Overview
Features and Benefits
- Synchronous Rectifier Control for High Efficiency
- Programmable Volt-Second Clamp
- Output Power Levels from 25W to 500W
- Low Current Start-Up
(LT1952: 460µA; VIN On/Off = 14.25V/8.75V)
(LT1952-1: 400µA; VIN On/Off = 7.75V/6.5V) - True PWM Soft-Start
- Low Stress Short Circuit Protection
- Precision 107mV Current Limit Threshold
- Adjustable Delay for Synchronous Timing
- Accurate Shutdown Threshold with Programmable Hysteresis
- Programmable Slope Compensation
- Programmable Leading Edge Blanking
- Programmable Frequency (100kHz to 500kHz)
- Synchronizable to an External Clock up to 1.5 • fOSC
- Internal 1.23V Reference
- 2.5V External Reference
- Current Mode Control
- Small 16-Pin SSOP Package
Product Details
The LT1952/LT1952-1 are current mode PWM controllers optimized to control the forward converter topology, using one primary MOSFET. The LT1952/LT1952-1 provide synchronous rectifier control, resulting in extremely high efficiency. A programmable Volt-Second clamp provides a safeguard for transformer reset that prevents saturation. This allows a single MOSFET on the primary side to reliably run at greater than 50% duty cycle for high MOSFET, transformer and rectifier utilization. The devices include soft-start for controlled exit from shutdown and undervoltage lockout. A precision 107mV current limit threshold, independent of duty cycle, combines with softstart to provide hiccup short circuit protection. The LT1952 is optimized for micropower bootstrap startup from high input voltages. The LT1952-1 allows startup from lower input voltages. Programmable slope compensation and leading edge blanking allow optimization of loop bandwidth with a wide range of inductors and MOSFETs. Each device can be programmed over a 100kHz to 500kHz frequency range and the part can be synchronized to an external clock. The error amplifier is a true op amp, allowing a wide range of compensation networks. The LT1952/LT1952-1 are available in a small 16-pin SSOP package.
Applications
- Telecommunications Power Supplies
- Industrial and Distributed Power
- Isolated and Non-Isolated 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.
Evaluation Kits (14)
Documentation
Reliability Data (1)
User Guides (14)
Tools & Simulations
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Reference Materials
Technical Articles (1)
Design Resources
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PCN-PDN Information
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Evaluation Boards
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.