FPGA power-supply requirements include voltage outputs ranging from 1.2 to 5V and current outputs from tens of milliamps to several amperes. The three possible power sources are: a low-dropout (LDO) linear regulator, a switch-mode DC-DC regulator, and a switch-mode power module. The ultimate choice depends on the system, the system budget, and time-to-market requirements. LDO regulators are used when board space is at a premium, low output noise is important, or the system requires a fast response to input voltage changes and load transients. LDOs only supply low to medium output currents as their efficiency is low (they are linear regulators). An input capacitor typically cuts the inductance and noise on the input to the LDO. The LDO also requires a capacitor on the output to handle system transients and provide stability. Dual output LDOs can also supply power for both the VCCINT and VCCO. Switch-mode regulators have an advantage when design efficiency is critical and the system requires high output currents. Switching supplies provide higher efficiency than LDOs, but their switching circuitry makes the output more noisy. Unlike LDOs, switch-mode regulators require inductors for dc-dc conversion. The ADP1706 is a 1 Amp, Low dropout, CMOS linear regulator available in a 3mm x 3mm, 8-lead LFCSP package. The ADP1706 is available in 16 fixed output voltage options from 0.75V to 3.3V and has programmable soft-start.