CA-IS3722HS Datasheet, Pinout, Equivalents, and Specs
The CA-IS3722HS is a high-performance, dual-channel digital isolator developed by Corebai, utilizing advanced capacitive isolation technology. It is engineered to provide robust galvanic isolation for digital signals in systems requiring high voltage protection and noise immunity. The device is characterized by its high data rate, low propagation delay, and high common-mode transient immunity (CMTI), making it suitable for industrial automation, motor control, and isolated communication interfaces.
Table of Contents
What is the CA-IS3722HS?
The CA-IS3722HS is a dual-channel digital isolator that transmits digital signals across a silicon dioxide (SiO₂) insulation barrier. This architecture ensures reliable data transfer between two distinct voltage domains while preventing ground loops and protecting sensitive circuitry from high voltage transients. The internal circuitry consists of a transmitter on one side that modulates the input signal into a high-frequency carrier, which is capacitively coupled across the isolation barrier to a receiver on the other side. The receiver demodulates the signal and restores it to its original digital state. This device is specifically designed for applications demanding high reliability and performance in harsh electrical environments, such as factory automation systems, isolated switch-mode power supplies (SMPS), and medical electronics.
Pinout Configuration and Packaging
The CA-IS3722HS is typically available in a standard 8-pin narrow-body SOIC package (SOIC-8), which is suitable for space-constrained applications. The pinout is logically divided into two isolated sides. Side 1 includes power (VDD1), ground (GND1), and the two input channels (INA, INB). Side 2 contains the corresponding isolated power (VDD2), ground (GND2), and the output channels (OUTA, OUTB). This clear separation simplifies PCB layout and helps maintain the integrity of the isolation barrier. An enable pin (EN) may also be present on one or both sides to control the output state, allowing for high-impedance outputs when disabled.
Core Architectural Features
- High-Speed Operation: Supports data rates up to 150 Mbps, making it suitable for high-speed serial interfaces like SPI and isolated CAN transceivers.
- Robust Isolation Barrier: Provides a galvanic isolation rating of up to 5 kVrms for 60 seconds, ensuring system safety and compliance with industry standards like UL1577.
- Superior Common-Mode Transient Immunity (CMTI): Features a typical CMTI of ±150 kV/μs, which provides high immunity to fast transients between the two isolated ground references, preventing data corruption in noisy environments.
- Low Propagation Delay and Skew: Exhibits a typical propagation delay of less than 15 ns with minimal channel-to-channel output skew, critical for timing-sensitive applications.
- Wide Supply Voltage Range: Operates with supply voltages from 2.5V to 5.5V on both sides, allowing for direct interfacing with a wide range of microcontrollers and logic families without level shifters.
Specifications Parameter Table
| Specification | Technical Details |
|---|---|
| Isolation Voltage (VISO) | 5000 Vrms for 1 minute |
| Maximum Data Rate | 150 Mbps |
| Supply Voltage Range (VDD1, VDD2) | 2.5 V to 5.5 V |
| Propagation Delay (tpd) | 13 ns (Typical, 5V supply) |
| Common-Mode Transient Immunity (CMTI) | ±150 kV/μs (Minimum) |
| Operating Temperature Range | -40°C to +125°C |
CA-IS3722HS Equivalents, Cross Reference, and Lifecycle
The CA-IS3722HS is an active production component. When considering alternatives, engineers often evaluate devices from other manufacturers that offer similar performance and pin configurations. Potential pin-to-pin compatible equivalents include the Texas Instruments ISO772x series and the Silicon Labs Si862x series. However, it is critical to compare key datasheet parameters such as CMTI, propagation delay, and isolation rating, as minor differences can impact system performance. Before finalizing a design or substitution, it is essential to Check CA-IS3722HS Inventory & Pricing to confirm availability and lead times. For a wider selection of components with varying channel counts and specifications, engineers can Browse Isolator Series to find the optimal part for their specific application.
Typical Application & Circuit Considerations
The CA-IS3722HS is frequently used to isolate communication interfaces such as SPI, UART, and RS-485 in industrial control systems, battery management systems (BMS), and solar inverters. For optimal performance, proper PCB layout is crucial. Power supply decoupling capacitors (typically 0.1 μF ceramic) should be placed as close as possible to the VDD1/GND1 and VDD2/GND2 pins to minimize supply ripple and ensure signal integrity. The PCB layout should maintain a clear keep-out area under and around the isolator package, with no copper traces or planes crossing the isolation barrier on any layer. This practice maximizes the creepage and clearance distances, ensuring the integrity of the high-voltage isolation.
Video Demonstration
Frequently Asked Questions (CA-IS3722HS FAQ)
Q: What is the role of the default output state in the CA-IS3722HS?
A: The default output state defines the logic level of the output pin when the input-side power supply (VDD1) is not present or the input channel is disabled. The CA-IS3722HS typically features a default-low or default-high option, specified by a suffix in the part number. This feature is critical for system safety, as it ensures that downstream components, such as motor drivers or power switches, enter a predictable and safe state during power-up, power-down, or fault conditions.
Q: How does the capacitive isolation technology in the CA-IS3722HS work?
A: The CA-IS3722HS uses a pair of high-voltage capacitors fabricated within the silicon die, separated by a robust silicon dioxide (SiO₂) dielectric. The transmitter circuit on the input side modulates the digital signal into a high-frequency RF carrier. This carrier is coupled across the capacitive barrier to the receiver on the isolated side. The receiver detects the carrier, demodulates it back into the original digital logic level, and drives the output. This method provides high immunity to magnetic fields and achieves high data rates with low power consumption compared to older optocoupler technology.
Q: What are the best practices for PCB layout when using the CA-IS3722HS to maximize CMTI?
A: To maximize Common-Mode Transient Immunity (CMTI), minimizing the parasitic capacitance between the isolated ground planes (GND1 and GND2) is paramount. The layout should have a distinct split between the GND1 and GND2 planes, with the isolator straddling this gap. No copper traces should cross this isolation gap on any layer. Placing stitching vias along the edge of each ground plane can help contain return currents and reduce noise coupling. Additionally, using low-inductance decoupling capacitors placed very close to the VDD/GND pins on both sides helps provide a stable power source during fast transient events.
Q: Can the CA-IS3722HS be used for isolating bidirectional signals like I2C?
A: The CA-IS3722HS is a unidirectional isolator, meaning each channel transmits data in one fixed direction. To isolate a bidirectional bus like I2C, which has SCL (unidirectional) and SDA (bidirectional) lines, two channels are required for the SDA line. One channel isolates the signal from the master to the slave, and a second channel isolates the signal from the slave back to the master. This requires external logic or a specialized I2C isolator IC that integrates this bidirectional capability internally.
Q: What is the significance of the 'HS' suffix in the CA-IS3722HS part number?
A: The 'HS' suffix in the CA-IS3722HS part number typically denotes "High Speed." This indicates that this specific variant of the isolator is optimized for high data rate applications, generally up to 150 Mbps. This contrasts with other variants that might be optimized for lower power consumption or lower speeds (e.g., 1 Mbps). The high-speed version achieves this performance through faster internal switching circuits, which may result in slightly higher quiescent current compared to its lower-speed counterparts.
Alan Carter
Senior Hardware Engineer & Component Specialist
Alan has over 15 years of expertise in embedded systems design, FPGA architecture, and global semiconductor supply chains. He specializes in component cross-referencing, lifecycle management, and helping OEMs navigate supply shortages.
