SEPIC/Boost Converter with 2A, 70V Switch, 9μA Quiescent Current, POR and Watchdog Timer
Features and Benefits
- 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
The LT8494 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 soft-start 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.
- Automotive ECU Power
- Power for Portable Products
- Industrial 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 2242A is a monolithic SEPIC converter featuring LT8494. The demo board is designed for 5V output from a 3V to 60V input at 450kHz switching frequency. The max output current is 1A when the input voltage is above 12V, and is reduced with lower input voltage. The quiescent current of LT8494 is less than 7μA when operating. Dual supply pins (VIN and BIAS) allow the part to automatically operate from the most efficient supply.
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.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, 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.
Models for the following parts are available in LTspice:
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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.