Features and Benefits
- Low Value DCR Current Sensing
- Programmable DCR Temperature Compensation
- ±0.5% 0.6V Output Voltage Accuracy
- Dual True Remote Sensing Differential Amplifiers
- Optional Fast Transient Operation
- Phase-Lockable Fixed Frequency 250kHz to 720kHz
- Dual, 180° Phased Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
- Dual N-Channel MOSFET Synchronous Drive
- Wide VIN Range: 4.5V to 38V Operation
- Output Voltage Range with Low DCR: 0.6V to 3.5V, without Low DCR: 0.6V to 5V
- Adjustable Soft-Start Current Ramping or Tracking
- Foldback Output Current Limiting
- Clock Input and Output for Up to 12-Phase Operation
- Short-Circuit Soft Recovery
- Output Overvoltage Protection
- Power Good Output Voltage Monitor
- 40-Lead QFN Packages
The LTC3875 is a dual output current mode synchronous step-down DC/DC controller that drives all N-channel synchronous power MOSFET stages. It employs a unique architecture which enhances the signal-to-noise ratio of the current sense signal, allowing the use of very low DC resistance power inductors to maximize the efficiency in high current applications. This feature also reduces the switching jitter commonly found in low DCR applications.
The LTC3875 features two high speed remote sense differential amplifiers, programmable current sense limits from 10mV to 30mV and DCR temperature compensation to limit the maximum output current precisely over temperature.
A unique thermal balancing function adjusts per phase current in order to minimize the thermal stress for multichip single output applications. The LTC3875 also features a precise 0.6V reference with guaranteed accuracy of ±0.5% that provides an accurate output voltage from 0.6V to 3.5V. A 4.5V to 38V input voltage range allows it to support a wide variety of bus voltages. The LTC3875 is available in a low profile 40-lead 6mm × 6mm (0.5mm pitch) and 40-lead 5mm × 5mm (0.4mm pitch) QFN packages.
- Servers and Instruments
- Telecom Systems
- DC Power Distribution 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 (4)
Demonstration circuit 2225A is a high efficiency, high density, 4-phase synchronous buck converter with a 4.5V to 14V input voltage range. It can supply up to 160A of load current with a 1.0V output. This demo board has two each LTC3875EUJ feature-rich dual phase current mode synchronous buck controllers with very low DCR current sensing capability, on-chip drivers and remote output voltage sensing. This board is set up with 0.32mΩ DCR output inductors. The temperature compensation function offers an option for accurate current limit over a wide temperature range with DCR sensing. To shut down the converter, set the RUN pin voltage below 1V (SW1: OFF). Use JP1 jumper to select Burst Mode® operation, pulse skipping mode or forced continuous mode operation at light load.
Demonstration circuit 2142A is a high efficiency, high density, 4-phase synchronous buck converter with a 4.5V to 14V input range. It can supply 120A maximum load current at a 1.0V output. This demo board incorporates the LTC3875EUJ and LTC3874IUFD master/slave controllers.
Demonstration circuit 2055A is a high efficiency, high density, 4-phase synchronous buck converter with a 4.5V to 14V input range. It can supply 120A maximum load current at a 1.0V output. This demo board has two LTC3875EUJ controllers. The LTC3875 is a feature-rich dual-phase synchronous buck controller with very low DCR current sensing capability, on-chip drivers and remote output voltage sensing. This board is set up with 0.32mΩ DCR inductor. The temperature compensation function can guarantee accurate current limit over a wide temperature range with DCR sensing.
Demonstration circuit 2000A is a high efficiency, high density, synchronous buck converter with a 4.5V to 14V input range. It can supply 30A maximum load current at a 1.0V output and at a 1.5V output separately. The demo board includes a LTC3875EUJ controller. The LTC3875 is a feature-rich dual phase synchronous buck controller with very low DCR current sensing capability, on-chip drivers and remote output voltage sensing. This board is set up with a 0.32mΩ DCR inductor. The temperature compensation function can guarantee accurate current limit over a wide temperature range with DCR sensing.
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.
Design tools for the following parts are available in LTpowerCAD:
LTC3875 Companion Parts
Recommended Related Parts
LT Journal (4)
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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.