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

Typical Application click for larger image	Connection Diagram click for larger image
Typical Performance click for larger image

Parameters Values 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

Datasheets

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

Application Notes

Title		Size	Date	Other Language
	AN-1798: Application Note 1798 Designing with Electro-Chemical Sensors	135 Kbytes	24-Jun-08	中文
	AN-1852: Application Note 1852 Designing With pH Electrodes	190 Kbytes	25-Sep-08

Other Technical Documents

Title		Type	Date
	Understanding Precision Comparator Applications (Part 2 of 2)	External Article	2008-03-05
	Understanding Precision Comparator Applications (Part 1 of 2)	External Article	2008-03-03

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LMP7721MA/NOPB RoHS Status	SOIC NARROW	Full production Lead Time: 6 weeks	Distributor Region Qty AVNET-EM Worldwide 227 DIGI-KEY Worldwide 500 FARNELL Europe and Asia 2319 MOUSER Worldwide 120 NEWARK Americas 282 RS COMPONENTS Worldwide 3	$4.70 each at 1K+ pcs	rail of 95
LMP7721MAX/NOPB RoHS Status	SOIC NARROW	Full production Lead Time: 6 weeks	Distributor Region Qty DIGI-KEY Worldwide 0	$4.70 each at 1K+ pcs	reel of 2500

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LMP7721.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LMP7721 is located at RoHS Status.

Part Number(s) (NSID)	Description	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LMP7721MAEVALMF/NOPB	LMP7721 Multi-Function Evaluation Board	Full production Lead Free (RoHS)	Distributor Region Qty ARROW Worldwide 4 AVNET-EM Worldwide 1 DIGI-KEY Worldwide 0 MOUSER Worldwide 5 TAYLOR Americas 4	$110.00 each	1
The LMP7721 Evaluation Board provides a platform to test the performance of the LMP7721 Ultra-low input bias current operational amplifier. The LMP7721 amplifier is optimized for ultra low input bias current applications by utilizing internal guarding techniques and a special package pin-out to isolate the amplifier`s inputs from its power supply and output pins. This pinout also allows room for proper guarding around the input pins and feedback circuitry. The LMP7721 Multi-Function Evaluation board may be used to evaluate the LMP7721 in the inverting, noninverting and Transimpedance (`TIA` or `I to V`) configurations. The layout has been optimized for sub-picoamp operation using conventional FR4 materials through careful layout and guarding techniques. A second LMP7715 precision amplifier (U2) acts as a guard driver to provide active guarding to the input circuits. The LMP7715 buffer samples the voltage on the LMP7721`s summing node and drives the guard traces to an identical potential. Contents: LMP7721 Assembled Evaluation Board LMP7721 Datasheet LMP7721MA Multi-Function Evaluation Board User Guide

National Semiconductor follows the provisions of the Product Stewardship Guide for Customers (CSP-9-111C1) and Banned Substances and Materials of Interest Specification (CSP-9-111S2) for regulatory environmental compliance. Details may be found at: www.national.com/en/packaging/greennopb.html. Lead free products are RoHS compliant.

Lead Free product status is available through the search tool located here

Part Number(s) (NSID)	Weight (milligrams)	Type	Pins	MSL Rating	Peak Reflow	RoHS Status	CAD Symbols	Models	Package Marking Format
LMP7721MA/NOPB	69.761	SOIC NARROW	8	1	260	Detail	Download	spice file	NSZXTT LMP77 21MA
LMP7721MAX/NOPB	69.761	SOIC NARROW	8	1	260	Detail	Download	spice file	NSZXTT LMP77 21MA

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LMP7721.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LMP7721 is located at RoHS Status.

CAD Symbols and Models Download LMP7721 CAD Symbols

Models spice file

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LMP7721MA	VIP50CLZ3	0	5670	0	0	945000	4	268146330
LMP7721MAX	VIP50CLZ3	0	5670	0	0	945000	4	268146330

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.

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LMP7721.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LMP7721 is located at RoHS Status.

LMP827x LMP223x LMP7721 Precision Amplifiers Loading video... Sensing Solutions In Factory Automation Loading video... Op Amp Eval Board Cleaning for Femptoamp Bias Current Performance Loading video...

LMP827x LMP223x LMP7721 Precision Amplifiers Date: 2008-03-18 Length: 0:5:12 Sensing Solutions In Factory Automation Date: 2009-07-10 Length: 0:50:00 Op Amp Eval Board Cleaning for Femptoamp Bias Current Performance Date: 2010-03-02 Length: 0:10:47