LTC3546 - Dual Synchronous, 3A/1A or 2A/2A Configurable Step-Down DC/DC Regulator

Features

  • VIN Range: 2.25V to 5.5V
  • VOUT Range: 0.6V to 5V
  • Programmable Frequency Operation; 2.25MHz, or Adjustable Between 0.75MHz to 4MHz
  • Low RDS(ON) Internal Switches
  • High Efficiency: Up to 96%
  • No Schottky Diodes Required
  • Short-Circuit Protected
  • Current Mode Operation for Excellent Line and Load Transient Response
  • Low Ripple Burst Mode Operation (30mVP-P), IQ = 160μA
  • Ultralow Shutdown Current: IQ < 1μA
  • Low Dropout Operation: 100% Duty Cycle
  • Power Good Output For Each Channel
  • Externally or Internally Programmable Burst Level
  • External or Internal Soft-Start or Supply Tracking
  • Available in Thermally Enhanced 28-Lead (4mm × 5mm) QFN and TSSOP Packages
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LTC3546 Typical Application
LTC3546 Typical Application

Description

The LTC®3546 is a dual, constant-frequency, synchronous step down DC/DC converter for medium power applications. The design consists of 2A and 1A primary output switches. In addition to the 2A/1A capability, a 1A dependant output switch can be externally connected to either of the primary outputs to produce 3A/1A dual regulator or 2A/2A dual regulator configurations.

Supply operation is from 2.25V to 5.5V. The switching frequency can be set to 2.25MHz, adjustable from 0.75MHz to 4MHz, or synchronized to an external clock. Each output is adjustable from 0.6V to 5V and has output tracking on power-up. Internal synchronous low RDS(ON) power switches provide high efficiency without external Schottky diodes.

User-selectable modes (Burst Mode® operation, pulse skipping and forced continuous) allow a trade-off between ripple noise and power efficiency. Burst Mode operation provides high efficiency at light loads. Pulse-skipping mode provides low ripple noise at light loads.

The device is capable of low dropout configurations and both channels can operate at 100% duty cycle. In shutdown, the device draws <1μA.

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
LTC3546EFE#PBF TSSOP-28 FE E 05-08-1663 (EB) Yes
LTC3546EFE#TRPBF TSSOP-28 FE E 05-08-1663 (EB) Yes
LTC3546EUFD#PBF 4x5 QFN-28 UFD E 05-08-1712 Yes
LTC3546EUFD#TRPBF 4x5 QFN-28 UFD E 05-08-1712 Yes
LTC3546IFE#PBF TSSOP-28 FE I 05-08-1663 (EB) Yes
LTC3546IFE#TRPBF TSSOP-28 FE I 05-08-1663 (EB) Yes
LTC3546IUFD#PBF 4x5 QFN-28 UFD I 05-08-1712 Yes
LTC3546IUFD#TRPBF 4x5 QFN-28 UFD I 05-08-1712 Yes


LTC3546 Package Drawing
LTC3546 Package Drawing

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
LTC3546EFE#PBF TSSOP-28 E $5.57 $3.90 Yes
LTC3546EFE#TRPBF TSSOP-28 E $3.96 Yes
LTC3546EUFD#PBF 4x5 QFN-28 E $5.36 $3.75 Yes
LTC3546EUFD#TRPBF 4x5 QFN-28 E $3.81 Yes
LTC3546IFE#PBF TSSOP-28 I $6.56 $4.59 Yes
LTC3546IFE#TRPBF TSSOP-28 I $4.65 Yes
LTC3546IUFD#PBF 4x5 QFN-28 I $6.30 $4.41 Yes
LTC3546IUFD#TRPBF 4x5 QFN-28 I $4.47 Yes
Buy NowRequest Samples
* 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
DC1086A LTC3546UFD Demo Board | Dual Synchronous 2+1A or 2A 1+1A, 4MHz Step Down DC/DC Regulator $125.00
DC1087A LTC3546UFD Demo Board | Dual Synchronous 3A/1A or 2A/2A,Configurable Step Down DC/DC Regulator $125.00
Buy Now
Click here to view our complete list of demo boards

Designed for Automotive and Transportation Applications

AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC3546IFE#PBF TSSOP-28 I $6.56 $4.59 Yes
LTC3546IFE#TRPBF TSSOP-28 I $4.65 Yes
LTC3546IUFD#PBF 4x5 QFN-28 I $6.30 $4.41 Yes
LTC3546IUFD#TRPBF 4x5 QFN-28 I $4.47 Yes
Buy NowRequest Samples
* 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.

Applications

  • Netbooks/Ultra-Mobile PCs
  • PC Cards
  • Wireless and DSL Modems
  • Point of Load DC/DC Conversion

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice:
LTC3546

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