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LTC3851-1: Synchronous Step-Down Switching Regulator Controller Data Sheet4/15/2009PDF357K
Alternative Parts
Overview
Features and Benefits
- 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
Product Details
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
Product Categories
Product Lifecycle
Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Documentation & Resources
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R526 Reliability Data3/26/2018PDF365 K
Tools & Simulations
LTspice
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.
Models for the following parts are available in LTspice:
LTC3851
LTC3851-1
LTC3851A
LTC3851A-1
LTpowerCAD
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
Design tools for the following parts are available in LTpowerCAD:
LTC3851A
LTC3851A-1
Design Resources
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 Number | Material Declaration | Reliability Data | Pin/Package Drawing | CAD Symbols, Footprints & 3D Models |
|---|---|---|---|---|
| LTC3851EMSE-1#PBF | Material Declaration | Reliability Data | 16-Lead MSOP w/ EP | |
| LTC3851EMSE-1#TRPBF | Material Declaration | Reliability Data | 16-Lead MSOP w/ EP | |
| LTC3851EUD-1#PBF | Material Declaration | Reliability Data | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | |
| LTC3851EUD-1#TRPBF | Material Declaration | Reliability Data | 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP) | |
| LTC3851IMSE-1#PBF | Material Declaration | Reliability Data | 16-Lead MSOP w/ EP | |
| LTC3851IMSE-1#TRPBF | Material Declaration | Reliability Data | 16-Lead MSOP w/ EP | |
| Wafer Fabrication Data | R526 Reliability Data |
PCN-PDN Information
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Support & Discussions
Sample & Buy
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Lead Times
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Sampling
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