The IRFZ34NSTRR: The D2PAK (TO-263) surface-mount package with exposed tab is sized for power-dissipation applications up to 68 W when the tab is soldered to a copper plane.
Rds(on) and gate drive — what the 10 V spec means for your design
Package and thermal management in the D2PAK
The TO-263-3 (D2PAK) package is a surface-mount power package with a large exposed metal tab on the bottom. The 3.8 W rating at ambient (still air) is a no-heatsink reference — real designs must use the tab as the primary thermal path. The D2PAK footprint is the same as the through-hole TO-220 in terms of die size, making this a direct surface-mount alternative for designs that originally used a TO-220 part.
Obsolete — sourcing reality for IRFZ34NSTRR
Sourcing this part now relies on the surplus and broker market — factory overruns, end-of-life buy leftovers, and inventory from independent distributors. When evaluating surplus lots, check the date-code spread and packaging condition — sealed factory reels with consistent date-codes from a single production run are the preferred sourcing grade.
Second-source and replacement considerations
The through-hole sibling IRFZ34N (TO-220 package) shares the same die and electrical ratings but differs in mounting. For a surface-mount replacement, the closest functional match would be a current-production N-channel MOSFET in D2PAK with similar voltage, current, and on-resistance ratings from Infineon's current HEXFET portfolio or from competitors such as Vishay, ON Semiconductor, or STMicroelectronics. A parametric search for 55-60 V, 25-30 A, <50 mOhm Rds(on) in D2PAK is the practical cross-reference approach.