FM2148 FMSH 5mVrms Earth Leakage Protection IC

The FMSH FM2148 is an analog ic.

Key Specifications

Design Notes

• The trip threshold is specified over a tolerance band, not at a single point. Design the sense resistor against the worst-case ends of that band, or nuisance tripping will appear at temperature extremes.
• These circuits are usually supplied from a capacitive dropper or a resistive divider off the mains. Verify the supply current budget against the datasheet before adding load.
• Package choice drives creepage. For mains-referenced parts, use the widest package the layout allows and keep the specified clearance to the low-voltage side.
• Check the temperature coefficient of the threshold if the product must hold accuracy over an outdoor temperature range.

Common Questions

What is the trip threshold?

the threshold above. The threshold is specified over a tolerance band, so size the sense element against the band ends rather than the typical value.

What does this device do?

the function described above. It integrates the control loop that would otherwise need a board of discrete parts.

Which packages are offered?

the package listed above. For mains-referenced circuits choose the package that meets the creepage requirement of the layout.

How is it powered?

Typically from a capacitive dropper or resistive divider off the mains rail. Check the supply current budget in the datasheet before adding any load to that rail.