Designers of high-reliability DC/DC power supplies can achieve this quickly and easily with this MOSFET from Diodes.
The DMN3027LFG has an RDS(ON) of 26mΩ at 4.5V, which is low enough to discharge a 15mF capacitor in less than 10ms but not so low that sharply rising current peaks could cause EMI issues or give rise to transient thermal stresses, potentially damaging the MOSFET or capacitor bank.
Under the typical FPGA low-voltage rail conditions of 1V, this current is self-limited by the MOSFET channel resistance as specified in the Safe Operating Area (SOA). This SOA is given at a +60°C ambient temperature with minimal heat-sinking to support the typical application conditions, allowing peak currents up to 20A to be safely handled in under 10ms.
The DMN3027LFG is offered in a PowerDI3333 package, which has a low thermal resistance from junction to exposed pad of less than 10°C/W, enabling dissipation of up to 3W. It is priced at $0.25 each in 10,000 unit quantities.