Analog Devices Inc. LTC3872EDDB-1#TRMPBF

Overview

LTC3872EDDB-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% output voltage accuracy, and runs at 550kHz switching frequency-enabling compact 3.3V-to-5V, 2A telecom and IP phone power supplies.

For engineers reviewing the LTC3872EDDB-1#TRMPBF datasheet, LTC3872EDDB-1#TRMPBF pinout, LTC3872EDDB-1#TRMPBF application, or LTC3872EDDB-1#TRMPBF equivalent, key selection criteria include No RSENSE operation, adjustable current limit via IPRG pin, internal soft-start, pulse-skipping at light load, and DFN package thermal performance (θ_JA = 76°C/W).

Technical Context

The LTC3872EDDB-1#TRMPBF implements a No RSENSE current sensing architecture that monitors the voltage drop across the external MOSFET's R_DS(ON), eliminating discrete sense resistors and improving efficiency. Its fixed 550kHz oscillator enables small inductor selection while maintaining stable current-mode control with internal slope compensation for duty cycles >50%.

It features a precision 1.2V reference (±1.5%), undervoltage lockout at 2.3V (rising), shutdown threshold at 0.85V on RUN/SS, and supports both internal and external soft-start. Unlike the standard LTC3872, the -1 variant omits frequency foldback during current limit, preserving constant switching frequency under overload.

Key Specifications

Pinout & Package

Package: 8-lead (3mm × 2mm) plastic DFN with exposed pad (Pin 9 = GND), rated for θ_JA = 76°C/W and maximum junction temperature of 150°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3872ETS8-1#TRPBF, the LTC3872EDDB-1#TRMPBF offers superior thermal performance (76°C/W vs 195°C/W) for continuous 2A loads, while TPS61088RHLR trades configurability for integration - making LTC3872EDDB-1#TRMPBF optimal for thermally demanding, flexible industrial boost designs.

Availability

LTC3872EDDB-1#TRMPBF is available at Aetrix Electronics and suitable for telecom power supplies, IP phone power supplies, and 24V industrial controls requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LTC3872EDDB-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 its high-performance power management portfolio with rigorous qualification and long-term product support.

The LTC3872EDDB-1#TRMPBF belongs to the LTC3872 family of No RSENSE boost controllers, designed specifically for high-efficiency, low-component-count DC/DC conversion in space- and thermal-constrained applications.

FAQ

What is the maximum output voltage supported by the LTC3872EDDB-1#TRMPBF?

The LTC3872EDDB-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 42V automotive auxiliary rails and telecom 48V systems. The actual achievable output depends on external MOSFET BVDSS, diode PIV rating, and inductor saturation current - all must be selected to withstand the full VO plus transients.

Does the LTC3872EDDB-1#TRMPBF require an external current sense resistor?

No, the LTC3872EDDB-1#TRMPBF uses No RSENSE architecture to sense current through the R_DS(ON) of the external N-channel MOSFET, eliminating the need for a discrete sense resistor. This improves efficiency, reduces board area, and lowers BOM cost. An external resistor may be used optionally on the SW pin for applications requiring higher accuracy or isolation.

What is the purpose of the IPRG pin on the LTC3872EDDB-1#TRMPBF?

The IPRG pin on the LTC3872EDDB-1#TRMPBF sets the peak current limit threshold: 80mV (IPRG = GND), 180mV (IPRG = floating), or 285mV (IPRG = VIN). This adjusts the maximum inductor current without external components, allowing optimization for different MOSFET R_DS(ON) values and load requirements in the LTC3872EDDB-1#TRMPBF design.

Can the LTC3872EDDB-1#TRMPBF operate with a 3.3V input to generate 5V at 2A?

Yes, the LTC3872EDDB-1#TRMPBF is validated for 3.3V-to-5V, 2A boost operation per its typical application circuit (Figure TA01b). With 550kHz switching, a 1µH inductor, and appropriate MOSFET/diode selection, it achieves >90% efficiency. Input voltage must remain ≥2.75V; minimum duty cycle constraints and MOSFET R_DS(ON) must be verified for full-load thermal performance.

How does the LTC3872EDDB-1#TRMPBF handle light-load conditions?

The LTC3872EDDB-1#TRMPBF employs pulse-skipping mode at light loads: when ITH falls near 0.85V, the current comparator remains tripped, causing cycle skipping while maintaining regulation. This preserves constant frequency operation down to very low loads, minimizing output ripple, audible noise, and RF emissions - unlike burst-mode controllers that modulate frequency.