LT3688
PRODUCTIONDual 800mA Step-Down Switching Regulator with Power-On Reset and Watchdog Timer
- Part Models
- 10
- 1ku List Price
- Starting From $5.46
Overview
- Wide Input Range:
- Operation from 3.8V to 36V
- Low Ripple (<25mVP-P ) Burst Mode Operation:
- IQ = 115μA at 12VIN to 3.3V and 5V
- Programmable, Defeatable Window Watchdog Timer
- Two Independently Programmable Power-On-Reset Timers
- Synchronizable, Adjustable 350kHz-2.2MHz Switching Frequency
- Two 800mA Output Switching Regulators with Internal Power Switches
- Programmable Input Undervoltage Lockout with Hysteresis
- Thermally Enhanced 24-Pin TSSOP and 4mm × 4mm QFN Packages
The LT3688 is an adjustable frequency (350kHz to 2.2MHz) dual monolithic step-down switching regulator with two power-on reset timers and a watchdog timer. The regulator operates off inputs up to 36V. Low ripple Burst Mode® operation maintains high efficiency at low output current while keeping output ripple below 25mV in a typical application, with input quiescent current of just 115μA. Shutdown circuitry reduces input supply current to less than 1μA while EN/UVLO is pulled low.
The reset and watchdog timeout periods are both adjustable using external capacitors. Tight accuracy specifications and glitch immunity ensure reliable reset operation without false triggering. The open collector RST pins will pull down if the monitored output voltage drops 10% below the programmed value. The LT3688 watchdog timer monitors for watchdog falling edges grouped too close together or too far apart.
The LT3688 is available in 24-Pin TSSOP and 4mm × 4mm QFN packages, each with an exposed pad for low thermal resistance.
Applications
- Automotive Electronic Control Units
- Industrial Power Supplies
- High-Reliability μProcessor Systems
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 |
|---|---|---|---|
| LT3688EFE#PBF | 24-Lead TSSOP w/ EP | ||
| LT3688EFE#TRPBF | 24-Lead TSSOP w/ EP | ||
| LT3688EUF#PBF | 24-Lead QFN (4mm x 4mm x 0.75mm w/ EP) | ||
| LT3688EUF#TRPBF | 24-Lead QFN (4mm x 4mm x 0.75mm w/ EP) | ||
| LT3688HFE#PBF | 24-Lead TSSOP w/ EP | ||
| LT3688HFE#TRPBF | 24-Lead TSSOP w/ EP | ||
| LT3688IFE#PBF | 24-Lead TSSOP w/ EP | ||
| LT3688IFE#TRPBF | 24-Lead TSSOP w/ EP | ||
| LT3688IUF#PBF | 24-Lead QFN (4mm x 4mm x 0.75mm w/ EP) | ||
| LT3688IUF#TRPBF | 24-Lead QFN (4mm x 4mm x 0.75mm w/ EP) |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
May 18, 2026 - 26_0072 Epoxy Change for Select TSSOP Products |
||
| LT3688EFE#PBF | PRODUCTION | |
| LT3688EFE#TRPBF | PRODUCTION | |
| LT3688HFE#PBF | PRODUCTION | |
| LT3688HFE#TRPBF | PRODUCTION | |
| LT3688IFE#PBF | PRODUCTION | |
| LT3688IFE#TRPBF | PRODUCTION | |
|
Apr 6, 2022 - 22_0068 Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL |
||
| LT3688EFE#PBF | PRODUCTION | |
| LT3688EFE#TRPBF | PRODUCTION | |
| LT3688HFE#PBF | PRODUCTION | |
| LT3688HFE#TRPBF | PRODUCTION | |
| LT3688IFE#PBF | PRODUCTION | |
| LT3688IFE#TRPBF | PRODUCTION | |
|
Feb 20, 2022 - 21_0269 Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products |
||
| LT3688EUF#PBF | PRODUCTION | |
| LT3688EUF#TRPBF | PRODUCTION | |
| LT3688IUF#PBF | PRODUCTION | |
| LT3688IUF#TRPBF | PRODUCTION | |
This is the most up-to-date revision of the Data Sheet.
Software Resources
Can't find the software or driver you need?
Request a Driver/SoftwareHardware Ecosystem
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Tools & Simulations
LTspice 1
Models for the following parts are available in LTspice:
- LT3688
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
LT3688EFE Demo Board | 7V ≤ VIN ≤ 36V, 60V Transients, VOUT1 = 5V @ 0.8A, VOUT2 = 3.3V @ 0.8A