The ACPL-C78A/C780/C784 isolation amplifier family was designed for current sensing in electronic motor drive and automotive applications. 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), which provides the precision and stability in high noise motor control environments.
The current sensor can also be used for general analog signal isolation applications requiring high accuracy, stability, and linearity under similarly severe noise conditions. They are offered with gain tolerance of ±1% (ACPL-C78A), ±3% (ACPL-C780) and ±5% (ACPL-C784) to suit application need. The ACPL-C78A/C780/C784 utilizes sigma-delta analog-to-digital converter technology, chopper stabilized amplifiers, and a fully differential circuit topology.
Together, these features deliver unequaled isolation-mode noise rejection, as well as excellent offset and gain accuracy and stability over time and temperature. This performance is delivered in a compact, auto-insertable, Stretched SO-8 (SSO-8) package (with 30% smaller footprint compared to the DIP-8 package) that meets 8 mm clearance and creepage requirements and worldwide regulatory safety standards.
