LTC3565EMSE#TRPBF Analog Devices 1.25A Step-Down DC-DC Converter

ElecSuppliers Part Number GuideAug 22, 2026

LTC3565EMSE#TRPBF is a synchronous step-down switching regulator from Analog Devices designed for compact power management applications. The device integrates the main switching components needed to build an efficient buck converter and can deliver up to 1.25 A of output current.

The LTC3565 is designed for applications where a relatively small power-management IC needs to provide an adjustable lower-voltage rail from a higher input supply.

LTC3565EMSE#TRPBF Key Specifications

LTC3565EMSE#TRPBF operates from a 2.5 V to 5.5 V input supply and supports an adjustable output voltage down to 0.8 V. The regulator can provide up to 1.25 A of output current.

The device uses a constant-frequency current-mode architecture and operates at a switching frequency of approximately 2.25 MHz. The relatively high switching frequency allows designers to use smaller external inductors and capacitors, helping reduce the overall size of the power supply.

The LTC3565 also supports Burst Mode operation for improved efficiency when the load is light. This can be useful in portable and battery-powered equipment where reducing standby power consumption is important.

Synchronous Buck Converter Design

The LTC3565 is a synchronous buck converter, meaning the switching power stage uses an integrated high-side and low-side switching architecture rather than relying on an external Schottky diode for the main freewheeling path.

Synchronous rectification can improve conversion efficiency, particularly when the output voltage is relatively low and the load current is significant.

For a typical application, the external circuit requires an inductor, input and output capacitors and feedback components. The output voltage is determined through the feedback network, allowing the same regulator to be configured for different output rails.

LTC3565EMSE#TRPBF Output Voltage

The adjustable output capability makes LTC3565EMSE#TRPBF useful for generating common low-voltage rails used by processors, controllers, communication devices and other digital electronics.

An output voltage as low as 0.8 V allows the regulator to support modern low-voltage integrated circuits.

When selecting the feedback resistors, designers need to consider the regulator's feedback reference, resistor tolerance and the required output-voltage accuracy. PCB leakage and noise can also become relevant when very low output voltages are being generated.

LTC3565EMSE#TRPBF Applications

LTC3565EMSE#TRPBF can be used in portable electronic equipment, embedded systems, industrial electronics, networking equipment and other compact devices requiring efficient DC-DC conversion.

It can also be used to generate local supply rails from a single lithium-ion battery or another low-voltage DC source.

The 2.5 V to 5.5 V input range makes it suitable for systems powered from common low-voltage sources, including single-cell battery systems and regulated 5 V supplies.

High-Frequency Power Conversion

The approximately 2.25 MHz switching frequency is one of the important characteristics of the LTC3565.

A higher switching frequency generally allows the external inductor and capacitors to be smaller than those required by a lower-frequency converter with otherwise similar operating conditions. This can help reduce PCB area.

The tradeoff is that switching losses and electromagnetic interference need to be considered carefully. The PCB layout should keep high-current switching loops short and provide an appropriate ground layout around the regulator and its external components.

For compact products, achieving good efficiency therefore depends not only on the IC but also on the selected inductor, capacitor, switching frequency and PCB layout.

LTC3565EMSE#TRPBF Package

The LTC3565EMSE#TRPBF is supplied in a 10-lead MSOP package with an exposed thermal pad. The exposed pad provides an electrical and thermal connection to the PCB and should be connected according to the manufacturer's layout recommendations.

The MSOP package provides a relatively compact solution for a 1.25 A buck converter, making the device suitable for space-constrained power-management designs.

Thermal performance should still be evaluated under the actual input voltage, output voltage and load-current conditions. Although the switching MOSFETs are integrated, the PCB remains an important part of the thermal path.

LTC3565EMSE#TRPBF Efficiency Considerations

The efficiency of a buck converter depends strongly on the relationship between input voltage, output voltage and load current.

At higher load currents, conduction losses become more important. At light loads, switching and quiescent losses become increasingly relevant. The LTC3565's Burst Mode capability is intended to improve efficiency under suitable light-load conditions.

The external inductor also has a significant effect on overall efficiency. Its resistance, saturation current and core losses should be considered when selecting the power-stage components.

LTC3565EMSE#TRPBF Replacement Considerations

When replacing LTC3565EMSE#TRPBF, engineers should compare more than the input and output voltage ranges.

Important parameters include maximum output current, switching frequency, control architecture, feedback voltage, package, pin configuration and thermal characteristics.

A converter with the same nominal current rating may still require a different PCB layout or external component configuration. Therefore, a replacement should be evaluated at the complete circuit level before being treated as a drop-in alternative.

The exact suffix #TRPBF should also be retained during procurement because it identifies the specific ordering and packaging configuration.

LTC3565EMSE#TRPBF for Compact Power Supplies

LTC3565EMSE#TRPBF combines a 1.25 A output capability, adjustable low-voltage output, synchronous buck architecture and high switching frequency in a compact package.

These characteristics make it suitable for compact power supplies where board space and conversion efficiency are both important. It is particularly useful when a 2.5 V to 5.5 V input needs to be converted to a lower regulated voltage for processors, sensors or other digital circuits.

For new designs, engineers should select the inductor and capacitors together with the regulator and follow the manufacturer's recommended PCB layout. For replacement projects, the complete electrical and mechanical specifications should be checked before substituting another DC-DC converter.