LMV321LICT

Product Overview

The STMicroelectronics LMV321LICT is a low-voltage, low-power operational amplifier designed for precision signal conditioning in battery-powered and portable applications. It features a single-supply operation with a wide voltage range and rail-to-rail input and output stages, allowing it to interface with signals close to ground and supply rails. The device offers low input bias current, low offset voltage, and low noise, making it suitable for a variety of analog front-end applications including sensor amplification, active filtering, and data acquisition systems.

The LMV321LICT is optimized for low power consumption, enabling extended battery life in portable devices while maintaining adequate bandwidth and slew rate for many general-purpose analog signal processing needs.

Key Features

* Wide single-supply voltage operation: 2.5 V to 5.5 V
* Rail-to-rail input and output capability
* Low input bias current: typically 1 pA
* Low input offset voltage: typically 1 mV
* Low supply current: approximately 230 µA per amplifier
* Unity gain bandwidth: 3 MHz typical
* Slew rate: 1 V/µs typical
* Low total harmonic distortion (THD): 0.002% at 1 kHz
* Input voltage noise density: 22 nV/√Hz at 1 kHz
* Operating temperature range: -40°C to +125°C
* Output short-circuit protection
* Available in a small footprint SOT-23-5 package
* Stable for gains equal to or greater than 1 (unity gain stable)
* CMOS input stage for low bias current and low offset
* Lead-free and RoHS compliant

Electrical Specifications

* Supply Voltage (V\_S): 2.5 V to 5.5 V
* Input Common-Mode Voltage Range: Extends from ground to V\_S - 1.5 V
* Output Voltage Swing: Within 20 mV of rails at 100 kΩ load
* Input Offset Voltage (V\_OS): Typically 1 mV, maximum 7 mV over temperature
* Input Bias Current (I\_B): Typically 1 pA, maximum 20 pA
* Input Offset Current (I\_OS): Typically 1 pA, maximum 20 pA
* Supply Current (I\_S): Typically 230 µA
* Unity Gain Bandwidth (f\_T): 3 MHz typical
* Slew Rate (SR): 1 V/µs typical
* Total Harmonic Distortion + Noise (THD+N): 0.002% at 1 kHz
* Input Voltage Noise Density: 22 nV/√Hz at 1 kHz
* Output Short-Circuit Current Limit: ±40 mA typical
* Operating Temperature Range: -40°C to +125°C
* Package Type: SOT-23-5

Functional Description

The LMV321LICT features a rail-to-rail input stage capable of sensing input signals down to ground level and up to near the positive supply voltage, allowing operation in low-voltage, single-supply systems without the need for negative supplies. The output stage is similarly rail-to-rail, ensuring maximum output signal range in low-voltage conditions.

Its CMOS input stage results in ultra-low input bias currents, minimizing input errors especially important in high-impedance sensor interfaces. Low offset voltage and low noise improve signal accuracy and fidelity, crucial in precision measurement and filtering applications.

The device is unity-gain stable and can be configured as a buffer, amplifier, integrator, or active filter, suitable for general-purpose analog signal processing.

Typical Application Circuit

A typical application involves using the LMV321LICT as an amplifier or buffer stage for sensor signals in battery-powered measurement devices. Connected in a non-inverting amplifier configuration with gain set by external resistors, it amplifies low-level signals while preserving signal integrity. Power supply decoupling capacitors close to the device pins help minimize noise and maintain stable operation.

Applications

* Sensor signal conditioning and amplification
* Portable and battery-powered instrumentation
* Active filters and integrators
* Data acquisition front ends
* Medical devices and wearable electronics
* Low-voltage analog signal processing
* Consumer electronics requiring low power analog stages
* General-purpose operational amplifier needs in low-voltage systems

Protection and Reliability Features

* Output short-circuit protection safeguards the device against accidental shorting of the output to ground or supply rails.
* Stable operation under capacitive loads, suitable for driving various filter configurations.
* Robust performance over extended temperature range ensures reliable operation in harsh environments.
* CMOS input stage reduces input leakage, maintaining accuracy over long periods and varying conditions.

Mechanical and Thermal Characteristics

The LMV321LICT is supplied in a small SOT-23-5 package, ideal for compact and space-sensitive designs. The device offers efficient heat dissipation for its power class, allowing operation at full specification over a wide temperature range without additional cooling.

* Package Dimensions: Compact SOT-23-5 surface mount
* Thermal Resistance Junction-to-Ambient (θ\_JA): Approximately 220°C/W on a standard PCB
* Mounting: Surface mount with low profile, suitable for automated assembly

Design Considerations

* To maximize accuracy, use precision resistors for gain setting and proper PCB layout to minimize noise pickup.
* Provide adequate power supply bypassing with ceramic capacitors close to the device supply pins.
* The rail-to-rail inputs and outputs simplify single-supply designs, but ensure input signals stay within specified voltage range for best performance.
* Consider device noise and offset specifications in sensitive measurement systems to achieve desired signal-to-noise ratio.
* Verify the output load does not exceed device short-circuit current ratings to ensure long-term reliability.

Conclusion

The STMicroelectronics LMV321LICT is a low-voltage, low-power operational amplifier offering rail-to-rail input/output, low offset, and low noise performance in a compact SOT-23-5 package. Its wide supply voltage range and low quiescent current make it ideal for portable, battery-operated applications as well as industrial and consumer electronics. With robust input bias and offset characteristics, stable operation, and protection features, it provides a reliable and precise analog front-end solution in a space-efficient form factor.