Original Part
Alternative Part
1. LF347D Substitution Conclusion
The LF347D can directly substitute the TL084ID, as both are quad JFET-input operational amplifiers with highly similar key parameters (3MHz bandwidth, 13V/µs slew rate, and compatible packages). The main differences are that the LF347D exhibits slightly higher input bias current (50pA vs. 30pA) and larger offset voltage (5mV vs. 3mV), which may introduce marginally greater error in ultra-high-precision DC applications. However, it draws significantly higher supply current (8mA vs. 1.4mA), resulting in higher power dissipation, while offering stronger output drive capability (40mA vs. 10mA) and a wider supply voltage range (7–36V). In summary, direct substitution is acceptable for general AC signal processing or in applications where power consumption is not critical, though the impact of precision and power differences on the specific circuit should be considered.
2. LM2902DR2G Substitution Conclusion
The LM2902DR2G is not recommended as a direct replacement for the TL084ID, as it is a standard bipolar-input op-amp with fundamentally different characteristics compared to the JFET-input TL084ID. Key differences include an input bias current as high as 90nA (3000 times greater than the TL084ID), resulting in very low input impedance that makes it unsuitable for high-impedance sensing or low-current detection applications. It also has lower bandwidth (1MHz vs. 3MHz) and an unspecified slew rate (typically <1V/µs), leading to significantly degraded high-frequency response and transient performance. On the other hand, it supports a lower minimum supply voltage (3V vs. 10V), making it suitable for single-supply, low-voltage applications. Substitution may be considered only in general amplification circuits where input impedance and bandwidth are not critical and supply voltage is constrained; in most cases, circuit compatibility should be re-evaluated.
Analysis ID: C538-41A4000
Based on part parameters and for reference only. Not to be used for procurement or production.
SkyChip © 2026, Email: sales@skychip.com