1 Features

1? Unless Otherwise Noted, Typical Values at TA =

25°C, V S = 5 V.

? Input Bias Current (VCM = 1 V)

– Maximum at 25°C ±20 fA

– Maximum at 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 battery?

Slew Rate (Falling Edge) 12.76 V/μs

? Supply Voltage 1.8 V to 5.5 V

? Operating Temperature Range ?40°C to 125°C

? 8-Pin SOIC

2 Applications

? Photodiode Amplifier

? High Impedance Sensor Amplifier

? Ion Chamber Amplifier

? Electrometer Amplifier

? pH Electrode Amplifier

? Transimpedance Amplifier

3 Description

The LMP7721 is the industry’s lowest specified input

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

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/√Hz), 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 1.8 V to

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

operated, portable applications. The LMP7721 is part

of the LMP? precision amplifier family.

As part of Texas Instruments' 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.