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 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. Applications • Photodiode amplifier • High impedance sensor amplifier • Ion chamber amplifier • Electrometer amplifier • pH electrode amplifier • Transimpedance amplifier

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Datasheet

Title		Size	Date	Other Language
	LMP7721 3 Femtoampere Input Bias Current Precision Amplifier	602 Kbytes	14-Mar-08	日本語

Featured Application Notes

Title		Size	Date	Other Language
	AN-1796: Application Note 1796 LMP7721 Evaluation Board	147 Kbytes	16-Apr-09	中文
	AN-1852: Application Note 1852 Designing With pH Electrodes	190 Kbytes	25-Sep-08
	AN-1798: Application Note 1798 Designing with Electro-Chemical Sensors	135 Kbytes	24-Jun-08	中文

More Application Notes

Title		Size	Date	Other Language
	AN-1515: Application Note 1515 A Comprehensive Study of the Howland Current Pump	227 Kbytes	29-Jan-08
	AN-1559: Application Note 1559 Practical RTD Interface Solutions	215 Kbytes	10-Oct-07	日本語 中文
	AN-1841: Application Note 1841 LMH1982 Evaluation Board User Guide	913 Kbytes	21-May-08	中文

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LMP7721MA	VIP50CLZ3	0	1755	0	0	315000	12	89382110
LMP7721MAE	VIP50CLZ3	0	1755	0	0	315000	12	89382110
LMP7721MAX	VIP50CLZ3	0	1755	0	0	315000	12	89382110

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.

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