Features and Benefits
- Pin Compatible with LTC3307(3A) and LTC3309(6A)
- High Efficiency: 8mΩ NMOS, 31mΩ PMOS
- Programmable Frequency 3MHz to 10MHz
- Tiny Inductor and Capacitors
- Peak Current Mode Control
- 22ns Minimum On-Time
- Wide Bandwidth, Fast Transient Response
- Silent Switcher® Architecture
- Ultralow EMI Emissions
- Low Ripple Burst Mode®Operation with IQ of 40μA
- Safely Tolerates Inductor Saturation in Overload
- VIN Range: 2.25V to 5.5V
- VOUT Range: 0.5V to VIN
- VOUT Accuracy: ±1% Over Temperature Range
- Precision 400mV Enable Threshold, 1μA in Shutdown
- Power Good, Internal Compensation and Soft-Start
- Thermally Enhanced 2mm × 2mm LQFN Package
- AEC-Q100 Qualified for Automotive Applications
The LTC3308B is a very small, high efficiency, low noise, monolithic synchronous 4A step-down DC/DC converter operating from a 2.25V to 5.5V input supply. Using constant frequency, peak current mode control at switching frequencies 3MHz to 10MHz and minimum on-time as low as 22ns, this regulator achieves fast transient response with small external components. Silent Switcher architecture minimizes EMI emissions.
The LTC3308B operates in forced continuous or pulse-skipping mode for low noise, or low-ripple Burst Mode operation for high efficiency at light loads, ideal for battery-powered systems. The IC regulates output voltages as low as 500mV. Other features include output overvoltage protection, short-circuit protection, thermal shutdown, clock synchronization, and up to 100% duty cycle operation for low dropout.
The LTC3308B is available in a low profile 12-lead 2mm × 2mm × 0.74mm LQFN package with exposed pad for low thermal resistance.
- Optical Networking, Servers, Telecom
- Automotive, Industrial, Communications
- Distributed DC Power Systems (POL)
- FPGA, ASIC, μP Core 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 (1)
Demonstration circuit 3054A-B features the LTC3308B 5V, 4A synchronous step-down Silent Switcher® operating as a 6.6MHz, 3.3V to 1.8V 4A buck regulator. The LTC3308B supports adjustable output voltages from 0.5V to VIN, and operating frequencies from 3MHz up to 10MHz. The LTC3308B is a compact, ultralow emission, high efficiency, and high speed synchronous monolithic step-down switching regulator. A minimum on-time of 22ns enables high VIN to low VOUT conversion ratios at high switching frequencies.
The DC3054A-B operating mode may be selected as Burst Mode® operation, skip or forced continuous (FC) mode. Setting JP1 to the FC/SYNC position will allow the LTC3308B to sync to a clock frequency from 3MHz to 10MHz. The LTC3308B operates in forced continuous mode when syncing to an external clock. The DC3054A-B is set to a fixed 6.6MHz.
The DC3054A-B is set to a fixed 6.6MHz frequency by connecting RT to VIN through a 0Ω resistor, R9. The frequency can be easily changed by removing R9 and setting an appropriate resistor in the R4 location to obtain the desired frequency. Refer to the LTC3308B data sheet for the proper RT value for a desired switching frequency.
The LTC3308B data sheet gives a complete description of the device, operation and application information. The data sheet must be read in conjunction with the demo manual. The LTC3308B is assembled in a 2mm × 2mm 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.
Documentation & Resources
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.
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:
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.View our quality and reliability program and certifications for more information.
Sample & Buy
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.