ACPL-C78A

ACPL-C78A, ACPL-C780, ACPL-C784 Miniature Isolation Amplifiers Data Sheet Description The ACPL-C78A/C780/C784 isolation amplifier family was designed for current sensing in electronic motor drives. In a typical implementation, motor currents flow through an external resistor and the resulting analog voltage drop is sensed by the ACPL-C78A/C780/C784. A differential output voltage is created on the other side of the ACPL-C78A/ C780/C784 optical isolation barrier. This differential output voltage is proportional to the motor current and can be converted to a single-ended signal by using an op-amp as shown in the recommended application circuit. Since common-mode voltage swings of several hundred volts in tens of nanoseconds are common in modern switching inverter motor drives, the ACPL-C78A/C780/C784 was designed to ignore very high common-mode transient slew rates (of at least 10 kV/µs). The high CMR capability of the ACPL-C78A/C780/C784 isolation amplifier provides the precision and stability needed to accurately monitor motor current in high noise motor control environments, providing for smoother control (less “torque ripple”) in various types of motor control applications. The product can also be used for general analog signal isolation applications requiring high accuracy, stability, and linearity under similarly severe noise conditions. For general applications, we recommend the ACPL-C780 (gain tolerance of ±3%) and the ACPL-C784 (gain tolerance of ±5%). For precision a...