LTC1778 - Wide Operating Range, No RSENSE Step-Down Controller
Features
- No Sense Resistor Required
- True Current Mode Control
- Optimized for High Step-Down Ratios
- tON(MIN) <=100ns
- Extremely Fast Transient Response
- Stable with Ceramic COUT
- Dual N-Channel MOSFET Synchronous Drive
- Power Good Output Voltage Monitor (LTC1778)
- Adjustable On-Time (LTC1778-1)
- Wide VIN Range: 4V to 36V
- ±1% 0.8V Voltage 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 16-Pin Narrow SSOP Package
Typical Application
Description
The LTC1778 is a synchronous stepdown switching regulator controller optimized for CPU power. The controller uses a valley current control architecture to deliver very low duty cycles with excellent transient response without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in VIN.
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 by disabling discontinuous operation when the main output is lightly loaded.
Fault protection is provided by internal foldback current limiting, an output overvoltage comparator and optional short-circuit shutdown timer. 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 0.8V up to (0.9)VIN at the output.
Packaging
For complete and up to date package information and drawings, please refer to our packaging page
SSOP-16
Order Info
- Part numbers ending in PBF are lead free. Please contact LTC marketing for information on lead based finish parts.
- 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 | Pins | Temp | Price (1-99) | Price (1k)* | RoHS Data |
|---|---|---|---|---|---|---|
| LTC1778EGN | SSOP | 16 | E | $3.07 | $2.70 | View |
| LTC1778EGN#PBF | SSOP | 16 | E | $3.07 | $2.70 | View |
| LTC1778EGN#TR | SSOP | 16 | E | $2.76 | View | |
| LTC1778EGN#TRPBF | SSOP | 16 | E | $2.76 | View | |
| LTC1778EGN-1 | SSOP | 16 | E | $3.07 | $2.70 | View |
| LTC1778EGN-1#PBF | SSOP | 16 | E | $3.07 | $2.70 | View |
| LTC1778EGN-1#TR | SSOP | 16 | E | $2.76 | View | |
| LTC1778EGN-1#TRPBF | SSOP | 16 | E | $2.76 | View | |
| LTC1778IGN | SSOP | 16 | I | $4.43 | $3.10 | View |
| LTC1778IGN#PBF | SSOP | 16 | I | $4.43 | $3.10 | View |
| LTC1778IGN#TR | SSOP | 16 | I | $3.16 | View | |
| LTC1778IGN#TRPBF | SSOP | 16 | I | $3.16 | View | |
| 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 |
|---|---|---|---|
| DC378A | LTC1778EGN | No Rsense Wide Operating Range DC/DC | $125.00 | |
| DC385A | LTC1778EGN | IMVPII I/O Power Supply, Vin=5V-25V, | $125.00 | |
| Buy Now | |||
Applications
- Notebook and Palmtop Computers, PDAs
- Distributed Power Systems
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Simulate
LTspice IV is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. To download LTspice IV and other FREE simulation tools, please visit our Design Simulation page.
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Related models available in LTspice IV
LTC1778-1
LTC1778
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.
