The TPS3306-18DGKRG4 from Texas Instruments is a multi-voltage supervisor that monitors two supply rails with fixed thresholds of 1.68 V and 2.93 V, covering nominal 1.8 V and 3.3 V lines in mixed-voltage designs. The active-low, open-drain output asserts when either monitored voltage drops below its threshold, and releases after a 70 ms minimum reset timeout once both rails are valid.
70 ms reset timeout — what it buys the system
The 70 ms minimum reset timeout gives the downstream processor or FPGA enough time to complete its power-on reset sequence before the supervisor releases the reset line. This prevents spurious boot attempts when the supply rails are still ramping or have not fully settled after a brown-out event.