LTC3621 - 17V, 1A Synchronous Step-Down Regulator with 3.5μA Quiescent Current

Features

  • Wide VIN Range: 2.7V to 17V
  • Wide VOUT Range: 0.6V to VIN
  • 95% Max Efficiency
  • Low IQ < 3.5μA, Zero-Current Shutdown
  • Constant Frequency (1MHz/2.25MHz)
  • Full Dropout Operation with Low IQ
  • 1A Rated Output Current
  • ±1% Output Voltage Accuracy
  • Current Mode Operation for Excellent Line and Load Transient Response
  • Synchronizable to External Clock
  • Pulse-Skipping, Forced Continuous, Burst Mode® Operation
  • Internal Compensation and Soft-Start
  • Overtemperature Protection
  • Compact 6-Lead DFN (2mm × 3mm) Package or Thermally-Enhanced MS8E Package with Power Good Output and Independent SGND Pin

Typical Application

LTC3621 Typical Application
LTC3621 Typical Application

Description

The LTC®3621/LTC3621-2 is a high efficiency 17V, 1A synchronous monolithic step-down regulator. The switching frequency is fixed to 1MHz or 2.25MHz with a ±40% synchronizing range. The regulator features ultralow quiescent current and high efficiencies over a wide VOUT range.

The step-down regulator operates from an input voltage range of 2.7V to 17V and provides an adjustable output range from 0.6V to VIN while delivering up to 1A of output current. A user-selectable mode input is provided to allow the user to trade off ripple noise for light load efficiency; Burst Mode operation provides the highest efficiency at light loads, while pulse-skipping mode provides the lowest voltage ripple. The MODE pin can also be used to allow the user to sync the switching frequency to an external clock.

LTC3621 Options

PART NAME FREQUENCY VOUT
LTC3621 1.00MHz Adjustable
LTC3621-3.3 1.00MHz 3.3V
LTC3621-5 1.00MHz 5V
LTC3621-2 2.25MHz Adjustable
LTC3621-23.3 2.25MHz 3.3
LTC3621-25 2.25MHz 5V

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
LTC3621EDCB-2#PBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-2#TRMPBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-2#TRPBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-23.3#PBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-23.3#TRMPBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-23.3#TRPBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-25#PBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-25#TRMPBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-25#TRPBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-3.3#PBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-3.3#TRMPBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-3.3#TRPBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-5#PBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-5#TRMPBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB-5#TRPBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB#PBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB#TRMPBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EDCB#TRPBF 2x3 DFN-6 DCB E 05-08-1715 Yes
LTC3621EMS8E-2#PBF MS-8E MS8E E 05-08-1662 Yes
LTC3621EMS8E-2#TRPBF MS-8E MS8E E 05-08-1662 Yes
LTC3621EMS8E-23.3#PBF MS-8E MS8E E 05-08-1662 Yes
LTC3621EMS8E-23.3#TRPBF MS-8E MS8E E 05-08-1662 Yes
LTC3621EMS8E-25#PBF MS-8E MS8E E 05-08-1662 Yes
LTC3621EMS8E-25#TRPBF MS-8E MS8E E 05-08-1662 Yes
LTC3621EMS8E-3.3#PBF MS-8E MS8E E 05-08-1662 Yes
LTC3621EMS8E-3.3#TRPBF MS-8E MS8E E 05-08-1662 Yes
LTC3621EMS8E-5#PBF MS-8E MS8E E 05-08-1662 Yes
LTC3621EMS8E-5#TRPBF MS-8E MS8E E 05-08-1662 Yes
LTC3621EMS8E#PBF MS-8E MS8E E 05-08-1662 Yes
LTC3621EMS8E#TRPBF MS-8E MS8E E 05-08-1662 Yes
LTC3621HMS8E-2#PBF MS-8E MS8E H 05-08-1662 Yes
LTC3621HMS8E-2#TRPBF MS-8E MS8E H 05-08-1662 Yes
LTC3621HMS8E-23.3#PBF MS-8E MS8E H 05-08-1662 Yes
LTC3621HMS8E-23.3#TRPBF MS-8E MS8E H 05-08-1662 Yes
LTC3621HMS8E-25#PBF MS-8E MS8E H 05-08-1662 Yes
LTC3621HMS8E-25#TRPBF MS-8E MS8E H 05-08-1662 Yes
LTC3621HMS8E-3.3#PBF MS-8E MS8E H 05-08-1662 Yes
LTC3621HMS8E-3.3#TRPBF MS-8E MS8E H 05-08-1662 Yes
LTC3621HMS8E-5#PBF MS-8E MS8E H 05-08-1662 Yes
LTC3621HMS8E-5#TRPBF MS-8E MS8E H 05-08-1662 Yes
LTC3621HMS8E#PBF MS-8E MS8E H 05-08-1662 Yes
LTC3621HMS8E#TRPBF MS-8E MS8E H 05-08-1662 Yes
LTC3621IDCB-2#PBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-2#TRMPBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-2#TRPBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-23.3#PBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-23.3#TRMPBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-23.3#TRPBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-25#PBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-25#TRMPBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-25#TRPBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-3.3#PBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-3.3#TRMPBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-3.3#TRPBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-5#PBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-5#TRMPBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB-5#TRPBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB#PBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB#TRMPBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IDCB#TRPBF 2x3 DFN-6 DCB I 05-08-1715 Yes
LTC3621IMS8E-2#PBF MS-8E MS8E I 05-08-1662 Yes
LTC3621IMS8E-2#TRPBF MS-8E MS8E I 05-08-1662 Yes
LTC3621IMS8E-23.3#PBF MS-8E MS8E I 05-08-1662 Yes
LTC3621IMS8E-23.3#TRPBF MS-8E MS8E I 05-08-1662 Yes
LTC3621IMS8E-25#PBF MS-8E MS8E I 05-08-1662 Yes
LTC3621IMS8E-25#TRPBF MS-8E MS8E I 05-08-1662 Yes
LTC3621IMS8E-3.3#PBF MS-8E MS8E I 05-08-1662 Yes
LTC3621IMS8E-3.3#TRPBF MS-8E MS8E I 05-08-1662 Yes
LTC3621IMS8E-5#PBF MS-8E MS8E I 05-08-1662 Yes
LTC3621IMS8E-5#TRPBF MS-8E MS8E I 05-08-1662 Yes
LTC3621IMS8E#PBF MS-8E MS8E I 05-08-1662 Yes
LTC3621IMS8E#TRPBF MS-8E MS8E I 05-08-1662 Yes


LTC3621 Package Drawing
LTC3621 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
LTC3621EDCB-2#PBF 2x3 DFN-6 E $3.64 Yes
LTC3621EDCB-2#TRMPBF 2x3 DFN-6 E $3.64 $2.60 Yes
LTC3621EDCB-2#TRPBF 2x3 DFN-6 E $3.64 $2.55 Yes
LTC3621EDCB-23.3#PBF 2x3 DFN-6 E $3.64 Yes
LTC3621EDCB-23.3#TRMPBF 2x3 DFN-6 E $3.64 $2.60 Yes
LTC3621EDCB-23.3#TRPBF 2x3 DFN-6 E $3.64 $2.55 Yes
LTC3621EDCB-25#PBF 2x3 DFN-6 E $3.64 Yes
LTC3621EDCB-25#TRMPBF 2x3 DFN-6 E $3.64 $2.60 Yes
LTC3621EDCB-25#TRPBF 2x3 DFN-6 E $3.64 $2.55 Yes
LTC3621EDCB-3.3#PBF 2x3 DFN-6 E $3.64 Yes
LTC3621EDCB-3.3#TRMPBF 2x3 DFN-6 E $3.64 $2.60 Yes
LTC3621EDCB-3.3#TRPBF 2x3 DFN-6 E $3.64 $2.55 Yes
LTC3621EDCB-5#PBF 2x3 DFN-6 E $3.64 Yes
LTC3621EDCB-5#TRMPBF 2x3 DFN-6 E $3.64 $2.60 Yes
LTC3621EDCB-5#TRPBF 2x3 DFN-6 E $3.64 $2.55 Yes
LTC3621EDCB#PBF 2x3 DFN-6 E $3.64 Yes
LTC3621EDCB#TRMPBF 2x3 DFN-6 E $3.64 $2.60 Yes
LTC3621EDCB#TRPBF 2x3 DFN-6 E $3.64 $2.55 Yes
LTC3621EMS8E-2#PBF MS-8E E $3.64 $2.55 Yes
LTC3621EMS8E-2#TRPBF MS-8E E $2.61 Yes
LTC3621EMS8E-23.3#PBF MS-8E E $3.64 $2.55 Yes
LTC3621EMS8E-23.3#TRPBF MS-8E E $2.61 Yes
LTC3621EMS8E-25#PBF MS-8E E $3.64 $2.55 Yes
LTC3621EMS8E-25#TRPBF MS-8E E $2.61 Yes
LTC3621EMS8E-3.3#PBF MS-8E E $3.64 $2.55 Yes
LTC3621EMS8E-3.3#TRPBF MS-8E E $2.61 Yes
LTC3621EMS8E-5#PBF MS-8E E $3.64 $2.55 Yes
LTC3621EMS8E-5#TRPBF MS-8E E $2.61 Yes
LTC3621EMS8E#PBF MS-8E E $3.64 $2.55 Yes
LTC3621EMS8E#TRPBF MS-8E E $2.61 Yes
LTC3621HMS8E-2#PBF MS-8E H $4.37 $3.06 Yes
LTC3621HMS8E-2#TRPBF MS-8E H $3.12 Yes
LTC3621HMS8E-23.3#PBF MS-8E H $4.37 $3.06 Yes
LTC3621HMS8E-23.3#TRPBF MS-8E H $3.12 Yes
LTC3621HMS8E-25#PBF MS-8E H $4.37 $3.06 Yes
LTC3621HMS8E-25#TRPBF MS-8E H $3.12 Yes
LTC3621HMS8E-3.3#PBF MS-8E H $4.37 $3.06 Yes
LTC3621HMS8E-3.3#TRPBF MS-8E H $3.12 Yes
LTC3621HMS8E-5#PBF MS-8E H $4.37 $3.06 Yes
LTC3621HMS8E-5#TRPBF MS-8E H $3.12 Yes
LTC3621HMS8E#PBF MS-8E H $4.37 $3.06 Yes
LTC3621HMS8E#TRPBF MS-8E H $3.12 Yes
LTC3621IDCB-2#PBF 2x3 DFN-6 I $4.02 Yes
LTC3621IDCB-2#TRMPBF 2x3 DFN-6 I $4.02 $2.86 Yes
LTC3621IDCB-2#TRPBF 2x3 DFN-6 I $4.02 $2.81 Yes
LTC3621IDCB-23.3#PBF 2x3 DFN-6 I $4.02 Yes
LTC3621IDCB-23.3#TRMPBF 2x3 DFN-6 I $4.02 $2.86 Yes
LTC3621IDCB-23.3#TRPBF 2x3 DFN-6 I $4.02 $2.81 Yes
LTC3621IDCB-25#PBF 2x3 DFN-6 I $4.02 Yes
LTC3621IDCB-25#TRMPBF 2x3 DFN-6 I $4.02 $2.86 Yes
LTC3621IDCB-25#TRPBF 2x3 DFN-6 I $4.02 $2.81 Yes
LTC3621IDCB-3.3#PBF 2x3 DFN-6 I $4.02 Yes
LTC3621IDCB-3.3#TRMPBF 2x3 DFN-6 I $4.02 $2.86 Yes
LTC3621IDCB-3.3#TRPBF 2x3 DFN-6 I $4.02 $2.81 Yes
LTC3621IDCB-5#PBF 2x3 DFN-6 I $4.02 Yes
LTC3621IDCB-5#TRMPBF 2x3 DFN-6 I $4.02 $2.86 Yes
LTC3621IDCB-5#TRPBF 2x3 DFN-6 I $4.02 $2.81 Yes
LTC3621IDCB#PBF 2x3 DFN-6 I $4.02 Yes
LTC3621IDCB#TRMPBF 2x3 DFN-6 I $4.02 $2.86 Yes
LTC3621IDCB#TRPBF 2x3 DFN-6 I $4.02 $2.81 Yes
LTC3621IMS8E-2#PBF MS-8E I $4.02 $2.81 Yes
LTC3621IMS8E-2#TRPBF MS-8E I $2.87 Yes
LTC3621IMS8E-23.3#PBF MS-8E I $4.02 $2.81 Yes
LTC3621IMS8E-23.3#TRPBF MS-8E I $2.87 Yes
LTC3621IMS8E-25#PBF MS-8E I $4.02 $2.81 Yes
LTC3621IMS8E-25#TRPBF MS-8E I $2.87 Yes
LTC3621IMS8E-3.3#PBF MS-8E I $4.02 $2.81 Yes
LTC3621IMS8E-3.3#TRPBF MS-8E I $2.87 Yes
LTC3621IMS8E-5#PBF MS-8E I $4.02 $2.81 Yes
LTC3621IMS8E-5#TRPBF MS-8E I $2.87 Yes
LTC3621IMS8E#PBF MS-8E I $4.02 $2.81 Yes
LTC3621IMS8E#TRPBF MS-8E I $2.87 Yes
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* 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
DC1863A LTC3621 Demo Board | 1MHz, 2.7V ≤ VIN ≤ 17V, Vout = 1.2V/1.8V/2.5V/3.3V/5V/Adj @ 1A $100.00
DC1864A LTC3621-2 Demo Board | 2.25MHz, 2.7V ≤ VIN ≤ 17V, Vout = 1.2V/1.8V/2.5V/3.3V/5V/Adj @ 1A $100.00
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Applications

  • Portable-Handheld Scanners
  • Industrial and Embedded Computing
  • Automotive Applications
  • Emergency Radio

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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:

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Models for the following parts are available in LTspice:
LTC3621
LTC3621-2

LTpowerCAD

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To open the project file for this circuit:

Design tools for the following parts are available in LTpowerCAD:
LTC3621
LTC3621-2

Technical Support