LT3514 - Triple Step-Down Switching Regulator with 100% Duty Cycle Operation
Features
- Wide Input Voltage Range: 3.2V to 36V
(40V Transient) - Three Outputs: 2A, 1A, 1A
- 100% Duty Cycle Operation
- Resistor-Programmed Constant Frequency
- Short-Circuit Robust
- Wide SYNC Range: 350kHz to 2.2MHz
- Anti-Phase Switching Reduces Ripple
- Feedback Voltage: 800mV
- Independent Run/Soft-Start Pins
- Shutdown with UVLO
- Internal Compensation
- Thermal Shutdown
- Tiny 28-Lead (4mm × 5mm) Thermally Enhanced QFN Package
- 24-Lead Exposed Pad TSSOP
Typical Application
Description
The LT®3514 consists of three buck regulators (2A, 1A, 1A output current). The device has a wide operating input range of 3.2V to 36V. An on-chip boost regulator allows each channel to operate up to 100% duty cycle. The LT3514 is designed to minimize external component count and results in a simple and small application circuit.
The LT3514 operates robustly in fault conditions. Cycleby- cycle peak current limit and catch diode current limit sensing protect the IC during overload conditions. Thermal shutdown protects the power switches at elevated temperatures. Soft-start helps control the peak inductor current during startup.
The LT3514 also features output voltage tracking and sequencing, programmable frequency, programmable undervoltage lockout, and a power good pin to indicate when all outputs are in regulation.
The LT3514 has one fewer channel (CH2) than the LT3504, and has one channel (CH3) that outputs 2A instead of 1A. The LT3514 in QFN is pin compatible with the LT3504. The LT3504 provides four 1A outputs.
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LT3514EFE#PBF | TSSOP-24 | FE | E | 05-08-1771 | Yes |
| LT3514EFE#TRPBF | TSSOP-24 | FE | E | 05-08-1771 | Yes |
| LT3514EUFD#PBF | 4x5 QFN-28 | UFD | E | 05-08-1712 | Yes |
| LT3514EUFD#TRPBF | 4x5 QFN-28 | UFD | E | 05-08-1712 | Yes |
| LT3514IFE#PBF | TSSOP-24 | FE | I | 05-08-1771 | Yes |
| LT3514IFE#TRPBF | TSSOP-24 | FE | I | 05-08-1771 | Yes |
| LT3514IUFD#PBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
| LT3514IUFD#TRPBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- 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 | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LT3514EFE#PBF | TSSOP-24 | E | $5.36 | $3.75 | Yes | |
| LT3514EFE#TRPBF | TSSOP-24 | E | $3.81 | Yes | ||
| LT3514EUFD#PBF | 4x5 QFN-28 | E | $5.00 | $3.50 | Yes | |
| LT3514EUFD#TRPBF | 4x5 QFN-28 | E | $3.56 | Yes | ||
| LT3514IFE#PBF | TSSOP-24 | I | $5.90 | $4.13 | Yes | |
| LT3514IFE#TRPBF | TSSOP-24 | I | $4.19 | Yes | ||
| LT3514IUFD#PBF | 4x5 QFN-28 | I | $5.50 | $3.85 | Yes | |
| LT3514IUFD#TRPBF | 4x5 QFN-28 | I | $3.91 | Yes | ||
| 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 |
|---|---|---|---|
| DC1980A | LT3514 Demo Board | 5.4V to 36VIN, Triple Output; VOUT1 = 5V @ 1A, VOUT2 = 3.3V @ 2A, VOUT3 = 1.8V @ 1A | $175.00 | |
| Buy Now | |||
Applications
- Automotive Battery Regulation
- Industrial Control Supplies
- Wall Transformer Regulation
- Distributed Supply Regulation
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Design Tools
LTspice
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Models for the following parts are available in LTspice:
LT3514
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.
