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- LTC3854 Project - Synchronous Step-Down Switching Supply with Inductor DCR Current Sensing (4.5-14V to 1.5V @ 15A)
- LTC3854 Project - Synchronous Step-Down Switching Supply with Inductor DCR Current Sensing (4.5-25V to 2.5V @ 5A)
- LTC3854 Project - Synchronous Step-Down Switching Supply with Inductor DCR Current Sensing (4.5-34V to 2.5V @ 12A)
- LTC3854 Project - Synchronous Step-Down Switching Supply with Rsense Current Sensing (4.5-14V to 1.5V @ 15A)
- LTC3854 Project - Synchronous Step-Down Switching Supply with Rsense Current Sensing (4.5-34V to 2.5V @ 12A)
Features
- Wide Operating VIN Range: 4.5V to 38V
- RSENSE or DCR Current Sensing
- ±1% 0.8V Reference Accuracy Over Temperature
- 400kHz Switching Frequency
- Dual N-channel MOSFET Synchronous Drive
- Very Low Dropout Operation: 97% Duty Cycle
- Starts Up Into Pre-Biased Output
- Adjustable Output Voltage Soft-Start
- Output Current Foldback Limiting (Disabled During Soft-Start)
- Output Overvoltage Protection
- 5V LDO for External Gate Drive
- OPTI-LOOP® Compensation Minimizes COUT
- Low Shutdown IQ: 15μA
- Tiny Thermally Enhanced 12-Pin 2mm × 3mm DFN and MSOP Packages
Typical Application
Description
The LTC3854 is a high performance synchronous stepdown switching DC/DC controller that drives an all N-channel synchronous power MOSFET stage.
The LTC3854 features a 400kHz constant frequency current mode architecture. The LTC3854 operates from a 4.5V to 38V (40V absolute maximum) input voltage range and regulates the output voltage from 0.8V to 5.5V.
The RUN/SS pin provides both soft-start and enable features. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. Current foldback limits MOSFET dissipation during short circuit conditions. Current foldback functions are disabled during soft-start.
The LTC3854 has a minimum on-time at 75ns, making it well suited for high step-down ratios. The strong onboard MOSFET drivers allow the use of high power external MOSFETs to produce output currents up to 20A.
3x2 DFN-12,MS-12E
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LTC3854EDDB#PBF | DFN | 12 | E | $2.39 | |
| LTC3854EDDB#TRMPBF | DFN | 12 | E | $2.36 | $1.70 |
| LTC3854EDDB#TRPBF | DFN | 12 | E | $2.36 | $1.65 |
| LTC3854EMSE#PBF | MSOP | 12 | E | $2.36 | $1.65 |
| LTC3854EMSE#TRPBF | MSOP | 12 | E | $1.71 | |
| LTC3854IDDB#PBF | DFN | 12 | I | $2.69 | |
| LTC3854IDDB#TRMPBF | DFN | 12 | I | $2.69 | $1.93 |
| LTC3854IDDB#TRPBF | DFN | 12 | I | $2.69 | $1.88 |
| LTC3854IMSE#PBF | MSOP | 12 | I | $2.69 | $1.88 |
| LTC3854IMSE#TRPBF | MSOP | 12 | I | $1.94 |
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.
| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC1271A | LTC3854EDDB Demo Board | 4.5V ≤ VIN ≤ 14V, VOUT = 1.5V @ 15A | $100.00 | |
| DC1450A | LTC3854EDDB Demo Board | 4.5V ≤ VIN ≤ 26V, VOUT = 2.5V @ 5A | $100.00 | |
| DC1487A | LTC3854EMSE Demo Board | 4.5V ≤ VIN ≤ 34V, VOUT = 2.5V @ 12A | $100.00 |