60V/100mA Synchronous Buck DC-DC ConverterMarch 24, 2020 by Paul Shepard
The LT®8618 from Analog Devices is a compact, high speed synchronous monolithic step-down switching regulator that delivers up to 100mA with high efficiency at constant switching frequency, even up to 2.2MHz. It accepts a wide input voltage range up to 65V (transients only, 60V for continuous operation), and consumes only 2.5µA of quiescent current.
The LT8618 is designed for use in industrial sensors, industrial internet of things nodes, 4mA to 20mA current loops, flow meters, automotive housekeeping supplies and similar applications.
Top and bottom power switches are included with all necessary circuitry to minimize the need for external components. Low ripple Burst Mode operation enables high efficiency down to very low output currents while keeping the output ripple below 10mVP-P.
Additional features provide for flexible and robust operation. Internal compensation with peak current mode topology allows the use of small inductors and results in fast transient response and good loop stability. The EN/UV pin has an accurate 1V threshold and can be used to program VIN under voltage lockout or to shut down the LT8618 reducing the input supply current to 1µA. If there are no fault conditions, a PG flag signals when VOUT is within ±7.5% of the programmed output voltage.
Thermal shutdown provides additional protection. The LT8618 is available in a small 10-Lead 3mm × 2mm DFN package with exposed pad for low thermal resistance.
Summary of Specifications and Features
- High Efficiency Synchronous Operation
- 90% Efficiency at 30mA, 12VIN to 3.3VOUT
- Ultralow Quiescent Current Burst Mode® Operation
- < 2.5µA IQ Regulating 48VIN to 3.3VOUT
- Output Ripple < 10mVP-P
- 4V to 60V Input Operation Range (65V Max)
- Fast Minimum Switch-On Time: 35ns
- Adjustable Switching Frequency: 200kHz to 2.2MHz
- Fixed 3.3V Output Voltage Version
- Allows Tiny Inductors
- Accurate 1V Enable Pin Threshold
- Internal Compensation
- Output Soft-Start and Tracking
- Small 10-Lead 3mm × 2mm DFN
- AEC-Q100 Qualification in Progress