LTC3778 - Wide Operating Range, No RSENSE Step-Down Controller
Features
- Wide VIN Range: 4V to 36V
- Sense Resistor Optional
- True Current Mode Control
- 2% to 90% Duty Cycle at 200kHz
- tON(MIN)</=100ns
- Stable with Ceramic COUT
- Dual N-Channel MOSFET Synchronous Drive
- Power Good Output Voltage Monitor
- ±1% 0.6V Reference
- Adjustable Current Limit
- Adjustable Switching Frequency
- Programmable Soft-Start
- Output Overvoltage Protection
- Optional Short-Circuit Shutdown Timer
- Micropower Shutdown: IQ </=30µA
- Available in a 1mm 20-Lead TSSOP Package
Typical Application
Description
The LTC3778 is a synchronous step-down switching regulator controller for computer memory, automobile and other DC/DC power supplies. The controller uses a valley current control architecture to deliver very low duty cycles without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in VIN and VOUT.
Discontinuous mode operation provides high efficiency operation at light loads. A forced continuous control pin reduces noise and RF interference, and can assist secondary winding regulation when the main output is lightly loaded. SENSE+ and SENSE– pins provide true Kelvin sensing across the optional sense resistor or the sychronous MOSFET.
Fault protection is provided by internal foldback current limiting, an output overvoltage comparator, optional short-circuit shutdown timer and input undervoltage lockout. Soft-start capability for supply sequencing is accomplished using an external timing capacitor. The regulator current limit level is user programmable. Wide supply range allows operation from 4V to 36V at the input and from 0.6V up to (0.9)VIN at the output.
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 |
|---|---|---|---|---|---|
| LTC3778EF#PBF | TSSOP-20 | F | E | 05-08-1650 (F20) | Yes |
| LTC3778EF#TRPBF | TSSOP-20 | F | E | 05-08-1650 (F20) | 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 | |
|---|---|---|---|---|---|---|
| LTC3778EF#PBF | TSSOP-20 | E | $3.96 | $3.35 | Yes | |
| LTC3778EF#TRPBF | TSSOP-20 | E | $3.47 | 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 |
|---|---|---|---|
| DC389A-A | LTC3778EF | High Efficiency Notebook CPU Power Supply, Mobile Tualatin, Vin = 7.5V - 24V, Vcore = 1.4V/23Amax + VID | $125.00 | |
| DC389A-B | LTC3778EF | High Efficiency Notebook CPU Power Supply, Low Voltage Tualatin, Vin = 7.5V - 24V, Vcore = 1.15V/15Amax + VID | $125.00 | |
| DC389A-C | LTC3778EF | High Efficiency Notebook CPU Power Supply, Ultra Low Voltage Tualatin, Vin = 7.5V - 24V, Vcore = 1.1V/13Amax + VID | $125.00 | |
| Buy Now | |||
Applications
- Notebook and Palmtop Computers, PDAs
- Battery Chargers
- Distributed Power Systems
- DDR Memory Power Supply
- Automobile DC Power Supply
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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:
LTC3778
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.
