SI8921BD-IS4

Special Purpose Amplifiers Overview

The Skyworks SI8921BD-IS4 is a galvanically isolated analog amplifier designed for current shunt measurement. It features a low-voltage differential input with a full-scale range of ±250 mV and an internal gain of 8.2x, producing a differential output. The device utilizes CMOS isolation technology to support up to 5.0 kVRMS withstand voltage per UL1577. Key electrical parameters include a typical input offset of ±0.40 µV, a typical gain error of ±0.06%, and a bandwidth of approximately 600 kHz. It operates on supply voltages between 3 V and 5.5 V.

Special Purpose Amplifiers Feature Summary

• Galvanic isolation using proprietary CMOS technology for high reliability
• Low signal delay of 0.8 µs for rapid fault response
• Excellent drift specifications including 0.5 µV/°C offset drift
• Fail-safe output mode during loss of input supply voltage

Special Purpose Amplifiers Applications

• Industrial, HEV, and renewable energy inverters
• AC, brushless, and DC motor controls and drives
• Isolated switch mode and UPS power supplies
• Automotive onboard chargers and battery management systems

Special Purpose Amplifiers Procurement Notes

Verify the specific suffix IS4 indicates Moisture Sensitivity Level 2A (MSL2A) at 260 °C, distinct from standard MSL2. Confirm the wide-body stretched SOIC-8 package dimensions match PCB layout requirements. Ensure compliance with RoHS directives by checking the manufacturer's Certificate of Conformance. Validate that the 5.0 kVRMS insulation rating meets system safety standards such as UL1577 or CSA 62368-1.

Special Purpose Amplifiers Selection Notes

Select this part when a differential output is required for connection to a differential ADC. The ±250 mV input range suits applications where higher sense resistor values are used compared to the ±62.5 mV variant. Verify that the 600 kHz bandwidth is sufficient for the switching frequency of the target inverter or drive system. Consider the 0.8 µs signal delay when designing control loops requiring precise timing synchronization.

Special Purpose Amplifiers Part Context

This component belongs to the Si8921/Si8922 family of isolated amplifiers. The Si8921 series provides a differential output, whereas the Si8922 series offers a single-ended output. Both share similar isolation characteristics and input ranges but differ in output topology. The 'B' designation specifies the ±250 mV linear input range, while 'D' denotes the 5.0 kVRMS insulation rating.

Special Purpose Amplifiers Replacement Considerations

Public confirmed substitute part numbers: None.