What three rails does it watch and what trips the reset?
The MAX6355MSUT monitors three supply voltages with factory-set thresholds of 2.93 V and 4.38 V, plus a third adjustable input for a rail you choose — the adjustable pin lets you set the trip point with an external resistor divider, so it handles non-standard voltages like a 1.8-V core or a 3.0-V I/O rail without a second supervisor IC. When any monitored rail drops below its threshold, the reset output pulls low and stays asserted for a minimum of 100 ms after all rails return above threshold — that 100 ms hold-off gives the system power supplies time to stabilise before the processor or FPGA starts executing code. The output is open-drain, active-low, so you can wire-OR it with other reset sources or pull it up to a different voltage than the supervisor's supply — handy when the supervisor runs off a 5-V rail but the reset signal feeds a 3.3-V logic input.
The pin pitch is 0.95 mm, which is routable on a two-layer board with 6/6 mil trace/space rules.
Lifecycle and compliance — what the record says
It is marked RoHS non-compliant, so if your BOM requires RoHS exemption or you are building for a market that still accepts lead-bearing solder (military, some industrial), this part stays in the approved list. For RoHS-mandated builds, request the lead-free variant from the same family.