply Current vs Temperature 0V 0V AV = 1 NO LOAD AV = 1, NO LOAD 50µs/DIV INPUT PULSE 0V TO 3.8V LT2078/79 • TPC27 100µs/DIV LT2078/79 • TPC28 20789fa 8 LT 2078/LT 2079 W W SI PLIFIED SCHEMATIC 1/2 LT2078, 1/4 LT2079 V+ 10k 10k 2.2k 5.6k 11.5k 5k 3.6k 1.3k Q54 1 Q16 Q6 Q5 Q14 Q15 Q53 2 1 Q32 Q52 Q47 Q4 Q46 Q37 Q29 Q3 Q30 Q24 1 V– 3 Q12 8.6k 4 Q11 C1 50pF Q40 3k Q25 Q35 V 1 2.9k 30Ω Q44 C5 2.5pF Q27 IN + 600Ω 600Ω Q41 + Q26 C4 4pF OUT IN – 12.5k Q1 Q21 150k Q18 Q28 Q2 Q22 V+ Q31 C3 40pF J1 Q36 Q33 Q48 Q19 Q50 Q42 Q49 Q39 Q9 Q23 Q10 Q17 C2 175pF Q7 Q8 V+ Q34 6.2k 6.2k 9.1k Q45 Q20 1.35k Q51 Q55 10k Q38 30Ω 700k Q43 4A 5.35k 700k V– LT2078/79 • SIMPLIFIED SCHEM 20789fa 9 LT2078/LT 2079 U W U U 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. 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 5V R – 99R – 100mV 1mV + LT2078/79 • F02a Figure 1a. Gain 100 Amplifier 1mV + OUTPUT SATURATION ≈ 3.5mV LT2078/79 • F02b Figure 1b. Voltage Follower 20789fa 10 LT 2078/LT 2079 U W U U 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 LT2078 LT2079 Temperature Coefficient ∆VOS Average Noninverting IB Match of Noninverting IB CMRR Match PSRR Match 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 4V 4V 4V 2V 2V 2V 0V 0V 0V 6VP-P INPUT –1V TO 5V 1ms/DIV 1ms/DIV OP-90 EXHIBITS OUTPUT PHASE REVERSAL LT2078/79 • F01a UNITS µV µV µV/°C nA nA dB dB 1ms/DIV LT2078/LT2079 NO PHASE REVERSAL LT2078/79 • F01b LT2078/79 • F01C Figure 2. Voltage Follower with Input Exceeding the Negative Common Mode Range (VS = 5V, 0V) 20789fa 11 LT2078/LT 2079 U U W U 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) 2 2 0 0 0 100 –100 INPUT (mV) INPUT (mV) OUTPUT (V) 4 VS = 5V, 0V 200µs/DIV 0 VS = 5V, 0V 200µs/DIV LT2078/79 • F03 LT2078/79 • F04 Figure 3. Comparator Rise Response Time to 10mV, 5mV, 2mV Overdrives Figure 4. Comparator Fall Response Time to 10mV, 5mV, 2mV Overdrives U TYPICAL APPLICATIONS Micropower, 10ppm/°C, ±5V Reference 2M LT1034BC-1.2 10M 9V 220k 3V 5VOUT 120k 3 + – 1 1M 510k 4 –9V 20k 1M 1M –IN 8 1/2 LT2078 2 160k 1% Gain of 10 Difference Amplifier 6 1M 1/2 LT2078 5 +IN – + 7 –5.000VOUT LT2078/79 • TA03 510k 1% SUPPLY CURRENT = 9V BATTERY = 115µA –9V BATTERY = 85µA 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 – 1/2 LT2078 + 10M OUTPUT 0.0035V TO 2.4V LT2078/79 • TA04 BANDWIDTH= 20kHz OUTPUT OFFSET= 0.7mV OUTPUT NOISE= 80µVP-P (0.1Hz TO 10Hz) 260µVRMS 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 20789fa 12 LT 2078/LT 2079 U TYPICAL APPLICATIONS Picoampere Input Current, Triple Op Amp Instrumentation Amplifier with Bias Current Cancellation 3 –IN + 2 R2 1M 1 1/4 LT2079 1M 9V R1 1M – 2R 20M 9 7 1/4 LT2079 5 +IN R 10M 12 2R 20M 10 + + – 2 10M 3 OUTPUT 4mV TO 8.2V + + ( 4 5 7 OUTPUT 8V TO –9V + LT2078/79 • TA06 ) Absolute Value Circuit (Full-Wave Rectifier) 200k 200k – INPUT 2 OUTPUT 1/2 LT2078 5V 3.5V 8 0V – 1/2 LT2078 + 3 3.5V 1 5 1N4148 + 4 VOMIN = 6mV NO DISTORTION TO 100Hz + 1/2 LT2078 6 7 OUTPUT – –3.5V 1.8V LT2078/79 • TA08 0V –1.8V 1/2 LT2078 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 11 1.8V 100k – GAIN = 1 + 2R1 R3 = 100 FOR VALUES SHOWN RG R2 14 3V 1M 6 2kHz 8mV 0.8mVP-P (0.1Hz TO 10Hz) 1.4mVRMS OVER FULL BANDWIDTH (DOMINATED BY RESISTOR NOISE) INPUT RESISTANCE = 10M 2M INPUT 100k BANDWIDTH= OUTPUT OFFSET= OUTPUT NOISE= = LT2078/79 • TA05 Half-Wave Rectifier 2M 1 –9V 1M R3 9.1M 9V 4 – – 8 10M 8 1/2 LT2078 –IN 1/4 LT2079 R2 1M 1/4 LT2079 13 R1 1M – 10M +IN R3 9.1M RG 200k 6 85V, –100V Common Mode Range Instrumentation Amplifier (AV = 10) VOMIN = 4mV NO DISTORTION TO 100Hz LT2078/79 • TA07 Programmable Gain Amplifier (Single Supply) 1.11k 10k 100k 1M 3V TO 18V 2 – 1/4 LT2079 3 + 3V TO 18V 11 4 11 1 1 6 2 – 1/4 LT2079 5 13 A 7 + 9 10 ERROR DUE TO SWITCH ON RESISTANCE, LEAKAGE CURRENT, NOISE AND TRANSIENTS ARE ELIMINATED 1/4 LT2079 12 + + C 8 8 7 CD4016B 13 5 6 GAIN 1000 100 10 14 OUT LT2078/79 • TA09 9 – 1/4 LT2079 IN 4 3 B – PIN 13 HIGH LOW LOW CD4016B PIN 5 LOW HIGH LOW PIN 6 LOW LOW HIGH 20789fa 13 LT2078/LT 2079 U TYPICAL APPLICATIONS Single Supply, Micropower, Second Order Lowpass Filter with 60Hz Notch 0.02µF 27.6k 0.1% 27.6k 0.1% 3 IN + 0.01µF 6 5V 8 1 1/2 LT2078 2 – 2.64M 0.1% 2.64M 0.1% – 5 OUTPUT TYPICAL OFFSET ≈ 600µV 7 1/2 LT2078 + 2000pF 0.5% 4 5.1M 1% 120k 5% 1.35M 0.1% 100pF 1000pF 0.5% 1000pF 0.5% fC = 40Hz Q = 30 LT2078/79 • TA10 Micropower Multiplier/Divider 505k 0.1% – 220pF 4 30k 5% + 30k 5% 11 14 Q1,Q2, Q3, Q4 = MAT-04 TYPICAL LINEARITY = 0.01% OF FULL-SCALE OUTPUT (X)(Y) OUTPUT = , POSITIVE INPUTS ONLY (Z) 1/4 LT2079 10k GAIN 499k 0.5% 13 12 X + Y+ Z + OUT 500k OUT POSITIVE SUPPLY CURRENT = 165µA + 500k NEGATIVE SUPPLY CURRENT = 165µA + –1.5V TO –9V X INPUT (5mV TO 50V) 505k 0.1% 2 – 3 + 9 – 10 + 220pF Q2 Z INPUT (5mV TO 50V) 220pF Q3 7 1/4 LT2079 5 Q1 + 9V 6 – Y INPUT (5mV TO 50V) 505k 0.1% 1/4 LT2079 Q4 8 BANDWIDTH (< 3VP-P SIGNAL): X AND Y INPUTS = 10kHz Z INPUT = 4kHz OUTPUT (5mV TO 8V) 1 1/4 LT2079 30k 5% lt2078/79 • TA11 Micropower Dead Zone Generator Q4 1M** 2 INPUT VSET DEAD ZONE CONTROL INPUT 0.4V TO 5V 1M* 1M** – Q2 Q3 1 470k 1/4 LT2079 510k 3 + 1M* Q1 2N4393 9 – 10 + 1M** GAIN 200k 8 1M 1M** 13 – 510k 12 + 1/4 LT2079 1N914 1/4 LT2079 14 VOUT LT2078/79 • TA12 9V 6 – 5 + 1M 680k 4 510k Q6 2N4393 VSET VOUT 1000pF 7 1/4 LT2079 1N914 1M Q5 11 –9V VIN 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 20789fa 14 LT 2078/LT 2079 U TYPICAL APPLICATIONS Lead-Acid Low-Battery Detector with System Shutdown BATTERY OUTPUT 2M 1% 2M 1% 910k 5% 3 12V + 1 1/2 LT2078 2 LO = BATTERY LOW (IF VS < 10.90V) – 5 8 + 1/2 LT2078 255k 1% 6 280k 1% – LO = SYSTEM SHUTDOWN (IF VS < 10.05V) 7 4 LT1004-1.2 LT2078/79 • TA13 TOTAL SUPPLY CURRENT = 105µA U PACKAGE DESCRIPTION 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 8 .245 MIN 7 6 5 .160 ±.005 .150 – .157 (3.810 – 3.988) NOTE 3 .228 – .244 (5.791 – 6.197) .030 ±.005 TYP 1 RECOMMENDED SOLDER PAD LAYOUT .010 – .020 × 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) 3 4 .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 2 .014 – .019 (0.355 – 0.483) TYP 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) .050 (1.270) BSC SO8 0303 20789fa 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 LT2078/LT 2079 U PACKAGE DESCRIPTION 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 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 14 N 2 3 N/2 N/2 RECOMMENDED SOLDER PAD LAYOUT 1 .010 – .020 × 45° (0.254 – 0.508) 3 2 5 4 6 .053 – .069 (1.346 – 1.752) .008 – .010 (0.203 – 0.254) .004 – .010 (0.101 – 0.254) 0° – 8° TYP .050 (1.270) BSC .014 – .019 (0.355 – 0.483) TYP .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN 7 S14 0502 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) U TYPICAL APPLICATION Platinum RTD Signal Conditioner with Curvature Correction 3V (LITHIUM) 13k* 8 LT1004-1.2 1 + 4 12.3k* 3 10k* 1/2 LT2078 – 1µF 2 50k 5°C TRIM 43.2k** 1k** 5k 220°C TRIM 1k** 6 – 5 + 1/2 LT2078 RP = ROSEMOUNT 118MF ** = TRW MAR-6 0.1% * = 1% METAL FILM 1k** RP 1k AT 0°C 1µF 7 0.02V TO 2.2VOUT = 2°C TO 220°C ±0.1°C 1.21M* (SELECT AT 110°C) LT2078/79 • TA14 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1178/LT1179 Dual/Quad 17µA Max, Single Supply Precision Op Amps 70µV VOS Max and 2.5µV/°C Drift Max, 85kHz GBW, 0.04V/µs Slew Rate, Input/Output Common Mode Includes Ground LT1211/LT1212 14MHz, 7V/µs Single Supply Dual and Quad Precision Op Amps 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 20789fa 16 Linear Technology Corporation LT/GP 0903 1K REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 1996