Dual Synchronous 400mA/800mA, 2.25MHz Step-Down DC/DC Regulator
Features and Benefits
- High Efficiency: Up to 95%
- Very Low Quiescent Current: Only 40μA
- Low Output Ripple Burst Mode® Operation
- 2.25MHz Constant Frequency Operation
- High Switch Current: 0.7A and 1.2A
- No Schottky Diodes Required
- Low RDS(ON) Internal Switches: 0.35Ω
- Current Mode Operation for Excellent Line and Load Transient Response
- Short-Circuit Protected
- Low Dropout Operation: 100% Duty Cycle
- Ultralow Shutdown Current: IQ < 1μA
- Output Voltages from 5V down to 0.6V
- Power-On Reset Output
- Externally Synchronizable Oscillator
- Small Thermally Enhanced MSOP and 3mm × 3mm DFN Packages
The LTC3548 is a dual, constant frequency, synchronous step down DC/DC converter. Intended for low power applications, it operates from 2.5V to 5.5V input voltage range and has a constant 2.25MHz switching frequency, allowing the use of tiny, low cost capacitors and inductors with a profile ≤1mm. Each output voltage is adjustable from 0.6V to 5V. Internal synchronous 0.35Ω, 0.7A/1.2A power switches provide high efficiency without the need for external Schottky diodes.
A user selectable mode input is provided to allow the user to trade-off noise ripple for low power efficiency. Burst Mode operation provides high efficiency at light loads, while Pulse-Skipping Mode provides low noise ripple at light loads.
To further maximize battery runtime, the P-channel MOSFETs are turned on continuously in dropout (100% duty cycle), and both channels draw a total quiescent current of only 40μA. In shutdown, the device draws <1μA.
|LTC3548A||Improved Burst Mode, Improved ESD, 2 Adjustable Outputs|
|LTC3548-2||One Fixed 1.8V Output, 1 Adjustable|
|LTC3548-1||Fixed 1.8V and 1.575V Outputs|
|LTC3548||2 Adjustable Outputs|
- PDAs/Palmtop PCs
- Digital Cameras
- Cellular Phones
- Portable Media Players
- PC Cards
- Wireless and DSL Modems
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 DC822 is a Dual Channel Synchronous, 2.25MHz Step-Down DC/DC Regulator featuring the LTC3548. The DC822 has an input voltage range of 2.5V to 5.5V. The jumper-selectable 1.2V/1.5V/1.8V output is capable of delivering up to 800mA of current. The 2.5V output is capable of delivering up to 400mA of output current.
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:
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.