Two FETs in one PowerVDFN package
The Infineon IPG20N04S409AATMA1 is a dual N-channel MOSFET from the OptiMOS series, packing two 40V-rated transistors into a single 8-pin PowerVDFN case (PG-TDSON-8-4). The AEC-Q101 automotive qualification tells you this part was designed for the under-hood environment — it lives through the -55°C to 175°C junction temperature range that engine-bay electronics see.
8.6 mOhm at 10V — the conduction-loss number that matters
The 8.6 mOhm Rds(on) is specified at Vgs=10V, which is the standard gate-drive level for a 12V automotive system. At 17A load, that resistance drops about 2.5W per channel — the 54W package power limit (Tc) gives you thermal headroom for both channels conducting simultaneously in a half-bridge or dual-load-switch configuration, as long as the PCB copper area under the exposed pad pulls the heat away. Gate charge is 28 nC at 10V, and input capacitance Ciss is 2250 pF at 25V drain.
PG-TDSON-8-4 footprint — what the board sees
The 8-PowerVDFN package (Infineon calls it PG-TDSON-8-4) is a surface-mount, leadless package with an exposed drain pad on the bottom.