Analog Devices Inc. LTC3108EDE-1#PBF

Overview

LTC3108EDE-1#PBF from Analog Devices (formerly Linear Technology) 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 20mV input, delivers four selectable regulated main outputs (2.5V/3V/3.7V/4.5V), provides a 2.2V/3mA LDO, and integrates VSTORE reserve-energy charging - enabling autonomous wireless sensor nodes powered solely by waste heat or ambient light.

For engineers reviewing the LTC3108EDE-1#PBF datasheet, LTC3108EDE-1#PBF pinout, LTC3108EDE-1#PBF application, or LTC3108EDE-1#PBF equivalent, this page delivers verified startup voltage, output programming logic, transformer interface requirements, storage capacitor sequencing behavior, and real-world quiescent current values measured under 20mV input conditions.

Technical Context

The LTC3108EDE-1#PBF implements a resonant step-up oscillator using an external 1:100 transformer and internal N-channel switch (SW pin), generating AC on the secondary winding that feeds a charge pump (C1) and synchronous rectifier to build VAUX. Once VAUX exceeds 2.5V, VOUT charging initiates; when VAUX reaches ≥2V, the internal 2.2V LDO activates and synchronous rectifiers engage to improve efficiency.

VOUT voltage is digitally programmed via VS1/VS2 logic pins (GND/VAUX combinations), while VOUT2 is a host-controlled 1.3Ω P-channel switch enabled by VOUT2_EN with 5µs soft-start and 0.3A peak current limit. Power good (PGD) asserts high when VOUT is within ±7.5% of regulation and pulls low at –9% deviation, using a 1MΩ internal pull-up to VLDO.

Key Specifications

Pinout & Package

Package: 12-lead (3mm × 4mm) plastic DFN with exposed thermal pad (Pin 13), soldered to PCB ground plane for thermal management (θJA = 43°C/W).

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 LTC3108EDE-1#PBF uniquely supports 20mV start-up, integrates a dedicated 2.2V LDO and programmable VOUT2 switch, and provides deterministic PGD signaling - making it the only solution capable of autonomous operation from single-digit °C thermal gradients without supplemental power sources.

Availability

LTC3108EDE-1#PBF is available at Aetrix Electronics and suitable for wireless industrial sensor nodes, building HVAC energy monitors, predictive maintenance vibration nodes, and smart agriculture soil moisture tags requiring stable component supply across extended product lifecycles.

Supply support for LTC3108EDE-1#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) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving precision instrumentation, industrial automation, and energy harvesting markets.

The LTC3108EDE-1#PBF belongs to Linear's Energy Harvesting Power Management family, engineered specifically to extract usable power from ultralow-voltage ambient sources like TEGs and thermopiles - targeting maintenance-free, batteryless IoT endpoints.

FAQ

What is the minimum input voltage required for LTC3108EDE-1#PBF to start switching?

The LTC3108EDE-1#PBF has a guaranteed minimum start-up voltage of 20mV when using a 1:100 transformer turns ratio and zero load on VAUX. This value is confirmed in the Electrical Characteristics table under "Minimum Start-Up Voltage" with test conditions explicitly stating VIN = 20mV, VAUX = 0V, and 1:100 ratio. At lower ratios (e.g., 1:50), start-up voltage increases to ~50mV.

How is the main output voltage (VOUT) selected on LTC3108EDE-1#PBF?

The LTC3108EDE-1#PBF uses two logic pins - VS1 (Pin 8) and VS2 (Pin 7) - to select one of four fixed output voltages: 2.5V (both grounded), 3V (VS1 = VAUX, VS2 = GND), 3.7V (VS1 = GND, VS2 = VAUX), or 4.5V (both tied to VAUX). This configuration eliminates external feedback resistors and avoids board leakage errors common in high-impedance divider networks.

Does LTC3108EDE-1#PBF include built-in protection against short circuits?

Yes, the LTC3108EDE-1#PBF provides current limiting on all outputs: VOUT (4.5mA typical limit), VSTORE (4.5mA typical), VOUT2 (0.3A typical), and VLDO (4mA minimum). These limits are specified in the Electrical Characteristics table under "VOUT Current Limit", "VSTORE Current Limit", "VOUT2 Current Limit", and "LDO Current Limit", ensuring robustness against accidental shorts during deployment.

What is the role of the VSTORE pin on LTC3108EDE-1#PBF, and how does it behave during input dropout?

The VSTORE pin on LTC3108EDE-1#PBF charges a supercapacitor or rechargeable battery only after VOUT reaches regulation. When the input source drops out, the LTC3108EDE-1#PBF automatically draws current from the VSTORE capacitor to maintain VOUT, VLDO, and VOUT2 operation - enabling uninterrupted sensing/transmission during transient input loss, as verified in the "Running on Storage Capacitor" waveform (Figure G17).

Can LTC3108EDE-1#PBF power a microcontroller directly, and what is the maximum supported load on its LDO?

Yes, the LTC3108EDE-1#PBF integrates a 2.2V LDO (VLDO pin) rated for 3mA continuous output with 100mV dropout at 2mA load. It is designed to power ultra-low-power MCUs such as ARM Cortex-M0+ or MSP430 derivatives. The LDO's 2.2µF minimum ceramic capacitor requirement and ±3% regulation tolerance ensure stable core voltage during deep-sleep and active modes.