Analog Devices Inc. LTC3872ETS8-1#TRMPBF

Overview

LTC3872ETS8-1#TRMPBF from Analog Devices (formerly Linear Technology) is a constant-frequency current-mode boost DC/DC controller driving an external N-channel MOSFET without requiring a sense resistor. It operates from 2.75V to 9.8V input, delivers up to 60V output, achieves ±1.5% V_OUT accuracy, and runs at 550kHz switching frequency-enabling compact 3.3V-to-5V, 2A telecom and IP phone power supplies.

For engineers reviewing the LTC3872ETS8-1#TRMPBF datasheet, LTC3872ETS8-1#TRMPBF pinout, LTC3872ETS8-1#TRMPBF application, or LTC3872ETS8-1#TRMPBF equivalent, key selection considerations include No RSENSE™ sensing architecture, adjustable current limit via IPRG pin, internal soft-start, pulse-skipping at light load, and thermal performance in the TS8 (SOT-23-8) package with exposed pad.

Technical Context

The LTC3872ETS8-1#TRMPBF implements a No RSENSE™ current-sense architecture that monitors voltage drop across the external MOSFET's R_DS(ON), eliminating discrete sense resistors and improving efficiency. Its constant-frequency 550kHz current-mode control ensures fast line/load transient response and stable operation up to 90% duty cycle.

It integrates undervoltage lockout (UVLO) with 2.3V rising threshold, shutdown control via RUN/SS pin (0.85V falling threshold), and internal slope compensation for duty cycles >50%. The ITH pin serves as the error amplifier output and current comparator threshold reference, directly linking feedback error to peak inductor current regulation.

Key Specifications

Pinout & Package

Package: 8-lead ThinSOT™ (TS8), 1mm profile, exposed thermal pad (Pin 9 = GND). Pin 1–8 arranged in standard TSOT-23 layout with GND on both ends and SW/NGATE on opposite corners for optimal switching node routing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar boost controller applications.

Compared with LTC3872EDDB-1#TRPBF, the LTC3872ETS8-1#TRMPBF trades thermal margin for ultra-compact size; versus MAX17595ATP+, it delivers higher efficiency and simpler layout at the cost of vendor-specific feature set and no integrated PMBus interface.

Availability

LTC3872ETS8-1#TRMPBF is available at Aetrix Electronics and suitable for telecom power supplies, IP phone power supplies, and 42V automotive systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LTC3872ETS8-1#TRMPBF 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 maintains full technical and manufacturing continuity for all Linear power products.

The LTC3872 series is designed specifically for high-efficiency, low-component-count boost, SEPIC, and flyback converters where No RSENSE™ sensing, compact packaging, and robust industrial temperature operation are critical.

FAQ

What is the maximum output voltage supported by the LTC3872ETS8-1#TRMPBF?

The LTC3872ETS8-1#TRMPBF supports output voltages up to 60V, as confirmed by its SW pin absolute maximum rating of –0.3V to 60V. This enables use in high-ratio boost, SEPIC, and flyback configurations - for example, generating 48V from 12V in telecom systems. The actual achievable V_OUT depends on external MOSFET BVDSS and diode PIV ratings, not the controller itself.

Does the LTC3872ETS8-1#TRMPBF require an external current sense resistor?

No, the LTC3872ETS8-1#TRMPBF implements Linear's No RSENSE™ architecture and senses current via the voltage drop across the external N-channel MOSFET's R_DS(ON). This eliminates the need for a discrete sense resistor, reducing power loss, board area, and BOM cost - a defining feature confirmed across all functional diagrams and application circuits in the official datasheet.

What is the purpose of the IPRG pin on the LTC3872ETS8-1#TRMPBF?

The IPRG pin on the LTC3872ETS8-1#TRMPBF selects the peak current sense threshold: 105mV (IPRG = GND), 180mV (IPRG = floating), or 285mV (IPRG = VIN). This adjusts the maximum switch current without changing external components - allowing one PCB layout to support multiple output current levels by modifying only the IPRG connection.

Can the LTC3872ETS8-1#TRMPBF operate with a 3.3V input to generate 5V at 2A?

Yes, the LTC3872ETS8-1#TRMPBF is explicitly validated for this use case: the Typical Application circuit on page 1 of the datasheet shows a 3.3V input delivering 5V at 2A using a 1µH inductor and standard external components. With 550kHz operation and No RSENSE™ sensing, it achieves >90% efficiency across the full load range per Figure TA01b.

What thermal considerations apply to the LTC3872ETS8-1#TRMPBF in the TS8 package?

The LTC3872ETS8-1#TRMPBF in the TS8 package has θ_JA = 195°C/W. To maintain T_J ≤ 125°C at full load, the PCB must provide adequate copper area under the exposed pad (Pin 9 = GND) and minimize ambient temperature rise. Derating is required above 70°C ambient; for high-power or high-temperature environments, the DFN variant (LTC3872EDDB-1#TRPBF) offers θ_JA = 76°C/W.