Analog Devices Inc. LTC3589HUJ-2#PBF

Overview

LTC3589HUJ-2#PBF from Analog Devices (formerly Linear Technology) is a highly integrated 8-rail power management IC for ARM-based application processors, featuring three step-down DC/DC converters (1.6A, 1.2A, 1.2A), one 1.2A buck-boost regulator (1.8V–5.0V), three 250mA LDOs, and an always-on 25mA LDO. It supports i.MX53/51, PXA, and OMAP processors in handheld instruments and portable industrial devices.

For engineers reviewing the LTC3589HUJ-2#PBF datasheet, LTC3589HUJ-2#PBF pinout, LTC3589HUJ-2#PBF application, or LTC3589HUJ-2#PBF equivalent, key selection considerations include I²C-programmable voltage sequencing, dynamic voltage scaling, 8µA standby current, thermal grade (–40°C to 150°C), and QFN-40 package compatibility with multirail SoC power architectures.

Technical Context

The LTC3589HUJ-2#PBF implements a hierarchical power architecture: three independent synchronous buck regulators (Buck1–Buck3) with programmable soft-start and slew-rate control, one buck-boost regulator (BB_OUT) supporting bidirectional current limiting and reverse-burst suppression, and four LDOs-including a dedicated always-on LDO1_STBY with 0.8V feedback reference. All rails are coordinated via a single I²C interface (400kHz, address 0x68).

Sequencing is configurable either through hardware pin-strapping (EN1–EN4, VSTB, PWR_ON) or full I²C register control, enabling precise power-up/down timing across eight outputs. Fault reporting includes PGOOD, RSTO, IRQ, and PBSTAT signals, while thermal protection activates at 150°C junction temperature-consistent with its H-grade qualification.

Key Specifications

Pinout & Package

Package: 40-pin 6mm × 6mm × 0.75mm exposed-pad QFN (UJ). Exposed pad (Pin 41) must be soldered to PCB ground for thermal and electrical integrity. θ_JA = 33°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multirail PMIC applications.

Compared with TPS659122ZQV and MAX20049ATL+T, the LTC3589HUJ-2#PBF uniquely combines eight independently controllable rails-including a programmable buck-boost output-with 150°C operation and hardware-assisted sequencing, making it optimal for thermally demanding, high-complexity portable SoC platforms.

Availability

LTC3589HUJ-2#PBF is available at Aetrix Electronics and suitable for handheld instruments, portable industrial devices, and automotive infotainment systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC3589HUJ-2#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 acquired Linear Technology in 2017 and continues its legacy of precision analog and power management ICs for high-reliability applications.

The LTC3589 product line was designed specifically for advanced portable microprocessor systems-integrating multiple switching regulators, LDOs, and intelligent sequencing into a single QFN package to reduce footprint and simplify power architecture design for ARM-based SoCs.

FAQ

What is the maximum junction temperature rating for the LTC3589HUJ-2#PBF?

The LTC3589HUJ-2#PBF is rated for a maximum junction temperature of 150°C and is qualified for continuous operation across –40°C to +150°C ambient temperatures. This H-grade specification makes it suitable for under-hood automotive and industrial edge applications where thermal derating is critical. The device includes overtemperature protection that activates above 150°C to prevent permanent damage.

Does the LTC3589HUJ-2#PBF support dynamic voltage scaling (DVS) for all three buck regulators?

Yes, the LTC3589HUJ-2#PBF supports independent I²C-programmable DVS for Buck1, Buck2, and Buck3. Each buck regulator's output voltage can be adjusted in 12.5mV steps across its full range (e.g., Buck1: 0.3625V–0.765V feedback range, corresponding to ~0.7V–1.5V typical output). This enables real-time voltage adaptation to processor workload, reducing dynamic power consumption without firmware intervention.

How does the VSTB pin function in the LTC3589HUJ-2#PBF?

The VSTB (Voltage Standby) pin on the LTC3589HUJ-2#PBF simultaneously toggles up to four user-configured rails between their programmed "run" and "standby" output voltages. When asserted, it triggers fast, coordinated voltage transitions-enabling rapid entry into and exit from low-power states. This eliminates the need for software-controlled sequencing during sleep/wake cycles, improving system responsiveness and reducing firmware complexity.

What is the purpose of the always-on LDO1_STBY in the LTC3589HUJ-2#PBF?

The always-on LDO1_STBY in the LTC3589HUJ-2#PBF delivers a regulated 25mA output with 0.8V feedback reference, remaining active even when all other regulators are disabled. It powers critical low-power circuitry such as real-time clocks, wake-up comparators, or secure boot logic-enabling sub-10µA system deep-sleep states. Its 200mV dropout at 25mA ensures stable operation down to VIN = 3.0V.

Can the LTC3589HUJ-2#PBF be used with Freescale i.MX53 processors?

Yes, the LTC3589HUJ-2#PBF is explicitly designed to support Freescale i.MX53/51 processors, providing all eight required power rails-including core (1.2V), memory (1.35V), GPU (1.0V), and multiple I/O voltages-at appropriate current levels and sequencing. Its I²C interface allows full configuration of voltage levels and timing to match i.MX53 power requirements, and its 150°C rating supports fanless enclosure designs common in industrial i.MX53 deployments.