LTC3126 - 42V, 2.5A Synchronous Step-Down Regulator with No-Loss Input PowerPath
Datasheet Documentation
Reliability Data
LT Journal
Press Release


Typical Application

LTC3126 Typical Application
LTC3126 Typical Application


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.


4x5 QFN-28,TSSOP-28

LTC3126 Package Drawing
LTC3126 Package Drawing
Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price
LTC3126EFE#TRPBF TSSOP 28 E $9.35 $6.56
LTC3126EUFD#PBF QFN 28 E $8.93 $6.25
LTC3126IFE#TRPBF TSSOP 28 I $10.28 $7.21
LTC3126EFE#PBF TSSOP 28 E $9.29 $6.50
LTC3126EUFD#TRPBF QFN 28 E $8.99 $6.31
LTC3126HFE#PBF TSSOP 28 H $10.57 $7.40
LTC3126HFE#TRPBF TSSOP 28 H $10.63 $7.46
LTC3126IUFD#PBF QFN 28 I $9.83 $6.88
LTC3126IFE#PBF TSSOP 28 I $10.22 $7.15
LTC3126IUFD#TRPBF QFN 28 I $9.89 $6.94
* 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 Linear Technology sales office or authorized distributor.

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