LT3645
PRODUCTION36V 500mA Step-Down Regulator and 200mA LDO
- Part Models
- 10
- 1ku List Price
- Starting From $3.45
Overview
- Wide Input Range:
- Operation from 3.6V to 36V
- Overvoltage Lockout Protects Circuit Through 55V Transients on Input
- 500mA Output Current Switching Regulator
- High Switching Frequency: 750kHz
- 200mA Low Dropout Linear Regulator
- 1.2V to 16V Input; 0.8V to 8V Output
- 310mV Dropout Voltage VCC2 to OUT2
- Precision Programmable Undervoltage Lockout
- Short-Circuit Robust
- Internal Soft-Start
- <2μA Shutdown Current
- Small Thermally Enhanced 16-Lead (3mm × 3mm) QFN and 12-Lead MSE Packages
The LT3645 is a dual output regulator combining a 500mA buck regulator and a 200mA low dropout linear regulator (LDO). The wide input voltage range of 3.6V to 36V makes the LT3645 suitable for regulating power from a wide variety of sources, including 24V industrial supplies and automotive batteries. Its high operating frequency allows the use of tiny, low cost inductors and capacitors, resulting in a very small solution.
Cycle-by-cycle current limit and frequency foldback provide protection against shorted outputs. Soft-start and frequency foldback eliminate input current surge during start-up.
The linear regulator operates from the VCC2 pin at voltages down to 1.2V. It supplies 200mA of output current with a typical dropout voltage of 310mV.
Other features of the LT3645 include a <2μA shutdown, short circuit protection, soft-start and thermal shutdown. The LT3645 is available in the thermally enhanced 16-lead (3mm × 3mm) QFN package, or a 12-lead MSE package.
Applications
- Automotive CMOS Image Sensors
- Industrial/Automotive Micro-Controller Supply
Documentation
Data Sheet 1
User Guide 1
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.
| Part Model | Pin/Package Drawing | Documentation | CAD Symbols, Footprints, and 3D Models |
|---|---|---|---|
| LT3645EMSE#PBF | 12-Lead MSOP w/ EP | ||
| LT3645EMSE#TRPBF | 12-Lead MSOP w/ EP | ||
| LT3645EUD#PBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LT3645EUD#TRPBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LT3645HMSE#PBF | 12-Lead MSOP w/ EP | ||
| LT3645HMSE#TRPBF | 12-Lead MSOP w/ EP | ||
| LT3645IMSE#PBF | 12-Lead MSOP w/ EP | ||
| LT3645IMSE#TRPBF | 12-Lead MSOP w/ EP | ||
| LT3645IUD#PBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LT3645IUD#TRPBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
Feb 14, 2025 - 25_0016 Bond Wire Change from Gold to Copper Wire (Notification Only) |
||
| LT3645EMSE#PBF | PRODUCTION | |
| LT3645EMSE#TRPBF | PRODUCTION | |
| LT3645EUD#PBF | PRODUCTION | |
| LT3645EUD#TRPBF | PRODUCTION | |
| LT3645IMSE#PBF | PRODUCTION | |
| LT3645IMSE#TRPBF | PRODUCTION | |
|
Jun 5, 2024 - 24_0003 Epoxy Change from Henkel 8290 to 8290A for MSOP Package (2) |
||
| LT3645EMSE#PBF | PRODUCTION | |
| LT3645EMSE#TRPBF | PRODUCTION | |
| LT3645HMSE#PBF | PRODUCTION | |
| LT3645HMSE#TRPBF | PRODUCTION | |
| LT3645IMSE#PBF | PRODUCTION | |
| LT3645IMSE#TRPBF | PRODUCTION | |
|
Feb 4, 2020 - 20_0129 Laser Mark Conversion for 12-Lead MSOP Packages Assembled in ADPG and UTAC |
||
| LT3645EMSE#PBF | PRODUCTION | |
| LT3645EMSE#TRPBF | PRODUCTION | |
| LT3645HMSE#PBF | PRODUCTION | |
| LT3645HMSE#TRPBF | PRODUCTION | |
| LT3645IMSE#PBF | PRODUCTION | |
| LT3645IMSE#TRPBF | PRODUCTION | |
|
Apr 9, 2025 - 25_0016 Bond Wire Change from Gold to Copper Wire (Notification Only) |
||
| LT3645HMSE#PBF | PRODUCTION | |
| LT3645HMSE#TRPBF | PRODUCTION | |
| LT3645IUD#PBF | PRODUCTION | |
| LT3645IUD#TRPBF | PRODUCTION | |
This is the most up-to-date revision of the Data Sheet.
Software Resources
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Tools & Simulations
LTspice 1
Models for the following parts are available in LTspice:
- LT3645
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Evaluation Kits
LT3645EMSE Demo Board | VIN = 5V to 36V, VOUT1 = 3.3V @ 300mA, VOUT2= 2.5V @ 200mA