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Overview
Features and Benefits
- Dual, 180° Phased Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
- High Efficiency: Up to 95%
- RSENSE or DCR Current Sensing
- ±1% 0.8V Output Voltage Accuracy
- Phase-Lockable Fixed Frequency 250kHz to 780kHz
- Supports Pre-Biased Output
- Dual N-Channel MOSFET Synchronous Drive
- Wide VIN Range: 4V to 30V Operation
- Adjustable Soft-Start Current Ramping or Tracking
- Foldback Output Current Limiting
- Output Overvoltage Protection
- Power Good Output Voltage Monitor
- 28-Pin Narrow SSOP Package
Product Details
The LTC3850-2 is a high performance dual synchronous step-down switching regulator controller that drives all N-channel power MOSFET stages. A constant-frequency current mode architecture allows a phase-lockable frequency of up to 780kHz. Power loss and supply noise are minimized by operating the two controller output stages out of phase.
OPTI-LOOP® compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3850-2 features a precision 0.8V reference and a power good output indicator. A wide 4V to 30V input supply range encompasses most battery chemistries and intermediate bus voltages.
Independent TK/SS pins for each controller ramp the output voltages during start-up. 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 and allows the IC to be synchronized to an external clock.
The LTC3850-2 is identical to the LTC3850-1, except they have different pin assignments.
| Features | |
| LTC3850 | SSOP-28 and QFN-28 Packages |
| LTC3850-1 | ILIM function replaced with an EXTVCC function, SSOP-28 package only |
| LTC3850-2 | The LTC3850-2 is identical to the LTC3850-1 SSOP-28, except they have different pin-outs |
Applications
- Notebook and Palmtop Computers
- Portable Instruments
- Battery-Operated Digital Devices
- DC Power Distribution Systems
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
Reliability Data (1)
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:
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:
Reference Materials
Voltage vs. Current Mode Control Curent Sharing in a PolyPhase DC/DC...
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.
Support & Discussions
LTC3850-2 Discussions
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
