CA-IS3720HS Channel Digital Isolators

CA-IS3720HS Description

Devices of the CA-IS372x series are high-performance dual-channel digital isolators, known for their precise timing characteristics and low power consumption. Isolating CMOS digital I/Os is one of the many functions the CA-IS372x family of devices performs while also providing low emissions and high electromagnetic immunity. Every version of the device comes equipped with a Schmitt trigger input, which provides high noise immunity. Each isolation channel includes a transmitter and receiver geographically separated by an insulation barrier made of silicon dioxide (SiO2). The CA-IS3720 device has two channels that travel in the same direction. In contrast, the CA-IS3721 device has one forward-direction channel and one reverse-direction channel, and the CA-IS3722 device has a channel configuration that is opposite to that of the CA-IS3721 device.

All devices have a fail-safe mode option. If the device’s input power or signal is lost, the default output for devices with the suffix L is low, while the default output for devices with the suffix H is high. The high insulation capability of the CA-IS372x devices protects the local ground from noise and radiation from a data bus or other circuits, preventing it from entering and potentially disrupting or damaging the sensitive circuitry. This is accomplished by avoiding noise and surges from entering the local ground. Achieving high CMTI levels ensures the accurate transmission of digital signals. The CA-IS372x devices are offered in both standard 8-pin SOIC and wide-body 8-pin SOIC package configurations. In addition, the CA-IS372x components can also be purchased in an 8-pin wide-body SOIC package. All the products have an isolation rating of 3.75 kVrms, and those in wide-body packages can withstand insulation of up to 5 kVrms.

Key Features

• Signal Rate: DC to 150Mbps
• Wide Operating Supply Voltage: 2.5V to 5.5V
• Wide Operating Temperature Range: -40°C to 125°C
• No Start-Up Initialization Required
• Default Output High and Low Options
• High Electromagnetic Immunity
• High CMTI: ±100kV/µs (Typical)

Detailed Description

Theoretical Framework of How Something Works The family of devices known as CA-IS37xx uses a straightforward ON-OFF keying (OOK) modulation technique to send signals across the SiO2 isolation capacitors. These capacitors provide dependable isolation between the input and the output, as well as a high-frequency signal path. The carrier frequency is modulated onto the input signal by the transmitter (TX). This means that the TX delivers a signal with a high frequency across the isolation barrier in one input state, but it provides no signal across the barrier in the other input state. After that, the receiver will attempt to reconstruct the input signal using the in-band energy that it has detected. This straightforward architecture provides a dependable isolated data path and does not call for additional considerations or initialization on the user’s part when the system is started.

The signal path based on capacitors has been designed with fundamental differential components to achieve the highest possible level of noise immunity. This type of noise immunity is also referred to as common-mode transient immunity. To reduce the amount of electromagnetic interference (EMI) caused by the carrier signal and the IO switching, sophisticated circuitry techniques are utilized. When compared to the architecture that is coupled via induction, the one that is coupled via capacitance offers much greater electromagnetic immunity. The OOK modulation scheme eliminates the missing-pulse error that can happen when using the pulse modulation method.

Application and Implementation

The CA-IS372x CMOS digital isolator requires two external VDD bypass capacitors in the 0.1–1 microfarad range. This is in contrast to optocouplers, which need additional components to improve performance, provide bias, or limit current. Because the leakage current drawn by its TTL-level compatible input terminals is only a few microamps, it is possible to drive them without additional external buffering circuits. The characteristic impedance of the output terminals is 50 (rail-to-rail swing), and they are offered in both forward and reverse channel configurations.

Frequently Asked Questions

● How Do Digital Isolation Devices Work?

This is accomplished by digital isolation devices, which use semiconductor process technology to fabricate electronic components like transformers and capacitors, transmitting digital information in the place of optical signals. This technology boosts both efficiency and the ability to combine different features.

● What’s the Distinction Between an Optocoupler and a Digital Isolator?

The purpose of a digital isolator is to ensure compliance with safety regulations while keeping costs to a minimum. Optocouplers, a standard isolator, have the highest costs, as they require a lot of power and can’t handle data rates higher than 1 Mbps. Optocouplers with better power efficiency and higher speeds are commercially available, but they come at a price.

● Why would you use a digital isolator?

To transmit digital information across an isolation barrier, integrated devices known as digital isolators are used. The input signal is modulated by a transmit IC before being sent across a bond wire and high voltage capacitive barrier to the receiver IC.

● What is an analog isolator?

Digital isolators from Analog Devices, such as our magnetically isolated Coupler products, allow designers to implement powerful solutions with as many as six independent inputs and outputs.

Conclusion

High-performance dual-channel digital isolators, the CA-IS372x devices feature isolation ratings of up to 3.75 kVRMS (narrow-body package) and 5kVRMS (wide-body package) and a super-fast data rate. Isolating CMOS digital I/Os while maintaining high EM immunity and low emissions is possible with the CA-IS372x devices. There is a capacitive silicon dioxide (SiO2) insulation barrier between the logic input and output buffer in each isolation channel. A Schmitt trigger is built into the information of each isolation channel to improve noise immunity further.

For example, isolated digital I/O can take advantage of the CA-two IS3720’s channels for unidirectional digital signal transfer. The CA-IS3721/CA-IS3722 devices are well-suited for separating a transceiver’s Tx and Rx lines, making them useful for RS485, CAN, and other types of communication. The default output of devices with the suffix L is low, and the default output of devices with the suffix H is high when the input is either unpowered or open-circuit.

The operating temperature range for the CA-IS372x family is -40°C to +125°C, and they are offered in an 8-pin SOIC narrow-body package, an 8-pin SOIC wide-body package, and a 16-pin SOIC wide-body package, respectively.

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