Overview
The INA326EA/250, produced by Texas Instruments, is a high-performance, low-cost, precision instrumentation amplifier. It features rail-to-rail input and output, making it suitable for a wide range of applications from general-purpose to high-accuracy. This amplifier is known for its excellent long-term stability and very low 1/f noise, ensuring low offset voltage and drift throughout its operational life. The INA326EA/250 is available in an 8-pin MSOP (DGK) package and operates over an industrial temperature range of –40°C to +85°C, with extended operation up to +125°C.
Key Specifications
| Parameter | Condition | Min | Typ | Max | Units |
|---|---|---|---|---|---|
| Supply Voltage | +5.5V | V | |||
| Input Offset Voltage, RTI | VS = +5V, VCM = VS/2 | ±20 | ±100 | ±124 | µV |
| Input Impedance, Differential | 10^10 || 2 Ω || pF | ||||
| Input Impedance, Common-Mode | 10^10 || 14 Ω || pF | ||||
| Operating Temperature Range | –40°C | +125°C | °C | ||
| Storage Temperature Range | –65°C | +150°C | °C | ||
| Junction Temperature | +150°C | °C | |||
| Lead Temperature (soldering, 10s) | +300°C | °C |
Key Features
- Precision and Low Offset: The INA326EA/250 offers low DC errors and a high degree of precision, making it suitable for high-accuracy applications.
- Rail-to-Rail Input and Output: The amplifier can process input signals that extend beyond the positive and negative power-supply rails, providing true rail-to-rail input behavior.
- High Common-Mode Rejection Ratio (CMRR): The unique internal topology of the INA326 ensures excellent CMRR without the need for accurately matched resistors.
- Low Noise and Drift: The amplifier features very low 1/f noise and excellent long-term stability, ensuring minimal offset voltage and drift over temperature.
- Input Protection: The inputs are protected with internal diodes clamped to the power-supply rails, preventing damage from signals that exceed the supply rails by more than 0.5V).
- Enable/Shutdown Function (INA327): Although not present in the INA326EA/250, the INA327 variant includes an enable/shutdown function, which can significantly reduce power consumption in battery-operated applications).
Applications
- General-Purpose Instrumentation: Suitable for a variety of general-purpose instrumentation applications due to its high accuracy and low noise).
- Thermocouple and Bridge Transducer Interfaces: The INA326EA/250 is ideal for interfacing with thermocouples and bridge transducers, providing accurate and stable signal amplification).
- Medical and Industrial Equipment: Its precision and stability make it a good choice for medical and industrial equipment where accurate signal processing is critical).
- Automotive and Aerospace: The amplifier's robust performance over a wide temperature range makes it suitable for use in automotive and aerospace applications).
Q & A
- What is the operating temperature range of the INA326EA/250?
The operating temperature range is –40°C to +125°C, with specified performance over –40°C to +85°C.
- What is the input offset voltage of the INA326EA/250?
The input offset voltage is typically ±100 µV, with a maximum of ±124 µV over temperature.
- What is the common-mode rejection ratio (CMRR) of the INA326EA/250?
The CMRR is excellent due to the unique internal topology, but specific values are not provided in the datasheet. It is noted that CMRR is not affected by resistance in the reference connections or sockets.
- How is the gain set in the INA326EA/250?
The gain is set using external resistors R1 and R2, with the overall gain described by the equation: G = 2 * (R2/R1).
- What is the input impedance of the INA326EA/250?
The differential input impedance is approximately 10^10 Ω || 2 Ω || pF, and the common-mode input impedance is approximately 10^10 Ω || 14 Ω || pF.
- Does the INA326EA/250 have input protection?
Yes, the inputs are protected with internal diodes clamped to the power-supply rails, preventing damage from signals that exceed the supply rails by more than 0.5V.
- What is the typical quiescent current of the INA326EA/250?
The typical quiescent current is around 2.4 mA, but this can vary with temperature and supply voltage.
- Can the INA326EA/250 be used in single-supply applications?
Yes, the INA326EA/250 can be used in single-supply applications, but it may require adjustments in the gain-setting resistors to ensure full output swing.
- How does the INA326EA/250 handle common-mode signals near the power-supply rails?
The INA326EA/250 uses a unique internal topology to achieve true rail-to-rail input behavior, allowing it to linearly process inputs up to 20mV below the negative power-supply rail and 100mV above the positive power-supply rail.
- What is the purpose of the output filter in the INA326EA/250?
The output filter minimizes auto-correction circuitry noise and can also serve as an anti-aliasing filter ahead of an Analog-to-Digital (A/D) converter.
