Analog Devices Inc. LTC3624HMSE-25#PBF

Overview

LTC3624HMSE-25#PBF from Analog Devices (formerly Linear Technology) is a 2.25MHz, 2A synchronous step-down DC/DC regulator in a 12-lead MSOP package with exposed thermal pad. It operates from 2.7V to 17V input, delivers fixed 5V output with ±1% accuracy, and achieves 95% peak efficiency while drawing only 3.5µA quiescent current in Burst Mode - ideal for battery-powered emergency radios and portable instrumentation requiring long standby life.

For engineers reviewing the LTC3624HMSE-25#PBF datasheet, LTC3624HMSE-25#PBF pinout, LTC3624HMSE-25#PBF application, or LTC3624HMSE-25#PBF equivalent, key selection criteria include its 2.25MHz switching frequency for compact filter design, H-grade 150°C junction temperature rating, fixed 5V output with internal feedback, and MODE/SYNC pin configurability for Burst Mode, pulse-skipping, or forced continuous operation.

Technical Context

The LTC3624HMSE-25#PBF implements a constant-frequency peak current mode control architecture with internal compensation and 1ms soft-start. Its 2.25MHz oscillator enables use of small 2.2µH inductors and low-ESR ceramic capacitors, while the integrated PMOS/NMOS power switches feature 200mΩ/115mΩ R_DS(ON) at V_IN = 5V.

It supports three operating modes via the MODE/SYNC pin: Burst Mode (3.5µA I_Q, 800mA peak clamp), pulse-skipping (low V_OUT ripple), or forced continuous (stable frequency at zero load). Overtemperature protection triggers at 150°C, and PGOOD provides ±7.5% output voltage monitoring with 32-cycle blanking delay.

Key Specifications

Pinout & Package

Package: 12-lead plastic MSOP with exposed thermal pad (Pin 13), rated for θ_JA = 40°C/W and θ_JC = 10°C/W. Exposed pad must be soldered to PCB ground for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3624EMSE-25#PBF, the LTC3624HMSE-25#PBF offers extended thermal range without trade-offs in efficiency or size; versus TPS62825RVL, it provides critical system-level features - PGOOD, overvoltage lockout, and higher junction temperature rating - at the cost of slightly higher quiescent current.

Availability

LTC3624HMSE-25#PBF is available at Aetrix Electronics and suitable for battery-powered emergency radios, portable instrumentation, and industrial control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC3624HMSE-25#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 maintains full product support, datasheets, and application engineering for the LTC portfolio.

The LTC3624 family is designed for high-efficiency, ultralow-I_Q step-down regulation in space-constrained, battery-sensitive applications - emphasizing thermal robustness, mode flexibility, and minimal external components.

FAQ

What is the output voltage tolerance of the LTC3624HMSE-25#PBF over temperature and load?

The LTC3624HMSE-25#PBF delivers a fixed 5.0V output with ±1% regulation accuracy across –40°C to +150°C junction temperature, full load (0–2A), and input voltage range (2.7–17V). This is achieved via an internal 0.6V reference and trimmed feedback network, eliminating external resistor errors. The ±1% includes line, load, and temperature effects as specified in the Electrical Characteristics table under "VOUT Regulated Fixed Output Voltage".

Does the LTC3624HMSE-25#PBF require an external feedback resistor divider?

No, the LTC3624HMSE-25#PBF does not require an external feedback resistor divider. As a fixed 5V output variant, the FB pin is internally connected to the output; the datasheet explicitly states "For fixed VOUT options, connect FB pin directly to VOUT" - and this connection is implemented internally. External resistors are unnecessary and would disrupt regulation.

What is the minimum on-time limitation of the LTC3624HMSE-25#PBF and how does it affect low-VIN operation?

The LTC3624HMSE-25#PBF has a typical minimum on-time of 60ns. At its 2.25MHz switching frequency, this imposes a practical minimum duty cycle of ~13.5%. When VIN approaches VOUT (e.g., VIN < 5.8V for 5V output), the controller enters dropout and maintains regulation via 100% duty cycle - enabled by internal slope compensation and peak current limit maintenance. Below ~4.5V input, forced continuous mode is recommended to avoid minimum on-time violation.

How does the PGOOD pin of the LTC3624HMSE-25#PBF behave during startup and load transients?

The PGOOD pin of the LTC3624HMSE-25#PBF goes high only after VOUT reaches and remains within ±7.5% of 5V for 32 consecutive switching cycles (~14µs at 2.25MHz). During load transients, it includes a 32-cycle blanking window on the falling edge to prevent false low assertions. It is an open-drain output requiring an external pull-up; internal 280Ω pulldown activates when out-of-regulation.

Can the LTC3624HMSE-25#PBF be synchronized to an external clock, and what is the acceptable frequency range?

Yes, the LTC3624HMSE-25#PBF can be synchronized to an external clock applied to the MODE/SYNC pin. The sync range is ±40% of its nominal 2.25MHz frequency - i.e., 1.35MHz to 3.15MHz. Sync engagement occurs within 2–3 external clock cycles; loss of sync is detected after ~2µs of missing edges, after which the part reverts to internal oscillator operation.