ACPL-7970-300E

The ACPL-7970 is a 1-bit, second-order sigma-delta (S-?) 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 5 V power supply with dynamic range of 78 dB with 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 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 10 MHz, and the data are encoded and transmitted 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 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-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.

• 10 MHz internal clock
• 1-bit, second-order sigma-delta modulator
• 16 bits resolution no missing codes (12 bits ENOB)
• 78 dB SNR
• 6 mV/°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
• 25 kV/ms common-mode transient immunity
• Safety and regulatory approvals:
  • IEC/EN/DIN EN 60747-5-5: 891 Vpeak working insulation voltage
  • UL 1577: 5000 Vrms/1min isolation voltage
  • CSA: Component