Texas Instruments INA331IDGKR

The INA331IDGKR, produced by Texas Instruments, is a rail-to-rail output, low-power CMOS instrumentation amplifier. It is a modified version of the classic 'two op amp' instrumentation amplifier, with an additional gain amplifier. This device is designed for low-cost, low-noise amplification of differential signals and is suitable for a wide range of applications, including battery-powered and multi-channel systems. The INA331IDGKR operates over a supply range of +2.7V to +5.5V and is fully specified over a temperature range of –55°C to +125°C.

• Low Cost and Low Noise: The INA331IDGKR offers low-cost, low-noise amplification of differential signals with a low quiescent current of 415µA.
• High Gain Accuracy: The device provides high gain accuracy with a gain error less than 0.1% and a gain drift of 2ppm/°C.
• Flexible Gain Setting: The gain can be set with external resistors for gains greater than 5, using the equation G = 5 + 5(R2/R1).
• Low Offset Voltage: The device has a low input offset voltage of ±250µV.
• High CMRR: It features a high common-mode rejection ratio (CMRR) of 94dB DC.
• Rail-to-Rail Output: The INA331IDGKR has a rail-to-rail output stage, allowing the output to swing to within 25mV of the supply rail for resistive loads greater than 10kΩ.
• Shutdown Feature: The device includes a shutdown feature that reduces the quiescent current to 0.01µA, making it suitable for battery-powered applications.
• High Input Impedance: The INA331IDGKR has a high input impedance of 10^13Ω, making it ideal for use with high-impedance sources.

• Differential Line Receivers with Gain: Suitable for applications requiring differential signal amplification with gain.
• Field Utility Meters: Used in metering applications where accurate signal amplification is required.
• PCMCIA Cards: Applicable in PCMCIA card designs where low power and high precision are necessary.
• Audio Amplifiers: Can be used in audio applications requiring low noise and high gain accuracy.
• Communication Systems: Suitable for communication systems needing precise signal amplification.
• Test Equipment: Used in various test equipment applications where high precision and low noise are critical.
• Automotive Instrumentation: Applicable in automotive systems requiring accurate and reliable signal amplification.
• Medical ECG Applications: Can be configured as a low-cost ECG amplifier for moderate accuracy heart-rate applications.

1. What is the operating supply voltage range of the INA331IDGKR?

   The INA331IDGKR operates over a supply range of +2.7V to +5.5V.

2. What is the typical quiescent current of the INA331IDGKR?

   The typical quiescent current is 415µA.

3. How is the gain of the INA331IDGKR set?

   The gain can be set with external resistors using the equation G = 5 + 5(R2/R1).

4. What is the input offset voltage of the INA331IDGKR?

   The input offset voltage is ±250µV.

5. What is the common-mode rejection ratio (CMRR) of the INA331IDGKR?

   The CMRR is 94dB DC.

6. Does the INA331IDGKR have a shutdown feature?

   Yes, the device includes a shutdown feature that reduces the quiescent current to 0.01µA.

7. What is the input impedance of the INA331IDGKR?

   The input impedance is 10^13Ω.

8. What are some common applications of the INA331IDGKR?

   Common applications include differential line receivers, field utility meters, PCMCIA cards, audio amplifiers, communication systems, test equipment, automotive instrumentation, and medical ECG applications.

9. How does the INA331IDGKR handle high-impedance feedback networks?

   For high-impedance feedback networks, a feedback capacitor can be added to improve dynamic performance and stability.

10. Is the INA331IDGKR suitable for driving capacitive-input A/D converters?

    Yes, the INA331IDGKR is optimized for directly driving capacitive-input A/D converters due to its low output impedance at high frequencies.