LT1952 - Single Switch Synchronous Forward Controller

Features

  • 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
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LT1952 Typical Application
LT1952 Typical Application

Description

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.

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
LT1952EGN-1#PBF SSOP-16 GN E 05-08-1641 (GN16) Yes
LT1952EGN-1#TRPBF SSOP-16 GN E 05-08-1641 (GN16) Yes
LT1952EGN#PBF SSOP-16 GN E 05-08-1641 (GN16) Yes
LT1952EGN#TRPBF SSOP-16 GN E 05-08-1641 (GN16) Yes
LT1952IGN-1#PBF SSOP-16 GN I 05-08-1641 (GN16) Yes
LT1952IGN-1#TRPBF SSOP-16 GN I 05-08-1641 (GN16) Yes
LT1952IGN#PBF SSOP-16 GN I 05-08-1641 (GN16) Yes
LT1952IGN#TRPBF SSOP-16 GN I 05-08-1641 (GN16) Yes
LT1952MPGN-1#PBF SSOP-16 GN MP 05-08-1641 (GN16) Yes
LT1952MPGN-1#TRPBF SSOP-16 GN MP 05-08-1641 (GN16) Yes
LT1952MPGN#PBF SSOP-16 GN MP 05-08-1641 (GN16) Yes
LT1952MPGN#TRPBF SSOP-16 GN MP 05-08-1641 (GN16) Yes


LT1952 Package Drawing

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
LT1952EGN-1#PBF SSOP-16 E $3.93 $3.30 Yes
LT1952EGN-1#TRPBF SSOP-16 E $3.36 Yes
LT1952EGN#PBF SSOP-16 E $3.93 $3.30 Yes
LT1952EGN#TRPBF SSOP-16 E $3.36 Yes
LT1952IGN-1#PBF SSOP-16 I $4.34 $3.65 Yes
LT1952IGN-1#TRPBF SSOP-16 I $3.71 Yes
LT1952IGN#PBF SSOP-16 I $4.34 $3.65 Yes
LT1952IGN#TRPBF SSOP-16 I $3.71 Yes
LT1952MPGN-1#PBF SSOP-16 MP $13.36 $9.35 Yes
LT1952MPGN-1#TRPBF SSOP-16 MP $9.41 Yes
LT1952MPGN#PBF SSOP-16 MP $13.36 $9.35 Yes
LT1952MPGN#TRPBF SSOP-16 MP $9.41 Yes
Buy NowRequest Samples
* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

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
DC1317A-A LT1952EGN-1 Active Reset Demoboard | Vin=34V - 75V Vout=3.3V @ 35A $175.00
DC1317A-B LT1952EGN-1 Active Reset Demoboard | Vin=18V-72V Vout=5V @ 25A $175.00
DC1317A-C LT1952EGN-1/LTC3900 Demo Board | Active Reset, Vin=18V-72V Vout=12V @ 10A $175.00
DC1317A-D LT1952EGN-1 Active Reset Demo Board | Vin=18V-72V Vout=24V @ 5A $175.00
DC1317A-E LT1952EGN-1 Active Reset Demo Board | Vin=18V-72V Vout=5V @ 12A $150.00
DC1317A-F LT1952EGN-1 Active Reset Demo Board | Vin=9V-36V Vout=3.3 @ 22A $150.00
DC1317A-G LT1952EGN-1/LTC3900 Demo Board | Active Reset, Vin=9V-36V Vout=12V @ 5A $175.00
DC1317A-H LT1952-1 Isolated Demo Board I Sync Forward Controller, Active Reset, 9V ≤ VIN ≤ 36V, 48V @1.5A $175.00
DC759A LT1952EGN, LTC1698EGN | 48Vin to 5V at 20A Converter, +Vin = 36V - 72V, +Vout = +5V at 20A $175.00
DC830A LT1952EGN-1 | 48Vin to3.3V, 40A Isolated Quarter Brick Teleom DC/DC Converter $175.00
DC968A-A LT1952EGN-1, LTC3900CS8, LT4430ES6 Demo Board | Vin=34V-75V Vout=3.3V @ 30A $150.00
DC968A-B LT1952EGN-1, LTC3900CS8, LT4430ES6 Demo Board | Vin=18V-36V, Vout=5V @ 20A $175.00
DC968A-C LT1952EGN-1, LTC3900CS8, LT4430ES6 Demo Board | Vin=36V-75V, Vout=12V @ 12A $150.00
DC968A-D LT1952EGN-1, LTC3900CS8, LT4430ES6 Demo Board | Vin=36V-75V, Vout=28V @ 4A $175.00
Buy Now
Click here to view our complete list of demo boards

Designed for Automotive and Transportation Applications

AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LT1952IGN-1#PBF SSOP-16 I $4.34 $3.65 Yes
LT1952IGN-1#TRPBF SSOP-16 I $3.71 Yes
LT1952IGN#PBF SSOP-16 I $4.34 $3.65 Yes
LT1952IGN#TRPBF SSOP-16 I $3.71 Yes
LT1952MPGN-1#PBF SSOP-16 MP $13.36 $9.35 Yes
LT1952MPGN-1#TRPBF SSOP-16 MP $9.41 Yes
LT1952MPGN#PBF SSOP-16 MP $13.36 $9.35 Yes
LT1952MPGN#TRPBF SSOP-16 MP $9.41 Yes
Buy NowRequest Samples
* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Applications

  • Telecommunications Power Supplies
  • Industrial and Distributed Power
  • Isolated and Non-Isolated DC/DC Converters

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Design Tools

LTspice

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Models for the following parts are available in LTspice:
LT1952
LT1952-1

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