Efficient 2MHz Industrial Isolated Input ICs: Secondary-Side Power Only

Novosense Microelectronics, a Shanghai-based analog and mixed signal IC company, has developed a pair of isolated digital input chips specifically designed for 24V industrial control applications. These chips, known as the NSI8604 and NSI8608, offer input/output isolation and require power only on the output side.

The NSI8604 is a 4-channel chip packaged in SSOP16, while the NSI8608 is an 8-channel chip packaged in SSOP20. Both chips are capable of converting voltages in the range of -60V to 60V to logic signals, with a data rate ranging from dc to 2Mbit/s and a propagation delay of 380ns.

"While these chips are compatible with the current input form of optocouplers, they provide a higher degree of system integration and eliminate the need for a field-side power supply, resulting in simplified system design," stated Novosense Microelectronics. The company also mentioned that the chips are pin-compatible with alternative technologies.

The input current of these chips is limited to 2.1mA (typical), and the input side includes a rectifier. The inputs are described as "sinking or sourcing" and support "bi-directional digital functionality." However, further clarification is needed regarding the polarity of the inputs and the minimum voltage. Electronics Weekly has reached out to Novosense Microelectronics for more information.

The NSI8604 and NSI8608 operate with a supply voltage ranging from 2.5V to 5.5V and can withstand temperatures from -40°C to 125°C. Inside the chips, isolation is achieved through capacitive coupling across a SiO2 barrier using on-off keying (OOK modulation). The isolation capability is up to 3kVrms, and the chips offer a CMTI (common-mode transient immunity) of at least 35kV/μs.

"Each IC meets the performance criteria for switch types 1, 2, and 3 in IEC 61131-2 and is compatible with the I/O level of most microcontrollers," stated Novosense Microelectronics. The company also mentioned that the chips are compliant with IEC 61131-2 Type 1 and 3.

The NSI8604 and NSI8608 chips have chip level ESD (electrostatic discharge) protection of ±4kV HBM (human body model). They are UL recognized for 3kVrms (1min per UL1577), CQC certified to GB4943.1-2011, and have CSA component notice SA approval (IEC60950-1) and DIN VDE V 0884-11:2017-01 certifications.

These isolated digital input chips are expected to find applications in programmable logic controllers (PLCs), servos, and inverters. Novosense Microelectronics, founded in 2013, continues to innovate in the field of analog and mixed signal ICs.

Editor's note: Please note that some details mentioned above are subject to clarification as the data sheet for these chips is not yet publicly available. Novosense Microelectronics has been contacted for further information. For more information about the NSI8604 chip, visit the product page. Additionally, electronic alternatives to opto-isolators, such as mosfet gate drivers and relay ICs, are becoming more prevalent. Texas Instruments offers some notably innovative alternatives.