LTC1735 High Efficiency Synchronous Step-Down Switching Regulator

The LTC®1735 is a synchronous step-down switching regulator controller that drives external N-channel power MOSFETs using a fixed frequency architecture. Burst Mode™ operation provides high efficiency at low load currents. The precision 0.8V reference is compatible with future generation microprocessors. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values.

The operating frequency (synchronizable up to 500kHz) is set by an external capacitor allowing maximum flexibility in optimizing efficiency. A forced continuous control pin reduces noise and RF interference and can assist secondary winding regulation by disabling Burst Mode operation when the main output is lightly loaded.

Protection features include internal foldback current limiting, output overvoltage crowbar and optional shortcircuit shutdown. Soft-start is provided by an external capacitor that can be used to properly sequence supplies. The operating current level is user-programmable via an external current sense resistor. Wide input supply range allows operation from 4V to 30V (36V maximum).

产品特点 Features
  • Synchronizable/Programmable Fixed Frequency
  • OPTI-LOOP™ Compensation Minimizes COUT
  • ±1% Output Voltage Accuracy
  • Dual N-Channel MOSFET Synchronous Drive
  • Wide VIN Range: 4V to 36V Operation
  • VOUT Range: 0.8V to 6V
  • Internal Current Foldback
  • Output Overvoltage Crowbar Protection
  • Latched Short-Circuit Shutdown Timer with Defeat Option
  • Very Low Dropout Operation: 99% Duty Cycle
  • Forced Continuous Control Pin
  • Optional Programmable Soft-Start
  • Remote Output Voltage Sense
  • Power Good Output (LTC1735F Only)
  • Logic Controlled Micropower Shutdown: IQ < 25µA
  • LTC1435 Pin Compatible with Minor Component Changes
  • Available in 16-Lead Narrow SSOP, SO Packages and 20-Lead TSSOP Package (LTC1735F Only)
应用
  • Notebook and Palmtop Computers, PDAs
  • Cellular Telephones and Wireless Modems
  • DC Power Distribution Systems
典型应用图
LTC1735 典型应用
参数
LTC1735 参数
LTC1735 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) *
LTC1735CF TSSOP 20 C $3.91  $3.30 
LTC1735CF#PBF TSSOP 20 C $3.91  $3.30 
LTC1735CF#TR TSSOP 20 C $3.42 
LTC1735CF#TRPBF TSSOP 20 C $3.42 
LTC1735CGN SSOP 16 C $3.80  $3.25 
LTC1735CGN#PBF SSOP 16 C $3.80  $3.25 
LTC1735CGN#TR SSOP 16 C $3.31 
LTC1735CGN#TRPBF SSOP 16 C $3.31 
LTC1735CGN-1 SSOP 16 C $3.80  $3.25 
LTC1735CGN-1#PBF SSOP 16 C $3.80  $3.25 
LTC1735CGN-1#TR SSOP 16 C $3.31 
LTC1735CGN-1#TRPBF SSOP 16 C $3.31 
LTC1735CS SO 16 C $3.65  $3.10 
LTC1735CS#PBF SO 16 C $3.65  $3.10 
LTC1735CS#TR SO 16 C $3.16 
LTC1735CS#TRPBF SO 16 C $3.16 
LTC1735CS-1 SO 16 C $3.65  $3.10 
LTC1735CS-1#PBF SO 16 C $3.65  $3.10 
LTC1735CS-1#TR SO 16 C $3.16 
LTC1735CS-1#TRPBF SO 16 C $3.16 
LTC1735EGN SSOP 16 E $4.25  $3.60 
LTC1735EGN#PBF SSOP 16 E $4.25  $3.60 
LTC1735EGN#TR SSOP 16 E $3.66 
LTC1735EGN#TRPBF SSOP 16 E $3.66 
LTC1735IF TSSOP 20 I $6.52  $4.30 
LTC1735IF#PBF TSSOP 20 I $6.52  $4.30 
LTC1735IF#TR TSSOP 20 I $4.42 
LTC1735IF#TRPBF TSSOP 20 I $4.42 
LTC1735IGN SSOP 16 I $5.05  $4.25 
LTC1735IGN#PBF SSOP 16 I $5.05  $4.25 
LTC1735IGN#TR SSOP 16 I $4.31 
LTC1735IGN#TRPBF SSOP 16 I $4.31 
LTC1735IGN-1 SSOP 16 I $5.05  $4.25 
LTC1735IGN-1#PBF SSOP 16 I $5.05  $4.25 
LTC1735IGN-1#TR SSOP 16 I $4.31 
LTC1735IGN-1#TRPBF SSOP 16 I $4.31 
LTC1735IS SO 16 I $4.90  $4.05 
LTC1735IS#PBF SO 16 I $4.90  $4.05 
LTC1735IS#TR SO 16 I $4.11 
LTC1735IS#TRPBF SO 16 I $4.11 
LTC1735IS-1 SO 16 I $4.90  $4.05 
LTC1735IS-1#PBF SO 16 I $4.90  $4.05 
LTC1735IS-1#TR SO 16 I $4.11 
LTC1735IS-1#TRPBF SO 16 I $4.11 
LTC1735 数据手册及相关资料下载
  1. 数据手册(英文) : LTC1735 - High Efficiency Synchronous Step-Down Switching Regulator.PDF
  2. 数据手册(中文) : LTC1735 - High Efficiency Synchronous Step-Down Switching Regulator.PDF
  3. 应用指南 (英文) : AN76 - OPTI-LOOP Architecture Reduces Output Capacitance and Improves Transient Response.PDF
  4. 设计要点(英文) : Design Solutions 10 - Active Voltage Positioning Reduces Output Capacitors.PDF
  5. 设计要点 (英文) : DN199 - LTC1735 Provides Low Cost, Efficient Mobile CPU Power.PDF
  6. 设计要点 (英文) : DN209 - 2-Step Voltage Regulation Improves Performance and Decreases CPU Temperature in Portable Computers.PDF
  7. 设计要点 (英文) : DN279 - Microprocessor Core Supply Voltage Set by I2C Bus Without VID Lines.PDF
  8. 可靠性数据 : R384 Reliability Data .PDF