Analog Devices Inc. LTC3119IUFD#TRPBF

Overview

LTC3119IUFD#TRPBF from Analog Devices is a monolithic 18V, 5A synchronous buck-boost DC/DC converter with 2.5V–18V input and 0.8V–18V output voltage ranges, proprietary 4-switch PWM architecture, 400kHz–2MHz programmable switching frequency, and maximum power point control (MPPC) for photovoltaic or supercapacitor backup systems. It delivers 5A continuous output in buck mode (VIN > 6V) and operates down to 250mV after startup.

For engineers reviewing the LTC3119IUFD#TRPBF datasheet, LTC3119IUFD#TRPBF pinout, LTC3119IUFD#TRPBF application, or LTC3119IUFD#TRPBF equivalent, key selection criteria include seamless buck-boost transition, ultralow-noise PWM operation, MPPC capability for energy harvesting, thermal performance in 4mm × 5mm QFN, and compatibility with burst mode for <35µA no-load IQ.

Technical Context

The LTC3119IUFD#TRPBF implements a current-mode controlled 4-switch buck-boost topology enabling continuous regulation across VIN = VOUT, VIN < VOUT, and VIN > VOUT without mode switching transients. Its internal VCC LDO (3.7V ±150mV) powers control circuitry and supports up to 10mA external load, while integrated 30mΩ N-channel switches minimize conduction loss.

Operation includes Burst Mode® for light-load efficiency (31µA typical IQ), programmable RT-based oscillator (400kHz–2MHz), PLL-based synchronization up to 2MHz, and accurate RUN pin comparator (1.205V threshold, 90mV hysteresis) for custom UVLO. MPPC functionality regulates input voltage via resistive divider on MPPC pin (798mV threshold).

Key Specifications

Pinout & Package

The LTC3119IUFD#TRPBF is housed in a thermally enhanced 28-lead 4mm × 5mm plastic QFN package with exposed PGND pad (Pin 29) requiring soldering to PCB ground plane for thermal performance (θJA = 22°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck-boost converter applications.

Compared with TPS63020DSJR and MAX20406AATJ+, the LTC3119IUFD#TRPBF uniquely combines 18V input, 5A output, MPPC, and ultralow-noise PWM in a single monolithic solution-enabling compact, high-performance designs for energy-harvesting and mission-critical backup systems where other alternatives require supplemental ICs or compromise on key specs.

Availability

LTC3119IUFD#TRPBF is available at Aetrix Electronics and suitable for solar battery chargers, RF power supplies, and system backup power supplies requiring stable component supply, extended temperature operation (–40°C to 125°C), and long-term industrial lifecycle support.

Supply support for LTC3119IUFD#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 (formerly Linear Technology) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, communications, and industrial markets.

The LTC3119IUFD#TRPBF belongs to the LTC® high-efficiency power conversion product line, designed specifically for demanding applications requiring seamless buck-boost operation, wide input range, and advanced features like MPPC and ultralow-noise PWM.

FAQ

What is the minimum input voltage for continuous operation of the LTC3119IUFD#TRPBF?

The LTC3119IUFD#TRPBF operates continuously down to 250mV after startup when the VCC rail is maintained externally (e.g., bootstrapped from VOUT). During initial startup, the minimum input is 2.5V to meet VCC UVLO threshold (2.35V falling). This capability enables full energy extraction from supercapacitors and depleted batteries, a key advantage over standard buck-boost ICs.

How does the MPPC function work on the LTC3119IUFD#TRPBF?

The LTC3119IUFD#TRPBF's MPPC pin monitors input voltage via an external resistive divider and regulates it to 798mV ±24mV. When enabled, this forces the converter to draw current such that VIN remains at the MPP voltage-maximizing power transfer from photovoltaic panels or supercapacitors. The feature is disabled by tying MPPC to VCC, and requires no additional ICs or complex control loops.

Can the LTC3119IUFD#TRPBF synchronize to an external clock, and what are the constraints?

Yes, the LTC3119IUFD#TRPBF can synchronize to an external clock applied to the PWM/SYNC pin using its internal PLL. The external clock must exceed the frequency set by the RT resistor (e.g., RT = 76.8kΩ → ~1MHz), with ≥100ns pulse width. The PLL only increases internal oscillator frequency-so RT must be configured for a lower base frequency than the sync signal to ensure lock.

What thermal considerations apply to the LTC3119IUFD#TRPBF in 5A operation?

The LTC3119IUFD#TRPBF has θJA = 22°C/W in its 4mm × 5mm QFN package. At 5A output with 12V input/5V output, typical power dissipation is ~1.2W; this yields ~26°C rise above ambient. Successful 5A operation requires the exposed PGND pad (Pin 29) to be soldered to a ≥2cm² internal or external copper ground plane with ≥4 thermal vias to inner layers.

Does the LTC3119IUFD#TRPBF support output voltages below 1V?

Yes, the LTC3119IUFD#TRPBF supports output voltages as low as 0.8V, set by the FB resistor divider. The 795mV feedback reference is trimmed to ±18mV over temperature, enabling stable, precise low-voltage regulation-for example, powering 0.9V FPGA cores or 0.85V ASIC supplies-without external amplification or compensation adjustments.