The LT3078 is a low voltage, ultra-low noise, high power-supply rejection ratio (PSRR), and ultra-fast transient response linear regulator. The device supplies up to 5A with a typical dropout voltage of 55mV. A 4.7μF reference bypass capacitor decreases output voltage noise to 1.3μVRMS (10Hz to 100kHz). The wide bandwidth and high PSRR deliver the best performance without the need of bulky capacitors, which save space and cost. The LT3078 is ideal for powering high-performance FPGAs, data converters, RF, and all noise-sensitive signal chain applications.The output voltage is digitally selectable in 50mV increments from 0.5V to 1.2V, 100mV increments from 1.2V to 1.8V, and discrete levels at 2V, 2.5V, 3V, 3.3V, and 4.2V. The LT3078’s unity-gain operation provides virtually constant output noise, PSRR, and bandwidth independent of the programmed output voltage. In addition, the LT3078 incorporates a unique tracking feature (VIOC) to control the upstream switching regulator to maintain a constant voltage across the LT3078 and minimize power dissipation.A precision current monitor enables system energy management and allows the user to minimize input power-supply size and cost. Built-in protection includes UVLO, internal current limit, and thermal shutdown with hysteresis. The LT3078 is available in a compact 22-lead (3mm X 4mm) LQFN package (Laminate package with QFN footprint).APPLICATIONSRF Power Supplies: PLLs, VCOs, Mixers, LNAs, PAsHigh Speed/High Precision Data ConvertersLow Noise InstrumentationPost-Regulator for Switching SuppliesFPGA and DSP Power SuppliesMedical Applications