The IRFZ34NL is an N-channel enhancement-mode power MOSFET from Infineon's HEXFET® family, built on a planar stripe-technology process.
Obsolete — last-time-buy is past, surplus is the channel
Infineon lists the IRFZ34NL as obsolete. The last-time-buy window has closed, so new production is no longer available from the factory. Sourcing now runs through independent distribution — surplus inventory, new-old-stock, or broker channels. If you are qualifying a replacement, the pin-compatible IRFZ34N (non-leaded variant) is the direct functional equivalent in the same HEXFET family, sharing the same 55 V / 29 A / 40 mΩ ratings and TO-262 footprint. For new designs, look at Infineon's current-generation 55 V automotive-grade MOSFETs in TO-262 or D²Pak — the IRFZ44 series successors with lower Rds(on) and improved switching performance.
Through-hole TO-262 — thermal and layout notes
The TO-262 package (I²Pak compatible, three long leads) is a through-hole power package with a metal tab that carries the drain. The 68 W power dissipation at case temperature assumes the tab is bolted to a heatsink with thermal interface material — without it, the 3.8 W ambient rating is the limit. The 10 V gate drive voltage is specified for minimum Rds(on); driving with 5 V logic will roughly double the on-resistance, so use a dedicated gate driver or a 10 V rail.