LT8494 - SEPIC/Boost DC/DC Converter with 2A, 70V Switch, and 7μA Quiescent Current

Features

  • Low Ripple Burst Mode® Operation:
    7μA IQ at 12VIN to 5VOUT
    Output Ripple (<10mV Typ.)
  • Dual Supply Pins:
    Improves Efficiency
    Reduces Minimum Supply Voltage to ~1V after
    Start-Up to Extend Battery Life
  • Wide Input Voltage Range of ~1V to 60V (2.5V to 32V for Start-Up)
  • PG Functional for Input Supply Down to 1.3V
  • FMEA Fault Tolerant in TSSOP Package
  • Fixed Frequency PWM, SEPIC/BOOST/FLYBACK Topologies
  • NPN Power Switch: 2A/70V
  • Programmable Switching Frequency: 250kHz to 1.5MHz
  • UVLO Programmable on SWEN Pin
  • Soft-Start Programmable with One Capacitor
  • Small 20-Lead QFN or 20-Lead TSSOP Packages

Typical Application

LT8494 Typical Application
LT8494 Typical Application
LT8494 Typical Application

Description

The LT®8494 is an adjustable frequency (250kHz to 1.5MHz) monolithic switching regulator. Quiescent current can be less than 7μA when operating and is ~0.3μA when SWEN is low. The LT8494 can be configured as either a SEPIC, boost or flyback converter.

The low ripple Burst Mode operation maintains high efficiency at low output current while keeping output ripple below 10mV. Dual supply pins (VIN and BIAS) allow the part to automatically operate from the most efficient supply. Input supply voltage can be up to 60V for SEPIC topologies and up to 32V (with ride-through up to 60V) for boost and flyback topologies. After start-up, battery life is extended since the part can draw current from its output (BIAS) even when VIN voltage drops below 2.5V.

Using a resistor divider on the SWEN pin provides a programmable undervoltage lockout (UVLO) for the converter. A power good flag signals when VOUT reaches 92% of the programmed output voltage.

Additional features such as frequency foldback and softstart are integrated. The LT8494 is available in 20-lead QFN and 20-lead TSSOP packages with exposed pads for low thermal resistance. Fault tolerance in the TSSOP allows for adjacent pin shorts or an open without raising the output voltage above its programmed value.

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
LT8494EFE#PBF TSSOP-20 FE E 05-08-1663 (CB) Yes
LT8494EFE#TRPBF TSSOP-20 FE E 05-08-1663 (CB) Yes
LT8494EUF#PBF 4x4 QFN-20 UF E 05-08-1710 Yes
LT8494EUF#TRPBF 4x4 QFN-20 UF E 05-08-1710 Yes
LT8494HFE#PBF TSSOP-20 FE H 05-08-1663 (CB) Yes
LT8494HFE#TRPBF TSSOP-20 FE H 05-08-1663 (CB) Yes
LT8494IFE#PBF TSSOP-20 FE I 05-08-1663 (CB) Yes
LT8494IFE#TRPBF TSSOP-20 FE I 05-08-1663 (CB) Yes
LT8494IUF#PBF 4x4 QFN-20 UF I 05-08-1710 Yes
LT8494IUF#TRPBF 4x4 QFN-20 UF I 05-08-1710 Yes


LT8494 Package Drawing
LT8494 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
LT8494EFE#PBF TSSOP-20 E $4.07 $2.85 Yes
LT8494EFE#TRPBF TSSOP-20 E $2.91 Yes
LT8494EUF#PBF 4x4 QFN-20 E $4.07 $2.85 Yes
LT8494EUF#TRPBF 4x4 QFN-20 E $2.91 Yes
LT8494HFE#PBF TSSOP-20 H $4.84 $3.39 Yes
LT8494HFE#TRPBF TSSOP-20 H $3.45 Yes
LT8494IFE#PBF TSSOP-20 I $4.49 $3.14 Yes
LT8494IFE#TRPBF TSSOP-20 I $3.20 Yes
LT8494IUF#PBF 4x4 QFN-20 I $4.49 $3.14 Yes
LT8494IUF#TRPBF 4x4 QFN-20 I $3.20 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
DC2242A LT8494EFE Demo Board | SEPIC, 3V ≤ VIN ≤ 60V; VOUT = 5V @ 1A Contact Factory
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Click here to view our complete list of demo boards

Applications

  • Automotive ECU Power
  • Power for Portable Products
  • Industrial Supplies

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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 IV:
LT8494

Technical Support