SEPIC/Boost Converter with 2A, 70V Switch, 9μA Quiescent Current, POR and Watchdog Timer

The LT8495 is an adjustable frequency (250kHz to 1.5MHz) monolithic switching regulator with a power-on reset and watchdog timer. Quiescent current can be less than 9μA when operating and is ~0.3μA when SWEN, WDE and RSTIN are low. Configurable as 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.

The reset and watchdog timeout periods are independently adjustable using external capacitors. Using a resistor divider on the SWEN pin provides a programmable undervoltage lockout (UVLO) for the converter. A resistor divider connected to RSTIN provides UVLO control that asserts the RST pin.

Additional features such as frequency foldback and soft-start are integrated. Fault tolerance in the TSSOP allows for adjacent pin shorts or an open without raising the output voltage above its programmed value. The LT8495 is available in 20-lead QFN and 20-lead TSSOP packages with exposed pads for low thermal resistance.

Applications

* Automotive ECU Power

* Power for Portable Products

* Industrial Supplies

* Wide Input Voltage Range of ~1V to 60V (2.5V to 32V for Start-Up)

* Low Ripple Burst Mode® Operation

* 9μA IQ at 12VIN to 5.0VOUT

* Output Ripple (<10mV Typ.)

* Dual Supply Pins:

* Improves Efficiency

* Reduces Minimum Supply Voltage to ~1V after Start-Up to Extend Battery Life

* Integrated 2A/70V Power Switch

* Programmable Watchdog Timer Can Operate When VIN Supply Is Removed

* Programmable Power-On Reset Timer (POR) with RST Functional for Input Supply Down to 1.3V

* FMEA Fault Tolerant in TSSOP Package

* Fixed Frequency PWM, SEPIC/BOOST/FLYBACK Topologies

* Programmable Switching Frequency: 250kHz to 1.5MHz

* UVLO Programmable on SWEN and RSTIN Pins

* Soft-Start Programmable with One Capacitor

* Small 20-Lead QFN or 20-Lead TSSOP Packages