OPA4322AIPWR

The OPA4322AIPWR from Texas Instruments is a quad-channel, precision CMOS operational amplifier optimized for low-power, high-impedance sensor applications. The device combines 20MHz gain-bandwidth product and 10V/μs slew rate with an ultra-low input bias current of 0.5pA, making it ideal for interfacing with high-impedance sensors such as photodiodes, pH probes, and piezoelectric transducers. The rail-to-rail input and output stages maximize dynamic range in single-supply applications from 1.8V to 5.5V. With a low input offset voltage of 400μV and voltage noise density of 7nV/√Hz, the OPA4322 delivers precision performance for signal conditioning. Each channel consumes only 1.4mA, making the quad package efficient for multi-channel systems.

The OPA4322AIPWR uses a CMOS input stage that provides virtually zero input bias current (0.5pA), eliminating the offset errors caused by bias current flowing through high-impedance source resistors. The rail-to-rail input stage uses complementary PMOS/NMOS differential pairs that cover the entire supply range. The output stage uses a class-AB push-pull architecture for rail-to-rail output swing with low distortion. Internal EMI filtering on the inputs reduces susceptibility to RF interference. Phase reversal protection circuitry ensures the output does not invert when the input common-mode range is exceeded. The amplifier is internally compensated for unity-gain stability and can drive capacitive loads up to 1nF without oscillation.

• Photodiode TIA: Transimpedance amplifier for optical sensors with 0.5pA bias current
• Medical Instrumentation: ECG/EEG front-end amplification with high input impedance
• Multi-Channel DAQ: Quad op-amp for simultaneous 4-channel sensor signal conditioning
• Portable Audio: Low-voltage audio preamplifier with low noise and RRO
• Chemical Sensors: pH and gas sensor interface requiring ultra-low input current