Analog Devices Inc. LT8609AEDDM-5#TRPBF

Overview

LT8609AEDDM-5#TRPBF from Analog Devices is a 42V, 3A synchronous step-down regulator in a 10-lead 3mm × 3mm side-wettable DFN package, featuring fixed 5V output, 2.5µA quiescent current in Burst Mode, 45ns minimum on-time, and spread-spectrum EMI reduction. It delivers high efficiency (>93% at 1A, 12V_IN→5V_OUT) for automotive infotainment power rails.

For engineers reviewing the LT8609AEDDM-5#TRPBF datasheet, LT8609AEDDM-5#TRPBF pinout, LT8609AEDDM-5#TRPBF application, or LT8609AEDDM-5#TRPBF equivalent, key selection criteria include fixed 5V output accuracy (±7.5% PG threshold), AEC-Q100 qualification, ultralow I_Q under light load, and SYNC-enabled low-EMI operation - critical for noise-sensitive automotive and industrial systems.

Technical Context

The LT8609AEDDM-5#TRPBF uses peak current mode control with internal compensation, enabling fast transient response and stable operation with small inductors (e.g., 2.2µH). Its fixed 5V output eliminates external feedback resistors, simplifying layout while maintaining ±1% output voltage regulation over temperature and line.

It integrates a 3.5V internal LDO (INTVCC) powering gate drivers and control logic, supports programmable soft-start via TR/SS pin (6.39× scaling to V_OUT), and features an open-drain Power Good flag (PG) asserting when V_OUT is within ±7.5% of 5V - essential for system sequencing and fault monitoring.

Key Specifications

Pinout & Package

LT8609AEDDM-5#TRPBF is housed in a 10-lead, 3mm × 3mm plastic side-wettable DFN package (DDM) with exposed thermal pad (Pin 11 = GND), θ_JA = 45°C/W, requiring soldering of the exposed pad for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT8609AEDDM-5#TRPBF, the MSOP variant trades AOI support and thermal performance for board-level compatibility, while the 3.3V variant shares mechanical fit but requires full schematic and validation rework due to output voltage and feedback architecture differences.

Availability

LT8609AEDDM-5#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, and telematics control units requiring stable component supply with AEC-Q100 assurance and long-term production continuity.

Supply support for LT8609AEDDM-5#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, and automotive markets.

The LT8609 family is designed for high-efficiency, low-EMI DC/DC conversion in space-constrained, noise-sensitive applications - especially automotive subsystems demanding ultralow quiescent current and AEC-Q100 reliability.

FAQ

What is the output voltage tolerance of the LT8609AEDDM-5#TRPBF under full load and temperature range?

The LT8609AEDDM-5#TRPBF delivers a nominal 5.0V output with ±1% typical accuracy over –40°C to +125°C junction temperature and full 0–3A load range, as confirmed by datasheet Table on page 4 (V_OUT = 4.97V to 5.03V at 100mA, extended to 5.11V max under worst-case conditions). This tight regulation eliminates need for post-regulation LDOs in most 5V logic applications.

Can the LT8609AEDDM-5#TRPBF operate with input voltage below 5V, and what is its minimum operating input?

Yes, the LT8609AEDDM-5#TRPBF operates down to 3.0V input, enabling use in automotive cold-crank scenarios (e.g., 6V battery sag). Its minimum on-time of 45ns allows stable 5V output even at 2MHz switching frequency with high input-to-output ratios - verified in datasheet Figure 8609 G38 showing regulation from 3.5V_IN.

How does the SYNC pin function on the LT8609AEDDM-5#TRPBF, and what are the valid voltage states?

The SYNC pin on LT8609AEDDM-5#TRPBF supports three modes: grounded (Burst Mode, lowest I_Q), floating (pulse-skipping), or biased to 3.2–5.0V (spread-spectrum EMI reduction). It does not accept external clock signals - unlike the adjustable LT8609 variants - and has no connection in LT8609B versions. This is explicitly defined in the "PIN FUNCTIONS" section (page 11).

Is the LT8609AEDDM-5#TRPBF pin-compatible with other LT8609A variants in the same DFN package?

Yes, all LT8609A DFN variants (LT8609AEDDM-3.3#TRPBF, LT8609AEDDM-5#TRPBF, LT8609AEDDM#TRPBF) share identical 10-pin DDM pinout and footprint. However, the -3.3 and -5 versions route VOUT instead of FB, and their internal feedback dividers differ - making them mechanically compatible but electrically non-interchangeable without schematic revision.

What thermal derating applies to the LT8609AEDDM-5#TRPBF at 3A continuous load in a standard 2-layer PCB?

On a standard 2-layer PCB with 1oz copper and the exposed pad fully soldered, LT8609AEDDM-5#TRPBF sustains 3A continuous output up to +85°C ambient (θ_JA = 45°C/W, P_D ≈ 1.2W → ΔT ≈ 54°C). Above 85°C ambient, output current must be reduced per Figure 8609 G31; full 3A is only guaranteed at T_A ≤ 70°C with adequate airflow or 4-layer board thermal relief.