Datasheet Si86Px (Skyworks) - 9

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DATA SHEET Si86Px 3.2. Power Isolation
Figure 13. “Isolated Power Transfer” below illustrates the concept behind the isolated power transfer system, which consists of three main parts described below.
3.2.1. DC-to-AC Conversion
The dc-to-ac conversion is performed by the NMOS cross-coupled pair and an LC tank. This pair on the primary side (input voltage domain) enables the LC tank to oscillate in near Class-D mode, pumping energy into the LC tank at a frequency determined by the system passive components. The primary-side transformer winding can experience voltages up to 3 x VI due to the near Class-D mode operation of the oscillator. The oscillation can be turned on or off by means of switches that cut off the current path to the transformer. The Class-D operation of the oscillator provides zero cross switching, enhancing efficiency by limiting the time the NMOS devices can dissipate a high amount of power. The oscillator on/off control requires a means of preventing instant discharges of the transformer windings and the resulting high voltages at the transformer terminals. Snubber clamps are included to protect the device by providing a discharge path for node voltages exceeding device limitations.
3.2.2. AC-to-AC Conversion
The ac-to-ac conversion utilizes an air-core transformer with a 1:N turns ratio (where N is approximately 1) to convert ac electrical energy into magnetic flux, which is then coupled to the secondary side (output voltage domain) and converted back to electrical energy. The transformer provides 3.75 kVRMS isolation while transferring energy between the primary-to-secondary voltage domains.
3.2.3. AC-to-DC Conversion
The ac-to-dc conversion is achieved by means of an on-chip, full-wave rectifier using Schottky diodes in conjunction with cross-coupled NMOS devices. This improves power transfer efficiency as the voltage drop across the NMOS devices can be much lower than the forward voltage of the Schottky diodes. Skyworks Solutions, Inc. • Phone [949] 231-3000 • sales@skyworksinc.com • www.skyworksinc.com 207353A • Skyworks Proprietary Information • Products and Product Information are Subject to Change without Notice 9 March 23, 2026 Document Outline Applications Features Safety Regulatory Approvals (Pending) Description 1. Functional Block Diagrams 2. Pin Descriptions 2.1. WB SOIC-16 2.2. WB SOIC-20 3. Functional Description 3.1. Digital Isolation 3.2. Power Isolation 3.2.1. DC-to-AC Conversion 3.2.2. AC-to-AC Conversion 3.2.3. AC-to-DC Conversion 4. Digital Isolator Device Operation 4.1. Logic Operation 4.2. Device Startup 4.3. Undervoltage Lockout 4.4. Thermal Protection 4.5. Fault Tolerance and Protection 4.5.1. Overload/Short Circuit Protection 4.5.2. Time-Out Block 4.5.3. Overvoltage Protection 5. Electrical Specifications 5.1. Si86P5x: 5 V Supply Input and 3.3 to 5 V Continuous Supply Output 5.2. Si86P4x: 3.3 V to 5 V Continuous Supply Input and 3.3 V Supply Output 5.3. Si86P3x: 3.3 V Supply Input and 3.3 V Supply Output 5.4. Supply Input Current Characteristics 5.5. Electrical Characteristics—Digital Isolator 5.5.1. Logic Input and Output Characteristics 5.5.2. Supply Current Characteristics 5.6. Timing Characteristics 5.7. Typical Performance Characteristics 5.8. Thermal Characteristics 5.9. Safety Certifications and Specifications (Pending) 6. Application Information 6.1. Recommended Application Circuits 6.2. Power Supply and Layout Considerations 6.3. Hysteretic Control and Programmable Output Voltage 7. Package and Handling Information 7.1. WB SOIC-16 Top Marking 7.2. WB SOIC-20 Top Marking 7.3. WB SOIC-16 Package 7.4. WB SOIC-20 Package 7.5. WB SOIC-16 Land Pattern 7.6. WB SOIC-16 Tape and Reel Information 7.7. WB SOIC-20 Land Pattern 7.8. WB SOIC-20 Tape and Reel Information 8. Ordering Information 9. Revision History