ACPL-C784-500E

The ACPL-C78A/C780/C784 family of isolation amplifiers is 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 is 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, the ACPL-C780 (gain tolerance of ±3%) and the ACPL-C784 (gain tolerance of ±5%) are recommended. For precision applications, the ACPL-C78A with part-to-part gain tolerance of ±1% is offered. The ACPL-C78A/C780/C784 utilizes sigma-delta (Σ - Δ) 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 that meets worldwide regulatory safety standards.

Applications

• Motor Phase and Rail Current Sensing
• Inverter Current Sensing
• DC bus voltage sensing
• General Purpose Current Sensing and Monitoring
• General Purpose Analog Signal Isolation

Key features

• 15 kV/μs Common-Mode Rejection at VCM = 1000 V
• Compact, Auto-Insertable Stretched SO-8 Package
• 0.00025 V/V/°C Gain Drift vs. Temperature
• 0.3 mV Input Offset Voltage
• 100 kHz Bandwidth
• 0.004% Nonlinearity
• Worldwide Safety Approval: UL 1577 (5000 Vrms/1 min.), CSA and IEC/EN/DIN EN 60747-5-5
• Advanced Sigma-Delta (Σ - Δ) A/D Converter Technology
• Fully Differential Amplifier