Overview
The INA121U/2K5, produced by Texas Instruments, is a FET-input, low power instrumentation amplifier known for its excellent accuracy and versatility. This amplifier features a three-op amp design and is remarkably compact, making it ideal for a variety of general-purpose applications. It is particularly suited for use with high impedance sources due to its low bias current of ±4pA. The INA121U/2K5 can operate on power supplies ranging from ±2.25V to ±18V, making it suitable for battery-operated and single 5V systems. Its quiescent current is only 450µA, contributing to its energy efficiency.
Key Specifications
| Parameter | Value | Units |
|---|---|---|
| Input Offset Voltage | ±200 | µV |
| Input Offset Drift | ±2 | µV/°C |
| Input Noise | 20 nV/√Hz at f = 1kHz (G = 100) | nV/√Hz |
| Common-Mode Rejection Ratio (CMRR) | 106 dB at G = 100 | dB |
| Supply Voltage Range | ±2.25V to ±18V | V |
| Quiescent Current | ±450 µA | µA |
| Input Protection | ±40 V | V |
| Operating Temperature Range | -40°C to +85°C | °C |
| Package Options | 8-pin plastic DIP, SO-8 surface mount |
Key Features
- Low Bias Current: ±4 pA, allowing use with high impedance sources.
- Low Quiescent Current: ±450 µA, making it energy-efficient.
- Low Input Offset Voltage and Drift: ±200 µV and ±2 µV/°C, respectively, ensuring high accuracy.
- Low Input Noise: 20 nV/√Hz at f = 1kHz (G = 100).
- High Common-Mode Rejection Ratio (CMRR): 106 dB at G = 100.
- Wide Supply Range: ±2.25V to ±18V, suitable for various power supply configurations.
- Low Nonlinearity Error: 0.001% max.
- Input Protection: Up to ±40V without damage.
- Compact Packaging: Available in 8-pin plastic DIP and SO-8 surface mount packages.
Applications
- Low-Level Transducer Amplifiers: Suitable for bridge, RTD, and thermocouple applications.
- Physiological Amplifiers: Used in ECG, EEG, EMG, and respiratory monitoring.
- High Impedance Transducers: Ideal for high impedance sources.
- Capacitive Sensors: Applicable in capacitive sensing applications.
- Multi-Channel Data Acquisition: Used in data acquisition systems.
- Portable, Battery Operated Systems: Suitable due to its low power consumption.
- General Purpose Instrumentation: Versatile for various general-purpose instrumentation needs).
Q & A
- What is the input offset voltage of the INA121U/2K5?
The input offset voltage is ±200 µV.
- What is the common-mode rejection ratio (CMRR) of the INA121U/2K5?
The CMRR is 106 dB at a gain of 100.
- What is the quiescent current of the INA121U/2K5?
The quiescent current is ±450 µA.
- What is the operating temperature range of the INA121U/2K5?
The operating temperature range is -40°C to +85°C.
- How is the gain of the INA121U/2K5 set?
The gain is set by connecting a single external resistor, RG, between pins 1 and 8.
- What are the package options for the INA121U/2K5?
The package options include 8-pin plastic DIP and SO-8 surface mount.
- What is the input protection voltage of the INA121U/2K5?
The input protection voltage is up to ±40V.
- Is the INA121U/2K5 suitable for battery-operated systems?
Yes, it is suitable due to its low power consumption and wide supply range.
- What are some common applications of the INA121U/2K5?
Common applications include low-level transducer amplifiers, physiological amplifiers, high impedance transducers, capacitive sensors, and multi-channel data acquisition systems.
- How does the INA121U/2K5 handle high frequency common-mode signals?
The INA121U/2K5 provides excellent rejection of high frequency common-mode signals, but proper input balancing and grounding are necessary to maintain this performance.
