18V, 2A Buck-Boost DC/DC Converter with Low-Loss Dual Input PowerPath
Features and Benefits
- 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
The LTC3126 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 multicell stacks of most battery chemistries. Additional features include 1μA current in shutdown, internal soft-start and thermal protection. The LTC3126 is available in thermally enhanced 28-lead 4mm × 5mm QFN and 28-lead TSSOP packages.
- Portable Industrial/Communications Test Equipment
- Battery and Supercapacitor Backup Power
- Automotive Power with Battery Backup
- Uninterruptible Power Supplies
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration Circuit 2215A, features the LTC3126, a synchronous buck converter with an integrated lossless input PowerPath™. Pin selectable (JP2) ideal diode-OR and priority input modes, with programmable undervoltage lockout thresholds provide control over the transition between input sources. The unique all N-channel architecture provides efficient operation from either of two input sources to a programmable output voltage. In this application the valid input voltage range is set to be from 4.3V to 42V on VIN1 and from 6V to 8.4V on VIN2 providing flexibility and voltage margin for a variety of applications and power sources. VIN2 can operate to 42V. Other input voltage ranges are possible by adjusting the VSET1/2 threshold values (set by resistors R9 thru R12) accordingly.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Models for the following parts are available in LTspice:
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Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.