Features and Benefits
- 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
- Output Voltage Range: 0V to 15V
- Programmable Power Good
- Fast Start-Up Capability
- Precision Enable/UVLO
- Parallelable for Lower Noise and Higher Current
- Internal Current Limit with Foldback
- Minimum Output Capacitor: 4.7μF Ceramic
- Reverse Battery and Reverse Current Protection
- 10-Lead MSOP and 3mm × 3mm DFN Packages
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.
- 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
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (2)
Demonstration Circuit 2429A is a PLL/VCO Supply and Reference Frequency Board that features the LT3042, an ultralow noise and ultrahigh PSRR RF linear regulator. When powered from a 6V to 20V lab or wall wart supply, the DC2429A produces four ultralow noise supplies using seven LT3042s. These supplies include a fixed 3.3V/800mA supply (four LT3042's in parallel), a fixed 5V/200mA supply, a fixed 3.3V/200mA supply that powers an onboard 100MHz ultralow jitter crystal oscillator, and an adjustable voltage (2.5V to 15V), 200mA supply ideal for powering external VCOs. The DC2429 ensures PLL/VCO evaluation meets data sheet performance.
DC2246B is a linear regulator demonstration circuit featuring the LT3042EDD, which is a 200mA, ultralow noise, and ultrahigh power supply rejection ratio (PSRR) RF low dropout (LDO) regulator with programmable current limit.
DC2246B operates over an input voltage range of 3.8V to 20V and is configured for 3.3V at its output. It features ultralow output voltage noise (0.8µVRMS from 10Hz to 100kHz) and very high PSRR (79dB at 1MHz).
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
Models for the following parts are available in LTspice:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
Design tools for the following parts are available in LTpowerCAD:
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