LMC6442

LMC6442Dual Micropower Rail-to-Rail Output Single Supply Operational AmplifierGeneral DescriptionThe LMC6442is ideal for battery powered systems,where very low supply current (less than one microamp per ampli-fier)and Rail-to-Rail output swing is required.It is character-ized for 2.2V to 10V operation,and at 2.2V supply,the LMC6442is ideal for single (Li-Ion)or two cell (NiCad or al-kaline)battery systems.The LMC6442is designed for battery powered systems that require long service life through low supply current,such as smoke and gas detectors,and pager or personal communi-cations systems.Operation from single supply is enhanced by the wide com-mon mode input voltage range which includes the ground (or negative supply)for ground sensing applications.Very low (5fA,typical)input bias current and near constant supply cur-rent over supply voltage enhance the LMC6442’s perfor-mance near the end-of-life battery voltage.Designed for closed loop gains of greater than plus two (or minus one),the amplifier has typically 9.5KHz GBWP (Gain Bandwidth Product).Unity gain can be used with a simple compensation circuit,which also allows capacitive loads of up to 300pF to be driven,as described in the Application Notes section.For compact assembly the LMC6442is available in the MSOP 8pin package,about one half the size required by the SOIC 8pin package.8pin DIP and 8pin SOIC are also available.Key Specifications Features(Typical,V S =2.2V)h Output Swing to within 30mV of supply rail h High voltage gain 103dB h Gain Bandwidth Product 9.5KHz h Guaranteed for: 2.2V,5V,10V h Low Supply Current 0.95µA/Amplifier h Input Voltage Range −0.3V to V +-0.9V h Power consumption2.1µW/AmplifierhStable for A V ≥+2or A V ≤−1Applicationsn Portable instrumentsn Smoke/gas/CO/fire detectors n Pagers/cell phones n Instrumentation n Thermostatsn Occupancy sensors n CamerasnActive badgesConnection DiagramDS100064-40Top ViewAugust 2000LMC6442Dual Micropower Rail-to-Rail Output Single Supply Operational Amplifier©2000National Semiconductor Corporation Absolute Maximum Ratings (Note 1)If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distributors for availability and specifications.ESD Tolerance (Note 2)2kVDifferential Input Voltage ±Supply VoltagesVoltage at Input/Output Pin (V +)+0.3V,(V −)−0.3VSupply Voltage (V +−V −):16VCurrent at Input Pin (Note 10)±5mA Current at Output Pin(Notes 3,7)±30mALead Temp.(soldering 10sec)260˚CStorage Temp.Range:−65˚C to +150˚CJunction Temp.(Note 4)150˚COperating Ratings (Note 1)Supply Voltage 1.8V ≤V S ≤11V Junction Temperature−40˚C <T J <+85˚CRange:LMC6442AI,LMC6442I Thermal Resistance (θJA )M Package,8-pin Surface Mount193˚C/W MSOP Package235˚C/W N Package,8-pin Molded DIP115˚C/W2.2V Electrical CharacteristicsUnless otherwise specified,all limits guaranteed for T J =25˚C,V +=2.2V,V −=0V,V CM =V O =V +/2,and R L =1M Ωto V +/2.Boldface limits apply at the temperature extremes.SymbolParameterConditionsTyp (Note 5)LMC6442AI Limit (Note 6)LMC6442ILimit (Note 6)UnitsDC Electrical Characteristics V OS Input Offset Voltage −0.75±3±4±7±8mV max TCV OS Temp.coefficient of inputoffset voltage 0.4µV/˚C I B Input Bias Current (Note 14)0.00544pA max I OS Input Offset Current (Note 14)0.002522pA max CMRR Common Mode Rejection Ratio−0.1V ≤V CM ≤0.5V9267676767dB min C IN Common Mode Input Capacitance4.7pF PSRR Power Supply Rejection Ratio V S =2.5V to 10V 9575757575dB min V CMInput Common-Mode Voltage RangeCMRR ≥50dB1.31.050.95 1.050.95V min −0.3−0.20−0.20V max A VLarge Signal Voltage Gain Sourcing (Note 11)100dB min Sinking(Note 11)94V O =0.22V to 2V1038080V OOutput SwingV ID =100mV (Note 13) 2.18 2.152.15 2.152.15V min V ID =−100mV (Note 13)2260606060mV max I SCOutput Short Circuit CurrentSourcing,V ID =100mV (Notes 12,13)5018171817µA minSinking,V ID =−100mV (Notes 12,13)5020192019I SSupply Current (2amplifiers)R L =open1.902.43.02.63.2µA maxV +=1.8V,R L =open2.10AC Electrical Characteristics SRSlew Rate (Note 8)2.2V/msL M C 6442 22.2V Electrical Characteristics(Continued)Unless otherwise specified,all limits guaranteed for T J =25˚C,V +=2.2V,V −=0V,V CM =V O =V +/2,and R L =1M Ωto V +/2.Boldface limits apply at the temperature extremes.SymbolParameterConditionsTyp (Note 5)LMC6442AI Limit (Note 6)LMC6442ILimit (Note 6)UnitsAC Electrical Characteristics GBWP Gain-Bandwidth Product 9.5KHz φmPhase Margin(Note 15)63Degree5V Electrical CharacteristicsUnless otherwise specified,all limits guaranteed for T J =25˚C,V +=5V,V −=0V,V CM =V O =V +/2,and R L =1M Ωto V +/2.Boldface limits apply at the temperature extremes.SymbolParameterConditionsTyp (Note 5)LMC6442AILimit (Note 6)LMC6442I Limit (Note 6)UnitsDC Electrical Characteristics V OS Input Offset Voltage −0.75±3±4±7±8mV max TCV OS Temp.coefficient of input offset voltage 0.4µV/˚C I B Input Bias Current (Note 14)0.00544pA max I OS Input Offset Current (Note 14)0.002522pA max CMRR Common Mode Rejection Ratio−0.1V ≤V CM ≤3.5V10270707070dB min C IN Common Mode Input Capacitance4.1pF PSRR Power Supply Rejection Ratio V S =2.5V to 10V 9575757575dB min V CMInput Common-Mode Voltage RangeCMRR ≥50dB4.13.853.75 3.853.75V min −0.4−0.20−0.20V max A VLarge Signal Voltage Gain Sourcing (Note 11)100dB min Sinking (Note 11)94V O =0.5V to 4.5V1038080V OOutput SwingV ID =100mV (Note 13) 4.99 4.954.95 4.954.95V min V ID =−100mV (Note 13)2050505050mV max I SCOutput Short Circuit CurrentSourcing,V ID =100mV (Notes 12,13)500300200300200µA min Sinking,V ID =−100mV (Notes 12,13)350200150200150I SSupply Current (2amplifiers)R L =open1.902.43.0 2.63.2µA max AC Electrical Characteristics SR Slew Rate (Note 8)4.1 2.52.5V/ms GBWP Gain-Bandwidth Product 10KHz φm Phase Margin(Note 15)64Degree THDTotal Harmonic DistortionA V =+2,f =100Hz,R L =10M Ω,V OUT =1Vpp0.08%LMC6442310V Electrical CharacteristicsUnless otherwise specified,all limits guaranteed for T J =25˚C,V +=10V,V −=0V,V CM =V O =V +/2,and R L =1M Ωto V +/2.Boldface limits apply at the temperature extremes.SymbolParameterConditionsTyp (Note 5)LMC6442AILimit (Note 6)LMC6442I Limit (Note 6)UnitsDC Electrical Characteristics V OS Input Offset Voltage −1.5±3±4±7±8mV max TCV OS Temp.coefficient of input offset voltage 0.4µV/˚C I B Input Bias Current (Note 14)0.00544pA max I OS Input Offset Current (Note 14)0.002522pA max CMRR Common Mode Rejection Ratio−0.1V ≤V CM ≤8.5V10570707070dB min C IN Common Mode Input Capacitance3.5pF PSRR Power Supply Rejection Ratio V S =2.5V to 10V 9575757575dB min V CMInput Common-Mode Voltage RangeCMRR ≥50dB9.18.858.758.858.75V min −0.4−0.20−0.20V max A VLarge Signal Voltage Gain Sourcing (Note 11)120dB min Sinking (Note 11)100V O =0.5V to 9.5V1048080V OOutput SwingV ID =100mV (Note 13)9.999.979.979.979.97V min V ID =−100mV(Note 13)2250505050mV max I SCOutput Short Circuit CurrentSourcing,V ID =100mV (Notes 12,13)21001200100012001000µA min Sinking,V ID =−100mV (Notes 12,13)900600500600500I SSupply Current (2amplifiers)R L =open1.902.43.0 2.63.2µA max AC Electrical Characteristics SR Slew Rate(Note 8)4.1 2.52.5V/ms GBWP Gain-Bandwidth Product 10.5KHz φm Phase Margin(Note 15)68Degree e n Input-Referred Voltage Noise R L =open f =10Hz 170nV/√Hz i nInput-Referred Current Noise R L =open f =10Hz 0.0002pA/√Hz Crosstalk Rejection(Note 9)85dBL M C 6442 4Electrical Characteristics(continued)Note1:Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.Operating Ratings indicate conditions for which the device is intended to be functional,but specific performance is not guaranteed.For guaranteed specifications and the test conditions,see the Electrical Characteristics. Note2:Human body model,1.5kΩin series with100pF.Note3:Applies to both single-supply and split-supply operation.Continuous short circuit operation at elevated ambient temperature can result in exceeding the maximum allowed junction temperature of150˚C.Output currents in excess of±30mA over long term may adversely affect reliability.Note4:The maximum power dissipation is a function of T J(max),θJA,and T A.The maximum allowable power dissipation at any ambient temperature is P D=(T J-(max)-T A)/θJA.All numbers apply for packages soldered directly into a PC board.Note5:Typical Values represent the most likely parametric norm.Note6:All limits are guaranteed by testing or statistical analysis unless otherwise specified.Note7:Do not short circuit output to V+,when V+is greater than13V or reliability will be adversely affected.Note8:Slew rate is the slower of the rising and falling slew rates.Note9:Input referred,V+=10V and R L=10MΩconnected to5V.Each amp excited in turn with1KHz to produce about10Vpp output.Note10:Limiting input pin current is only necessary for input voltages that exceed absolute maximum input voltage ratings.Note11:R L connected to V+/2.For Sourcing Test,V O>V+/2.For Sinking tests,V O<V+/2.Note12:Output shorted to ground for sourcing,and shorted to V+for sinking short circuit current test.Note13:V ID is differential input voltage referenced to inverting input.Note14:Limits guaranteed by design.Note15:See the Typical Performance Characteristics and Application Notes sections for more details.Typical Performance Characteristics VS=5V,Single Supply,T A=25˚C unless otherwise specifiedTotal Supply Currentvs Supply VoltageDS100064-8Total Supply Currentvs Supply Voltage(Negative Input Overdrive)DS100064-9Total Supply Currentvs Supply Voltage(Positive Input Overdrive)DS100064-10Input Bias Currentvs TemperatureDS100064-41Offset Voltage vsCommon Mode Voltage(V S=2.2V)DS100064-6Offset Voltage vsCommon Mode Voltage(V S=5V)DS100064-7LMC64425Typical Performance CharacteristicsV S =5V,Single Supply,T A =25˚C unless otherwisespecified (Continued)Offset Voltage vsCommon Mode Voltage (V S =10V)DS100064-42Swing Towards V −vs Supply Voltage DS100064-3Swing Towards V +vs Supply VoltageDS100064-2Swing From Rail(s)vs Temperature DS100064-1Output Source Current vs Output VoltageDS100064-49Output Sink Current vs Output VoltageDS100064-48Maximum Output Voltage vs Load ResistanceDS100064-24Large Signal Voltage Gain vs Supply VoltageDS100064-52Open Loop Gain/Phase vs FrequencyDS100064-19L M C 6442 6Typical Performance Characteristics VS=5V,Single Supply,T A=25˚C unless otherwise specified(Continued)Open LoopGain/Phase vsFrequency For Various C L(Z L=1MΩII C L)DS100064-26Open LoopGain/Phase vsFrequency For Various C L(Z L=100KΩII C L)DS100064-25Gain Bandwidth Productvs Supply VoltageDS100064-21Phase Margin(Worst Case)vs Supply VoltageDS100064-23CMRR vs FrequencyDS100064-34PSRR vs FrequencyDS100064-15Positive Slew Rate vsSupply VoltageDS100064-12Negative Slew Rate vsSupply VoltageDS100064-11Cross-Talk Rejectionvs FrequencyDS100064-18LMC64427Typical Performance CharacteristicsV S =5V,Single Supply,T A =25˚C unless otherwisespecified (Continued)Input Voltage Noise vs FrequencyDS100064-16Output Impedance vs FrequencyDS100064-33THD+N vs FrequencyDS100064-28THD+N vs AmplitudeDS100064-27Maximum Output Swing vs FrequencyDS100064-53Small Signal Step Response(A V =+2)(C L =12pF,100pF)DS100064-29Large Signal Step Response(A V =+2)(C L =100pF)DS100064-30Small Signal Step Response(A V =−1)(C L =1M ΩII 100pF,200pF)DS100064-51Small Signal Step Response(A V =+1)For Various C LDS100064-31L M C 6442 8Typical Performance Characteristics VS=5V,Single Supply,T A=25˚C unless otherwisespecified(Continued)Applications InformationUsing LMC6442in unity gain applications:LMC6442isoptimized for maximum bandwidth and minimal externalcomponents when operating at a minimum closed loop gainof+2(or−1).However,it is also possible to operate the de-vice in a unity gain configuration by adding external compen-sation as shown in Figure1:Using this compensation technique it is possible to drive ca-pacitive loads of up to300pF without causing oscillations(see the Typical Performance Characteristics for step re-sponse plots).This compensation can also be used withother gain settings in order to improve stability,especiallywhen driving capacitive loads(for optimum performance,R cand C c may need to be adjusted).Using“T”Network:Compromises need to be made whenever high gain invert-ing stages need to achieve a high input impedance as well.This is especially important in low current applications whichtend to deal with high resistance ing a traditionalinverting amplifier,gain is inversely proportional to the resis-tor value tied between the inverting terminal and input whilethe input impedance is equal to this value.For example,inorder to build an inverting amplifier with an input impedanceof10MΩand a gain of100,one needs to come up with afeedback resistor of1000MΩ-an expensive task.An alternate solution is to use a“T”Network in the feedbackpath,as shown in Fig.2.Closed loop gain,A V is given by:It must be noted,however,that using this scheme,the real-izable bandwidth would be less than the theoretical maxi-mum.With feedback factor,β,defined as:BW(−3dB)≈GBWP•βIn this case,assuming a GBWP of about10KHz,the ex-pected BW would be around50Hz(vs100Hz with the con-ventional inverting amplifier).Looking at the problem from a different view,with R F definedby A V•Rin,one could select a value for R in the“T”Networkand then determine R1based on this selection:Large Signal StepResponse(A V=+1)(C L=200pF)DS100064-32DS100064-35FIGURE1.A V=+1Operation by adding C c and R cDS100064-36FIGURE2.“T”Network Used to Replace High ValueResistorDS100064-22FIGURE3.“T”Network Values for Various Values of RLMC64429Applications Information(Continued)For convenience,Fig.3shows R1vs R F for different values of R.Design Considerations for Capacitive Loads:As with many other opamps,the LMC6442is more stable at higher closed loop gains when driving a capacitive load.Figure 4shows minimum closed loop gain versus load capacitance,to achieve less than 10%overshoot in the output small sig-nal response.In addition,the LMC6442is more stable when it provides more output current to the load and when its out-put voltage does not swing close to V −.The LMC6442is more tolerant to capacitive loads when the equivalent output load resistance is lowered or when output voltage is 1V or greater from the V −supply.The capacitive load drive capability is also improved by adding an isolating resistor in series with the load and the output of the device.Figure 5shows the value of this resistor for various capaci-tive loads (A V =−1),while limiting the output to less than 10%overshoot.Referring to the Typical Performance Characteristics plot of Phase Margin (Worst Case)vs Supply Voltage,note that Phase Margin increases as the equivalent output load resis-tance is lowered.This plot shows the expected Phase Mar-gin when the device output is very close to V −,which is the least stable condition of paring this Phase Margin value to the one read off the Open Loop Gain/Phase vs Frequency plot,one can predict the improvement in Phase Margin if the output does not swing close to V −.This dependence of Phase Margin on output voltage is minimized as long as the output load,R L ,is about 1M Ωor less.Output Phase Reversal:The LMC6442is immune against this behavior even when the input voltages exceed the com-mon mode voltage range.Output Time Delay:Due to the ultra low power consump-tion of the device,there could be as long as 2.5ms of time delay from when power is applied to when the device output reaches its final value.DS100064-47FIGURE 4.Minimum Operating Gain vs Capactive LoadDS100064-43FIGURE 5.Isolating Resistor Value vs Capactive LoadL M C 6442 10Application CircuitsMicropower Single Supply Voltage to Frequency ConverterDS100064-45V+=5V:I S<10µA,f/V C =4.3(Hz/V)DS100064-46Gain Stage with Current Boosting DS100064-54Offset Nulling SchemesDS100064-44LMC644211Ordering InformationPackage Temperature RangeNSC Drawing SuppliedAS Package MarkingIndustrial −40˚C to +85˚C Military −55˚C to+125˚C8-pin SO-8LMC6442AIM,LMC6442IM -M08A Rails LMC6442AIM LMC6442IMLMC6442AIMX,LMC6442IMX-M08A2.5K Tape and Reel MSOPLMC6442AIMM,LMC6442AIMMX,LMC6442IMM,LMC6442IMMX -MUA08ARails A08A LMC6442AIMMX,LMC6442IMMX-MUA08A 3K Tape and Reel 8-pin DIP LMC6442AIN,LMC6442IN-N08E Rails LMC6442AIN,LMC6442IN 8-pin CDIP -5962-9761301QPA J08A Rails LMC6442AMJ-QML 5962-976130IQPA 10-pin SO-5962-9761301QXAWG10ATraysLMC6442AMWG-Q 9761301QXAL M C 6442 12Physical Dimensionsinches (millimeters)unless otherwise noted8-Lead (0.150″Wide)Molded Small Outline Package,JEDECOrder Number LMC6442AIM or LMC6442IM or LMC6442AIMX or LMC6442IMXNS Package Number M08A8-Lead (0.300″Wide)Molded Dual-In-Line Package Order Number LMC6442AIN or LMC6442IN or LMC6442INXNS Package Number N08ELMC644213Physical Dimensionsinches (millimeters)unless otherwise noted (Continued)LIFE SUPPORT POLICYNATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION.As used herein:1.Life support devices or systems are devices or systems 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.2.A critical component is any component of 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 Corporation AmericasTel:1-800-272-9959Fax:1-800-737-7018Email:support@National Semiconductor EuropeFax:+49(0)180-5308586Email:europe.support@Deutsch Tel:+49(0)6995086208English Tel:+44(0)8702402171Français Tel:+33(0)141918790National Semiconductor Asia Pacific Customer Response Group Tel:65-2544466Fax:65-2504466Email:ap.support@National Semiconductor Japan Ltd.Tel:81-3-5639-7560Fax:81-3-5639-75078-Lead (0.118″Wide)Molded Mini Small Outline PackageOrder Number LMC6442AIMM or LMC6442IMM or LMC6442AIMMX or LMC6442IMMXNS Package Number MUA08AL M C 6442D u a l M i c r o p o w e r R a i l -t o -R a i l O u t p u t S i n g l e S u p p l y O p e r a t i o n a l A m p l i f i e rNational does not assume any responsibility for use of any circuitry described,no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.。