LT3689
LT3689-5
PRODUCTION
700mA Step-Down Regulator with Power-On Reset and Watchdog Timer
- Part Models
- 20
- 1ku List Price
- Starting From $4.42
Overview
- Wide Input Range:
- Operation from 3.6V to 36V
- Overvoltage Lockout Protects Circuits through 60V Transients
- 85μA IQ at 12VIN to 3.3VOUT
- Low Ripple Burst Mode® Operation Allows Output Ripple <15mVP-P
- Programmable, Defeatable Watchdog Timer with Window or Timeout Control
- Programmable Power-On Reset Timer (POR)
- Synchronizable, Adjustable 350kHz to 2.2MHz Switching Frequency
- 700mA Output Switching Regulator with Internal Power Switch
- Fixed 5V or Adjustable Output Voltage
- 800mV Feedback Voltage
- Programmable Input Undervoltage Lockout with Hysteresis
- 16-Pin 3mm × 3mm QFN and 16-Pin MSOP Packages
The LT3689 is an adjustable frequency (350kHz to 2.2MHz) monolithic step-down switching regulator with a power-on reset and watchdog timer. The regulator operates from inputs up to 36V and withstands transients up to 60V. Low ripple Burst Mode® operation maintains high efficiency at low output current while keeping output ripple below 15mV in a typical application, with input quiescent current of just 85μA. Shutdown circuitry reduces input supply current to less than 1μA while EN/UVLO is pulled low. Using a resistor divider on the EN/UVLO pin provides a programmable undervoltage lockout. Current limit, frequency foldback and thermal shutdown provide fault protection.
The reset and watchdog timeout periods are independently adjustable using external capacitors. Tight accuracy specifications and glitch immunity ensure reliable reset operation of a system without false triggering. The open collector RST will pull down if output voltage drops 10% below the programmed value. The watchdog timer is pin-selectable for window or timeout modes. In timeout mode, WDO pulls low if too long of a period passes before a watchdog transition is detected. In window mode, the LT3689 monitors for WDI falling edges grouped too close together or too far apart.
Applications
- Automotive Electronic Control Units
- Industrial Power Supplies
Documentation
Data Sheet 1
User Guide 1
Technical Articles 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 |
|---|---|---|---|
| LT3689EMSE#PBF | 16-Lead MSOP w/ EP | ||
| LT3689EMSE#TRPBF | 16-Lead MSOP w/ EP | ||
| LT3689EMSE-5#PBF | 16-Lead MSOP w/ EP | ||
| LT3689EMSE-5#TRPBF | 16-Lead MSOP w/ EP | ||
| LT3689EUD#PBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LT3689EUD#TRPBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LT3689EUD-5#PBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LT3689EUD-5#TRPBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LT3689HMSE#PBF | 16-Lead MSOP w/ EP | ||
| LT3689HMSE#TRPBF | 16-Lead MSOP w/ EP | ||
| LT3689HMSE-5#PBF | 16-Lead MSOP w/ EP | ||
| LT3689HMSE-5#TRPBF | 16-Lead MSOP w/ EP | ||
| LT3689IMSE#PBF | 16-Lead MSOP w/ EP | ||
| LT3689IMSE#TRPBF | 16-Lead MSOP w/ EP | ||
| LT3689IMSE-5#PBF | 16-Lead MSOP w/ EP | ||
| LT3689IMSE-5#TRPBF | 16-Lead MSOP w/ EP | ||
| LT3689IUD#PBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LT3689IUD#TRPBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LT3689IUD-5#PBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LT3689IUD-5#TRPBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
Jun 5, 2024 - 24_0003 Epoxy Change from Henkel 8290 to 8290A for MSOP Package (2) |
||
| LT3689EMSE#PBF | PRODUCTION | |
| LT3689EMSE#TRPBF | PRODUCTION | |
| LT3689EMSE-5#PBF | PRODUCTION | |
| LT3689EMSE-5#TRPBF | PRODUCTION | |
| LT3689HMSE#PBF | PRODUCTION | |
| LT3689HMSE#TRPBF | PRODUCTION | |
| LT3689IMSE-5#PBF | PRODUCTION | |
| LT3689IMSE-5#TRPBF | PRODUCTION | |
|
Feb 4, 2020 - 20_0132 Laser Top Mark for 16-Lead MSOP Packages Assembled in ADPG and UTAC |
||
| LT3689EMSE#PBF | PRODUCTION | |
| LT3689EMSE#TRPBF | PRODUCTION | |
| LT3689EMSE-5#PBF | PRODUCTION | |
| LT3689EMSE-5#TRPBF | PRODUCTION | |
| LT3689HMSE#PBF | PRODUCTION | |
| LT3689HMSE#TRPBF | PRODUCTION | |
| LT3689HMSE-5#PBF | PRODUCTION | |
| LT3689HMSE-5#TRPBF | PRODUCTION | |
| LT3689IMSE#PBF | PRODUCTION | |
| LT3689IMSE#TRPBF | PRODUCTION | |
| LT3689IMSE-5#PBF | PRODUCTION | |
| LT3689IMSE-5#TRPBF | PRODUCTION | |
|
Oct 11, 2022 - 22_0244 Epoxy Change from Henkel 8290 to 8290A for MSOP Package |
||
| LT3689HMSE-5#PBF | PRODUCTION | |
| LT3689HMSE-5#TRPBF | PRODUCTION | |
| LT3689IMSE#PBF | PRODUCTION | |
| LT3689IMSE#TRPBF | PRODUCTION | |
|
Apr 18, 2022 - 22_0050 UTAC Thai Limited (UTL) as Alternate Assembly Site for MSOP Packages / Devices |
||
| LT3689HMSE-5#PBF | PRODUCTION | |
| LT3689HMSE-5#TRPBF | PRODUCTION | |
| LT3689IMSE#PBF | PRODUCTION | |
| LT3689IMSE#TRPBF | PRODUCTION | |
This is the most up-to-date revision of the Data Sheet.
Software Resources
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Request a Driver/SoftwareHardware Ecosystem
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Tools & Simulations
LTspice 2
- LT3689-5 Demo Circuit - Step-Down Regulator with POR & WDT (4.5-36V to 5V@700mA)
- LT3689 Demo Circuit - Step-Down Regulator w/ POR & WDT (4.5-36V to 3.3V@700mA)
Models for the following parts are available in LTspice:
- LT3689
- LT3689-5
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
LT3689EUD Demo Board | 4.5V ≤ VIN ≤ 36V (60V Transients), VOUT = 3.3V @ 700mA