The ACPL-C797 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 ACPL-C797 uses a 5 V power supply with dynamic range of 80 dB and an appropriate digital filter. The differential inputs of ±200 mV (full scale ±320 mV) are ideal for direct connection to shunt resistors or other low-level signal sources in applications such as motor phase current measurement.
The analog input is continuously measured by the sigma-delta modulator by over-sampling using an on-board clock. The signal information is contained in the modulator data, as a density of ones with data rate of 10 MHz. Data is then encoded and transmitted across the isolation boundary where it is recovered and decoded into 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 3 V to 5.5 V.
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 C797 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 SO-16 package, the isolated ADC delivers the reliability, small size, superior isolation and over-temperature performance motor drive designers need to accurately measure current. This design alternative delivers a lower price when compared to traditional current transducers.
An external clock version modulator ACPL-796J (SO-16 package) is also available.
- 10 MHz internal clock
- 1-bit, second-order sigma-delta modulator
- 16 bits resolution no missing codes (12 bits ENOB)
- TBD dB minimum SNR
- 3.5 µV/°C maximum offset drift
- ±1% maximum gain error
- Internal reference voltage
- ±200 mV linear range with single 5 V supply (±320 mV full scale)
- 3 V to 5.5 V wide supply range for digital interface
- –40°C to +105°C operating temperature range
- Stretched SO-8 package
- 25 kV/µs common-mode transient immunity
- Safety and regulatory Approval (pending):
- UL 1577 (5000 Vrms/1 min.)
- IEC/EN/DIN EN 60747-5-5
- Options available are :
- 000E: Lead Free Option
- 060E: IEC/EN/DIN EN 60747-5-5 Option
- 500E: Tape and Reel Packaging Option
- Motor Phase and Rail Current Sensing
- Power Inverter Current and Voltage Sensing
- Industrial Process Control
- Data Acquisition Systems
- General Purpose Current and Voltage Sensing
- Traditional Current Transducer Replacements