Analog Devices Inc. LT3383EUJM#PBF

Overview

LT3383EUJM#PBF from Analog Devices is a multioutput power management IC integrating four synchronous buck DC/DC converters (2.5A, 2.5A, 1.5A, 1.5A) and three 300mA LDO regulators (two adjustable, one fixed 1.8V) for portable application processor systems. It supports pin-strapped power-on sequencing, delivers 2.25MHz switching frequency, draws only 12µA standby current, and operates from 2.7V to 5.5V input - enabling compact, high-efficiency power rails in space-constrained SoC designs.

For engineers reviewing the LT3383EUJM#PBF datasheet, LT3383EUJM#PBF pinout, LT3383EUJM#PBF application, or LT3383EUJM#PBF equivalent, key selection considerations include verified 40-lead 6mm × 6mm QFN wettable flanks package compatibility, confirmed 725mV feedback reference across all regulators, validated independent enable sequencing logic, and documented thermal derating behavior up to 125°C junction temperature.

Technical Context

The LT3383EUJM#PBF implements four independent buck regulators with pulse-skipping mode operation, 100% duty cycle capability, and soft-start ramping at 0.8V/ms for BUCK1–BUCK4. Each buck uses a precision 725mV feedback reference and supports programmable output via external resistor dividers.

Three integrated LDOs operate with separate input supplies (VIN_L1–VIN_L3), fixed 725mV reference for LDO1/LDO2, and factory-trimmed 1.8V output for LDO3. All regulators feature independent enable inputs with dual-threshold logic (0.75V typical rising, 0.4V precision after first enable), PWR_ON master control with 3ms delay, and open-drain PGOOD reporting based on ±6% output tolerance windows.

Key Specifications

Pinout & Package

LT3383EUJM#PBF is housed in a 40-lead 6mm × 6mm plastic QFN package with wettable flanks and exposed ground pad (Pin 41). The package requires soldering the exposed pad to a continuous PCB ground plane via multiple vias for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multi-rail power management applications.

Compared with TPS65917B1ZQWT and MAX20029ATJ/V+T, LT3383EUJM#PBF uniquely balances adjustable LDO outputs, independent LDO input supplies, and 12µA standby current - making it optimal for portable, battery-sensitive designs requiring analog rail customization without sacrificing sequencing control.

Availability

LT3383EUJM#PBF is available at Aetrix Electronics and suitable for mobile application processors, automotive infotainment systems, and industrial edge AI gateways requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LT3383EUJM#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.

The LT3383EUJM#PBF belongs to Analog Devices' Power Management IC product line, engineered specifically for advanced portable application processor systems requiring compact, highly integrated, and thermally robust multi-rail power solutions.

FAQ

What is the maximum junction temperature rating for LT3383EUJM#PBF?

The LT3383EUJM#PBF is rated for operation up to 125°C junction temperature. This is specified for the "E" grade variant, which is distinct from the "H" grade (150°C) and "I" grade (125°C, automotive-qualified). Thermal design must ensure θJA ≤ 33°C/W using the exposed pad soldered to a 2500mm² ground plane to avoid exceeding this limit under full load.

Does LT3383EUJM#PBF support true 100% duty cycle operation in dropout mode?

Yes, LT3383EUJM#PBF supports 100% duty cycle operation. When the input voltage approaches the output voltage, the buck regulators maintain regulation by fully turning on the PMOS switch, allowing output voltage to track PVIN minus I_LOAD × R_DS(ON). This behavior is explicitly confirmed in the datasheet's "STEP-DOWN SWITCHING REGULATORS" section and enables seamless transition into dropout without output collapse.

How does the PWR_ON pin interact with individual enable inputs on LT3383EUJM#PBF?

The PWR_ON pin acts as a hardware master gate: when pulled low, it inhibits all EN_Bx and EN_Lx inputs regardless of their logic state; when high, it permits those enables to function. A 3ms delay occurs between PWR_ON going high and the first enable becoming active - a timing parameter verified in Figure 3 of the datasheet and critical for coordinating with upstream pre-regulators.

Can LT3383EUJM#PBF's LDO3 output be adjusted, or is it strictly fixed at 1.8V?

LDO3 on LT3383EUJM#PBF is factory-trimmed to a fixed 1.8V output with ±3% tolerance (1.746V to 1.854V). Unlike LDO1 and LDO2, it has no feedback pin (FB_L3 is not implemented), and its output cannot be adjusted via external resistors. This is confirmed in the "PIN FUNCTIONS" section (Pin 4: LDO3) and "ELECTRICAL CHARACTERISTICS" table for LDO Regulator 3.

What is the purpose of the wettable flanks on the LT3383EUJM#PBF QFN package?

The wettable flanks on the LT3383EUJM#PBF's 40-lead QFN package enable automated optical inspection (AOI) of solder joints along the vertical sidewalls of the leads. This improves manufacturing yield and reliability verification in high-volume production - a requirement explicitly cited in the "PACKAGE DESCRIPTION" table and supported by Analog Devices' packaging documentation for the UJM variant.