LTC3851-1
PRODUCTIONSynchronous Step-Down Switching Regulator Controller
- Part Models
- 6
- 1ku List Price
- Starting From $2.64
Overview
- Wide VIN Range: 4V to 38V Operation
- RSENSE or DCR Current Sensing
- ±1% Output Voltage Accuracy
- Power Good Output Voltage Monitor
- Phase-Lockable Fixed Frequency: 250kHz to 750kHz
- Dual N-Channel MOSFET Synchronous Drive
- Very Low Dropout Operation: 99% Duty Cycle
- Adjustable Output Voltage Soft-Start or Tracking
- Output Current Foldback Limiting
- Output Overvoltage Protection
- OPTI-LOOP® Compensation Minimizes COUT
- Selectable Continuous, Pulse-Skipping or Burst Mode® Operation at Light Loads
- Low Shutdown IQ: 20μA
- VOUT Range: 0.8V to 5.5V
- Thermally Enhanced 16-Lead MSOP or 3mm × 3mm QFN Package
The LTC3851-1 is a high performance synchronous step-down switching regulator controller that drives an all N-channel synchronous power MOSFET stage. A constant frequency current mode architecture allows a phase-lockable frequency of up to 750kHz.
OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3851-1 features a precision 0.8V reference and a power good indicator. A wide 4V to 38V (40V absolute maximum) input supply range encompasses most battery configurations and intermediate bus voltages.
The TK/SS pin ramps the output voltage during start-up and shutdown with coincident or ratiometric tracking. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The MODE/PLLIN pin selects among Burst Mode operation, pulse skipping mode or continuous inductor current mode at light loads and allows the IC to be synchronized to an external clock.
The LTC3851-1 is identical to the LTC3851 except that the ILIM pin is replaced by PGOOD.
| Features | |
| LTC3851 | Not Recommended For New Designs |
| LTC3851-1 | Not Recommended For New Designs |
| LTC3851A | Adjustable Current Limit |
| LTC3851A-1 | PGOOD Output |
Applications
- Automotive Systems
- Telecom Systems
- Industrial Equipment
- Distributed DC Power Systems
Documentation
Data Sheet 1
Application Note 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 |
|---|---|---|---|
| LTC3851EMSE-1#PBF | 16-Lead MSOP w/ EP | ||
| LTC3851EMSE-1#TRPBF | 16-Lead MSOP w/ EP | ||
| LTC3851EUD-1#PBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LTC3851EUD-1#TRPBF | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LTC3851IMSE-1#PBF | 16-Lead MSOP w/ EP | ||
| LTC3851IMSE-1#TRPBF | 16-Lead MSOP w/ EP |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
Feb 14, 2025 - 25_0016 Bond Wire Change from Gold to Copper Wire (Notification Only) |
||
| LTC3851EMSE-1#PBF | PRODUCTION | |
| LTC3851EMSE-1#TRPBF | PRODUCTION | |
| LTC3851EUD-1#PBF | PRODUCTION | |
| LTC3851EUD-1#TRPBF | PRODUCTION | |
| LTC3851IMSE-1#PBF | PRODUCTION | |
| LTC3851IMSE-1#TRPBF | PRODUCTION | |
|
Oct 11, 2022 - 22_0244 Epoxy Change from Henkel 8290 to 8290A for MSOP Package |
||
| LTC3851EMSE-1#PBF | PRODUCTION | |
| LTC3851EMSE-1#TRPBF | PRODUCTION | |
|
Feb 4, 2020 - 20_0132 Laser Top Mark for 16-Lead MSOP Packages Assembled in ADPG and UTAC |
||
| LTC3851EMSE-1#PBF | PRODUCTION | |
| LTC3851EMSE-1#TRPBF | PRODUCTION | |
| LTC3851IMSE-1#PBF | PRODUCTION | |
| LTC3851IMSE-1#TRPBF | PRODUCTION | |
|
Jun 5, 2024 - 24_0003 Epoxy Change from Henkel 8290 to 8290A for MSOP Package (2) |
||
| LTC3851IMSE-1#PBF | PRODUCTION | |
| LTC3851IMSE-1#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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| Hot Swap Controllers 1 | ||
| LT4363 | RECOMMENDED FOR NEW DESIGNS | High Voltage Surge Stopper with Current Limit |
| Oscillators 1 | ||
| LTC6909 | PRODUCTION | 1 to 8 Output, Multiphase Silicon Oscillator with Spread Spectrum Modulation |
| Parts | Product Life Cycle | Description |
|---|---|---|
| LTC3851A-1 | PRODUCTION | Synchronous Step-Down Switching Regulator Controller |
Tools & Simulations
LTspice
Models for the following parts are available in LTspice:
- LTC3851
- LTC3851-1
- LTC3851A
- LTC3851A-1
LTpowerCAD
Design tools for the following parts are available in LTpowerCAD:
- LTC3851A
- LTC3851A-1
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.
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