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
LTC3861 - Dual, Multiphase Step-Down Voltage Mode DC/DC Controller with Accurate Current Sharing
Features
- Operates with Power Blocks, DrMOS or External Gate Drivers and MOSFETs
- Constant-Frequency Voltage Mode Control with Accurate Current Sharing
- ±0.75% 0.6V Voltage Reference
- Dual Differential Output Voltage Sense Amplifiers
- Multiphase Capability—Up to 12-Phase Operation
- Programmable Current Limit
- Safely Powers a Prebiased Load
- Programmable or PLL-Synchronizable Switching Frequency Up to 2.25MHz
- Lossless Current Sensing Using Inductor DCR or Precision Current Sensing with Sense Resistor
- VCC Range: 3V to 5.5V
- VIN Range: 3V to 24V
- Power Good Output Voltage Monitor
- Output Voltage Tracking Capability
- Programmable Soft-Start
- Available in a 36-Pin 5mm × 6mm QFN Package
Typical Application
Description
The LTC®3861 is a dual PolyPhase® synchronous stepdown switching regulator controller for high current distributed power systems, digital signal processors, and other telecom and industrial DC/DC power supplies. It uses a constant-frequency voltage mode architecture combined with very low offset, high bandwidth error amplifiers and a remote output sense differential amplifier per channel for excellent transient response and output regulation.
The controller incorporates lossless inductor DCR current sensing to maintain current balance between phases and to provide overcurrent protection. The chip operates from a VCC supply between 3V and 5.5V and is designed for stepdown conversion from VIN between 3V and 24V to output voltages between 0.6V and VCC – 0.5V.
The TRACK/SS pins provide programmable soft-start or tracking functions. Inductor current reversal is disabled during soft-start to safely power prebiased loads. The constant operating frequency can be synchronized to an external clock or linearly programmed from 250kHz to 2.25MHz. Up to six LTC3861 controllers can operate in parallel for 1-, 2-, 3-, 4-, 6- or 12-phase operation.
The LTC3861 is available in a 36-pin 5mm × 6mm QFN package.
Packaging
For complete and up to date package information and drawings, please refer to our packaging page
QFN-36
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 |
|---|---|---|---|---|---|---|
| LTC3861EUH-1#PBF | QFN | 32 | E | $3.94 | $2.76 | View |
| LTC3861EUH-1#TRPBF | QFN | 32 | E | $2.82 | View | |
| LTC3861EUHE#PBF | QFN | 36 | E | $4.11 | $2.88 | View |
| LTC3861EUHE#TRPBF | QFN | 36 | E | $2.94 | View | |
| LTC3861IUH-1#PBF | QFN | 32 | I | $4.37 | $3.06 | View |
| LTC3861IUH-1#TRPBF | QFN | 32 | I | $3.12 | View | |
| LTC3861IUHE#PBF | QFN | 36 | I | $4.54 | $3.18 | View |
| LTC3861IUHE#TRPBF | QFN | 36 | I | $3.24 | 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 |
|---|---|---|---|
| DC1822A | LTC3861EUHE with DrMOS Demo Board | 7V < VIN < 14V; VOUT1 = 1.5V @ 25A, VOUT2 = 1.2V @ 25A | Contact Factory | |
| Buy Now | |||
Applications
- High Current Distributed Power Systems
- DSP, FPGA and ASIC Supplies
- Datacom and Telecom Systems
- Industrial Power Supplies
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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:
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To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.
Related models available in LTspice IV
LTC3861
LTC3861-1
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.
