Overview
Features and Benefits
- Low Start-Up Current: <250µA
- 50ns Current Sense Delay
- Current Mode Operation: To 500kHz
- Pin Compatible with UC1842 Series
- Undervoltage Lockout with Hysteresis
- No Cross-Conduction Current
- Trimmed Bandgap Reference
- 1A Totem Pole Output
- Trimmed Oscillator Frequency and Sink Current
- Active Pull-Down on Reference and Output During Undervoltage Lockout
- High Level Output Clamp: 18V
- Current Sense Leading Edge Blanking
Product Details
The LT1241 series devices are 8-pin, fixed frequency, current mode, pulse width modulators. They are improved plug compatible versions of the industry standard UC1842 series. These devices have both improved speed and lower quiescent current. The LT1241 series is optimized for off-line and DC/DC converter applications. They contain a temperature-compensated reference, high gain error amplifier, current sensing comparator and a high current totem pole output stage ideally suited to driving power MOSFETs. Start-up current has been reduced to less than 250µA. Cross-conduction current spikes in the output stage have been eliminated, making 500kHz operation practical. Several new features have been incorporated. Leading edge blanking has been added to the current sense comparator. Trims have been added to the oscillator circuit for both frequency and sink current, and both of these parameters are tightly specified. The output stage is clamped to a maximum VOUT of 18V in the on state. The output and the reference output are actively pulled low during undervoltage lockout.
Applications
- Off-Line Converters
- DC/DC Converters
Product Categories
Product Lifecycle
Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Documentation & Resources
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R293 Reliability Data3/22/2018
Tools & Simulations
LTspice
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
LTspice Simulations
Models for the following parts are available in LTspice:
LT1245
Design Resources
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.
| Part Number | Material Declaration | Reliability Data | Pin/Package Drawing | CAD Symbols, Footprints & 3D Models |
|---|---|---|---|---|
| LT1245CN8#PBF | Material Declaration | Reliability Data | 8-Lead PDIP (Narrow 0.3 Inch) | |
| LT1245CS8#PBF | Material Declaration | Reliability Data | 8-Lead SOIC (Narrow 0.15 Inch) | |
| LT1245CS8#TRPBF | Material Declaration | Reliability Data | 8-Lead SOIC (Narrow 0.15 Inch) | |
| LT1245IN8#PBF | Material Declaration | Reliability Data | 8-Lead PDIP (Narrow 0.3 Inch) | |
| LT1245IS8#PBF | Material Declaration | Reliability Data | 8-Lead SOIC (Narrow 0.15 Inch) | |
| LT1245IS8#TRPBF | Material Declaration | Reliability Data | 8-Lead SOIC (Narrow 0.15 Inch) | |
| Wafer Fabrication Data | R293 Reliability Data |
PCN-PDN Information
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Lead Times
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