LT1681 Dual Transistor Synchronous Forward Controller

The LT®1681 controller simplifies the design of high power synchronous dual transistor forward DC/DC converters. The part employs fixed frequency current mode control and supports both isolated and nonisolated topologies. The IC drives external N-channel power MOSFETs and operates with input voltages up to 72V.

The LT1681’s operating frequency is programmable and can be synchronized up to 350kHz. Switch phase is also controlled during synchronized operation to accommodate multiple converter systems. Internal logic guarantees 50%maximum duty cycle operation to prevent transformer saturation.

The LT1681 incorporates a soft-start feature that provides a controlled increase in supplied current during start-up and after an undervoltage lockout or overvoltage/overcurrent event.

The part is available in a 20-lead wide SO package to support high voltage pin-to-pin clearance

产品特点 Features

High Voltage: Operation Up to 72V
Synchronizable Operating Frequency and Output Switch Phase for Multiple Controller Systems
Fixed Frequency Operation to 350kHz
Adaptive and Adjustable Blanking
Synchronous Rectifier Driver
Local 1% Voltage Reference
Undervoltage Lockout Protection with Hysteresis
Input Overvoltage Protection
Programmable Start Inhibit
Transformer Primary Saturation Protection
Optocoupler Feedback Support
Soft-Start Control

参数

应用

Isolated Telecommunication Systems
Personal Computers and Peripherals
Lead Acid Battery Backup Systems
Automotive and Heavy Equipment

典型应用图

LT1681 订购信息和价格参考Package Variations and Pricing

器件型号	封装	引脚	温度	价格 (以 1 ~ 99 片为批量)	价格 (以 1000 片为批量) *
LT1681ESW	SO	20	E	$5.92	$5.00
LT1681ESW#PBF	SO	20	E	$5.92	$5.00
LT1681ESW#TR	SO	20	E		$5.10
LT1681ESW#TRPBF	SO	20	E		$5.10
LT1681ISW	SO	20	I	$6.51	$5.50
LT1681ISW#PBF	SO	20	I	$6.51	$5.50
LT1681ISW#TR	SO	20	I		$5.60
LT1681ISW#TRPBF	SO	20	I		$5.60

LT1681 数据手册及相关资料下载

数据手册(英文) : LT1681 - Dual Transistor Synchronous Forward Controller.PDF
设计要点 (英文) : DN261 - Chip Set Offers Low Cost Alternative to 48V Telecom Modules.PDF
设计要点 (中文) : DN261 Chip Set Offers Low Cost Alternative to 48V Telecom Modules.PDF
可靠性数据 : R352 Reliability Data .PDF