INA321E/250G4

Overview

The INA321E/250G4 is a micro-power single-supply CMOS instrumentation amplifier manufactured by Texas Instruments. It features a 500 kHz bandwidth and a 400 mV/us slew rate, designed for high-precision signal conditioning in noisy environments. The device operates on a supply voltage range of 2.7 V to 5.5 V with a typical quiescent current of 40 uA per channel. Key electrical specifications include a common-mode rejection ratio (CMRR) of 90 dB, an input bias current of 10 pA, and an input offset voltage of 1 mV. It utilizes a VSSOP-8 package and supports an operating temperature range from -55°C to +125°C.

Feature Summary

• Provides rail-to-rail output swing for efficient use of low-voltage supplies
• Features internal configuration at 5 V/V gain with user-programmable external gain resistors
• Maintains high CMRR up to 3 kHz to reject line noise and harmonics
• Includes shutdown functionality with static current less than 1 uA

Applications

• Industrial sensor amplification for bridges, RTDs, and thermistors
• Physiological signal amplification including ECG, EEG, and EMG
• Signal conditioning for driving analog-to-digital converters
• Differential line receivers with integrated gain
• Portable test equipment and automotive instrumentation

Procurement Notes

Verify the specific suffix 'G4' against the manufacturer's official documentation to confirm lead-free compliance and RoHS status, as suffixes can indicate variations in packaging or material composition. Ensure the ordering part number matches the exact package type and temperature grade required for your design. Cross-reference the datasheet revision history to confirm that pinout assignments and electrical characteristics remain consistent with your schematic requirements before finalizing procurement.

Selection Notes

Select this component when designing circuits requiring low power consumption alongside moderate bandwidth and high precision. The internal 5 V/V gain setting simplifies resistor selection for standard applications, while external gain options provide flexibility. Consider the wide operating temperature range and low input bias current for high-impedance sensor interfaces. Evaluate the trade-off between the 40 uA quiescent current and the 500 kHz bandwidth to ensure it meets system power budgets without sacrificing necessary signal fidelity.

Part Context

The INA321 series represents Texas Instruments' solution for cost-effective, low-noise instrumentation amplification in compact packages. Designed as a CMOS alternative to bipolar devices, it offers superior input impedance and lower power dissipation. This series integrates precision matched components to achieve high common-mode rejection ratios, making it suitable for replacing discrete amplifier designs in space-constrained portable and industrial applications.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided source material.