TEXAS INSTRUMENTS INA138 Current Sense Amplifier, 2µA, SOT-23, 5 Pin

The TEXAS INSTRUMENTS INA138 and INA168 (INA1x8) are high-side, unipolar current shunt monitors, engineered for precise current measurement. With an exceptionally wide input common-mode voltage range and remarkably low quiescent current housed in a compact SOT-23 package, these devices are ideal for a broad spectrum of electronic applications. Their independent input common-mode and power-supply voltages offer significant design flexibility.

The INA138 supports a range from 2.7V to 36V, while the INA168 extends this up to 60V. A quiescent current of just 25µA minimises error, allowing the power supply to be connected on either side of the current measurement shunt. The device efficiently converts a differential input voltage into a current output, which is then reconverted to a voltage using an external load resistor. This architecture enables a versatile gain range from 1 to over 100, providing exceptional control over signal amplification.

While specifically designed for accurate current shunt measurement, the innovative circuit also opens the door to creative applications in general measurement and level-shifting tasks. Its high-performance specifications, including a gain bandwidth product of 800kHz and a common-mode rejection ratio (CMRR) of 120dB, ensure reliable operation in demanding environments. The device operates flawlessly across an extended temperature range from -40°C to 125°C, making it suitable for industrial, automotive, and consumer electronics.

Key Features:

• High-side, unipolar current shunt monitoring
• Wide input common-mode voltage range (2.7V to 60V for INA168)
• Ultra-low 25µA quiescent current
• Compact SOT-23-5 package for space-constrained designs
• External resistor sets gain from 1 to over 100
• High 120dB CMRR for excellent noise rejection
• Broad operating temperature range: -40°C to 125°C
• Low input offset voltage of 2mV and input bias