LTC3700 - Constant Frequency Step-Down DC/DC Controller with LDO Regulator
Features
- Dual Output Regulator in Tiny 10-Pin MSOP
- High Efficiency: Up to 94%
- Wide VIN Range: 2.65V to 9.8V
- Constant Frequency 550kHz Operation
- 150mA LDO Regulator with Current Limit and Thermal Shutdown Protection
- High Output Currents Easily Achieved
- Burst Mode® Operation at Light Load
- Low Dropout: 100% Duty Cycle
- Current Mode Operation for Excellent Line and Load Transient Response
- 0.8V Reference Allows Low Output Voltages
- Low Quiescent Current: 260µA Total
- Shutdown Mode Draws Only 10µA Supply Current
- Common Power Good Output for Both Supplies
Typical Application
Description
The LTC3700 is a constant frequency current mode stepdown (buck) DC/DC controller with excellent AC and DC load and line regulation. The on-chip 150mA low dropout (LDO) linear regulator can be powered from the buck controller’s input supply, its own independent input supply or the buck regulator’s output. The buck controller incorporates an undervoltage lockout feature that shuts down the controller when the input voltage falls below 2.1V.
The buck regulator provides a ±2.5% output voltage accuracy. It consumes only 210µA of quiescent current in normal operation with the LDO consuming an additional 50µA. In shutdown, a mere 10µA (combined) is consumed.
For applications where efficiency is a prime consideration, the buck controller is configured for Burst Mode operation which enhances efficiency at low output current. To further maximize the life of a battery source, the external P-channel MOSFET is turned on continuously in dropout (100% duty cycle). High constant operating frequency of 550kHz allows the use of a small external inductor.
The LDO is protected by both current limit and thermal shutdown circuits.
The LTC3700 is available in a tiny 10-pin MSOP.
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LTC3700EMS#PBF | MS-10 | MS | E | 05-08-1661 | Yes |
| LTC3700EMS#TRPBF | MS-10 | MS | E | 05-08-1661 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC3700EMS#PBF | MS-10 | E | $3.30 | $2.35 | Yes | |
| LTC3700EMS#TRPBF | MS-10 | E | $2.41 | Yes | ||
| Buy Now • Request Samples | ||||||
Demo Boards
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC463A | LTC3700EMS | Step-Down Regulator With LDO, 5 - 9Vin1, 3.3Vout1 @ 1A, Jmpr Sel. 3.3 - 5Vin2, 2.5Vout2 @ 150mA | $100.00 | |
| Buy Now | |||
Applications
- Notebook Computers
- Portable Instruments
- One or Two Li-Ion Battery-Powered Applications
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Design Tools
LTspice
LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice
Models for the following parts are available in LTspice:
LTC3700
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
