60V, 4A Synchronous Step-Down Regulator with Rail-to-Rail Programmable Output
Features and Benefits
- Wide VIN Range: 3.4V to 60V
- Wide VOUT Range: 0V to –28V
- Single Resistor VOUT Programming
- Integrated 110mΩ Top N-Channel/50mΩ Bottom N-Channel MOSFETs
- Regulated IQ: 440μA, Shutdown IQ: 15μA
- Board GND Referenced I/O Pins (RUN, PGOOD, MODE/SYNC)
- Accurate Resistor Programmable Frequency (300kHz to 3MHz) with ±50% Frequency Sync Range
- 92% Efficiency with 12 VIN and –5VOUT
- ±0.8% Output Voltage Accuracy
- Peak Current Mode Operation
- Burst Mode® Operation, Forced Continuous Mode
- Programmable Soft-Start
- Overtemperature Protection
- Available in 28-Lead (4mm x 5mm) QFN and TSSOP Packages
The LTC7149 is a high efficiency 60V, 4A synchronous monolithic step-down regulator for inverting output applications. The regulator features a single resistor programmable output voltage and high efficiency over a wide VOUT range.
The inverting regulator operates from an input voltage range of 3.4V to 60V and provides an adjustable output from (–28V) to zero volts while delivering up to 4A of inductor current. The switching frequency is also set with an external resistor. A user-selectable mode input is provided to allow the user to trade off ripple noise for efficiency at light loads; Burst Mode operation provides the highest efficiency at light loads, while forced continuous mode provides low output ripple. The MODE/SYNC pin can also be used to synchronize the switching frequency to an external clock. Internal level-shift circuits allow the I/O pins (RUN, MODE/SYNC, PGOOD) to be referenced to board GND.
The LTC7149 operates with a peak current mode architecture that allows for fast transient response with inherent cycle-to-cycle current limit protection.
- Industrial Applications
- Telecom Power Supplies
- Distributed Power Systems
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit 2354A is a high input voltage, high efficiency synchronous monolithic step-down converter with a negative output voltage featuring the LTC7149. DC2354A has a wide input voltage range from 3.5V up to 55V. The output voltage of the DC2354A can be set to –3.3V or –5V, and the “User Select” option allows the output voltage to be set from 0V to –60V; however the voltage difference between the output voltage (–VOUT) and maximum input voltage (VIN), should not exceed 60V. |–VOUT| + VIN < 60V. DC2354A is capable of delivering up to 4A of output current, nevertheless at lower input voltages, the load current should be reduced in accordance with the derating curves. DC2354A supports three operation modes: fixed-frequency modulation, Burst Mode™ operation and synchronization to an external clock. Fixed-frequency mode maximizes the output current, reduces output voltage ripple, and yields a low noise switching spectrum. Burst Mode operation employs a variable frequency switching algorithm that minimizes the no-load input quiescent current and improves efficiency at light loads.
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.
To open the project file for this circuit:
Step 1: Download and install LTpowerCAD on your computer.
Step 2: Click on the link(s) in the section below to download part-specific project files.
Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.
LTpowerCAD Project Files
Design tools for the following parts are available in LTpowerCAD:
LTC7149 Companion Parts
Recommended Related Parts
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Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.