Analog Devices Inc. LTC3105EMS#PBF

Overview

LTC3105EMS#PBF from Analog Devices (formerly Linear Technology) is a synchronous step-up DC/DC converter optimized for ultra-low-voltage, high-impedance energy harvesting sources. It starts up at 250mV, operates continuously from 225mV to 5V input, delivers up to 400mA output current, integrates a 6mA LDO with 2.2V nominal output, and features programmable maximum power point control (MPPC) for photovoltaic cells and thermoelectric generators.

For engineers reviewing the LTC3105EMS#PBF datasheet, LTC3105EMS#PBF pinout, LTC3105EMS#PBF application, or LTC3105EMS#PBF equivalent, key selection criteria include start-up voltage margin, MPPC threshold programming, AUX/LDO sequencing behavior, burst-mode quiescent current (24µA), and thermal shutdown integration in the 12-lead MSOP package.

Technical Context

The LTC3105EMS#PBF employs a proprietary Burst Mode® architecture with self-adjusting peak/valley current limits to maintain high efficiency across light-to-heavy loads while minimizing output ripple. Its dual-MOSFET synchronous rectifier enables VIN > VOUT operation and supports automatic power adjust-reducing peak inductor current to 100mA at light load and scaling up to 500mA under heavy load.

Maximum Power Point Control is implemented via a dedicated MPPC pin that sinks 10µA; connecting an external resistor sets the input voltage threshold (e.g., 400mV = 40kΩ). The integrated 2.2V LDO is powered from the AUX rail during startup and remains active until VOUT reaches regulation, enabling sensor/microcontroller bias before main output stabilization.

Key Specifications

Pinout & Package

The LTC3105EMS#PBF is housed in a 12-lead plastic MSOP package (3mm × 4.02mm, 0.65mm pitch) with exposed pad for thermal dissipation. Pin 1 is marked by a dot; exposed pad (Pin 7) must be soldered to PCB ground for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-up converter with MPPC applications.

Compared with MAX17710G+T and BQ25504RGTT, the LTC3105EMS#PBF offers the optimal balance of ultra-low start-up voltage, integrated MPPC, compact 12-lead MSOP footprint, and standalone operation-making it ideal for cost-sensitive, space-constrained industrial sensor nodes where discrete battery management is handled externally.

Availability

LTC3105EMS#PBF is available at Aetrix Electronics and suitable for solar-powered battery chargers, energy harvesting systems, remote industrial sensors, low-power wireless transmitters, and thermoelectric generator interfaces requiring stable component supply across extended temperature ranges.

Supply support for LTC3105EMS#PBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices acquired Linear Technology in 2017 and continues to develop and support its precision analog and power management portfolio.

The LTC3105EMS#PBF belongs to Linear's energy harvesting power management product line, designed specifically for autonomous, batteryless operation from microwatt-level ambient sources like photovoltaics and thermoelectrics.

FAQ

What is the minimum input voltage required for the LTC3105EMS#PBF to begin switching?

The LTC3105EMS#PBF has a guaranteed start-up voltage of 250mV under standard test conditions (200mΩ series source impedance, MPPC enabled). It can operate continuously down to 225mV once started. This specification makes the LTC3105EMS#PBF uniquely capable of booting directly from a single photovoltaic cell or low-output thermoelectric generator without auxiliary power.

How does the MPPC function work on the LTC3105EMS#PBF, and what external components are needed?

The MPPC pin on the LTC3105EMS#PBF sinks a precise 10µA current. Connecting a resistor (R_MPPC) from MPPC to GND sets the input voltage threshold as V_MPPC = 10µA × R_MPPC. For example, a 40kΩ resistor programs a 400mV threshold. A small capacitor (e.g., 10nF) may be added in parallel for noise filtering. No op-amps or external controllers are required-the LTC3105EMS#PBF implements full analog MPPT autonomously.

Can the LTC3105EMS#PBF power both a microcontroller and a radio transmitter simultaneously?

Yes-the LTC3105EMS#PBF provides two independent regulated rails: the main VOUT (adjustable 1.6V–5.25V, up to 400mA) and the auxiliary LDO (2.2V nominal, 6mA). The LDO powers microcontrollers and sensors during VOUT ramp-up, while VOUT supplies higher-current loads like RF transceivers. Both rails are internally sequenced to prevent brown-out during startup.

What is the purpose of the AUX pin on the LTC3105EMS#PBF, and how should it be decoupled?

The AUX pin on the LTC3105EMS#PBF serves as the initial start-up rail, charged before VOUT reaches regulation. It powers internal circuitry and the LDO during boot. A 1µF ceramic capacitor must be placed between AUX and GND-larger values increase start-up time and are discouraged. The LTC3105EMS#PBF automatically connects AUX to VOUT once VOUT exceeds AUX voltage, ensuring seamless handoff.

Does the LTC3105EMS#PBF support operation when input voltage exceeds output voltage?

Yes-the LTC3105EMS#PBF supports VIN > VOUT operation. When VIN rises above VOUT (or falls below 1.2V), the synchronous rectifiers disable and the converter enters critical conduction mode using only the N-channel MOSFET. This prevents reverse current flow and protects energy storage elements. Efficiency decreases in this mode, but regulation is maintained-a key feature for variable-source applications like solar under partial shading.