LTC1051/LTC1053 Dual/Quad Precision Zero-Drift Operational Amplifiers With Internal Capacitors DESCRIPTIO U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Dual/Quad Low Cost Precision Op Amp No External Components Required Maximum Offset Voltage: 5µV Maximum Offset Voltage Drift: 0.05µV/°C Low Noise 1.5µVP-P (0.1Hz to 10Hz) Minimum Voltage Gain: 120dB Minimum PSRR: 120dB Minimum CMRR: 114dB Low Supply Current: 1mA/Op Amp Single Supply Operation: 4.75V to 16V Input Common Mode Range Includes Ground Output Swings to Ground Typical Overload Recovery Time: 3ms Pin Compatible with Industry Standard Dual and Quad Op Amps U APPLICATIO S ■ ■ ■ ■ ■ ■ The LTC®1051/LTC1053 are high performance, low cost dual/quad zero-drift operational amplifiers. The unique achievement of the LTC1051/LTC1053 is that they integrate on chip the sample-and-hold capacitors usually required externally by other chopper amplifiers. Further, the LTC1051/LTC1053 offer better combined overall DC and AC performance than is available from other chopper stabilized amplifiers with or without internal sample/hold capacitors. The LTC1051/LTC1053 have an offset voltage of 0.5µV, drift of 0.01µV/°C, DC to 10Hz, input noise voltage typically 1.5µVP-P and typical voltage gain of 140dB. The slew rate of 4V/µs and gain bandwidth product of 2.5MHz are achieved with only 1mA of supply current per op amp. Overload recover times from positive and negative saturation conditions are 1.5ms and 3ms respectively, about a 100 or more times improvement over chopper amplifiers using external capacitors. Thermocouple Amplifiers Electronic Scales Medical Instrumentation Strain Gauge Amplifiers High Resolution Data Acquisition DC Accurate R C Active Filters , LTC and LT are registered trademarks of Linear Technology Corporation. The LTC1051 is available in an 8-lead standard plastic dual-in-line package as well as a 16-pin SW package. The LTC1053 is available in a standard 14-pin plastic package and an 18-pin SO. The LTC1051/LTC1053 are plug in replacements for most standard dual/quad op amps with improved performance. U TYPICAL APPLICATIO High Performance Low Cost Instrumentation Amplifier LTC1051 Noise Spectrum 120 5V R2 2 VIN 3 – 8 1/2 LTC1051 1 R1 6 + R1 = 499Ω, 0.1% R2 = 100k, 0.1% GAIN = 201 MEASURED CMRR ~ 120dB AT DC MEASURED INPUT VOS 3µV MEASURED INPUT NOISE 2µVP-P (DC – 10Hz) VIN 5 – 1/2 LTC1051 + 7 4 – 5V VOLTAGE NOISE DENSITY (nV√Hz) R2 R1 100 80 60 40 20 1051/53 TA01a 10 100 1k FREQUENCY (Hz) 10k 1051/53 TA01b 10513fa 1 LTC1051/LTC1053 W W W AXI U U ABSOLUTE RATI GS (Note 1) Total Supply Voltage (V + to V –) ............................ 16.5V Input Voltage ........................ (V + + 0.3V) to (V – – 0.3V) Output Short-Circuit Duration .......................... Indefinite Operating Temperature Range LTC1051M, LTC1051AM (OBSOLETE) .. –55°C to 125°C LTC1051C/LTC1053C ......................... – 40°C to 85°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C U U W PACKAGE/ORDER I FOR ATIO TOP VIEW OUT A 1 8 V+ – IN A 2 7 OUT B +IN A 3 6 –IN B V– 4 5 +IN B N8 PACKAGE 8-LEAD PDIP TJMAX = 150°C, θJA = 110°C/W J8 PACKAGE 8-LEAD CERDIP OBSOLETE PACKAGE ORDER PART NUMBER ORDER PART NUMBER TOP VIEW LTC1051CN8 LTC1051MJ8 LTC1051CJ8 LTC1051AMJ8 LTC1051ACJ8 OUT A 1 14 OUT D – IN A 2 13 – IN D +IN A 3 12 +IN D V+ 4 11 V – +IN B 5 10 +IN C – IN B 6 9 – IN C OUT B 7 8 OUT C LTC1053CN N PACKAGE 14-LEAD PDIP TJMAX = 150°C, θJA = 65°C/W Consider the N8 Package as an Alternate Source TOP VIEW ORDER PART NUMBER ORDER PART NUMBER TOP VIEW NC 1 18 NC NC 1 16 NC NC 2 15 NC OUT A 2 17 OUT D OUT A 3 14 V + –IN A 3 16 –IN D +IN A 4 15 +IN D LTC1051CSW –IN A 4 13 OUT B +IN A 5 12 –IN B V+ 5 V– 6 11 +IN B +IN B 6 13 +IN C NC 7 10 NC –IN B 7 12 –IN C NC 8 9 OUT B 8 11 OUT C NC NC 9 SW PACKAGE 16-LEAD PLASTIC SO LTC1053CSW 14 V – 10 NC SW PACKAGE 18-LEAD PLASTIC SO TJMAX = 150°C, θJA = 90°C/W TJMAX = 150°C, θJA = 85°C/W Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = ±5V unless otherwise noted. PARAMETER LTC1051/LTC1053 MIN TYP MAX CONDITIONS Input Offset Voltage Average Input Offset Drift ● Long Term Offset Drift LTC1051C/LTC1053C Input Offset Current ±0.5 ±5 ±0.0 ±0.05 ±0.0 ±0.05 RS = 100Ω, DC to 10Hz RS = 100Ω, DC to 1Hz 50 UNITS µV µV/°C nV/√Mo ±15 ±65 ±135 ±15 ±50 ±100 pA pA ±30 ±125 ±175 ±30 ±100 ±150 pA pA 1.5 0.4 2 ● Input Noise Voltage (Note 2) MAX ±5 ● (All Grades) LTC1051A TYP ±0.5 50 Input Bias Current MIN 1.5 0.4 µVP-P µVP-P 10513fa 2 LTC1051/LTC1053 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = ±5V unless otherwise noted. PARAMETER CONDITIONS Input Noise Current f = 10Hz Common Mode Rejection Ratio, CMRR VCM = V– LTC1051/LTC1053 MIN TYP MAX MIN 2.2 to 2.7V ● 106 100 130 114 110 LTC1051A TYP MAX UNITS 2.2 fA/√Hz 130 dB dB Differential CMRR LTC1051, LTC1053 (Note 3) VCM = V – to 2.7V Power Supply Rejection Ratio VS = ±2.375V to ±8V ● 116 140 120 140 dB Large Signal Voltage Gain RL = 10k, VOUT = ±4V ● 116 160 120 160 dB Maximum Output Voltage Swing RL = 10k RL = 100k ● ±4.5 ±4.5 ±4.85 ±4.95 ±4.7 ±4.85 ±4.95 V V Slew Rate RL = 10k, CL = 50pF 112 Gain Bandwidth Product Supply Current/Op Amp 112 4 4 V/µs 2.5 2.5 MHz No Load 1 ● Internal Sampling Frequency dB 2 2.5 1 3.3 2 2.5 mA mA 3.3 kHz The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = ±5V unless otherwise noted.VS = 5V, GND unless otherwise noted. PARAMETER CONDITIONS MIN LTC1051A/LTC1051/LTC1053 TYP MAX UNITS Input Offset Voltage ±0.5 ±5 Input Offset Drift ±0.01 ±0.05 Input Bias Current ±10 ±50 pA Input Offset Current ±20 ±80 pA Input Noise Voltage DC to 10Hz Supply Current/Op Amp No Load Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: For guaranteed noise specification contact LTC Marketing. 1.8 ● µV µV/°C µVP-P 1.5 mA Note 3: Differential CMRR for the LTC1053 is measured between amplifiers A and D, and amplifiers B and C. 10513fa 3 LTC1051/LTC1053 U W TYPICAL PERFOR A CE CHARACTERISTICS Common Mode Input Range vs Supply Voltage Sampling Frequency vs Supply Voltage 4.0 SAMPLING FREQUENCY, fS (kHz) COMMON MODE RANGE (V) 6 4 2 0 –2 VCM = V – –4 TA = 25°C 5 SAMPLING FREQUENCY, fS (kHz) 8 Sampling Frequency vs Temperature 3.5 3.0 2.5 –6 0 1 2 3 4 5 6 SUPPLY VOLTAGE (±V) 7 2.0 8 4 14 16 6 8 10 12 TOTAL SUPPLY VOLTAGE, V + TO V – (V) 2 –50 1.50 TA = 25°C 0.25 1.4 VOLTAGE GAIN (dB) SUPPLY CURRENT, IS (mA) SUPPLY CURRENT, IS (mA) 0.50 1.2 1.0 0.8 0.6 14 8 10 12 6 TOTAL SUPPLY VOLTAGE V + TO V – (V) 0 –50 16 50 25 0 75 100 –25 AMBIENT TEMPERATURE, TA (°C) 1051/53 G04 4 CMRR (dB) 4 14 16 8 10 12 6 TOTAL SUPPLY VOLTAGE, V + TO V – (V) 1051/53 G07 0 180 – 20 200 1k 10k 100k FREQUENCY (Hz) 220 10M 1M 1051/53 G06 Gain/Phase vs Frequency 160 120 140 100 120 80 – 60 VS = ±2.5V CL = 100pF – 80 RL ≥ 1k TA = 25°C –100 60 –120 40 –140 20 –160 0 –180 – 20 –200 100 80 60 40 ISINK 160 VS = ±5V TA = 25°C AC COMMON MODE IN = 0.5VP-P 20 0 1 10 100 1k FREQUENCY (Hz) 10k 100k 1051/53 G08 – 40 100 1k 10k 100k FREQUENCY (Hz) 1M PHASE SHIFT (DEGREES) ISOURCE 2 VOUT = V + 20 – 40 100 125 VOLTAGE GAIN (dB) VOUT = V – – 20 140 CMRR vs Frequency 6 – 10 40 1051/53 G05 Output Short-Circuit Current vs Supply Voltage 0 120 0.4 0.2 4 60 100 1.6 PHASE SHIFT (DEGREES) 0.75 80 60 VS = ±5V CL = 100pF 80 RL ≥ 1k TA = 25°C 100 120 VS = ±5V 1.8 1.25 125 Gain/Phase vs Frequency 2.0 1.00 50 25 0 75 100 –25 AMBIENT TEMPERATURE, TA (°C) 1051/53 G03 Supply Current vs Temperature Per Op Amp Supply Current vs Supply Voltage Per Op Amp SHORT-CIRCUIT OUTPUT CURRENT, IOUT (mA) 3 1051/53 G02 1051/53 G01 – 30 4 1 –8 0 VS = ±5V –220 10M 1051/53 G09 10513fa 4 LTC1051/LTC1053 U W TYPICAL PERFOR A CE CHARACTERISTICS Small Signal Transient Response Overload Recovery Large Signal Transient Response 400mV INPUT 0 OUTPUT 50mV /DIV OUTPUT 2V/DIV INPUT 100mV INPUT 6V 0 OUTPUT – 5V 2µs/DIV AV = 1, RL = 10k, CL = 100pF VS = ±5V, TA = 25°C 0.5ms AV = –100 VS = ±5V 1051/53 G10 2µs/DIV AV = 1, RL = 10k, CL = 100pF VS = ±5V, TA = 25°C 1051/53 G11 1051/53 G12 LTC1051/LTC1053 DC to 10Hz Noise VS = ±5V TA = 25°C 1.4µVP-P 1µV 10 SEC 1 SEC TEST CIRCUITS Electrical Characteristics Test Circuit DC 10Hz Noise Test Circuit 475k 100k 1M 0.01µF V+ 1k 2 3 – 1/2 LTC1051 + 10Ω 8 4 V– 6 2 OUTPUT 3 RL – 1/2 LTC1051 + 6 158k 0.1µF 316k 475k – LT1012 0.01µF TO X-Y RECORDER + FOR 1Hz NOISE BW INCREASE ALL THE CAPACITORS BY A FACTOR OF 10. 1051/53 TC01 10513fa 5 LTC1051/LTC1053 U W U U APPLICATIO S I FOR ATIO ACHIEVING PICOAMPERE/MICROVOLT PERFORMANCE Picoamperes In order to realize the picoampere level of accuracy of the LTC1051/LTC1053, proper care must be exercised. Leakage currents in circuitry external to the amplifier can significantly degrade performance. High quality insulation should be used (e.g., Teflon, Kel-F); cleaning of all insulating surfaces to remove fluxes and other residues will probably be necessary —particularly for high temperature performance. Surface coating may be necessary to provide a moisture barrier in high humidity environments. Board leakage can be minimized by encircling the input connections with a guard ring operated at a potential close to that of the inputs: in inverting configurations, the guard ring should be tied to ground; in noninverting connections, to the inverting input. Guarding both sides of the printed circuit board is required. Bulk leakage reduction depends on the guard ring width. Microvolts Thermocouple effects must be considered if the LTC1051/ LTC1053’s ultra low drift op amps are to be fully utilized. Any connection of dissimilar metals forms a thermoelectric junction producing an electric potential which varies with temperature (Seebeck effect.) As temperature sensors, thermocouples exploit this phenomenon to produce useful information. In low drift amplifier circuits, this effect is a primary source of error. Connectors, switches, relay contacts, sockets, resistors, solder, and even copper wire are all candidates for thermal EMF generation. Junctions of copper wire from different manufacturers can generate thermal EMFs of 200nV/°C— 4 times the maximum drift specification of the LTC1051/ LTC1053. The copper/kovar junction, formed when wire or printed circuit traces contact a package lead, has a thermal EMF of approximately 35µV/°C—700 times the maximum drift specification of the LTC1051/LTC1053. Minimizing thermal EMF-induced errors is possible if judicious attention is given to circuit board layout and component selection. It is good practice to minimize the number of junctions in the amplifier’s input signal path. Avoid connectors, sockets, switches and relays where possible. In instances where this is not possible, attempt to balance the number and type of junctions so that differential cancellation occurs. Doing this may involve deliberately introducing junctions to offset unavoidable junctions. When connectors, switches, relays and/or sockets are necessary, they should be selected for low thermal EMF activity. The same techniques of thermally balancing and coupling the matching junctions are effective in reducing the thermal EMF errors of these components. Resistors are another source of thermal EMF errors. Table 1 shows the thermal EMF generated for different resistors. The temperature gradient across the resistor is important, not the ambient temperature. There are two junctions formed at each end of the resistor and if these junctions are at the same temperature, their thermal EMFs will cancel each other. The thermal EMF numbers are approximate and vary with resistor value. High values give higher thermal EMF. Table 1. Resistor Thermal EMF RESISTOR TYPE THERMAL EMF/°C GRADIENT Tin Oxide ~mV/°C Carbon Composition ~450µV/°C Metal Film ~20µV/°C Wire Wound Evenohm Manganin ~2µV/°C ~2µV/°C Input Bias Current, Clock Feedthrough At ambient temperatures below 60°C, the input bias current of the LTC1051/LTC1053 op amps’ is dominated by the small amount of charge injection occurring during the sampling and holding of the op amps’ input offset voltage. The average value of the resulting current pulses is 10pA to 15pA with sign convention shown in Figure 1. IB+ + IB– TA < 60°C 1/2 LTC1051 – IB+ + TA > 85°C 1/2 LTC1051 IB– – (a) (b) 1051/53 F01 Figure 1. LTC1051 Bias Current 10513fa 6 LTC1051/LTC1053 U W U U APPLICATIO S I FOR ATIO RS = 0, AV =11V/V 20mV/DIV R2 100k RS = 100k, AV =11V/V 20mV/DIV RS = 0, AV =101V/V 20mV/DIV R1 1k – 1/2 LTC1051 RS RS = 100k, AV =101V/V 20mV/DIV 100µs/DIV 100µs/DIV (a) (b) + 1051/53 F02 (c) Figure 2. Clock Feedthrough The charge injection at the op amp input pins will cause small output spikes. This phenomenon is often referred to as “clock feedthrough” and can be easily observed when the closed-loop gain exceeds 10V/V (Figure 2). The magnitude of the clock feedthrough is temperature independent but it increases when the closed-loop gain goes up, when the source resistance increases and when the gain setting resistors increase (Figure 2a, 2b). It is important to note that the output small spikes are centered at 0V level and do not add to the output offset error budget. For instance, with RS = 1MΩ, the typical output offset voltage of Figure 2c is: VOS(OUT) ≈ 108 • IB+ + 101VOS(IN) A 10pA bias current will yield an output of 1mV ±100µV. The output clock feedthrough can be attenuated by lowering the value of the gain setting resistors, i.e. R2 = 10k, R1 = 100Ω, instead of 100k and 1k (Figure 2). Clock feedthrough can also be attenuated by adding a capacitor across the feedback resistor to limit the circuit bandwidth below the internal sampling frequency (Figure 3). Input Capacitance The input capacitance of the LTC1051/LTC1053 op amps is approximately 12pF. When the LTC1051/LTC1053 op amps are used with feedback factors approaching unity, the feedback resistor value should not exceed 7k for industrial temperature range and 5k for military temperature range. If a higher feedback resistor value is required, a feedback capacitor of 20pF should be placed across the feedback resistor. Note that the most common circuits with feedback factors approaching unity are unity gain followers and instrumentation amplifier front ends. (See Figure 4.) RS = 100k AV =101V/V 20mV/DIV As the ambient temperature rises, the leakage current of the input protection devices increases, while the charge injection component of the bias current, for all practical purposes, stays constant. At elevated temperatures (above 85°C) the leakage current dominates and the bias current of both inputs assumes the same sign. RS = 1MΩ AV =101V/V 100µs/DIV C 1000pF R1 1k 2 RS 3 – R2 100k 1/2 LTC1051 1 + 1051/53 F03 Figure 3. Adding a Feedback Capacitor to Eliminate Clock Feedthrough R2 < 7k, IF R1 > >R2 R1 2 3 – 1/2 LTC1051 1 + 1051/53 F04 Figure 4. Operating the LTC1051 with Feedback Factors Approaching Unity 10513fa 7 LTC1051/LTC1053 U W U U APPLICATIO S I FOR ATIO LTC1051/LTC1053 as AC Amplifiers Aliasing Although initially chopper stabilized op amps were designed to minimize DC offsets and offset drifts, the LTC1051/LTC1053 family, on top of its outstanding DC characteristics, presents efficient AC performance. For instance, at single 5V supply, each op amp typically consumes 0.5mA and still provides 1.8MHz gain bandwidth product and 3V/µs slew rate. This, combined with almost distortionless swing to the supply rails (Figure 8), makes the LTC1051/LTC1053 op amps nearly general purpose. To further expand this idea (the “aliasing” phenomenon) which can occur under AC conditions, should be described and properly evaluated. The LTC1051/LTC1053 are equipped with internal circuitry to minimize aliasing. Aliasing, no matter how small, occurs when the input signal approaches and exceeds the internal sampling rate. Aliasing is caused by the sampled data nature of the chopper op amps. A generalized study of this phenomenon is beyond the scope of a data sheet; however, a set of rules of thumb can answer many questions: B: MAG RANGE: 9dBV 1. Alias signals can be generally defined as output AC signals at a frequency of nfCLK ± mfIN. The nfCLK term is the internal sampling frequency of the chopper stabilized op amps and its harmonics; mfIN is the frequency of the input signal and its harmonics, if any. STATUS: PAUSED RMS: 25 20dBV R2 10k 5V 80dB 15dB /DIV R1 1k fIN 0.8VP-P –100 START: 100Hz X: 1825Hz BW: 47.742Hz Y: – 70.72dBV 0.1µF 2 3 – 1/2 LTC1051 fCLK – fIN 50pF STOP: 5 100Hz 2fIN VOUT + 0.1µF – 5V fIN = 750Hz 1 1051/53 F05a 2fCLK – fIN Figure 5a. Output Voltage Spectrum of 1/2 LTC1051 Operating as an Inverting Amplifier with Gain of 10, and Amplifying a 750Hz/800mV, Input AC Signal A: MAG RANGE: 11dBV STATUS: PAUSED RMS: 25 20dBV 74dB 15dB /DIV –100 CENTER: 10 000Hz X: 5550Hz 6fCLK – fIN BW: 95.485Hz Y: – 63.91dBV SPAN: 10 000Hz fIN = 10kHz Figure 5b. Same as Figure 5a, but the AC Input Signal is 900mV, 10kHz 10513fa 8 LTC1051/LTC1053 U W U U APPLICATIO S I FOR ATIO 2. If we arbitrarily accept that “aliasing” occurs when output alias signals reach an amplitude of 0.01% or more of the output signal, then: the approximate minimum frequency of an AC input signal which will cause aliasing is equal to the internal clock frequency multiplied by the square root of the op amp feedback factor. For instance, with closed-loop gain of –10, the feedback factor is 1/11 and if fCLK = 2.6kHz, alias signals can be detected when the frequency of the input signal exceeds 750Hz to 800Hz (Figure 5a). 3. The number of alias signals increases when the input signal frequency increases (Figure 5b). 13dBV B: MAG RANGE: 9dBV 4. When the frequency, fIN, of the input signal is less than fCLOCK, the alias signal(s) amplitude(s) directly scale with the amplitude of the incoming signal. The output “signal to alias ratio” cannot be increased by just boosting the input signal amplitude. However, when the input AC signal frequency well exceeds the clock frequency, the amplitude of the alias signals does not directly scale with the input amplitude. The “signal to alias ratio” increases when the output swings closely to the rails. (See Figure 5b and Figure 7.) It is important to note that the LTC1051/ LTC1053 op amps, under light loads (RL ≥ 10k), swing closely to the supply rails without generating harmonic distortion (Figure 8). STATUS: PAUSED RMS: 25 10k 5V 83.5dB 15dB /DIV 0.1µF 10k – 1/2 LTC1051 + –107 CENTER: 2 625Hz X: 2535Hz BW: 19.097Hz Y: – 74.16dBV NOTE: THE fCLK – fIN = 85Hz ALIAS FREQUENCY IS 95dB 2fCLK – fIN DOWN FROM THE OUTPUT LEVEL fCLK SPAN: 2 000Hz 50pF 0.1µF VIN = 10kHz 8VP-P – 5V 1051/53 F05a fIN = 2.685kHz Figure 6a. Output Voltage Spectrum of 1/2 LTC1051 Operating as a Unity-Gain Inverting Amplifier. VS = ±5V, RL = 10k, CL = 50pF, VIN = 8VP-P, 2.685kHz B: MAG RANGE: 9dBV STATUS: PAUSED RMS: 50 13dBV 15dB 80dB 15dB /DIV –107 CENTER: 10 000Hz X: 10000Hz 5fCLK – fIN fIN – 2fCLK BW: 95.485Hz Y: 7.98dBV SPAN: 10 000Hz 1kHz 2 • fCLK fIN – fCLK fIN = 10kHz 6fCLK – fIN NOTE: ALL ALIAS FREQUENCY 80dB TO 84dB DOWN FROM OUTPUT Figure 6b. Output Voltage Spectrum of 1/2 LTC1051 Operating as a Unity-Gain Inverting Amplifier. VS = ±5V, RL = 10k, CL = 50pF, VIN = 8VP-P, 10kHz 10513fa 9 LTC1051/LTC1053 U W U U APPLICATIO S I FOR ATIO 5. For unity-gain inverting configuration, all the alias frequencies are 80dB to 84dB down from the output signal (Figures 6a, 6b). Combined with excellent THD under wide swing, the LTC1051/LTC1053 op amps make efficient unity gain inverters. For gain higher than –1, the “signal to alias” ratio decreases at an approximate rate of –6dB per decade of closed-loop gain (Figure 9). 6. For closed-loop gains of –10 or higher, the “signal to alias” ratio degrades when the value of the feedback gain setting resistor increases beyond 50k. For instance, the SYSTEM BUSY, ONLY ABORT COMMANDS ALLOWED RANGE: 11dBV 68dB value of Figure 7 decreases to 56dB if a (1k, 100k) resistor set is used to set the gain of –100. 7. When the LTC1051/LTC1053 are used as noninverting amplifiers, all the previous approximate rules of thumb apply with the following exceptions: when the closed-loop gain is 10(V/V) and below, the “signal to alias” ratio is 1dB to 3dB less than the inverting case; when the closed-loop gain is 100(V/V), the degradation can be up to 9dB, especially when the input signal is much higher than the clock frequency (i.e. fIN = 10kHz). 8. The signal/alias ratio performance improves when the op amp has bandlimited loop gain. STATUS: PAUSED 20dBV R2 10k 5V 68dB 15dB /DIV R1 100Ω 0.1µF – 1/2 LTC1051 90mVP-P 10kHz –100 CENTER: 10 000Hz X: 5475Hz 6fCLK – fIN BW: 95.485Hz Y: –58.05dBV VOUT + 50pF 0.1µF SPAN: 10 000Hz – 5V 1051/53 F07 fIN =10kHz 10 9 VS = ±8V, TA ≤85°C VOUT ± SWING (±V) 8 7 6 VS = ±5V, TA ≤85°C 5 4 VS = ±2.5V, TA ≤85°C 3 2 NEGATIVE SWING POSITIVE SWING 1 0 0 1k 2k 3k 4k 5k 6k 7k 8k 9k 10k RL (LOAD RESISTANCE,Ω) 1051/53 G08 Figure 8. Output Voltage Swing vs Load OUTPUT SIGNAL TO ALIAS SIGNAL(S) RATIO (dB) Figure 7. Output Voltage Spectrum of 1/2 LTC1051 Operating as an Inverting Amplifier with a Gain of –100 and Amplifiying a 90mVP-P, 10kHz Input Signal. With a 9VP-P Output Swing the Measured 2nd Harmonic (20kHz) was 75 Down from the 10kHz Input Signal 90 VS = ±5V fIN ≤10kHz 80 70 60 50 40 30 20 10 1 10 INVERTING CLOSED-LOOP GAIN 100 1051/53 G09 Figure 9. Signal to Alias Ratio vs Closed-Loop Gain 10513fa 10 LTC1051/LTC1053 U TYPICAL APPLICATIO S Obtaining Ultralow VOS Drift and Low Noise The dual chopper op amp buffers the inputs of A1 and corrects its offset voltage and offset voltage drift. With the R, C values shown, the power-up warm up time is typically 20 seconds. The step response of the composite amplifier does not present settling tails. The LT1007 should be used when extremely low noise; VOS and VOS drift are sought when the input source resistance is low—for instance a 350Ω strain gauge bridge. The LT1012 or equivalent should be used when low bias current (100pA) is also required in conjunction with DC to 10Hz low noise and low VOS and VOS drift. The measured typical input offset voltages were less than 2µV. B + 5 2 3 – 1/2 LTC1051 + R4 1 6 + 1/2 LTC1051 7 – 5V C1 R5 OUT C2 3 2 – R1 1 + R2 R3 8 A1 6 OUT – A 1051/53 AC01a A1 R1 R2 R3 R4 R5 C1 C2 eOUT(DC – 1Hz)** eOUT(DC – 10Hz)** LT1007 3k 2k 340k 10k 100k 0.01µF 0.001µF 0.1µVP-P 0.15µVP-P LT1012* 750Ω 57Ω 250k 10k 100k 0.01µF 0.001µF 0.3µVP-P 0.4µVP-P * Interchange connections A and B . ** Noise measured in a 10 sec window. Peak-to-peak noise was also measured for 10 continuous minutes: With the LT1007 op amp the recorded noise was less than 0.2µVP-P for both DC-1Hz and DC-10Hz. LTC1051/LT1007 Peak-to-Peak Noise VS = ±5V 0.2µV/DIV DC TO 1Hz NOISE DC TO 10Hz NOISE 1 SEC/DIV 1051/53 AC01b 10513fa 11 LTC1051/LTC1053 U TYPICAL APPLICATIO S Paralleling Choppers to Improve Noise NOTE: THIS CIRCUIT CAN ALSO BE USED AS A DIFFERENCE AMPLIFIER FOR STRAIN GAUGES. CONNECT R2/3 AND R1/3 FROM NONINVERTING INPUTS, SHORTED TOGETHER, TO GROUND AND TO SOURCE RESPECTIVELY. R2 R1 VIN 2 3 Differential Voltage to Current Converter – 1/4 LTC1053 R 1 0.1µF 3 V1 R + 2 + 1 1/4 LTC1053 20k – 5V 5V 10k 10k 10k R2 0.1µF RG R1 6 5 13 – 1/4 LTC1053 R 7 12 + 5 4 – + 13 14 1/4 LTC1053 VOUT 11 V2 12 R2 9 10 – 1/4 LTC1053 – 1/4 LTC1053 10k 14 6 – 1/4 LTC1053 + 7 10 4 – 1/4 LTC1053 + + 10k 0.1µF VOUT/ VIN = 3(R2/R1); INPUT DC – 10Hz NOISE ≅ 0.8µVP-P = NOISE OF EACH PARALLELED OP AMP/√3 IOUT 8 11 –5V 10k R 8 20k 9 + • IOUT = 2(V2 – V1)/RG • BW = 100Hz • IOUTMAX = 1mA 0.1µF –5V R1 20k 10k 0.1µF 0.1µF 10k RLOAD 1051/53 AC03 1051/53 AC02 Multiplexed Differential Thermometer 100Ω 255k 1k 0.068µF 2 TYPE K – 3 + – 1/4 LTC1053 1 T2 ABSOLUTE TEMPERATURE + ABSOLUTE TEMPERATURE 0.1µF 10k 255k 100Ω 1k 5V 2 5V 0.068µF 6 K 7 TYPE K – LT1025A – 5 + 10k 1/4 LTC1053 7 T1 S1 10k + 13 – 4 1/4 LTC1053 12 0.1µF + 11 14 OUTPUT (DIFFERENTIAL TEMPERATURE) 10k GND 4 R– 100Ω 255k 5 1k 0.068µF 9 TYPE K – 10 + 0.1µF – 1/4 LTC1053 + 8 TREF ALL FIXED RESISTORS ARE 1% METAL FILM OUTPUT = TREF – T1 OR TREF – T2(10mV PER °C) ACCURACY = (±0.1% FROM 25°C TO 150°C) 1051/53 AC04 10513fa 12 LTC1051/LTC1053 U TYPICAL APPLICATIO S Dual Instrumentation Amplifier + Six Decade Log Amplifier 5V LTC1043 3 8 7 1µF 2 11 5V Q1 Q1 0.1µF 3k 0.1% 2 1nA < IIN <1mA 3 – 1/2 LTC1051 1 15.8k 0.1% 2M 8 7 1/2 LTC1051 1N4148 4 1k 13 14 6 5 0.22µF + LT1009 1k 0.1% VOUT = LOG VIN –2V –5V 0.1µF VOUT1 – 100k – 5V 5 1 1µF 5 1µF + 8 1/2 LTC1051 12 2.5V 2.5M 0.1% 6 – VIN 10k 0.1% INPUT 1 22pF + 0.0022µF + 6 2 INPUT 2 1/2 LTC1051 – 7 VOUT2 4 1µF 3 1051/53 AC05 Q1: TEL LAB TYPE Q81 ADJUST 2M POR. FOR NONLINEARITIES + GAIN = 101V/DIV 100k – 1k 18 15 17 16 4 5V 0.0047µF 0.22µF CMRR >100dB VOS ≅ 3µV INPUT REFERRED NOISE ≅ 2µVP-P 1051/53 AC06 Linearized Platinum Signal Conditioner 250k* 5V 3 2 + 10k* 8 1/2 LTC1051 – (LINEARITY CORRECTION LOOP) 5V 1 2.4k 274k* 4 50k ZERO ADJUST 0.1µF LT1009 2.5V 8.25k* 2k 4 8 7 11 1µF 6 5 1µF 6 2 887Ω 1µF 1µF 12 5 0V TO 4V = 0°C TO 400°C ±0.05°C + 1/2 LTC1051 – 7 1k GAIN ADJUST 5k 3 8.06k* 13 14 1/2 LTC1043 15 IK RP 100Ω AT 0°C 18 1/2 LTC1043 16 0.01µF RP = ROSEMOUNT 118MFRTD *1% FILM RESISTOR TRIM SEQUENCE: SET SENSOR TO 0°C VALUE. ADJUST ZERO FOR 0V OUT SET SENSOR TO 100°C VALUE. ADJUST GAIN FOR 1.000V OUT SET SENSOR TO 400°C VALUE. ADJUST LINEARITY FOR 4.000V OUT REPEAT AS REQUIRED. FOR MORE INFORMATION REFER TO AN3 1k 17 1051/53 AC07 10513fa 13 LTC1051/LTC1053 U PACKAGE DESCRIPTIO J Package 8-Lead CERDIP (Narrow 0.300, Hermetic) (LTC DWG # 05-08-1110) .300 BSC (7.62 BSC) CORNER LEADS OPTION (4 PLCS) .008 – .018 (0.203 – 0.457) 0° – 15° .015 – .060 (0.381 – 1.524) .023 – .045 (0.584 – 1.143) HALF LEAD OPTION .045 – .068 (1.143 – 1.650) FULL LEAD OPTION .405 (10.287) MAX .005 (0.127) MIN .200 (5.080) MAX 8 NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE OR TIN PLATE LEADS .014 – .026 (0.360 – 0.660) 5 .025 (0.635) RAD TYP .220 – .310 (5.588 – 7.874) 1 .045 – .065 (1.143 – 1.651) 6 7 2 3 4 .125 3.175 MIN .100 (2.54) BSC J8 0801 OBSOLETE PACKAGE N Package 8-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) .300 – .325 (7.620 – 8.255) ( .400* (10.160) MAX .065 (1.651) TYP .008 – .015 (0.203 – 0.381) +.035 .325 –.015 +0.889 8.255 –0.381 .130 ± .005 (3.302 ± 0.127) .045 – .065 (1.143 – 1.651) .120 (3.048) .020 MIN (0.508) MIN .018 ± .003 .100 (2.54) BSC ) (0.457 ± 0.076) 8 7 6 5 1 2 3 4 .255 ± .015* (6.477 ± 0.381) N8 1002 NOTE: 1. DIMENSIONS ARE INCHES MILLIMETERS *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm) N Package 14-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) .300 – .325 (7.620 – 8.255) .770* (19.558) MAX 14 13 12 11 10 9 8 .008 – .015 (0.203 – 0.381) .255 ± .015* (6.477 ± 0.381) +.035 .325 –.015 1 2 3 4 5 6 7 ( 8.255 +0.889 –0.381 NOTE: 1. DIMENSIONS ARE ) .045 – .065 (1.143 – 1.651) .130 ± .005 (3.302 ± 0.127) .020 (0.508) MIN .065 (1.651) TYP .120 (3.048) MIN .005 (0.125) .100 MIN (2.54) BSC INCHES MILLIMETERS *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm) .018 ± .003 (0.457 ± 0.076) N14 1002 10513fa 14 LTC1051/LTC1053 U PACKAGE DESCRIPTIO SW Package 16-Lead Plastic Small Outline (Wide 0.300) (LTC DWG # 05-08-1620) .050 BSC .045 ±.005 .030 ±.005 TYP .398 – .413 (10.109 – 10.490) NOTE 4 15 16 N 14 12 13 10 11 9 N .325 ±.005 .420 MIN .394 – .419 (10.007 – 10.643) NOTE 3 1 2 3 NOTE: 1. DIMENSIONS IN N/2 N/2 INCHES (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS. THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS 4. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) RECOMMENDED SOLDER PAD LAYOUT .005 (0.127) RAD MIN 2 1 .291 – .299 (7.391 – 7.595) NOTE 4 .010 – .029 × 45° (0.254 – 0.737) 3 5 4 7 6 8 .037 – .045 (0.940 – 1.143) .093 – .104 (2.362 – 2.642) 0° – 8° TYP .009 – .013 (0.229 – 0.330) .050 (1.270) BSC NOTE 3 .004 – .012 (0.102 – 0.305) .014 – .019 (0.356 – 0.482) TYP .016 – .050 (0.406 – 1.270) S16 (WIDE) 0502 SW Package 18-Lead Plastic Small Outline (Wide 0.300) (LTC DWG # 05-08-1620) .050 BSC .045 ±.005 .030 ±.005 TYP .447 – .463 (11.354 – 11.760) NOTE 4 N 18 17 16 15 14 13 12 11 10 N .325 ±.005 .420 MIN .394 – .419 (10.007 – 10.643) NOTE 3 1 2 3 N/2 NOTE: 1. DIMENSIONS IN N/2 RECOMMENDED SOLDER PAD LAYOUT .005 (0.127) RAD MIN .009 – .013 (0.229 – 0.330) .291 – .299 (7.391 – 7.595) NOTE 4 .010 – .029 × 45° (0.254 – 0.737) 1 2 3 .093 – .104 (2.362 – 2.642) 4 5 6 7 8 9 .037 – .045 (0.940 – 1.143) 0° – 8° TYP NOTE 3 .016 – .050 (0.406 – 1.270) .050 (1.270) BSC INCHES (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS. THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS 4. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) .004 – .012 (0.102 – 0.305) .014 – .019 (0.356 – 0.482) TYP S18 (WIDE) 0502 10513fa 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 LTC1051/LTC1053 U TYPICAL APPLICATIO S DC Accurate, 3rd Order, 100Hz, Butterworth Antialiasing Filter Dynamic Range 8V R1 16.5k R2 118k R3 21k C 0.1µF C2 0.1µF 2 3 THD + NOISE (%) C1 0.1µF VIN 0.1µF + 1/2 LTC1051 – 1 VOUT 0.01 R2A 10k 0.0001 0.1 1051/53 AC09 – 1/2 LTC1051 CA 0.22µF Dynamic Range + 60dB 0.1 C1B 0.0022µF R1B 50k THD + NOISE (%) C1A 0.022µF R3B 412k – 1/2 LTC1051 CB 0.022µF 120dB 5.0 1.0 VIN (VRMS), fIN = 30Hz 1051/53 AC08 R2B 50k R3A 26.7k VS = ±8V 100dB 0.001 DC Accurate, 18-Bit, 4th Order Antialiasing Bessel (Linear Phase), 100Hz, Lowpass Filter VIN 80dB VS = ±5V 0.1µF –8V WIDEBAND NOISE 9µVRMS THD + NOISE ≅ 0.0012%, 1VRMS < VIN < 2VRMS, VS = ±8V VOS(OUT) < 5µV R1A 10k 60dB 0.1 VS = ±5V 0.01 0.001 80dB VS = ±8V 100dB VOUT + WIDEBAND RMS NOISE 4.5µVRMS THD + NOISE ≅ 0.0005% (= 106dB DYNAMIC RANGE), 2VRMS ≤ VIN ≤ 3VRMS VOS OUT < 10µV 0.0001 0.1 1.0 VIN (VRMS), fIN = 30Hz 120dB 5.0 1051/53 AC10 1051/53 AC11 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1047 Dual µPower Zero-Drift 0p Amp IS = 80µA/0p Amp, 16-Lead SW Package LTC1049 Low Power Zero-Drift 0p Amp IS = 200µA, SO-8 Package LTC1050 Precision Zero-Drift Op Amp with Internal Capacitors VOS (Max) = 5µV, VSUPPLY (Max) = 16.5V LTC2050/LTC2051/LTC2052 Single/Dual/Quad Zero-Drift 0p Amps SOT-23/MS8/GN16 Packages LTC2053 Zero-Drift Instrumentation Amp Resistor Programmable Gain, R-R 10513fa 16 Linear Technology Corporation LW/TP 1202 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 1990