Analog Devices Inc. LTC3867IUF#TRPBF

Overview

LTC3867IUF#TRPBF from Analog Devices (formerly Linear Technology) is a current-mode synchronous step-down DC/DC controller driving all-N-channel MOSFET stages, featuring differential remote sense, nonlinear transient control, and programmable DCR temperature compensation. It operates from 4V to 38V input, regulates 0.6V–14V outputs, supports 200kHz–1.2MHz switching, and delivers precision 0.6V ±0.75% reference for telecom power systems.

For engineers reviewing the LTC3867IUF#TRPBF datasheet, LTC3867IUF#TRPBF pinout, LTC3867IUF#TRPBF application, or LTC3867IUF#TRPBF equivalent, key selection criteria include its 24-lead QFN package, differential remote sensing capability, programmable current-sense threshold (30–75mV), thermal shutdown with inductor temperature monitoring, and support for Burst Mode®, pulse-skipping, and forced continuous operation.

Technical Context

The LTC3867IUF#TRPBF implements a constant-frequency current-mode architecture with an integrated transconductance error amplifier (gm = 2 mmho) and nonlinear control loop that reduces output voltage excursions during load transients by eliminating clock latency. Its differential remote sense amplifier provides ±0.75% accuracy over –40°C to 125°C and supports true load-point regulation via DIFF+, DIFF–, and DIFFOUT pins.

It features dual-mode current sensing (RSENSE or DCR), programmable ITEMP-based DCR temperature compensation (27–33 µA), and IITSD-triggered thermal shutdown (950 mV trip). The controller integrates gate drivers with TG/BG RDS(ON) of 2.6 Ω / 1.5 Ω (pull-up) and 2.4 Ω / 1.1 Ω (pull-down), plus internal 5.3V INTVCC regulator (±2% load regulation).

Key Specifications

Pinout & Package

24-lead (4mm × 4mm) plastic QFN package with exposed signal ground (SGND) pad (Pin 25), requiring soldering to PCB for thermal and electrical performance. Pin 1 is RUN; Pin 25 is SGND and must be connected to system ground at a single point near the IC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous step-down controller applications.

Compared with LTC3867IUF#TRPBF, LTC3891IUFD#TRPBF adds integrated bias generation but removes differential sensing, while MP2918GL-Z trades discrete FET flexibility and precision control for monolithic integration-making LTC3867IUF#TRPBF optimal for high-accuracy, thermally managed, multi-FET POL applications.

Availability

LTC3867IUF#TRPBF is available at Aetrix Electronics and suitable for telecom power systems, industrial PLCs, automotive ADAS ECUs, and distributed data center PSUs requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across –40°C to 125°C.

Supply support for LTC3867IUF#TRPBF 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 analog and power management portfolio with rigorous qualification standards.

The LTC3867IUF#TRPBF belongs to Linear's high-efficiency synchronous controller product line, designed specifically for precision, high-current DC/DC conversion in demanding industrial, telecom, and automotive applications where remote sensing, thermal robustness, and transient response are critical.

FAQ

What is the maximum supported switching frequency for the LTC3867IUF#TRPBF?

The LTC3867IUF#TRPBF supports a maximum switching frequency of 1.2 MHz, set by the resistor connected between the FREQ pin and SGND. At this frequency, the device maintains stable current-mode operation with minimum on-time of 65 ns, enabling compact magnetics design for high-density power supplies. The LTC3867IUF#TRPBF also supports PLL synchronization up to 1.1 MHz when an external clock is applied to the MODE/PLLIN pin.

How does the LTC3867IUF#TRPBF implement differential remote sensing?

The LTC3867IUF#TRPBF uses dedicated DIFF+ and DIFF– pins to connect across the output load, feeding into an integrated high-precision differential amplifier (±0.75% accuracy, 4 MHz bandwidth). Its output (DIFFOUT) is routed to VFB, enabling true load-point regulation that rejects PCB trace IR drop. This architecture ensures the regulated voltage is measured directly at the load, not at the converter output, which is essential for sub-1V applications with high current.

Can the LTC3867IUF#TRPBF operate with pre-biased outputs?

Yes, the LTC3867IUF#TRPBF supports smooth start-up into pre-biased outputs. When enabled, it disables the bottom gate driver (BG) until the voltage on the TK/SS pin exceeds the VFB voltage, preventing reverse current flow from the output capacitor into the converter. This feature avoids disruptive discharge events and ensures controlled ramp-up even when the output is initially charged to a non-zero voltage.

What thermal protection mechanisms are built into the LTC3867IUF#TRPBF?

The LTC3867IUF#TRPBF includes two complementary thermal protections: (1) programmable inductor temperature-based shutdown via ITEMP and ITSD pins using an external NTC/PTC network, and (2) junction temperature monitoring with shutdown at TJ = 125°C. The ITEMP pin enables dynamic DCR compensation to maintain current limit accuracy across temperature, while ITSD triggers hiccup-mode shutdown if inductor temperature exceeds safe thresholds-both configurable without firmware.

Does the LTC3867IUF#TRPBF support synchronization to an external clock source?

Yes, the LTC3867IUF#TRPBF supports phase-locked loop (PLL) synchronization via the MODE/PLLIN pin. When an external clock (250 kHz–1.1 MHz) is applied, the internal oscillator locks to it, enabling deterministic timing across multiple converters to reduce EMI peaks. The PLL compensation network is fully integrated, requiring no external components. The FREQ pin resistor must still be populated to define the initial free-running frequency before lock.