Original Part
Alternative Part
1. AD621BRZ-RL Substitution Conclusion
Substitution is feasible, provided that the degradation in key performance parameters is acceptable. The AD621BRZ-RL is fully compatible with the LT1167AIS8 in terms of package, supply voltage range, and quiescent current. However, notable differences exist: the input bias current of the AD621BRZ-RL (500 pA) is ten times higher than that of the original part (50 pA), which will introduce greater input current error when measuring high-impedance signal sources. Its input offset voltage (50 µV) is also significantly higher than the original’s 15 µV, leading to reduced DC accuracy and higher inherent error in small‑signal amplification. Additionally, its output current capability (18 mA) is lower than the original’s 27 mA, resulting in slightly weaker drive capability for low‑impedance loads. If the application does not demand high input impedance, high DC accuracy, or strong load‑driving capability, and the bandwidth (800 kHz vs. 1 MHz GBW) meets the requirement, direct substitution can be considered.
2. AD621ARZ-RL Substitution Conclusion
Conditional substitution; careful evaluation of accuracy requirements is necessary. The AD621ARZ‑RL exhibits performance largely identical to the AD621BRZ‑RL, but its input offset voltage (75 µV) is further increased compared to the AD621BRZ‑RL (50 µV) and is five times higher than the original part (15 µV). This will introduce greater zero‑point error when amplifying weak DC or low‑frequency signals, necessitating additional zero‑trim or calibration measures in the system. Other differences, such as input bias current, output current, and bandwidth, are the same as those of the AD621BRZ‑RL. This substitute should only be considered in applications where input offset voltage is not critical or can be compensated via circuit calibration, and where other degraded parameters are acceptable.
Analysis ID: 3E16-7F4C000
Based on part parameters and for reference only. Not to be used for procurement or production.
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