LMP2012QML Dual High Precision, Rail-to-Rail Output Operational Amplifier General Description Features The LMP2012 is the first member of National's QML certified new LMP™ precision amplifier family. The LMP2012 offers unprecedented accuracy and stability. This device utilizes patented techniques to measure and continually correct the input offset error voltage. The result is an amplifier which is ultra stable over time and temperature. It has excellent CMRR and PSRR ratings, and does not exhibit the familiar 1/f voltage and current noise increase that plagues traditional amplifiers. The combination of the LMP2012 characteristics makes it a good choice for transducer amplifiers, high gain configurations, ADC buffer amplifiers, DAC I-V conversion, and any other 2.7V-5V application requiring precision and long term stability. Other useful benefits of the LMP2012 are rail-rail output, low supply current of 930 μA, and wide gain-bandwidth product of 3 MHz. These extremely versatile features found in the LMP2012 provide high performance and ease of use. The QMLV version of the LMP2012 has been rated to tolerate a total dose level of 50krad/(Si) radiation by test method 1019 of MIL-STD-883. ■ Available with radiation quarantee (For VS = 5V, Typical unless otherwise noted) ■ Low guaranteed VIO over temperature ■ Low noise with no 1/f ■ High CMRR ■ High PSRR ■ High AVOL ■ Wide gain-bandwidth product ■ High slew rate ■ Rail-to-rail output ■ No external capacitors required 60 µV 35nV/ 90 dB 90 dB 85 dB 3MHz 4V/µs 30mV Applications ■ ■ ■ ■ ■ ■ ■ Attitude and Orbital Controls Static Earth Sensing Sun Sensors Inertial Sensors Pressure Sensors Gyroscopes Earth Observation Systems Ordering Information NS Part Number NS Package Number Package Discription LMP2012WG-QMLV SMD Part Number 5962-0620601VZA WG10A 10LD CERAMIC SOIC LMP2012WGLQMLV 5962L0620601VZA 50K rd(Si) WG10A 10LD CERAMIC SOIC Connection Diagram 10LD Ceramic SOIC 20182202 Top View See NS Package Number WG10A © 2008 National Semiconductor Corporation 201822 www.national.com LMP2012QML Dual Quad High Precision, Rail-to-Rail Output Operational Amplifier October 20, 2008 LMP2012QML Absolute Maximum Ratings (Note 1) Supply Voltage Differential Input Voltage Power Dissipation (Note 2) Maximum Junction Temperature (TJmax) Common-Mode Input Voltage 5.8V ±Supply Voltage 714mW 150°C −0.3 ≤ VCM ≤ VCC +0.3V 30 mA 30 mA 50 mA −55°C to +125°C −55°C to +150°C +260°C Current at Input Pin Current at Output Pin Current at Power Supply Pin Operating Temperature Range Storage Temperature Range Ceramic SOIC Lead Temperature (soldering 10 sec.) Thermal Resistance θJA Ceramic SOIC (Still Air) Ceramic SOIC (500LF/Min Air Flow) 175°C/W 115°C/W θJC Ceramic SOIC Package Weight Ceramic SOIC ESD Tolerance (Note 3) 12.3°C/W 220mg 4000V Quality Conformance Inspection Mil-Std-883, Method 5005 - Group A www.national.com Subgroup Description Temp (°C) 1 Static tests at +25 2 Static tests at +125 3 Static tests at -55 4 Dynamic tests at +25 5 Dynamic tests at +125 6 Dynamic tests at -55 7 Functional tests at +25 8A Functional tests at +125 8B Functional tests at -55 9 Switching tests at +25 10 Switching tests at +125 11 Switching tests at -55 12 Setting time at +25 13 Setting time at +125 14 Setting time at -55 2 LMP2012QML LMP2012 Electrical Characteristics 2.7V DC Parameters The following conditions apply, unless otherwise specified. V+ = 2.7V, V- = 0V, V CM = 1.35V, VO = 1.35V and RL > 1 MΩ. Symbol VIO Parameter Conditions Notes Typ (Note 4) Min Max 0.8 Input Offset Voltage 36 Offset Calibration Time 10 IIB Input Bias Current −3 pA IIO Input Offset Current 6 pA CMRR Common Mode Rejection Ratio −0.3 ≤ VCM ≤ 0.9V 0 ≤ VCM ≤ 0.9V 95 Power Supply Rejection Ratio 120 AVOL Open Loop Voltage Gain 130 95 RL = 2 kΩ VO 1 2, 3 1 dB 90 RL = 10 kΩ 1 2, 3 dB 90 PSRR 2, 3 ms 12 130 1 μV 60 0.5 Subgroups Units 2, 3 95 1 90 2, 3 dB 124 90 1 2.68 2.64 1 2.63 2, 3 85 Output Swing RL = 10 kΩ to 1.35V VIN(diff) = ±0.5V 2, 3 0.033 0.060 V 1 0.075 2.65 2.615 1 2.6 RL = 2 kΩ to 1.35V VIN(diff) = ±0.5V 2,3 0.061 0.085 2, 3 V 1 0.105 IO Output Current IS Sourcing, VO = 0V VIN(diff) = ±0.5V 12 Sinking, VO = 5V VIN(diff) = ±0.5V 18 2, 3 5 1 3 2, 3 mA 5 1 3 2, 3 0.919 Supply Current per Channel 1.20 1.50 1 mA 2, 3 2.7V AC Parameters The following conditions apply, unless otherwise specified. V+ = 2.7V, V - = 0V, VCM = 1.35V, VO = 1.35V, and RL > 1 MΩ. Symbol Parameter Conditions Notes Typ (Note 4) Min Max Units Subgroups 1 5 MHz 4 GBW Gain-Bandwidth Product 3 SR Slew Rate 4 V/μs θm Phase Margin 60 Deg Gm Gain Margin −14 dB en Input-Referred Voltage Noise 35 enP-P Input-Referred Voltage Noise trec Input Overload Recovery Time RS = 100Ω, DC to 10 Hz 3 nV/ 850 nVPP 50 ms www.national.com LMP2012QML 2.7V DC Parameters – 50K Post Radiation Limits @ +25°C The following conditions apply, unless otherwise specified. V+ = 2.7V, V - = 0V, VCM = 1.35V, VO = 1.35V, and RL > 1 MΩ. Symbol IS Parameter Conditions Supply Current per Channel Notes Typ Min (Note 5) Max Units Subgroups 1.75 mA 1 Max Units Subgroups 5V DC Parameters The following conditions apply, unless otherwise specified. V+ = 5V, V- = 0V, V CM = 2.5V, VO = 2.5V and RL > 1MΩ. Symbol VIO Parameter Conditions Notes Input Offset Voltage Typ (Note 4) Min 0.12 36 60 Offset Calibration Time 0.5 IIB Input Bias Current −3 IIO Input Offset Current CMRR Common Mode Rejection Ratio 10 12 130 0 ≤ VCM ≤ 3.2 PSRR 120 Open Loop Voltage Gain RL = 10 kΩ 130 RL = 2 kΩ 132 95 dB 105 dB 95 90 Output Swing RL = 10 kΩ to 2.5V VIN(diff) = ±0.5V 4.978 1 2, 3 0.080 V IS Sourcing, VO = 0V VIN(diff) = ±0.5V 15 Sourcing, VO = 5V VIN(diff) = ±0.5V 17 2, 3 1 4.855 2, 3 0.125 V 0.930 2, 3 1 6 2, 3 mA 8 4 1 2, 3 1.20 1.50 www.national.com 1 8 6 Supply Current per Channel 1 4.875 0.150 Output Current 1 4.91 0.091 IO 2, 3 2, 3 0.095 4.919 1 2, 3 4.92 0.040 RL = 2 kΩ to 2.5V VIN(diff) = ±0.5V 2, 3 1 100 VO 2, 3 1 dB 90 AVOL 1 pA 100 90 Power Supply Rejection Ratio ms 1 2, 3 pA 6 −0.3 ≤ VCM ≤ 3.2 μV mA 1 2, 3 The following conditions apply, unless otherwise specified. V+ = 2.7V, V - = 0V, VCM = 1.35V, VO = 1.35V, and RL > 1 MΩ. Symbol Parameter Conditions Notes Typ (Note 4) Min Max Units Subgroups 1 5 MHz 4 GBW Gain-Bandwidth Product 3 SR Slew Rate 4 V/μs θm Phase Margin 60 Deg Gm Gain Margin −15 dB en Input-Referred Voltage Noise enP-P Input-Referred Voltage Noise trec Input Overload Recovery Time 35 RS = 100Ω, DC to 10 Hz nV/ 850 nVPP 50 ms 5V DC Parameters – 50K Post Radiation Limits @ +25°C The following conditions apply, unless otherwise specified. V+ = 5V, V - = 0V, VCM = 2.5V, VO = 2.5V, and RL > 1 MΩ. Symbol IS Parameter Conditions Supply Current per Channel Notes (Note 5) Typ Min Max Units Subgroups 1.75 mA 1 Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions. Note 2: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJmax (maximum junction temperature), θJA (package junction to ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any temperature is PDmax = (TJmax - TA)/ θJA or the number given in the Absolute Maximum Ratings, whichever is lower. Note 3: Human body model, 1.5 kΩ in series with 100 pF. Note 4: Typical values represent the most likely parametric norm. Note 5: Pre and post irradiation limits are identical to those listed under DC electrical characteristics except as listed in the Post Radiation Limits Table. These parts may be dose rate sensitive in a space environment and demonstrate enhanced low dose rate effect. Radiation end point limits for the noted parameters are guaranteed only for the conditions as specified in Mil-Std-883, Method 1019 5 www.national.com LMP2012QML 5V AC Parameters LMP2012QML Application Information tric absorption, which can cause delays of several seconds from turn-on until the amplifier's error has settled. THE BENEFITS OF LMP2012 NO 1/f NOISE Using patented methods, the LMP2012 eliminates the 1/f noise present in other amplifiers. That noise, which increases as frequency decreases, is a major source of measurement error in all DC-coupled measurements. Low-frequency noise appears as a constantly-changing signal in series with any measurement being made. As a result, even when the measurement is made rapidly, this constantly-changing noise signal will corrupt the result. The value of this noise signal can be surprisingly large. For example: If a conventional amplifier and a noise corner of has a flat-band noise level of 10nV/ 10 Hz, the RMS noise at 0.001 Hz is 1µV/ . This is equivalent to a 0.50 µV peak-to-peak error, in the frequency range 0.001 Hz to 1.0 Hz. In a circuit with a gain of 1000, this produces a 0.50 mV peak-to-peak output error. This number of 0.001 Hz might appear unreasonably low, but when a data acquisition system is operating for 17 minutes, it has been on long enough to include this error. In this same time, the LMP2012 will only have a 0.21 mV output error. This is smaller by 2.4 x. Keep in mind that this 1/f error gets even larger at lower frequencies. At the extreme, many people try to reduce this error by integrating or taking several samples of the same signal. This is also doomed to failure because the 1/f nature of this noise means that taking longer samples just moves the measurement into lower frequencies where the noise level is even higher. The LMP2012 eliminates this source of error. The noise level is constant with frequency so that reducing the bandwidth reduces the errors caused by noise. MORE BENEFITS The LMP2012 offers the benefits mentioned above and more. It has a rail-to-rail output and consumes only 950 µA of supply current while providing excellent DC and AC electrical performance. In DC performance, the LMP2012 achieves 130 dB of CMRR, 120 dB of PSRR and 130 dB of open loop gain. In AC performance, the LMP2012 provides 3 MHz of gain-bandwidth product and 4 V/µs of slew rate. HOW THE LMP2012 WORKS The LMP2012 uses new, patented techniques to achieve the high DC accuracy traditionally associated with chopper-stabilized amplifiers without the major drawbacks produced by chopping. The LMP2012 continuously monitors the input offset and corrects this error. The conventional chopping process produces many mixing products, both sums and differences, between the chopping frequency and the incoming signal frequency. This mixing causes large amounts of distortion, particularly when the signal frequency approaches the chopping frequency. Even without an incoming signal, the chopper harmonics mix with each other to produce even more trash. If this sounds unlikely or difficult to understand, look at the plot (Figure 2), of the output of a typical (MAX432) chopper-stabilized op amp. This is the output when there is no incoming signal, just the amplifier in a gain of -10 with the input grounded. The chopper is operating at about 150 Hz; the rest is mixing products. Add an input signal and the noise gets much worse. Compare this plot with Figure 3 of the LMP2012. This data was taken under the exact same conditions. The auto-zero action is visible at about 30 kHz but note the absence of mixing products at other frequencies. As a result, the LMP2012 has very low distortion of 0.02% and very low mixing products. OVERLOAD RECOVERY The LMP2012 recovers from input overload much faster than most chopper-stabilized op amps. Recovery from driving the amplifier to 2X the full scale output, only requires about 40 ms. Many chopper-stabilized amplifiers will take from 250 ms to several seconds to recover from this same overload. This is because large capacitors are used to store the unadjusted offset voltage. 20182216 FIGURE 1. The wide bandwidth of the LMP2012 enhances performance when it is used as an amplifier to drive loads that inject transients back into the output. ADCs (Analog-to-Digital Converters) and multiplexers are examples of this type of load. To simulate this type of load, a pulse generator producing a 1V peak square wave was connected to the output through a 10 pF capacitor. (Figure 1) The typical time for the output to recover to 1% of the applied pulse is 80 ns. To recover to 0.1% requires 860ns. This rapid recovery is due to the wide bandwidth of the output stage and large total GBW. 20182217 FIGURE 2. NO EXTERNAL CAPACITORS REQUIRED The LMP2012 does not need external capacitors. This eliminates the problems caused by capacitor leakage and dielecwww.national.com 6 20182204 FIGURE 3. INPUT CURRENTS The LMP2012's input currents are different than standard bipolar or CMOS input currents in that it appears as a current flowing in one input and out the other. Under most operating conditions, these currents are in the picoamp level and will have little or no effect in most circuits. These currents tend to increase slightly when the common-mode voltage is near the minus supply. At high temperatures, the input currents become larger, 0.5 nA typical, and are both positive except when the VCM is near V−. If operation is expected at low commonmode voltages and high temperature, do not add resistance in series with the inputs to balance the impedances. Doing this can cause an increase in offset voltage. A small resistance such as 1 kΩ can provide some protection against very large transients or overloads, and will not increase the offset significantly. 20182218 FIGURE 4. Extending Supply Voltages and Output Swing by Using a Composite Amplifier Configuration: In cases where substantially higher output swing is required with higher supply voltages, arrangements like the ones shown in Figure 5 and Figure 6 could be used. These configurations utilize the excellent DC performance of the LMP2012 while at the same time allow the superior voltage and frequency capabilities of the LM6171 to set the dynamic performance of the overall amplifier. For example, it is possible to achieve ±12V output swing with 300 MHz of overall GBW (AV = 100) while keeping the worst case output shift due to VOS less than 4 mV. The LMP2012 output voltage is kept at about mid-point of its overall supply voltage, and its input common mode voltage range allows the V- terminal to be grounded in one case (Figure 5, inverting operation) and tied to a small non-critical negative bias in another (Figure 6, noninverting operation). Higher closed-loop gains are also possible with a corresponding reduction in realizable bandwidth. Table 1 shows some other closed loop gain possibilities along with the measured performance in each case. 7 www.national.com LMP2012QML PRECISION STRAIN-GAUGE AMPLIFIER This Strain-Gauge amplifier (Figure 4) provides high gain (1006 or ~60 dB) with very low offset and drift. Using the resistors' tolerances as shown, the worst case CMRR will be greater than 108 dB. The CMRR is directly related to the resistor mismatch. The rejection of common-mode error, at the output, is independent of the differential gain, which is set by R3. The CMRR is further improved, if the resistor ratio matching is improved, by specifying tighter-tolerance resistors, or by trimming. LMP2012QML 20182219 20182220 FIGURE 5. FIGURE 6. TABLE 1. Composite Amplifier Measured Performance AV R1 Ω R2 Ω C2 pF BW MHz It should be kept in mind that in order to minimize the output noise voltage for a given closed-loop gain setting, one could minimize the overall bandwidth. As can be seen from Equation 1 above, the output noise has a square-root relationship to the Bandwidth. In the case of the inverting configuration, it is also possible to increase the input impedance of the overall amplifier, by raising the value of R1, without having to increase the feed-back resistor, R2, to impractical values, by utilizing a "Tee" network as feedback. See the LMC6442 data sheet (Application Notes section) for more details on this. SR en p-p (V/μs) (mVPP ) 50 200 10k 8 3.3 178 37 100 100 10k 10 2.5 174 70 100 1k 100k 0.67 3.1 170 70 500 200 100k 1.75 1.4 96 250 1000 100 100k 2.2 0.98 64 400 In terms of the measured output peak-to-peak noise, the following relationship holds between output noise voltage, en pp, for different closed-loop gain, AV, settings, where −3 dB Bandwidth is BW: 20182221 FIGURE 7. A) Very low offset voltage and offset voltage drift over time and temperature allow a high closed-loop gain setting without introducing any short-term or long-term errors. For example, when set to a closed-loop gain of 100 as the LMP2012 AS ADC INPUT AMPLIFIER The LMP2012 is a great choice for an amplifier stage immediately before the input of an ADC (Analog-to-Digital Converter), whether AC or DC coupled. See Figure 7 and Figure 8. This is because of the following important characteristics: www.national.com 8 Bandwidth = 2 Hz This example will result in about 2.2 mVPP (1.9 LSB) of output noise contribution due to the op amp alone, compared to about 594 μVPP (less than 0.5 LSB) when that op amp is replaced with the LMP2012 which has no 1/f contribution. If the measurement time is increased from 100 seconds to 1 hour, the improvement realized by using the LMP2012 would be a factor of about 4.8 times (2.86 mVPP compared to 596 μV when LMP2012 is used) mainly because the LMP2012 accuracy is not compromised by increasing the observation time. D) Rail-to-Rail output swing maximizes the ADC dynamic range in 5-Volt single-supply converter applications. Below are some typical block diagrams showing the LMP2012 used as an ADC amplifier (Figure 7 and Figure 8). 20182222 FIGURE 8. 9 www.national.com LMP2012QML analog input amplifier for a 12-bit A/D converter, the overall conversion error over full operation temperature and 30 years life of the part (operating at 50°C) would be less than 5 LSBs. B) Fast large-signal settling time to 0.01% of final value (1.4 μs) allows 12 bit accuracy at 100 KHZ or more sampling rate. C) No flicker (1/f) noise means unsurpassed data accuracy over any measurement period of time, no matter how long. Consider the following op amp performance, based on a typical low-noise, high-performance commerciallyavailable device, for comparison: Op amp flatband noise = 8nV/ 1/f corner frequency = 100 Hz AV = 2000 Measurement time = 100 sec LMP2012QML Revision History Date Released Revision Section Originator Changes 03/19/07 A Initial Release B. Petcher/B. Brown Initial Release 10/17/08 B Electrical Section www.national.com Robert Eddy Added typical parameters to 2.7V and 5V AC Electrical Sections. Revision A will be Archived. 10 LMP2012QML Physical Dimensions inches (millimeters) unless otherwise noted 10-Pin Ceramic SOIC NS Package Number WG10A 11 www.national.com LMP2012QML Dual Quad High Precision, Rail-to-Rail Output Operational Amplifier Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Design Support Amplifiers www.national.com/amplifiers WEBENCH www.national.com/webench Audio www.national.com/audio Analog University www.national.com/AU Clock Conditioners www.national.com/timing App Notes www.national.com/appnotes Data Converters www.national.com/adc Distributors www.national.com/contacts Displays www.national.com/displays Green Compliance www.national.com/quality/green Ethernet www.national.com/ethernet Packaging www.national.com/packaging Interface www.national.com/interface Quality and Reliability www.national.com/quality LVDS www.national.com/lvds Reference Designs www.national.com/refdesigns Power Management www.national.com/power Feedback www.national.com/feedback Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www.national.com/led PowerWise www.national.com/powerwise Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors Wireless (PLL/VCO) www.national.com/wireless THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS, IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS DOCUMENT. TESTING AND OTHER QUALITY CONTROLS ARE USED TO THE EXTENT NATIONAL DEEMS NECESSARY TO SUPPORT NATIONAL’S PRODUCT WARRANTY. EXCEPT WHERE MANDATED BY GOVERNMENT REQUIREMENTS, TESTING OF ALL PARAMETERS OF EACH PRODUCT IS NOT NECESSARILY PERFORMED. NATIONAL ASSUMES NO LIABILITY FOR APPLICATIONS ASSISTANCE OR BUYER PRODUCT DESIGN. BUYERS ARE RESPONSIBLE FOR THEIR PRODUCTS AND APPLICATIONS USING NATIONAL COMPONENTS. PRIOR TO USING OR DISTRIBUTING ANY PRODUCTS THAT INCLUDE NATIONAL COMPONENTS, BUYERS SHOULD PROVIDE ADEQUATE DESIGN, TESTING AND OPERATING SAFEGUARDS. EXCEPT AS PROVIDED IN NATIONAL’S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, NATIONAL ASSUMES NO LIABILITY WHATSOEVER, AND NATIONAL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE SALE AND/OR USE OF NATIONAL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness. National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. Copyright© 2008 National Semiconductor Corporation For the most current product information visit us at www.national.com National Semiconductor Americas Technical Support Center Email: [email protected] Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Technical Support Center Email: [email protected] German Tel: +49 (0) 180 5010 771 English Tel: +44 (0) 870 850 4288 National Semiconductor Asia Pacific Technical Support Center Email: [email protected] National Semiconductor Japan Technical Support Center Email: [email protected]