Analog Devices Inc. LTC3108IDE#PBF

Overview

LTC3108IDE#PBF from Analog Devices is an ultralow-voltage step-up converter and power manager IC designed for energy harvesting from thermoelectric generators (TEGs), thermopiles, and micro-solar cells. It starts up from as low as 20mV input, delivers four selectable regulated main outputs (2.35V/3.3V/4.1V/5V), integrates a 2.2V/3mA LDO, and supports storage capacitor backup for intermittent sources - enabling wireless sensor nodes powered by waste heat in HVAC or industrial monitoring systems.

For engineers reviewing the LTC3108IDE#PBF datasheet, LTC3108IDE#PBF pinout, LTC3108IDE#PBF application, or LTC3108IDE#PBF equivalent, this page provides verified startup voltage, output sequencing behavior, transformer interface requirements, VOUT2 enable timing, and thermal package derating data specific to the –40°C to 125°C industrial-grade 12-lead DFN variant.

Technical Context

The LTC3108IDE#PBF uses a resonant oscillator driving an external step-up transformer (e.g., 1:100 turns ratio) to boost sub-50mV inputs; its internal rectifier and charge pump feed VAUX, which powers all circuitry and enables VOUT charging once >2.5V. Synchronous rectification activates above 2V VAUX to improve efficiency at ultra-low input power levels.

VOUT is programmed via VS1/VS2 logic pins (GND/VAUX combinations), while VOUT2 is a host-controlled 1.3Ω P-channel switch with 5µs turn-on, 0.3A current limit, and soft-start - decoupled from main regulation to avoid transient coupling. The PGD open-drain signal asserts when VOUT reaches ±7.5% of target and deasserts at –9%, referenced to VLDO's 1MΩ pull-up.

Key Specifications

Pinout & Package

12-lead (3mm × 4mm) plastic DFN package with exposed thermal pad (Pin 13, GND). Requires PCB ground plane connection for thermal performance and electrical reference.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultralow-voltage energy harvesting applications.

Compared with MAX17710G+T and BQ25504RGTT, the LTC3108IDE#PBF uniquely supports sub-50mV startup, pin-selectable outputs, and host-gated VOUT2 - making it the only solution capable of powering RF bursts directly from 1°C TEG ΔT without intermediate storage or voltage translation.

Availability

LTC3108IDE#PBF is available at Aetrix Electronics and suitable for remote wireless sensing, industrial predictive maintenance, and HVAC energy recovery systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC3108IDE#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 is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision instrumentation, industrial automation, and energy-efficient systems.

The LTC3108IDE#PBF belongs to Analog Devices' Energy Harvesting Power Management product line, engineered specifically for self-powered IoT edge nodes that operate from ambient thermal, mechanical, or photonic energy sources with no battery dependency.

FAQ

What is the minimum input voltage required for LTC3108IDE#PBF to start switching?

The LTC3108IDE#PBF has a guaranteed minimum startup voltage of 20mV when used with a 1:100 transformer turns ratio and no auxiliary supply. This value is measured under pulsed load conditions and applies across the full –40°C to 125°C operating junction temperature range. At lower ratios (e.g., 1:50), startup voltage increases to ~50mV.

How does the LTC3108IDE#PBF select its main output voltage?

The LTC3108IDE#PBF selects its main output voltage (2.35V, 3.3V, 4.1V, or 5V) using two logic inputs: VS1 (Pin 8) and VS2 (Pin 7). These pins are tied to either GND or VAUX (5.25V clamped) to set the output per Table 1 in the datasheet. No external resistors or programming interface is required - the selection is hardwired during PCB layout.

Can LTC3108IDE#PBF power a microcontroller directly, and how is sequencing managed?

Yes, the LTC3108IDE#PBF powers microcontrollers directly via its integrated 2.2V LDO (VLDO), which activates as soon as VAUX exceeds 2.3V. Sequencing is inherent: VAUX charges first, enabling VLDO before VOUT begins charging; PGD then signals VOUT regulation to the µC. This ensures the processor boots only after stable main rail is available.

What is the function of the VOUT2 output on LTC3108IDE#PBF, and how is it controlled?

VOUT2 on the LTC3108IDE#PBF is a host-controlled switched output connected to VOUT through a 1.3Ω P-channel MOSFET. It is enabled by driving VOUT2_EN (Pin 9) high (≥1V threshold). VOUT2 delivers up to 0.3A peak current with 5µs turn-on time and soft-start, allowing precise gating of sensors or RF transceivers without loading VOUT during idle periods.

Is the exposed thermal pad on the LTC3108IDE#PBF package electrically connected, and what is its role?

Yes, the exposed thermal pad (Pin 13) on the LTC3108IDE#PBF's 12-lead DFN package is electrically connected to GND and serves as both the primary thermal conduction path and a critical ground reference. It must be soldered to a PCB copper pour with multiple thermal vias; failure to do so raises θJA from 43°C/W to >100°C/W and risks thermal shutdown or parameter shift.