LMP2012WG-QMLV

LMP2012QML Dual Quad High Precision, Rail-to-Rail Output Operational Amplifier October 20, 2008 LMP2012QML Dual High Precision, Rail-to-Rail Output Operational Amplifier General Description 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. Features ■ 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 LMP2012WG-QMLV LMP2012WGLQMLV SMD Part Number 5962-0620601VZA 5962L0620601VZA 50K rd(Si) NS Package Number WG10A WG10A Package Discription 10LD CERAMIC SOIC 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 Absolute Maximum Ratings (Note 1) Supply Voltage Differential Input Voltage Power Dissipation (Note 2) Maximum Junction Temperature (TJmax) Common-Mode Input Voltage 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)   θJC Ceramic SOIC Package Weight Ceramic SOIC ESD Tolerance (Note 3) 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 175°C/W 115°C/W 12.3°C/W 220mg 4000V Quality Conformance Inspection Mil-Std-883, Method 5005 - Group A Subgroup 1 2 3 4 5 6 7 8A 8B 9 10 11 12 13 14 Description Static tests at Static tests at Static tests at Dynamic tests at Dynamic tests at Dynamic tests at Functional tests at Functional tests at Functional tests at Switching tests at Switching tests at Switching tests at Setting time at Setting time at Setting time at Temp (°C) +25 +125 -55 +25 +125 -55 +25 +125 -55 +25 +125 -55 +25 +125 -55 www.national.com 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 Input Offset Voltage Offset Calibration Time IIB IIO CMRR Input Bias Current Input Offset Current Common Mode Rejection Ratio −0.3 ≤ VCM ≤ 0.9V 0 ≤ VCM ≤ 0.9V PSRR AVOL Power Supply Rejection Ratio Open Loop Voltage Gain 120 130 124 2.68 RL = 10 kΩ to 1.35V VIN(diff) = ±0.5V 0.033 2.65 RL = 2 kΩ to 1.35V VIN(diff) = ±0.5V IO Output Current Sourcing, VO = 0V VIN(diff) = ±0.5V Sinking, VO = 5V VIN(diff) = ±0.5V IS Supply Current per Channel 0.061 12 18 0.919 5 3 5 3 1.20 1.50 mA mA 2.615 2.6 0.085 0.105 V Conditions Notes Typ (Note 4) 0.8 0.5 −3 6 130 95 90 95 90 RL = 10 kΩ RL = 2 kΩ VO Output Swing 95 90 90 85 2.64 2.63 0.060 0.075 V dB Min Max 36 60 10 12 Units μV ms pA pA dB dB 1 2, 3 1 2, 3 1 2, 3 1 2, 3 1 2, 3 1 2,3 1 2, 3 1 2, 3 1 2, 3 1 2, 3 1 2, 3 Subgroups 1 2, 3 1 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 GBW SR θm Gm en enP-P trec Parameter Gain-Bandwidth Product Slew Rate Phase Margin Gain Margin Input-Referred Voltage Noise Input-Referred Voltage Noise Input Overload Recovery Time RS = 100Ω, DC to 10 Hz Conditions Notes Typ (Note 4) 3 4 60 −14 35 850 50 Min 1 Max 5 Units MHz V/μs Deg dB nV/ nVPP ms Subgroups 4 3 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 Supply Current per Channel Conditions Notes (Note 5) Typ Min Max 1.75 Units mA Subgroups 1 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 Input Offset Voltage Offset Calibration Time IIB IIO CMRR Input Bias Current Input Offset Current Common Mode Rejection Ratio −0.3 ≤ VCM ≤ 3.2 0 ≤ VCM ≤ 3.2 PSRR AVOL Power Supply Rejection Ratio Open Loop Voltage Gain RL = 10 kΩ RL = 2 kΩ VO Output Swing RL = 10 kΩ to 2.5V VIN(diff) = ±0.5V 120 130 132 4.978 0.040 RL = 2 kΩ to 2.5V VIN(diff) = ±0.5V 4.919 0.091 IO Output Current Sourcing, VO = 0V VIN(diff) = ±0.5V Sourcing, VO = 5V VIN(diff) = ±0.5V IS Supply Current per Channel 15 17 0.930 8 6 8 6 1.20 1.50 mA mA 4.875 4.855 0.125 0.150 V Conditions Notes Typ (Note 4) 0.12 0.5 −3 6 130 100 90 95 90 105 100 95 90 4.92 4.91 0.080 0.095 V dB dB dB Min Max 36 60 10 12 Units μV ms pA pA 1 2, 3 1 2, 3 1 2, 3 1 2, 3 1 2, 3 1 2, 3 1 2, 3 1 2, 3 1 2, 3 1 2, 3 1 2, 3 Subgroups 1 2, 3 1 2, 3 www.national.com 4 LMP2012QML 5V 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 GBW SR θm Gm en enP-P trec Parameter Gain-Bandwidth Product Slew Rate Phase Margin Gain Margin Input-Referred Voltage Noise Input-Referred Voltage Noise Input Overload Recovery Time RS = 100Ω, DC to 10 Hz Conditions Notes Typ (Note 4) 3 4 60 −15 35 850 50 Min 1 Max 5 Units MHz V/μs Deg dB nV/ nVPP ms Subgroups 4 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 Supply Current per Channel Conditions Notes (Note 5) Typ Min Max 1.75 Units mA Subgroups 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 Application Information 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. 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. tric absorption, which can cause delays of several seconds from turn-on until the amplifier's error has settled. 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. 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. NO EXTERNAL CAPACITORS REQUIRED The LMP2012 does not need external capacitors. This eliminates the problems caused by capacitor leakage and dielecwww.national.com 6 20182217 FIGURE 2. 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. 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 20182219 20182220 FIGURE 5. TABLE 1. Composite Amplifier Measured Performance AV R1 Ω 200 100 1k 200 100 R2 Ω 10k 10k 100k 100k 100k C2 pF 8 10 0.67 1.75 2.2 BW MHz 3.3 2.5 3.1 1.4 0.98 SR en p-p (V/μs) (mVPP ) 178 174 170 96 64 37 70 70 250 400 FIGURE 6. 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. 50 100 100 500 1000 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. 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: 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 www.national.com 8 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 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 Revision History Date Released 03/19/07 10/17/08 Revision A B Section Initial Release Electrical Section Originator B. Petcher/B. Brown Changes Initial Release Robert Eddy Added typical parameters to 2.7V and 5V AC Electrical Sections. Revision A will be Archived. www.national.com 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 Amplifiers Audio Clock Conditioners Data Converters Displays Ethernet Interface LVDS Power Management Switching Regulators LDOs LED Lighting PowerWise Serial Digital Interface (SDI) Temperature Sensors Wireless (PLL/VCO) www.national.com/amplifiers www.national.com/audio www.national.com/timing www.national.com/adc www.national.com/displays www.national.com/ethernet www.national.com/interface www.national.com/lvds www.national.com/power www.national.com/switchers www.national.com/ldo www.national.com/led www.national.com/powerwise www.national.com/sdi www.national.com/tempsensors www.national.com/wireless WEBENCH Analog University App Notes Distributors Green Compliance Packaging Design Support www.national.com/webench www.national.com/AU www.national.com/appnotes www.national.com/contacts www.national.com/quality/green www.national.com/packaging www.national.com/quality www.national.com/refdesigns www.national.com/feedback Quality and Reliability Reference Designs Feedback THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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