20V, 200mA, Ultralow Noise, Ultrahigh PSRR RF Linear Regulator

The LT3042 is a high performance low dropout linear regulator featuring LTC’s ultralow noise and ultrahigh PSRR architecture for powering noise sensitive RF applications. Designed as a precision current reference followed by a high performance voltage buffer, the LT3042 can be easily paralleled to further reduce noise, increase output current and spread heat on the PCB.

The device supplies 200mA at a typical 350mV dropout voltage. Operating quiescent current is nominally 2mA and drops to <<1μA in shutdown. The LT3042’s wide output voltage range (0V to 15V) while maintaining unity-gain operation provides virtually constant output noise, PSRR, bandwidth and load regulation, independent of the programmed output voltage. Additionally, the regulator features programmable current limit, fast start-up capability and programmable power good to indicate output voltage regulation.

The LT3042 is stable with a minimum 4.7μF ceramic output capacitor. Built-in protection includes reverse battery protection, reverse current protection, internal current limit with foldback and thermal limit with hysteresis. The LT3042 is available in thermally enhanced 10-Lead MSOP and 3mm × 3mm DFN packages.

Applications

* RF Power Supplies: PLLs, VCOs, Mixers, LNAs

* Very Low Noise Instrumentation

* High Speed/High Precision Data Converters

* Medical Applications: Imaging, Diagnostics

* Precision Power Supplies

* Post-Regulator for Switching Supplies

* Ultralow RMS Noise: 0.8μVRMS (10Hz to 100kHz)

* Ultralow Spot Noise: 2nV/√Hz at 10kHz

* Ultrahigh PSRR: 79dB at 1MHz

* Output Current: 200mA

* Wide Input Voltage Range: 1.8V to 20V

* Single Capacitor Improves Noise and PSRR

* 100μA SET Pin Current: ±1% Initial Accuracy

* Single Resistor Programs Output Voltage

* High Bandwidth: 1MHz

* Programmable Current Limit

* Low Dropout Voltage: 350mV