LTC1147 - High Efficiency Step-Down Switching Regulator Controllers
Features
- Very High Efficiency: Over 95% Possible
- Wide VIN Range: 3.5V* to 16V
- Current Mode Operation for Excellent Line and Load Transient Response
- High Efficiency Maintained Over Three Decades of Output Current
- Low 160µA Standby Current at Light Loads
- Logic Controlled Micropower Shutdown: IQ <20µA
- Short-Circuit Protection
- Very Low Dropout Operation: 100% Duty Cycle
- High Efficiency in a Small Amount of Board Space
- Output Can Be Externally Held High in Shutdown
- Available in 8-Pin SO Package
Typical Application
Description
The LTC1147 series are step-down switching regulator controllers featuring automatic BurstMode™ operation to maintain high efficiencies at low output currents. These devices drive an external P-channel power MOSFET at switching frequencies exceeding 400kHz using a constant off-time current mode architecture providing constant ripple current in the inductor.
The operating current level is user-programmable via an external current sense resistor. Wide input supply range allows operation from 3.5V* to 14V (16V maximum). Constant off-time architecture provides low dropout regulation limited by only the RDS(ON) of the external MOSFET and resistance of the inductor and current sense resistor.
The LTC1147 series incorporates automatic power saving Burst Mode operation to reduce switching losses when load currents drop below the level required for continuous operation. Standby power is reduced to only 2mW at VIN = 10V (at IOUT = 0). Load currents in Burst Mode operation are typically 0mA to 300mA.
For applications where even higher efficiency is required, refer to the LTC1148 data sheet and Application Note 54.
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 |
|---|---|---|---|---|---|
| LTC1147CN8-3.3#PBF | N-8 | N | C | 05-08-1510 (N8) | Yes |
| LTC1147CN8-5#PBF | N-8 | N | C | 05-08-1510 (N8) | Yes |
| LTC1147CS8-3.3#PBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LTC1147CS8-3.3#TRPBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LTC1147CS8-5#PBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LTC1147CS8-5#TRPBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LTC1147HVCS8-3.3#PBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LTC1147HVCS8-3.3#TRPBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LTC1147IS8-3.3#PBF | SO-8 | S8 | I | 05-08-1610 (S8) | Yes |
| LTC1147IS8-3.3#TRPBF | SO-8 | S8 | I | 05-08-1610 (S8) | Yes |
| LTC1147IS8-5#PBF | SO-8 | S8 | I | 05-08-1610 (S8) | Yes |
| LTC1147IS8-5#TRPBF | SO-8 | S8 | I | 05-08-1610 (S8) | Yes |
| LTC1147LCS8-3.3#PBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LTC1147LCS8-3.3#TRPBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LTC1147LCS8#PBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LTC1147LCS8#TRPBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LTC1147LIS8#PBF | SO-8 | S8 | I | 05-08-1610 (S8) | Yes |
| LTC1147LIS8#TRPBF | SO-8 | S8 | I | 05-08-1610 (S8) | 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 | |
|---|---|---|---|---|---|---|
| LTC1147CN8-3.3#PBF | N-8 | C | $2.90 | $2.50 | Yes | |
| LTC1147CN8-5#PBF | N-8 | C | $2.90 | $2.50 | Yes | |
| LTC1147CS8-3.3#PBF | SO-8 | C | $3.10 | $2.60 | Yes | |
| LTC1147CS8-3.3#TRPBF | SO-8 | C | $2.66 | Yes | ||
| LTC1147CS8-5#PBF | SO-8 | C | $3.10 | $2.60 | Yes | |
| LTC1147CS8-5#TRPBF | SO-8 | C | $2.66 | Yes | ||
| LTC1147HVCS8-3.3#PBF | SO-8 | C | $3.75 | $3.10 | Yes | |
| LTC1147HVCS8-3.3#TRPBF | SO-8 | C | $3.16 | Yes | ||
| LTC1147IS8-3.3#PBF | SO-8 | I | $3.75 | $3.10 | Yes | |
| LTC1147IS8-3.3#TRPBF | SO-8 | I | $3.17 | Yes | ||
| LTC1147IS8-5#PBF | SO-8 | I | $3.75 | $3.10 | Yes | |
| LTC1147IS8-5#TRPBF | SO-8 | I | $3.17 | Yes | ||
| LTC1147LCS8-3.3#PBF | SO-8 | C | $3.40 | $2.90 | Yes | |
| LTC1147LCS8-3.3#TRPBF | SO-8 | C | $2.96 | Yes | ||
| LTC1147LCS8#PBF | SO-8 | C | $3.40 | $2.90 | Yes | |
| LTC1147LCS8#TRPBF | SO-8 | C | $2.96 | Yes | ||
| LTC1147LIS8#PBF | SO-8 | I | $3.85 | $3.20 | Yes | |
| LTC1147LIS8#TRPBF | SO-8 | I | $3.26 | 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 |
|---|---|---|---|
| DC042A | LTC1147CS8-3.3 | HIGH EFFICIENCY 5V-3.3 SWITCHING REG | $100.00 | |
| Buy Now | |||
Applications
- Notebook and Palmtop Computers
- Portable Instruments
- Battery-Operated Digital Devices
- Cellular Telephones
- DC Power Distribution Systems
- GPS Systems
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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:
LTC1147-3.3
LTC1147-5
LTC1147L
LTC1147L-3.3
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.
