1. TLC25M2CDR Substitution Conclusion The TLC25M2CDR is a viable alternative to the ICL7621DCBAZ in terms of core electrical performance. However, the most critical difference lies in its output stage architecture: it features an open-drain configuration. Unlike the original part (which is presumed to have a push-pull output), it cannot actively drive a high-level output directly. An external pull-up resistor is mandatory, which increases design complexity and can potentially degrade rise time and load-driving capability. Beyond this key distinction, the TLC25M2CDR offers significant advantages in dynamic performance and precision compared to the original part. Its slew rate (2.9 V/µs vs. 0.16 V/µs) and bandwidth (1.7 MHz vs. 480 kHz) are markedly superior, making it better suited for high-speed or high-precision signal processing. Furthermore, its lower supply voltage limit extends down to 1.4V, enhancing its suitability for low-voltage systems. A trade-off is its higher quiescent current (285 µA per channel vs. 100 µA per channel), which is a disadvantage for power-sensitive applications. In applications where the open-drain output circuit is acceptable and can be properly implemented, and where ultra-low quiescent current is not a strict requirement, the TLC25M2CDR represents a performance-upgrade alternative. Otherwise, a different substitute with a push-pull output stage should be sought.