1. LT1803IS5TRM Substitution Conclusion The LT1803IS5TRM offers basic compatibility in package footprint and supply voltage range (2.3V to 12.6V) with the original part. However, its core performance characteristics differ significantly. Its slew rate (88 V/µs) and gain-bandwidth product (83 MHz) far exceed those of the OPA704 (3 V/µs, 3 MHz), providing substantially improved high-frequency response. The trade-off is that its input bias current (2.5 µA) and input offset voltage (1.5 mV) are orders of magnitude higher than the original part's specifications (1 pA, 160 µV). This introduces considerably higher DC error and leakage current, making it unsuitable for high-precision or low-level signal amplification applications. Furthermore, its quiescent current (2.5 mA) is over 15 times greater, leading to a significant increase in power dissipation. This device is only viable for systems prioritizing speed where the loss of DC accuracy and increased power consumption are acceptable. In such cases, a thorough re-evaluation of DC performance and thermal design is mandatory. It is not a direct drop-in replacement.