Original Part
General Purpose Digital Isolator 3750Vrms 1 Channel 15Mbps 35kV/µs CMTI 8-SOIC (0.154", 3.90mm Width)
Alternative Part
General Purpose Digital Isolator 2500Vrms 1 Channel 150Mbps 25kV/µs CMTI 8-SOIC (0.154", 3.90mm Width)
General Purpose Digital Isolator 2500Vrms 1 Channel 150Mbps 25kV/µs CMTI 8-SOIC (0.154", 3.90mm Width)
1. ISO721MDG4 Substitution Conclusion
Provided that the original design does not impose stringent requirements for high isolation voltage and low supply voltage, the ISO721MDG4 can serve as a high-performance substitute for the SI8718BC-A-ISR. The key differences are as follows: The ISO721MDG4 offers lower isolation voltage (2500Vrms) and common-mode transient immunity (25kV/µs) compared to the original part (3750Vrms, 35kV/µs). This results in reduced safety margin against high-voltage transients and noise interference, making it unsuitable for applications demanding higher insulation and noise immunity. However, its data rate (150Mbps) is significantly higher than that of the original part (15Mbps). Moreover, its dynamic performance metrics—including propagation delay, pulse width distortion, and rise/fall times—are markedly superior. Consequently, it delivers lower signal latency and higher fidelity in high-speed digital signal transmission. Additionally, its minimum supply voltage is 3V, whereas the original part supports 2.5V. Therefore, it cannot be used in systems that only provide a 2.5V logic level.
2. ISO722MDRG4 Substitution Conclusion
The substitution conclusion for the ISO722MDRG4 is identical to that for the ISO721MDG4, as the provided parameters indicate both devices share identical key performance specifications. The ISO722MDRG4 likewise represents an alternative with excellent high-speed performance but slightly inferior isolation robustness and supply flexibility. With its 2500Vrms isolation voltage and 3V minimum operating voltage, it is similarly unsuitable for applications where the original design relies on the SI8718BC's higher isolation rating or 2.5V supply voltage. In terms of signal transmission speed and timing accuracy, however, it can provide a significant performance improvement. Prior to actual substitution, it is necessary to verify any minor differences between the two TI part numbers (such as default output state), but the core conclusions regarding electrical and isolation characteristics remain the same.
Analysis ID: 2F64-E644000
Based on part parameters and for reference only. Not to be used for procurement or production.
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