Power Management
Switching Regulator
Step-Down (Buck) Regulators
Multiple Output Buck
Power Management
Switching Regulator
Step-Down (Buck) Regulators
Poly-Phase Buck Controllers
Power Management
Switching Regulator
Step-Down (Buck) Regulators
External Power Switch Buck Controllers
LTC3850 - Dual, 2-Phase Synchronous Step-Down Switching Controller
Features
- 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 24V (30V for LTC3850I) Operation
- Adjustable Soft-Start Current Ramping or Tracking
- Foldback Output Current Limiting
- Output Overvoltage Protection
- Power Good Output Voltage Monitor
- 28-Pin 4mm × 4mm, 4mm × 5mm QFN and Narrow SSOP Packages
Typical Application
Description
The LTC3850 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 features a precision 0.8V reference and a power good output indicator. A wide 4V to 24V (28V maximum/30V for LTC3850I) 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 is available in low profile 28-pin 4mm x 4mm, 4mm x 5mm QFN and narrow SSOP packages.
Packaging
For complete and up to date package information and drawings, please refer to our packaging page
SSOP-28, QFN-28
Order Info
- Part numbers ending in PBF are lead free. Please contact LTC marketing for information on lead based finish parts.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) | Price (1k)* | RoHS Data |
|---|---|---|---|---|---|---|
| LTC3850EGN#PBF | SSOP | 28 | E | $3.43 | $2.40 | View |
| LTC3850EGN#TRPBF | SSOP | 28 | E | $2.46 | View | |
| LTC3850EGN-1#PBF | SSOP | 28 | E | $3.43 | $2.40 | View |
| LTC3850EGN-1#TRPBF | SSOP | 28 | E | $2.46 | View | |
| LTC3850EUF#PBF | QFN | 28 | E | $3.43 | $2.40 | View |
| LTC3850EUF#TRPBF | QFN | 28 | E | $2.46 | View | |
| LTC3850EUFD#PBF | QFN | 28 | E | $3.43 | $2.40 | View |
| LTC3850EUFD#TRPBF | QFN | 28 | E | $2.46 | View | |
| LTC3850IGN#PBF | SSOP | 28 | I | $3.64 | $2.55 | View |
| LTC3850IGN#TR | SSOP | 28 | I | $2.61 | View | |
| LTC3850IGN#TRPBF | SSOP | 28 | I | $2.61 | View | |
| LTC3850IGN-1#PBF | SSOP | 28 | I | $3.64 | $2.55 | View |
| LTC3850IGN-1#TRPBF | SSOP | 28 | I | $2.61 | View | |
| LTC3850IGN-2#PBF | SSOP | 28 | I | $3.64 | $2.55 | View |
| LTC3850IGN-2#TRPBF | SSOP | 28 | I | $2.61 | View | |
| LTC3850IUF#PBF | QFN | 28 | I | $3.64 | $2.55 | View |
| LTC3850IUF#TRPBF | QFN | 28 | I | $2.61 | View | |
| LTC3850IUFD#PBF | QFN | 28 | I | $3.64 | $2.55 | View |
| LTC3850IUFD#TRPBF | QFN | 28 | I | $2.61 | View | |
| Buy Now • Request Samples | ||||||
Demo Boards
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 |
|---|---|---|---|
| DC1126A | LTC3850EUF Demo Board | 6.5V < Vin < 14V, Vout 1=3 | $150.00 | |
| DC1185A-A | LTC3850EUF Demo Board | $150.00 | |
| DC1185B-A | LTC3850EUF Demo Board | $150.00 | |
| DC1185B-B | LTC3850EUF Demo Board | $150.00 | |
| DC1231A-A | LTC3850EGN Demo Board | 6.5V < Vin < 24V, Vout 1=3 | $150.00 | |
| DC1231A-B | LTC3850EGN Demo Board | 6.5V < Vin < 24V, Vout 1=3 | $150.00 | |
| Buy Now | |||
Applications
- Notebook and Palmtop Computers
- Portable Instruments
- Battery-Operated Digital Devices
- DC Power Distribution Systems
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Simulate
LTspice IV is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. To download LTspice IV and other FREE simulation tools, please visit our Design Simulation page.
To launch a ready to run LTspice demonstration circuit for this part:
- Step 1: If you have not installed LTspice on this computer, download and install LTspice IV
- Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
- Step 3: If LTspice IV does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As". After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu
To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.
Related models available in LTspice IV
LTC3850-1
LTC3850-2
LTC3850
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
