Overview
The INA121PA, produced by Texas Instruments, is a FET-input, low power instrumentation amplifier known for its excellent accuracy and versatility. This amplifier is designed with a three-op amp configuration, which makes it ideal for a variety of general-purpose applications. It features low quiescent current, low input offset voltage, and high common-mode rejection, making it suitable for use in battery-operated and single 5V systems. The INA121PA operates on power supplies ranging from ±2.25V to ±18V and has a quiescent current of only 450µA, making it energy-efficient and reliable for various instrumentation needs.
Key Specifications
| Parameter | Conditions | Min | Typ | Max | Units |
|---|---|---|---|---|---|
| Input Offset Voltage, RTI | VS = ±15V, TA = +25°C | ±200 | ±200 | ±500 | µV |
| Input Offset Drift | VS = ±15V, TA = +25°C | ±2 | ±2 | ±5 | µV/°C |
| Common-Mode Rejection | VCM = –12.5V to 13.5V, G = 100 | 96 | 106 | 90 | dB |
| Bias Current | VCM = 0V | ±4 | ±4 | ±50 | pA |
| Power Supply Voltage Range | ±2.25 | ±18 | V | ||
| Quiescent Current | IO = 0V | ±450 | ±525 | µA | |
| Operating Temperature Range | –40 | 85 | °C |
Key Features
- Low Quiescent Current: ±450µA, making it suitable for battery-operated systems.
- Low Input Offset Voltage: ±200µV, with low offset drift of ±2µV/°C.
- High Common-Mode Rejection: Up to 106dB at G = 100.
- Wide Supply Range: Operates on power supplies from ±2.25V to ±18V.
- Low Nonlinearity Error: Maximum of 0.001%.
- Input Protection: Internal input protection up to ±40V without damage.
- Gain Flexibility: Gain can be set from 1 to 10,000 with a single external resistor.
- High Input Impedance: Approximately 10^12 Ω, suitable for high impedance sources).
Applications
- Low-Level Transducer Amplifiers: Bridge, RTD, Thermocouple).
- Physiological Amplifiers: ECG, EEG, EMG, Respiratory).
- High Impedance Transducers: Suitable for high impedance sources).
- Capacitive Sensors: Can be used with R/C input filters without large offsets).
- Multi-Channel Data Acquisition: Ideal for multiple channel applications).
- Portable, Battery Operated Systems: Low power consumption makes it suitable for portable systems).
- General Purpose Instrumentation: Versatile for various general-purpose instrumentation applications).
Q & A
- What is the typical quiescent current of the INA121PA?
The typical quiescent current is ±450µA).
- What is the input offset voltage of the INA121PA?
The input offset voltage is ±200µV).
- What is the common-mode rejection ratio (CMRR) of the INA121PA at a gain of 100?
The CMRR is up to 106dB at G = 100).
- What is the operating temperature range of the INA121PA?
The operating temperature range is –40°C to +85°C).
- How can the gain of the INA121PA be set?
The gain can be set from 1 to 10,000 with a single external resistor connected between pins 1 and 8).
- What is the maximum safe input voltage for the INA121PA?
The maximum safe input voltage is ±40V without damage).
- What are the package options for the INA121PA?
The package options include 8-pin plastic DIP and SO-8 surface mount).
- Can the INA121PA be used in battery-operated systems?
Yes, it can be used in battery-operated systems due to its low quiescent current).
- What is the typical input bias current of the INA121PA?
The typical input bias current is ±4pA).
- How does the INA121PA handle high frequency common-mode signals?
The INA121PA provides excellent rejection of high frequency common-mode signals due to its current-feedback topology).
