Digital isolation is an essential part of many industrial, automotive, energy and power-electronics systems. Digital isolators allow signals to cross an electrical isolation barrier while helping protect low-voltage control electronics from ground-potential differences, high-voltage transients and electrical noise.
Traditionally, engineers have selected digital isolation and isolated interface devices from established semiconductor manufacturers such as Texas Instruments, Analog Devices, Infineon and others. However, several Chinese analog semiconductor companies now offer broad isolation portfolios covering standard digital isolators, isolated CAN, isolated RS-485/RS-422, isolated I²C and devices that integrate isolated power.
These products may provide additional sourcing options for industrial automation, motor drives, battery-management systems, solar inverters, energy storage, charging infrastructure and other electrically demanding applications.
This article looks at selected devices from Chipanalog and NOVOSENSE and highlights important parameters engineers should evaluate when considering an alternative isolation solution.
Galvanic isolation prevents direct electrical conduction between different sections of a system while still allowing information or power to pass across the isolation barrier.
Typical reasons for using digital isolation include:
→ Breaking ground loops
→ Protecting low-voltage controllers from high-voltage circuitry
→ Improving communication reliability in electrically noisy environments
→ Isolating communication buses such as CAN and RS-485
→ Separating primary and secondary sides of power converters
→ Protecting measurement and control circuitry
→ Meeting system-level insulation and safety requirements
The following products illustrate some of the isolation and isolated-interface solutions currently available from Chinese analog semiconductor suppliers.
| Manufacturer | Example Device | Device Type | Isolation | Key Feature |
|---|---|---|---|---|
| Chipanalog | CA-IS372x | Dual-channel digital isolator | Up to 5kVRMS depending on package | Flexible channel direction options |
| NOVOSENSE | NSI824x | Quad-channel digital isolator | Up to 8kVRMS depending on version | Up to 150Mbps data rate |
| Chipanalog | CA-IS2062A | Isolated CAN transceiver | 2.5kVRMS | CAN FD up to 5Mbps with integrated isolated DC/DC |
| NOVOSENSE | NSI1050 | Isolated CAN transceiver | Package-dependent isolation ratings | Integrated digital isolation for CAN communication |
| Chipanalog | CA-IS2092A | Isolated RS-485 transceiver | 2.5kVRMS | Integrated isolated DC/DC converter |
| NOVOSENSE | NSI83085C | Isolated half-duplex RS-485 | Up to 5kVRMS | Up to 12Mbps data rate |
| NOVOSENSE | NSI8200 | Bidirectional I²C isolator | Multiple isolation-voltage options | I²C clock up to 2MHz |
| NOVOSENSE | NSiP882x | Digital isolator with isolated power | Up to 4.5kVRMS | Integrated isolated DC/DC converter |
The devices above serve different functions and should not be assumed to be interchangeable. They illustrate the increasing breadth of isolation technology now available from Chinese analog semiconductor manufacturers.
Shanghai Chipanalog Microelectronics has developed one of the broader isolation and interface portfolios among Chinese analog semiconductor companies.
Its current isolation and interface product families include:
→ Standard digital isolators
→ Enhanced digital isolators
→ High-voltage I/O digital isolators
→ Ultra-low-power digital isolators
→ Digital isolators with integrated isolated power
→ Isolated CAN transceivers
→ Isolated CAN transceivers with integrated power
→ Isolated RS-485/RS-422 transceivers
→ Isolated RS-485/RS-422 transceivers with integrated power
→ Isolated I²C
→ Isolated LVDS
→ Isolated digital input/output devices
The company offers both industrial and automotive-grade products across parts of the portfolio, making the product range potentially relevant to industrial automation, PLC systems, motor control, energy systems and automotive electronics.
The CA-IS372x family consists of dual-channel digital isolators designed to transfer CMOS digital signals across a galvanic isolation barrier.
Different versions provide two channels in the same direction or one channel in each direction. The latter configuration can be useful for isolating transmit and receive signals associated with communication interfaces such as CAN or RS-485.
Depending on the package option, the family supports isolation ratings extending up to 5kVRMS.
NOVOSENSE has also developed a substantial portfolio of digital isolation, isolated interface, sensing and driver products for industrial and automotive electronics.
Relevant isolation products include:
→ Dual-channel digital isolators
→ Quad-channel digital isolators
→ Digital isolators with integrated isolated power
→ Isolated CAN transceivers
→ Isolated RS-485 transceivers
→ Isolated I²C interfaces
→ Isolated digital-input devices
The NSI824x family consists of reinforced quad-channel digital isolators supporting data rates up to 150Mbps.
Different versions support insulation withstand ratings ranging from approximately 3kVRMS through 8kVRMS, depending on device and package configuration.
The family also supports high common-mode transient immunity, making it relevant to electrically noisy industrial and power-electronics environments.
CAN is widely used in automotive electronics but is also common in industrial automation, battery systems, energy storage, charging equipment, robotics and other distributed control systems.
An isolated CAN implementation combines galvanic isolation with the CAN physical-layer transceiver.
Integration can reduce component count compared with a design using a separate digital isolator, CAN transceiver and isolated power supply.
The CA-IS2062A combines an isolated CAN transceiver with an integrated isolated DC/DC converter.
Key characteristics include:
→ Classic CAN support up to 1Mbps
→ CAN FD support up to 5Mbps
→ 2.5kVRMS isolation rating
→ Integrated isolated DC/DC converter
→ Typical common-mode transient immunity of ±150kV/µs
→ Bus fault protection
→ Operating temperature from -40°C to 125°C
The integration of isolated power can be particularly attractive in applications where PCB area and component count need to be reduced.
NOVOSENSE’s NSI1050 is another isolated CAN transceiver intended for applications requiring galvanic separation between the controller and CAN bus.
The device is offered in different package configurations with different creepage, clearance and working-isolation characteristics. Engineers should therefore evaluate the exact package and safety requirements rather than comparing only the product family name.
RS-485 and RS-422 remain extremely common in industrial automation because they provide robust differential communication over relatively long distances and in electrically noisy environments.
Typical applications include PLCs, industrial drives, building automation, smart meters, factory equipment, instrumentation and security systems.
The CA-IS2092A combines an isolated RS-485 transceiver with an integrated isolated DC/DC converter.
This architecture can remove the requirement for a separate isolated power-supply module in many designs, helping reduce PCB area and external component count.
The family provides:
→ Up to 2.5kVRMS galvanic isolation
→ Integrated isolated DC/DC conversion
→ High common-mode transient immunity
→ ESD protection for the communication bus
→ Industrial operating-temperature capability
The NSI83085C is a high-reliability isolated half-duplex RS-485 transceiver supporting data rates up to 12Mbps.
Key characteristics include:
→ Up to 5kVRMS insulation withstand voltage
→ Data rate up to 12Mbps
→ High common-mode transient immunity
→ Bus-side ESD protection
→ Support for up to 256 transceivers on the bus
→ Industrial automation and smart-meter applications
I²C presents a different isolation challenge because the SDA and SCL signals use bidirectional open-drain communication.
A standard unidirectional digital isolator therefore cannot always be substituted directly into an I²C bus without additional circuitry.
Dedicated isolated I²C devices handle the bidirectional behavior required by the interface.
The NSI8200 family provides bidirectional I²C isolation and supports clock rates up to 2MHz.
Different versions provide different insulation-voltage options, making the family applicable to a range of industrial and power-electronics systems requiring isolated communication between control domains.
A conventional digital isolator separates signals but normally requires power supplies on both sides of the isolation barrier.
This frequently means that an isolated DC/DC converter or transformer-based power supply must be added to the design.
Integrating isolated power with the digital isolator can significantly simplify the system architecture.
The NSiP882x family combines dual digital-isolation channels with an integrated isolated DC/DC converter.
Key characteristics include:
→ Up to 4.5kVRMS insulation withstand voltage
→ Data rates up to 150Mbps
→ Integrated isolated power conversion
→ Multiple input/output voltage configurations
→ High common-mode transient immunity
→ Operation from -40°C to 125°C
Chipanalog also offers digital isolators and isolated CAN and RS-485 interfaces with integrated isolated power, indicating that system-level integration is becoming an increasingly important area of competition among isolation semiconductor suppliers.
→ Industrial automation – PLC I/O, factory networks, field communication and industrial controllers
→ Motor drives – isolation between control electronics and power stages
→ Battery-management systems – isolated communication between battery domains and system controllers
→ Energy storage – isolated CAN, RS-485 and control signals
→ Solar inverters – communication and control isolation in high-voltage power systems
→ EV charging – isolation between power, communication and control sections
→ Building automation – isolated fieldbus communication
→ Smart meters – isolated communication and measurement systems
→ Medical and instrumentation equipment – applications requiring separation between electrical domains
Two digital isolators may appear similar from their channel count and isolation-voltage rating while differing significantly in other characteristics.
Important parameters to compare include:
→ Number of isolation channels
→ Direction of each channel
→ Isolation withstand voltage
→ Working isolation voltage
→ Reinforced versus basic insulation requirements
→ Creepage and clearance
→ Common-mode transient immunity (CMTI)
→ Maximum data rate
→ Propagation delay
→ Pulse-width distortion
→ Supply-voltage range
→ Default output state when an input is unpowered
→ ESD and surge performance
→ EMC performance
→ Package and pinout
→ Operating-temperature range
→ Automotive qualification where required
→ Safety-agency approvals and applicable standards
For an isolated communication transceiver, engineers need to evaluate both the isolation characteristics and the communication-interface specifications.
Additional parameters can include:
→ CAN, CAN FD, RS-485 or RS-422 compatibility
→ Maximum communication speed
→ Bus fault-protection voltage
→ Common-mode input range
→ Number of nodes supported
→ Fail-safe receiver behavior
→ Driver dominant timeout
→ Bus-pin ESD protection
→ Whether isolated power is integrated
A device with the same number of channels, isolation rating and data rate should not automatically be considered a drop-in replacement for another digital isolator.
Differences may include:
→ Pinout
→ Package dimensions
→ Channel direction
→ Default logic state
→ Safety certification
→ Creepage and clearance
→ Working-voltage rating
→ EMC behavior
→ System-level insulation requirements
For this reason, an alternative digital isolator should normally be treated as a device for technical evaluation rather than assumed to be pin-compatible unless the relevant specifications have been verified.
If you are currently using a digital isolator, isolated CAN transceiver, isolated RS-485 device or another isolated interface and would like to identify possible alternative devices, send AnySilicon your existing part number and application requirements.
Useful information includes:
→ Current manufacturer
→ Current part number
→ Interface type
→ Number and direction of channels
→ Required isolation voltage
→ Required data rate
→ Supply voltage
→ Application
→ Qualification or safety requirements
→ Expected annual volume
→ Target production date
Submit your existing isolation IC part number to AnySilicon to identify potential alternative devices. Contact us here.
The products discussed in this article are examples of digital isolation and isolated-interface devices available from semiconductor manufacturers. Inclusion does not indicate that AnySilicon distributes, represents or endorses a particular manufacturer.
Isolation products are frequently used in systems involving potentially hazardous voltages. Engineers must evaluate the complete system-level safety, insulation and regulatory requirements rather than relying solely on the isolation rating stated for an individual semiconductor device.
Product specifications, certification status and availability can change. The latest manufacturer datasheet, qualification documentation and applicable safety standards should always be reviewed before a device is selected.