0

1

2

3

3.5

-20

-15

-10

-5

0

5

V

+

V

-

= 0V

1.5

0.5

2.5

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LMP7721

SNOSAW6E – JANUARY 2008 – REVISED DECEMBER 2014

LMP7721 3-Femtoampere Input Bias Current Precision Amplifier

1 Features

3 Description

The LMP7721 is the industry’s lowest specified input

1

•

bias current precision amplifier. The ultra-low input

bias current is 3 fA, with a specified limit of ±20 fA at

•

25°C and ±900 fA at 85°C. This is achieved with the

–

Maximum at 25°C ±20 fA

latest patent-pending technology of input bias current

cancellation amplifier circuitry. This technology also

–

Maximum at 85°C ±900 fA

maintains the ultra-low input bias current over the

•

Offset Voltage ±26 µV

entire input common-mode voltage range of the

•

Offset Voltage Drift

−1.5 μV/°C

amplifier.

•

DC Open-Loop Gain 120 dB

Other outstanding features, such as low voltage noise

•

DC CMRR 100 dB

(6.5

nV/

√Hz),

low

DC-offset

voltage

(±150

µV

maximum

at

25°C)

and

low-offset

voltage

•

Input Voltage Noise (at f = 1 kHz) 6.5 nV/

√Hz

temperature coefficient (

−1.5 µV/°C), improve system

•

THD 0.0007%

sensitivity

and

accuracy

in

high-precision

•

Supply Current 1.3 mA

applications. With a supply voltage range of 1.8 V to

5.5 V, the LMP7721 is the ideal choice for battery-

•

GBW 17 MHz

operated, portable applications. The LMP7721 is part

•

Slew Rate (Falling Edge) 12.76 V/

μs

of the LMP™ precision amplifier family.

•

Supply Voltage 1.8 V to 5.5 V

As part of Texas Instruments' PowerWise™ products,

•

Operating Temperature Range

−40°C to 125°C

the LMP7721 provides the remarkably wide-gain

•

8-Pin SOIC

bandwidth

product

(GBW)

of

17

MHz

while

consuming only 1.3 mA of current. This wide GBW

2 Applications

along with the high open-loop gain of 120 dB enables

accurate

signal

conditioning.

With

these

•

Photodiode Amplifier

specifications, the LMP7721 has the performance to

•

High Impedance Sensor Amplifier

excel in a wide variety of applications such as

•

Ion Chamber Amplifier

electrochemical cell amplifiers and sensor interface

circuits.

•

Electrometer Amplifier

•

pH Electrode Amplifier

The LMP7721 is offered in an 8-pin SOIC package

with a special pinout that isolates the amplifier’s input

•

Transimpedance Amplifier

from the power supply and output pins. With proper

board layout techniques, the unique pinout of the

Ultra-Low Input Bias Current

LMP7721 will prevent PCB leakage current from

reaching the input pins. Thus system error will be

further reduced.

Device Information(1)

PART NUMBER

PACKAGE

BODY SIZE (NOM)

LMP7721

SOIC (8)

4.90 mm × 3.90 mm

(1) For all available packages, see the orderable addendum at

the end of the datasheet.

1

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.