Original Part
Alternative Part
1. AD621BRZ-RL Substitution Conclusion
The AD621BRZ-RL is hardware-compatible with the INA128HD in terms of package, supply voltage range, and output current, providing a foundation for substitution. However, key differences exist: its bandwidth (800 kHz) and slew rate (1.2 V/µs) are notably lower than those of the original part (1.3 MHz, 4 V/µs), which may degrade response speed when processing high-frequency signals or fast transients, potentially making it unsuitable for applications with demanding dynamic performance. Additionally, its input offset voltage (50 µV) is higher than that of the INA128HD (25 µV), which could introduce greater DC error; system accuracy requirements must therefore be evaluated. On the other hand, its input bias current (500 pA) is significantly lower than the original’s (2 nA), making it more suitable for high-impedance signal sources and reducing errors due to input current. If the application does not require high bandwidth or fast transient response and can tolerate slightly higher offset voltage, the AD621BRZ-RL may serve as a substitute, though calibration or circuit adjustments may be needed to optimize accuracy.
2. AD621ARZ-RL Substitution Conclusion
The AD621ARZ-RL shares essentially the same parameters as the AD621BRZ-RL, but its input offset voltage increases further to 75 µV. This makes its DC accuracy notably inferior to the original part (25 µV) and may lead to greater zero-drift error in precision measurement applications, requiring reliance on external offset nulling or software calibration. Other differences align with those of the AD621BRZ-RL: lower bandwidth and slew rate limit high-frequency performance, while low input bias current benefits high-impedance sensing. Overall, its feasibility as a substitute is lower, unless the application is insensitive to offset voltage (e.g., already incorporates auto-calibration) and has relaxed dynamic performance requirements. For designs that prioritize the original part’s accuracy and speed, direct substitution is not recommended.
Analysis ID: B7CC-DC12000
Based on part parameters and for reference only. Not to be used for procurement or production.
SkyChip © 2026, Email: sales@skychip.com