ACPL-7970-500E

The ACPL- 7970 is a 1- bit, second- order sigma- delta (Σ - Δ) modulator converts an analog input signal into a highspeed data stream with galvanic isolation based on optical coupling technology. The ACPL- 7970 operates from a 5V power supply with dynamic range of 78 dB with an appropriate digital filter. The differential inputs of ±200mV (full scale ±320mV) 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 sampled by a means of sigma- delta 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 10MHz, and the data are encoded and transmited across the isolation boundary where they are 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 3V to 5.5V. Combined with superior optical coupling technology, the modulator delivers high noise margins and excellent immunity against isolation- mode transients. With 0.5mm minimum distance through insulation (DTI), the ACPL- 7970 provides reliable reinforced insulation and high working insulation voltage, which is suitable for fail- safe designs. This outstanding isolation performance is superior to alternatives including devices based on capacitive- or magnetic- coupling with DTI in micro- meter range. Offered in a DIP- 8 package, the isolated ADC delivers the reliability, small size, superior isolation and over- temperature performance motor drive designers need to accurately measure current at much lower price compared to traditional current transducers. The external clock version modulator ACPL- 796J (SO- 16 package) is also available.

Applications

• 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

Key features

• 10 MHz internal clock
• 1- bit, second- order sigma- delta modulator
• 16 bits resolution no missing codes (12 bits ENOB)
• 78 dB SNR
• 6μV / °C maximum offset drift
• ±1% maximum gain error
• Internal reference voltage
• ±200mV linear range with single 5V supply (±320mV full scale)
• 3V to 5.5V wide supply range for digital interface
• - 40°C to +105°C operating temperature range
• 25kV / μs common- mode transient immunity
• Safety and regulatory approvals:
• IEC/fN/DIN EN 60747- 5- 5: 891 Vpeak working insulation voltage
• UL 1577: 5000 Vrms/1min isolation voltage
• CSA: Component Acceptance Notice #5