Analog Devices Inc. LT8609AJDDM-5#TRPBF

Overview

LT8609AJDDM-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 high efficiency (>93% at 1A, 12V_IN to 5V_OUT) with 2MHz operation and supports spread-spectrum EMI reduction.

For engineers reviewing the LT8609AJDDM-5#TRPBF datasheet, LT8609AJDDM-5#TRPBF pinout, LT8609AJDDM-5#TRPBF application, or LT8609AJDDM-5#TRPBF equivalent, key selection criteria include its −40°C to +150°C junction temperature rating, fixed 5V output with internal feedback divider (8.95MΩ), 45ns minimum on-time, and SYNC-enabled low-EMI operation - critical for automotive infotainment, ADAS power rails, and industrial control systems requiring ultra-low I_Q and high reliability.

Technical Context

The LT8609AJDDM-5#TRPBF implements peak current mode control with internal compensation, enabling fast transient response and stable operation with small inductors (e.g., 2.2µH). Its oscillator frequency is set via external RT resistor (18.2kΩ yields 2MHz) and supports synchronization or spread-spectrum modulation via the SYNC pin.

Burst Mode® operation maintains <10mV_P-P output ripple while regulating at ultralow load currents, and the EN/UV pin provides accurate 1.05V rising threshold with 50mV hysteresis for programmable input UVLO or shutdown. The PG pin signals V_OUT within ±7.5% of 5V and fault conditions.

Key Specifications

Pinout & Package

LT8609AJDDM-5#TRPBF uses a 10-lead 3mm × 3mm plastic side-wettable DFN package (DDM) with exposed thermal pad (Pin 11 = GND), θ_JA = 45°C/W, θ_JC = 10°C/W. The exposed pad must be soldered to PCB for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT8609AEDDM-5#TRPBF and LT8609AJMSE#TRPBF, the LT8609AJDDM-5#TRPBF uniquely combines AEC-Q100 Grade H qualification, side-wettable DFN for automated optical inspection, and optimal thermal performance - making it the preferred choice for high-reliability automotive power rails where space, EMI, and temperature are critical constraints.

Availability

LT8609AJDDM-5#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment systems, ADAS camera modules, industrial PLC I/O, and telematics control units requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for LT8609AJDDM-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 automotive, industrial, communications, and healthcare markets.

The LT8609 family is designed for high-efficiency, low-EMI, wide-input synchronous buck conversion in space-constrained and thermally demanding environments - especially automotive and industrial applications requiring ultralow quiescent current and AEC-Q100 compliance.

FAQ

What is the guaranteed operating junction temperature range for the LT8609AJDDM-5#TRPBF?

The LT8609AJDDM-5#TRPBF is guaranteed over the full −40°C to +150°C junction temperature range per AEC-Q100 Grade H qualification. This rating is validated through design, characterization, and statistical process controls - enabling reliable operation in under-hood automotive locations where ambient temperatures exceed 125°C.

Does the LT8609AJDDM-5#TRPBF require external feedback resistors to set the 5V output?

No, the LT8609AJDDM-5#TRPBF integrates an internal 8.95MΩ feedback divider that precisely programs the 5.0V output. No external resistors are needed, simplifying layout, improving accuracy, and eliminating resistor tolerance drift - a key advantage over adjustable variants like the LT8609AJDDM.

How does the SYNC pin function on the LT8609AJDDM-5#TRPBF, and what are its valid voltage states?

The SYNC pin on the LT8609AJDDM-5#TRPBF supports three modes: grounded (0V) enables low-ripple Burst Mode®; floated enables pulse-skipping; and biased between 3.2V–5.0V enables spread-spectrum modulation. It does not accept external clock inputs above 5.0V, and voltages between 0.9V–2.7V are undefined per datasheet absolute maximum ratings.

What is the purpose of the TR/SS pin on the LT8609AJDDM-5#TRPBF, and how is it used in practice?

The TR/SS pin on the LT8609AJDDM-5#TRPBF controls soft-start timing and enables output voltage tracking. A capacitor from TR/SS to GND sets the 5V output ramp rate (V_OUT = TR/SS × 6.39); this allows controlled power-up sequencing with other rails. During fault or shutdown, the pin is actively pulled low via a 300Ω MOSFET.

Is the LT8609AJDDM-5#TRPBF pin-compatible with other members of the LT8609 family, such as the LT8609AEDDM-5#TRPBF?

Yes, the LT8609AJDDM-5#TRPBF is pin-compatible with the LT8609AEDDM-5#TRPBF and LT8609AHDDM-5#TRPBF - all share identical 10-lead DFN (3mm × 3mm) footprints, pin assignments, and electrical behavior. Only the temperature grade (J-grade = −40°C to +150°C) and qualification level differ; no PCB changes are required when upgrading from E- or H-grade variants.