SBASAA7A May 2021 – September 2021 AMC1411
Reinforced isolated amplifiers are commonly offered in SOIC packages with less than 9 mm of clearance and creepage specification. Equipment with working voltages greater than 850 V, impulse voltage requirements greater than 8000 V, systems designed for altitudes greater than 2000 m or for environments with pollution degree 2 or higher, may require clearance and creepage distances greater than 9 mm depending on the overvoltage category the system is designed for. Examples are 690-V unearthed (IT) 3-phase power network for high-reliability industrial applications or corner-earthed, 690-V, 3-phase systems commonly used for high-power AC motor drives.
The AMC1411 comes in a SOIC package with greater than 15 mm of creepage distance and is specifically designed for use in high-voltage systems that require accurate voltage monitoring and reinforced isolation between high-voltage and low-voltage parts of the system.
Figure 8-1 shows a 3-phase motor-drive application that uses the AMC1411 to monitor the 1200-V, DC-link voltage. The DC-link voltage is divided down to an approximate 2-V level across the bottom resistor (RSNS) of a high-impedance resistive divider that is sensed by the AMC1411. The output of the AMC1411 is a differential analog output voltage of the same value as the input voltage but is galvanically isolated from the high-side by a reinforced isolation barrier.
The wide creepage and clearance, high isolation voltage rating, and high common-mode transient immunity (CMTI) of the AMC1411 ensure reliable and accurate operation in harsh and high-noise environments.