LT1578 - 1.5A, 200kHz Step-Down Switching Regulator
Features
- 1.5A Switch Current
- High Efficiency—Low Loss 0.2Ohms Switch
- Constant 200kHz Switching Frequency
- 4V to 15V Input VoltageRange
- Minimum Output: 1.21V
- Low Supply Current: 1.9mA
- Low Shutdown Current: 20µA
- Easily Synchronizable Up to 400kHz
- Cycle-by-Cycle Current Limit
- Reduced EMI Generation
- Low Thermal Resistance SO-8 Package
- Uses Small Low Value Inductors
Typical Application
Description
The LT1578 is a 200kHz monolithic buck mode switching regulator. A 1.5A switch is included on the die along with all the necessary oscillator, control and logic circuitry. The topology is current mode for fast transient response and good loop stability. The LT1578 is a modified version of the LT1507 that has been optimized for noise sensitive applications. It will operate over a 4V to 15V input range. In addition, the reference voltage has been lowered to allow the device to produce output voltages down to 1.2V. Quiescent current has been reduced by a factor of two. Switch on resistance has been reduced by 30%. Switch transition times have been slowed to reduce EMI generation. The oscillator frequency has been reduced to 200kHz to maintain high efficiency over a wide output current range. The pinout has been changed to improve PC layout by allowing the high current, high frequency switching circuitry to be easily isolated from low current, noise sensitive control circuitry. The new SO-8 package includes a fused ground lead that significantly reduces the thermal resistance of the device to extend the ambient operating temperature range. Standard surface mount external parts can be used including the inductor and capacitors.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 |
|---|---|---|---|---|---|
| LT1578CS8-2.5#PBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LT1578CS8-2.5#TRPBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LT1578CS8#PBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LT1578CS8#TRPBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LT1578IS8-2.5#PBF | SO-8 | S8 | I | 05-08-1610 (S8) | Yes |
| LT1578IS8-2.5#TRPBF | SO-8 | S8 | I | 05-08-1610 (S8) | Yes |
| LT1578IS8#PBF | SO-8 | S8 | I | 05-08-1610 (S8) | Yes |
| LT1578IS8#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 | |
|---|---|---|---|---|---|---|
| LT1578CS8-2.5#PBF | SO-8 | C | $3.25 | $2.75 | Yes | |
| LT1578CS8-2.5#TRPBF | SO-8 | C | $2.81 | Yes | ||
| LT1578CS8#PBF | SO-8 | C | $3.25 | $2.75 | Yes | |
| LT1578CS8#TRPBF | SO-8 | C | $2.81 | Yes | ||
| LT1578IS8-2.5#PBF | SO-8 | I | $3.70 | $3.15 | Yes | |
| LT1578IS8-2.5#TRPBF | SO-8 | I | $3.21 | Yes | ||
| LT1578IS8#PBF | SO-8 | I | $3.70 | $3.15 | Yes | |
| LT1578IS8#TRPBF | SO-8 | I | $3.21 | 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 |
|---|---|---|---|
| DC303A | LT1578CS8 | 1.5A 200KHz Buck DC/DC with Shutdown & Sync, 5-15Vin, jumper selectable 3.3Vout or 5Vout @1.25A | Contact Factory | |
| Buy Now | |||
Applications
- Portable Computers
- Battery-Powered Systems
- Battery Charger
- Distributed Power 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:
LT1578
LT1578-2.5
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.
