Features and Benefits
- Silent Switcher®2 Architecture: Ultralow EMI Emissions
- High Efficiency: 4.5mΩ NMOS and 16mΩ PMOS
- Wide Bandwidth, Fast Transient Response
- Safely Tolerates Inductor Saturation in Overload
- VIN Range: 2.25V to 5.5V
- VOUT Range: 0.5V to VIN
- VOUT Accuracy: ±1%
- Peak Current Mode Control
- 35ns Minimum On-Time
- Programmable Frequency to 5MHz
- Shutdown Current: 1µA
- Precision 400mV Enable Threshold
- Output Soft-Start with Voltage Tracking
- Power Good Output
- Die Temperature Monitor
- Configurable for Paralleling Power Stages
- Thermally-Enhanced 3mm × 3mm LQFN Package
The LTC3310S is a very small, low noise, monolithic step-down DC/DC converter capable of providing up to 10A of output current from a 2.25V to 5.5V input supply. The part employs Silent Switcher 2 architecture with internal hot loop bypass capacitors to achieve both low EMI and high efficiency at switching frequencies as high as 5MHz. For systems with higher power requirements, multi-phasing parallel converters is readily implemented.
The LTC3310S uses a constant-frequency, peak current mode control architecture for fast transient response. A 500mV reference allows for low voltage outputs. 100% duty cycle operation delivers low drop out.
Other features include a power good signal when the output is in regulation, precision enable threshold, output overvoltage protection, thermal shutdown, a temperature monitor, clock synchronization, mode selection and output short circuit protection. The device is available in a compact 18-lead 3mm × 3mm LQFN package.
- Servers, Telecom Power Supplies
- Distributed DC Power Systems (POL)
- FPGA, ASIC, µP Core Supplies
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 DC2629A features the LTC®3310S 10A, Low Voltage, Synchronous Step-Down Silent Switcher® 2 operating as a 2MHz 3.3V to 1.2V 10A buck regulator. The LTC3310S supports output voltages from 0.5V to VIN with operating frequencies from 500kHz up to 5MHz. The LTC3310S is a compact, ultralow emission, high efficiency, and high speed synchronous monolithic step-down switching regulator. The integrated bypass capacitors optimize all the fast current loops and make it easier to minimize EMI/EMC emissions by reducing layout sensitivity. Fast minimum on-time of 35ns enables high VIN to low VOUT conversion at high frequency.
DC2629A is set up to run in Forced Continuous Mode with a 2MHz switching frequency but can be configured to Pulse Skip Mode and different switching frequencies. RT is connected to VIN which sets the MODE/SYNC pin as an input and allows the LTC3310S to sync from an external clock. Connecting the MODE/SYNC pin to VIN sets the mode to Forced Continuous Mode and connecting the MODE/SYNC pin to GND sets the mode to Pulse Skip Mode. The Efficiency vs. Load graph shows the efficiency and the power loss of the circuit with a 3.3V input in forced continuous mode operation.
The DC2629A also has an EMI filter to reduce conducted EMI. This EMI filter can be included by applying the input voltage at the VIN EMI terminal. The EMI performance of the board is shown in the EMI TEST RESULTS section. The red lines in the EMI performance graphs illustrate the CISPR25 Class 5 peak limits for the conducted and radiated emission tests.
The LTC3310S data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this demo. The LTC3310S is assembled in a 3mm x 3mm LQFN package with exposed pads for low thermal resistance. The layout recommendations for low EMI operation and maximum thermal performance are available in the data sheet section Low EMI PCB Layout.
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.
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:
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.