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.