LINEAR TECHNOLOGY LTC1735 User Guide
Summary
The LTC1735 is a high-efficiency synchronous step-down switching regulator designed for advanced DC power management systems. This manual provides comprehensive technical documentation, covering electrical characteristics across wide operating ranges (4V to 36V), including optimized features like OPTI-LOOP compensation and Burst Mode operation. It details the setup, advanced protection features (e.g., Undervoltage/Overvoltage Crowbar), and precise application usage. This documentation is essential for hardware engineers and power electronics designers building reliable, high-performance embedded systems such as notebooks, PDAs, and industrial power distribution networks.
Page 1 Text Content
LTC1735 High Efficiency
Synchronous Step-Down Switching Regulator
FEATURES DESCRIPTIO Synchronizable/Programmable Fixed Frequency The LTC®1735 is a synchronous step-down switching OPTI-LOOPTM Compensation Minimizes COUT regulator controller that drives external N-channel power ±1% Output Voltage Accuracy MOSFETs using a fixed frequency architecture. Burst Dual N-Channel MOSFET Synchronous Drive Mode TM operation provides high efficiency at low load Wide VIN Range: 4V to 36V Operation currents. The precision 0.8V reference is compatible with VOUT Range: 0.8V to 6V future generation microprocessors. OPTI-LOOP compen- Internal Current Foldback sation allows the transient response to be optimized over Output Overvoltage Crowbar Protection a wide range of output capacitance and ESR values. Latched Short-Circuit Shutdown Timer
The operating frequency (synchronizable up to 500k Hz) is
with Defeat Option
set by an external capacitor allowing maximum flexibility
Very Low Dropout Operation: 99% Duty Cycle
in optimizing efficiency. A forced continuous control pin
Forced Continuous Control Pin
reduces noise and RF interference and can assist second-
Optional Programmable Soft-Start
ary winding regulation by disabling Burst Mode operation
Remote Output Voltage Sense
when the main output is lightly loaded.
Power Good Output (LTC1735F Only)
Logic Controlled Micropower Shutdown: IQ < 25µA Protection features include internal foldback current lim- LTC1435 Pin Compatible with iting, output overvoltage crowbar and optional short- Minor Component Changes circuit shutdown. Soft-start is provided by an external Available in 16-Lead Narrow SSOP, SO Packages and capacitor that can be used to properly sequence supplies. 20-Lead TSSOP Package (LTC1735F Only) The operating current level is user-programmable via an external current sense resistor. Wide input supply range
APPLICATIO S allows operation from 4V to 30V (36V maximum).
, LTC and LT are registered trademarks of Linear Technology Corporation. Notebook and Palmtop Computers, PDAs Burst Mode and OPTI-LOOP are trademarks of Linear Technology Corporation.■
Cellular Telephones and Wireless Modems DC Power Distribution Systems
TYPICAL APPLICATIO
COSC CIN 5V TO 24V
0.1µF COSC TG
CB FDS6680A 50V
RUN/SS 0.22µF COUT: PANASONIC EEFUEOG181R
CIN: MARCON THCR70E1H226ZT
BOOST
ITH L1: PANASONIC ETQP6F2R0HFA
CC RSENSE: IRC LRF2010-01-R005J
330p F SW
RC CC2 LTC1735 L1
RSENSE
33k 100p F DB 2µH
0.005Ω VOUT
SGND VIN CMDSH-3
1% VOSENSE INTVCC
COUT 4.7µF 180µF
SENSE– BG 4V
20k FDS6680A MBRS340T3
SENSE+ PGND
Figure 1. High Efficiency Step-Down Converter
1735fc
Page Summary Contents For LINEAR TECHNOLOGY LTC1735 User Guide
Manual Details
| Brand | Linear |
|---|---|
| Pages | 32 |
| File Size | 401.47 KB |
| Published | May 25, 2026 |
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Frequently Asked Questions
What input voltage range does the LTC1735 support?
It operates from a wide input supply range, allowing operation from 4V to 36V (maximum).
How can I adjust the switching frequency?
The operating frequency is synchronizable up to 500kHz. This frequency is set by an external capacitor.
Does it have protection against output overvoltage?
Yes, it features Output Overvoltage Crowbar Protection and internal foldback current limiting for protection.
Which function optimizes efficiency at low loads?
The Burst Mode dual N-channel MOSFET synchronous drive mode provides high efficiency specifically at low load conditions.