How to find the right Isolation Amplifiers AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in Isolation Amplifiers
- Isolation rating
- Check both the withstand voltage and the continuous working voltage against your system. Look for recognized safety certifications such as UL 1577 and VDE. The withstand rating alone does not guarantee safe continuous operation at high voltage.
- CMTI
- For motor drives and switching inverters, choose high common-mode transient immunity. Fast switching edges corrupt the output of parts with low CMTI.
- Input range and topology
- Shunt-sensing isolated amplifiers have small input ranges, typically in the tens to hundreds of millivolts. Voltage sensing needs a divider into that range. Mismatched input range wastes resolution or saturates the part.
- High-side power
- Plan an isolated supply for the input side unless the part integrates one. Many isolation amplifiers need power on both sides of the barrier.
- Linearity, gain error and bandwidth
- Compare nonlinearity and gain drift for measurement work. Compare bandwidth for control loops. These specs separate precision measurement parts from basic monitoring parts.
Brands that matter
- Texas Instruments: Makes the AMC series of reinforced-isolation amplifiers and the ISO124.
- Analog Devices: Offers transformer- and iCoupler-based isolated amplifiers, including the classic AD210.
- Broadcom: Makes optically isolated amplifiers in the ACPL family, widely used in drives.
- Silicon Labs: Offers capacitive-isolation amplifiers for current and voltage sensing.
What to avoid
- Using a plain optocoupler for analog signals that need linearity.
- Routing PCB traces or placing ground pours across the isolation barrier, which defeats creepage and clearance.
- Unmarked or unbranded parts in safety-critical, mains-connected designs.
- Forgetting the isolated supply for the input side.
Questions
Isolation amplifier or isolated delta-sigma modulator?
An isolation amplifier outputs an analog signal for an existing ADC. An isolated modulator outputs a bitstream that needs a digital filter, usually in an MCU or FPGA, but it offers higher resolution.