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LTC3619B
400mA/800mA Synchronous Step-Down DC/DC with Average Input Current Limit
Overview
Features and Benefits
- Programmable Average Input Current Limit: ±5% Accuracy
- Dual Step-Down Outputs: Up to 96% Efficiency
- Low Noise Pulse-Skipping Operation at Light Loads
- Input Voltage Range: 2.5V to 5.5V
- Output Voltage Range: 0.6V to 5V
- 2.25MHz Constant-Frequency Operation
- Power Good Output Voltage Monitor for Each Channel
- Low Dropout Operation: 100% Duty Cycle
- Independent Internal Soft-Start for Each Channel
- Current Mode Operation for Excellent Line and Load Transient Response
- ±2% Output Voltage Accuracy
- Short-Circuit Protected
- Shutdown Current ≤ 1μA
- Available in Small Thermally Enhanced 10-Lead MS and 3mm × 3mm DFN Packages
Product Details
The LTC3619B is a dual monolithic synchronous buck regulator using a constant frequency current mode architecture.
The input supply voltage range is 2.5V to 5.5V, making it ideal for Li-Ion and USB powered applications. 100% duty cycle capability provides low dropout operation, extending the run time in battery-operated systems. Low output voltages are supported with the 0.6V feedback reference voltage. Channel 1 and channel 2 can supply 400mA and 800mA output current, respectively.
The LTC3619B’s programmable average input current limit is ideal for USB applications and for point-of-load power supplies because the LTC3619B’s limited input current will still allow its output to deliver high peak load currents without collapsing the input supply. When the sum of both channels’ currents exceeds the input current limit, channel 2 is current limited while channel 1 remains regulated. The operating frequency is internally set at 2.25MHz allowing the use of small surface mount inductors. Internal soft-start reduces in-rush current during start-up. The LTC3619B is available in small MSOP and 3mm × 3mm DFN packages. The LTC3619B is also available in a low quiescent current, high efficiency Burst Mode® version, LTC3619.
| Light Load Operation | |
| LTC3619 | Low Ripple Burst Mode (<20mVpp), IQ < 50μA |
| LTC3619B | Pulse Skip (<5mVpp) |
Applications
- High Peak Load Current Applications
- USB Powered Devices
- Supercapacitor Charging
- Radio Transmitters and Other Handheld Devices
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)
Documentation
Reliability Data (1)
Evaluation Kit Manuals (1)
Tools & Simulations
LTspice
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:
Reference Materials
Technical Articles (1)
Design Resources
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.
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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.
