LMP7721 - 3 Femtoampere Input Bias Current Precision Amplifier from the PowerWise® Family
Datasheet Packaging Samples & Pricing Eval. Boards Reliability Models Knowledge Base

Features

Unless otherwise noted, typical values at TA = 25°C, VS = 5V.

  • Input bias current (VCM = 1V)

    • max @ 25°C

    ±20 fA

    max @ 85°C

    ±900 fA

    Offset voltage

    ±26 µV

    Offset voltage drift

    −1.5 μV/°C

    DC Open loop gain

    120 dB

    DC CMRR

    100 dB

    Input voltage noise (at f = 1 kHz)

    6.5 nV/ √Hz

    THD

    0.0007%

    Supply current

    1.3 mA

    GBW

    17 MHz

    Slew rate (falling edge)

    12.76 V/μs

    Supply voltage

    1.8V to 5.5V

    Operating temperature range

    −40°C to 125°C

    8-Pin SOIC

    General Description

    The LMP7721 is the industry’s lowest guaranteed input bias current precision amplifier. More...


    Applications

    •Photodiode amplifier
    •High impedance sensor amplifier
    •Ion chamber amplifier
    •Electrometer amplifier
    •pH electrode amplifier
    •Transimpedance amplifier
    		  Typical Application
    click for larger image


    ParametersValues
    Offset Voltage max, 25C 0.15 mV
    TcVos 1.5 uV/degC
    CMRR 100 dB
    PSRR 96 dB
    Avol 120 dB
    Voltage Noise 6.5 nV/root(Hz)
    Max Input Bias Current 0.00002 nA
    Gain Bandwidth 17 MHz
    Supply Current Per Channel 1.3 mA
    PowerWise Rating 2 76.5 uA/MHz
    Slew Rate 10.5 Volts/usec
    Channels 1 Channels
    Supply Min 1.8 Volt
    Supply Max 5.5 Volt
    Input OutputType Vcm to V-, Not R-R Out
    Output Current 22 mA
    Shut down No
    Special Features 3 fA Guaranteed
    Temperature Min -40 deg C
    Temperature Max 125 deg C
    Function Op Amp
    PowerWise Yes


    Typical Performance

    click for larger image


    		  Connection Diagram
    click for larger image



    Datasheet
    RoHS Compliance Information Size in KbytesDate Click link below to Download
    LMP7721 3 Femtoampere Input Bias Current Precision Amplifier 602
    Kbytes    		 14-Mar-08 Download
    LMP7721 3 Femtoampere Input Bias Current Precision Amplifier (Japanese)
    		 1156 Kbytes   Download

    If you have trouble printing or viewing PDF file(s), see Printing Problems.


    Package Availability, Models, Samples & Pricing
    Part NumberPackageFactory Lead TimeModelsSamples &
    Electronic
    Orders    		Budgetary PricingStd
    Pack
    Size    		Package
    Marking
    Format
    TypePinsSpec.MSL
    Rating    		Peak
    Reflow    		RoHS
    Report    		CAD
    Symbols    		WeeksQtyQty$US each
    LMP7721MASOIC NARROW8NOPB1260RoHS N/A Full productionLMP7721.MOD
    		Samples
    Buy Now     		1K+$4.95rail
    of
    95    		NSZXTT
    LMP77
    21MA
    6 weeks500
    LMP7721MAXSOIC NARROW8NOPB1260RoHS N/A Full productionLMP7721.MOD
    		 
    Buy Now     		1K+$4.95reel
    of
    2500    		NSZXTT
    LMP77
    21MA
    6 weeksN/A
    LMP7721MAEVALEvaluation Board for the LMP7721Full productionLMP7721.MOD
    		 
    Buy Now     		1+$15.001-
    N/AN/A

    General Description

    The LMP7721 is the industry’s lowest guaranteed input bias current precision amplifier. The ultra low input bias current is 3 fA, with a guaranteed limit of ±20 fA at 25°C and ±900 fA at 85°C. This is achieved with the latest patent pending technology of input bias current cancellation amplifier circuitry. This technology also maintains the ultra low input bias current over the entire input common mode voltage range of the amplifier.

    Other outstanding features, such as low voltage noise (6.5 nV/ ), low DC offset voltage (±150 µV maximum at 25°C) and low offset voltage temperature coefficient (−1.5 µV/°C), improve system sensitivity and accuracy in high precision applications. With a supply voltage range of 1.8V to 5.5V, the LMP7721 is the ideal choice for battery operated portable applications. The LMP7721 is part of the LMP precision amplifier family.

    As part of National’s PowerWise products, the LMP7721 provides the remarkably wide gain bandwidth product (GBW) of 17 MHz while consuming only 1.3 mA of current. This wide GBW along with the high open loop gain of 120 dB enables accurate signal conditioning. With these specifications, the LMP7721 has the performance to excel in a wide variety of applications such as electrochemical cell amplifiers and sensor interface circuits.

    The LMP7721 is offered in an 8-pin SOIC package with a special pinout that isolates the amplifier’s input from the power supply and output pins. With proper board layout techniques, the unique pinout of the LMP7721 will prevent PCB leakage current from reaching the input pins. Thus system error will be further reduced.

    Reliability Metrics

    Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
    LMP7721MAVIP50CLZ301755003150001289382110
    LMP7721MAEVIP50CLZ301755003150001289382110
    LMP7721MAXVIP50CLZ301755003150001289382110

    Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

    For more information on Reliability Metrics, please click here.


    Application Notes

    TitleSize in Kbytes Date Click link below to Download
    AN-1796: Application Note 1796 LMP7721 Evaluation Board 147
    Kbytes    		 16-Apr-09 Download
    AN-1796 (Chinese): Application Note 1796 LMP7721 Evaluation Board
    		 304 Kbytes  
    AN-1852: Application Note 1852 Designing With pH Electrodes 190
    Kbytes    		 25-Sep-08 Download
    AN-1798: Application Note 1798 Designing with Electro-Chemical Sensors 135
    Kbytes    		 24-Jun-08 Download
    AN-1798 (Chinese): Application Note 1798 Designing with Electro-Chemical Sensors
    		 218 Kbytes  

    If you have trouble printing or viewing PDF file(s), see Printing Problems.

    [Information as of 7-Nov-2009]