Analog Devices Inc. LT8609AHDDM-5#TRPBF

Overview

LT8609AHDDM-5#TRPBF from Analog Devices is a 42V, 3A synchronous step-down regulator in a 10-lead 3mm × 3mm side-wettable DFN package, featuring 2.5µA quiescent current in Burst Mode®, fixed 5V output, ±7.5% power-good accuracy, and AEC-Q100 qualification for automotive applications. It delivers >93% efficiency at 1A/5V from 12V_IN, supports 200kHz–2.2MHz synchronization, and integrates peak current mode control with internal compensation.

For engineers reviewing the LT8609AHDDM-5#TRPBF datasheet, LT8609AHDDM-5#TRPBF pinout, LT8609AHDDM-5#TRPBF application, or LT8609AHDDM-5#TRPBF equivalent, key selection criteria include ultralow-I_Q operation under light loads, EMI-reduction via spread spectrum modulation, fast 45ns minimum on-time for high VIN/VOUT ratios, and automotive-grade thermal robustness up to 150°C junction temperature.

Technical Context

The LT8609AHDDM-5#TRPBF implements peak current mode control with internal compensation, enabling stable regulation using small inductors (e.g., 2.2µH) and fast transient response. Its oscillator frequency is set by an external RT resistor (18.2kΩ yields 2MHz) and can be synchronized or modulated via the SYNC pin for low-EMI operation.

This variant belongs to the LT8609A family and features medium-speed switch edges (lower EMI than LT8609), fixed 5V output referenced to an internal 8.95MΩ divider, and PG monitoring of VOUT within ±7.5%. It operates across –40°C to +150°C junction temperature and includes overtemperature protection.

Key Specifications

Pinout & Package

LT8609AHDDM-5#TRPBF uses a 10-lead, 3mm × 3mm plastic side-wettable DFN package (DDM) with exposed GND pad (Pin 11) requiring PCB soldering for thermal and electrical integrity. θ_JA = 45°C/W, θ_JC = 10°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT8609AEMSE-5#TRPBF, LT8609AHDDM-5#TRPBF offers superior manufacturability and thermal performance in space-constrained automotive modules; versus LT8609AJDDM-5#TRPBF, it provides cost-optimized Grade H qualification with identical package and functional behavior for most ECU applications.

Availability

LT8609AHDDM-5#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial sensor hubs, ADAS camera modules, and GSM transceiver power supplies requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LT8609AHDDM-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 industrial, automotive, communications, and healthcare markets.

The LT8609A product line delivers ultralow-quiescent-current synchronous buck regulators optimized for automotive and industrial applications demanding high efficiency at light loads, low EMI, and extended temperature operation.

FAQ

What is the guaranteed output voltage tolerance for LT8609AHDDM-5#TRPBF?

The LT8609AHDDM-5#TRPBF guarantees a fixed 5.0V output with ±2% initial tolerance (4.97V–5.03V at 100mA load, 25°C). Over temperature and line, the total variation remains within ±3.5% due to ±0.02%/V line regulation and ±7.5% power-good window - sufficient for powering standard 5V logic and analog circuitry in automotive environments.

Does LT8609AHDDM-5#TRPBF support external frequency synchronization?

Yes, LT8609AHDDM-5#TRPBF supports external synchronization via its SYNC pin. When driven with a CMOS clock (200kHz–2.2MHz), it aligns switching edges to the external source and disables frequency foldback. This enables deterministic EMI reduction in noise-sensitive systems like ADAS cameras and radar modules.

How does the TR/SS pin function on LT8609AHDDM-5#TRPBF?

On LT8609AHDDM-5#TRPBF, the TR/SS pin controls soft-start and output tracking. A capacitor from TR/SS to GND sets the 5V output ramp rate (6.39× scaling). During startup, the internal 2µA current source charges the capacitor, linearly increasing VOUT - preventing inrush current and enabling coordinated sequencing with other rails.

What thermal performance can be expected from LT8609AHDDM-5#TRPBF in a typical 4-layer PCB layout?

In a standard 4-layer board with 2oz copper, 100mm² exposed GND pad, and thermal vias under the DFN's exposed pad, LT8609AHDDM-5#TRPBF achieves θ_JA ≈ 38°C/W. At 3A continuous load and 12V_IN→5V_OUT, junction temperature rise is ~114°C above ambient - well within its 150°C max rating when ambient stays below 36°C.

Is LT8609AHDDM-5#TRPBF pin-compatible with other LT8609A variants in the DDM package?

Yes, LT8609AHDDM-5#TRPBF shares identical pinout, footprint, and thermal pad configuration with all other LT8609A DDM variants (e.g., LT8609AEDDM-5#TRPBF, LT8609AJDDM-5#TRPBF). The only differences are temperature grade (H vs E/J) and minor parametric tolerances - enabling drop-in replacement in existing designs with updated qualification documentation.