LTC3126 - 42V, 2.5A Synchronous Step-Down Regulator with No-Loss Input PowerPath
Features
- Seamless, Automatic Transition Between Two Input Power Sources
- Wide Input Voltage Range: 2.4V to 42V
- Wide Output Voltage Range: 0.818V to VIN
- Up to 2.5A Continuous Output Current
- Pin Selectable Priority and Ideal Diode-OR Modes
- Burst Mode® Operation, IQ = 2μA
- 95% Efficiency at 1A, VIN = 12V, VOUT = 5V
- 1μA Current in Shutdown
- Programmable Input UVLO Thresholds
- Input Valid, Priority Channel and PGOOD Indicators
- 200kHz to 2.2MHz Fixed Frequency PWM
- Synchronizable to an External Clock
- Current Mode Control with 60ns Minimum On-Time
- Minimal External Components
- Thermally Enhanced 28-Lead 4mm × 5mm QFN and 28-Lead TSSOP Packages
Typical Application
Description
The LTC®3126 is a high efficiency synchronous buck converter with an internal no-loss PowerPath™ supporting seamless operation from two separate input power sources. Pin selectable ideal diode-OR and priority input modes with user programmable undervoltage lockout thresholds provide full control over the transition between the input power sources. The fast, automatic switchover provided by the internal PowerPath eliminates the need for hold-up capacitors and minimizes disturbances on the output rail. An active input channel indicator and independent input and output power good signals provide complete feedback of the power system status.
A wide 2.4V to 42V input voltage range, 2.5A output current capability and 2μA Burst Mode operation quiescent current facilitate use of the LTC3126 with a wide variety of power sources including supercapacitors, automotive batteries, unregulated wall adapters and single to multi-cell stacks of most battery chemistries. Additional features include 1μA current in shutdown, internal softstart and thermal protection. The LTC3126 is available in thermally enhanced 28-lead 4mm × 5mm QFN and 28-lead TSSOP packages.
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 |
|---|---|---|---|---|---|
| LTC3126EFE#PBF | TSSOP-28 | FE | E | 05-08-1663 (EB) | Yes |
| LTC3126EFE#TRPBF | TSSOP-28 | FE | E | 05-08-1663 (EB) | Yes |
| LTC3126EUFD#PBF | 4x5 QFN-28 | UFD | E | 05-08-1712 | Yes |
| LTC3126EUFD#TRPBF | 4x5 QFN-28 | UFD | E | 05-08-1712 | Yes |
| LTC3126HFE#PBF | TSSOP-28 | FE | H | 05-08-1663 (EB) | Yes |
| LTC3126HFE#TRPBF | TSSOP-28 | FE | H | 05-08-1663 (EB) | Yes |
| LTC3126IFE#PBF | TSSOP-28 | FE | I | 05-08-1663 (EB) | Yes |
| LTC3126IFE#TRPBF | TSSOP-28 | FE | I | 05-08-1663 (EB) | Yes |
| LTC3126IUFD#PBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
| LTC3126IUFD#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 | |
|---|---|---|---|---|---|---|
| LTC3126EFE#PBF | TSSOP-28 | E | $9.29 | $6.50 | Yes | |
| LTC3126EFE#TRPBF | TSSOP-28 | E | $9.35 | $6.56 | Yes | |
| LTC3126EUFD#PBF | 4x5 QFN-28 | E | $8.93 | $6.25 | Yes | |
| LTC3126EUFD#TRPBF | 4x5 QFN-28 | E | $8.99 | $6.31 | Yes | |
| LTC3126HFE#PBF | TSSOP-28 | H | $10.57 | $7.40 | Yes | |
| LTC3126HFE#TRPBF | TSSOP-28 | H | $10.63 | $7.46 | Yes | |
| LTC3126IFE#PBF | TSSOP-28 | I | $10.22 | $7.15 | Yes | |
| LTC3126IFE#TRPBF | TSSOP-28 | I | $10.28 | $7.21 | Yes | |
| LTC3126IUFD#PBF | 4x5 QFN-28 | I | $9.83 | $6.88 | Yes | |
| LTC3126IUFD#TRPBF | 4x5 QFN-28 | I | $9.89 | $6.94 | 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 |
|---|---|---|---|
| DC2215A | LTC3126EUFD Demo Board | Dual Input Sync Buck, 4.3V ≤ VIN1 ≤ 42V, 6V ≤ VIN2 ≤ 8.4V (Operational to 42V), VOUT = 3.3V @ 2.5A | Contact Factory | |
| Buy Now | |||
Applications
- Portable Industrial/Communications Test Equipment
- Battery and Supercapacitor Backup Power
- Automotive Power with Battery Backup
- Uninterruptible Power Supplies
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Design Tools
Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:
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- Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
- LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
- And More!
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.
