Overview
The INA121UAG4, produced by Texas Instruments, is a FET-input, low power instrumentation amplifier designed for high accuracy and versatility. This amplifier is part of the INA121 series and is known for its low quiescent current, low input offset voltage, and high common-mode rejection ratio (CMRR). It is suitable for a wide range of applications, including low-level transducer amplifiers, physiological amplifiers, and high impedance transducers. The INA121UAG4 operates on power supplies as low as ±2.25V (+4.5V), making it ideal for battery-operated and single 5V systems.
Key Specifications
| Parameter | Min | Typ | Max | Units |
|---|---|---|---|---|
| Input Offset Voltage, RTI | ±200 | ±200 | ±500 | µV |
| Input Offset Drift | ±2 | ±2 | ±5 | µV/°C |
| Quiescent Current | ±450 | ±450 | ±525 | µA |
| Input Noise | 20 | 20 | 30 | nV/√Hz at f = 1kHz (G = 100) |
| Common-Mode Rejection Ratio (CMRR) | 96 | 106 | 106 | dB at G = 100 |
| Supply Voltage Range | ±2.25 | ±15 | ±18 | V |
| Input Bias Current | ±4 | ±4 | ±50 | pA |
| Operating Temperature Range | –40 | 85 | °C | |
| Package Type | SO-8 Surface Mount |
Key Features
- Low Quiescent Current: ±450µA, making it suitable for battery-operated systems.
- Low Input Offset Voltage: ±200µV, ensuring high accuracy.
- Low Input Offset Drift: ±2µV/°C, providing stable performance over temperature changes.
- Low Input Noise: 20nV/√Hz at f = 1kHz (G = 100), enhancing signal integrity.
- High Common-Mode Rejection Ratio (CMRR): 106dB at G = 100, for effective rejection of common-mode signals.
- Wide Supply Voltage Range: ±2.25V to ±18V, allowing flexibility in system design.
- Low Bias Current: ±4pA, suitable for use with high impedance sources.
- Internal Input Protection: Up to ±40V without damage.
Applications
- Low-Level Transducer Amplifiers: Bridge, RTD, Thermocouple.
- Physiological Amplifiers: ECG, EEG, EMG, Respiratory.
- High Impedance Transducers: Capacitive sensors and other high impedance sources.
- Multi-Channel Data Acquisition: Suitable for various data acquisition systems.
- Portable, Battery Operated Systems: Ideal for systems requiring low power consumption.
- General Purpose Instrumentation: Versatile enough for a variety of general-purpose applications.
Q & A
- What is the minimum supply voltage for the INA121UAG4?
The INA121UAG4 can operate on power supplies as low as ±2.25V (+4.5V). - What is the typical quiescent current of the INA121UAG4?
The typical quiescent current is ±450µA. - What is the input offset voltage of the INA121UAG4?
The input offset voltage is ±200µV. - How is the gain of the INA121UAG4 set?
The gain is set by connecting a single external resistor, RG, between pins 1 and 8. - What is the common-mode rejection ratio (CMRR) of the INA121UAG4?
The CMRR is 106dB at G = 100. - What is the operating temperature range of the INA121UAG4?
The operating temperature range is –40°C to 85°C. - Does the INA121UAG4 have internal input protection?
Yes, it has internal input protection up to ±40V without damage. - What are the package options for the INA121UAG4?
The package options include 8-pin plastic DIP and SO-8 surface mount. - How does the INA121UAG4 handle high impedance sources?
The INA121UAG4 is suitable for use with high impedance sources due to its low bias current (±4pA). - Can the INA121UAG4 be used in noisy environments?
Yes, it can be used in noisy environments with proper decoupling capacitors and careful layout to minimize noise.
