SI8922AB-ISR

Special Purpose Amplifiers Overview

The SI8922AB-ISR is a single-channel, galvanically isolated analog amplifier from the Si8922 series by Skyworks Solutions. It features a specified linear input range of ±62.5 mV and provides a single-ended output with a nominal gain of 32.8x. The device utilizes CMOS isolation technology to support up to 5.0 kVRMS withstand voltage per UL1577. Key electrical characteristics include a typical signal delay of 1 µs, an amplifier bandwidth of 600 kHz, and a typical input offset voltage of ±0.07 mV at 25 °C. It operates on supply voltages between 3.0 V and 5.5 V with a typical supply current of 4.5 mA.

Special Purpose Amplifiers Feature Summary

• Galvanically isolated architecture using proprietary CMOS technology for high common-mode transient immunity
• Low-voltage differential input optimized for direct connection to current shunt resistors
• Fail-safe output mode that activates upon loss of primary-side power supply
• Automotive-grade manufacturing flow available with AEC-Q100 qualification

Special Purpose Amplifiers Applications

• Current shunt measurement in industrial inverters
• High-efficiency vehicle (HEV) and renewable energy inverter systems
• AC, brushless, and DC motor control drives
• Isolated switch mode power supplies and UPS systems
• Automotive onboard chargers and battery management systems

Special Purpose Amplifiers Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation to confirm package type and moisture sensitivity level. The -IS suffix indicates a standard Moisture Sensitivity Level 2 rating, while other suffixes may differ. Ensure compliance with RoHS directives and check for automotive-specific PPAP documentation if required for the target application environment.

Special Purpose Amplifiers Selection Notes

Select this component when a single-ended output is required for low-voltage differential signals. The ±62.5 mV input range suits applications requiring higher gain amplification of small shunt voltages compared to the ±250 mV variant. Consider the 1 µs signal delay and 600 kHz bandwidth for fast fault detection loops. Verify that the SOIC-8 package clearance and creepage distances meet the safety insulation requirements of the final system design.

Special Purpose Amplifiers Part Context

This device belongs to the Si8921/Si8922 family of isolated amplifiers designed for precise current sensing. While the Si8921 provides a differential output, the Si8922 variant offers a single-ended output, simplifying interface connections to single-ended ADCs or controllers. Both share identical input specifications and isolation barriers but differ in output topology and pin configuration.

Special Purpose Amplifiers Replacement Considerations

SI8922AD-IS4

Special Purpose Amplifiers FAQ

What is the fail-safe output voltage when the VDDA supply is removed?

When the high-voltage-side supply voltage (VDDA) is removed, the Si8922 outputs a fail-safe voltage nominally equal to +2.8 V.

How does the Si8922 handle common-mode noise during switching events?

The device provides high common-mode transient immunity (CMTI), typically 75 kV/µs, allowing it to maintain accurate measurements in high-power switching environments like motor drives.

What is the maximum input voltage before clipping occurs for the ±62.5 mV model?

For the Si8922A (±62.5 mV input range), the maximum input voltage before clipping is approximately 77 mV.