Broadcom ACPL-C877

The ACPL-C877 is a 1-bit, second-order sigma-delta modulator that converts an analog input signal into a high-speed data stream through integration of galvanic isolation based on optical coupling technology. The wide 2V input voltage range and the high input impedance of 1GΩ makes the device well suited for direct connection to the resistive dividers in high-voltage applications including motor drives and renewable energy systems. The ACPL-C877 has a dynamic range of 76 dB with an appropriate digital filter and operates from a 5V power supply. The sigma-delta modulator continuously measures the analog input by over-sampling using an internally built precision clock. The signal information is contained in the modulator data, as a density of ones with a data rate of 10 MHz. The data is then encoded and transmitted across the isolation boundary where the clock and data are recovered and decoded into a high-speed data stream of digital ones and zeros. The original signal information can be reconstructed with a digital filter. The serial interface for data and clock has a wide supply range of 3V to 5.5V. Combined with superior optical coupling technology, the modulator delivers high noise margins and excellent immunity against isolation-mode transients. With 0.5 mm minimum distance through insulation (DTI), the ACPL C877 provides reliable reinforced insulation and high working insulation voltage, which is suitable for fail-safe designs. This isolation performance is superior to alternatives including devices based on capacitive- or magnetic-coupling with DTI in micro-meter range. Offered in a SSO8 package, the isolated ADC delivers the reliability, small size, superior isolation and over-temperature performance motor drive designers need to accurately measure voltage. An analog output version voltage sensor ACPL-C87A (SSO8 package) is also available.

Key features

• Superior Optical Isolation and Insulation
• 10 MHz internal clock
• 1-bit, second-order sigma-delta modulator
• -40°C to +110°C operating temperature range
• Output slew rate control
• 3V to 5.5V wide supply range for digital interface
• ±1% maximum gain error
• Safety and regulatory approval UL 1577: 5000 V_rms/1 min isolation voltage CAN/CSA-C22.2 No. 62368-1 IEC/EN/DIN EN 60747-5-5: 1414 V_peak working insulation voltage

Applications

• AC and servo motor drives
• Solar inverters and wind turbine inverters
• Isolated sensor interfaces
• Signal isolation in data acquisition systems
• General purpose voltage sensing
• Voltage sensing in insulation resistance measurements