Analog Devices Inc. LTC3624IMSE-2#PBF

Overview

LTC3624IMSE-2#PBF from Analog Devices (formerly Linear Technology) is a 17V, 2A synchronous step-down DC/DC regulator in a 12-lead MSOP package, operating at a fixed 2.25MHz switching frequency with ±40% synchronization range. It delivers adjustable output voltage from 0.6V to VIN, achieves 95% peak efficiency, maintains ±1% output accuracy, and draws only 3.5µA quiescent current in Burst Mode - ideal for battery-powered portable instrumentation requiring compact, high-efficiency power conversion.

For engineers reviewing the LTC3624IMSE-2#PBF datasheet, LTC3624IMSE-2#PBF pinout, LTC3624IMSE-2#PBF application, or LTC3624IMSE-2#PBF equivalent, key selection criteria include its 2.25MHz operation enabling small external components, ultralow IQ for extended battery life, MODE/SYNC-configurable light-load behavior (Burst, pulse-skipping, or forced continuous), and integrated overtemperature protection with 100% duty-cycle dropout capability.

Technical Context

The LTC3624IMSE-2#PBF employs a constant-frequency peak current mode control architecture with internal compensation and 1ms soft-start. Its 2.25MHz oscillator enables use of sub-3µH inductors and low-ESR ceramic capacitors while maintaining stable regulation across 2.7V–17V input and 0.6V–VIN output ranges.

It supports three operational modes via the MODE/SYNC pin: Burst Mode (3.5µA IQ, 800mA clamp), pulse-skipping (lower VOUT ripple, 132mA clamp), and forced continuous (cycle-by-cycle switching down to zero load). The device integrates PMOS/NMOS synchronous switches with 200mΩ/115mΩ RDS(ON) and features PGOOD with ±7.5% window and 32-cycle blanking delay.

Key Specifications

Pinout & Package

Package: 12-lead plastic MSOP (3mm × 4.1mm) with exposed thermal pad (Pin 13 = GND), θJA = 40°C/W, θJC = 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 TPS62840DLCR and MP2152GQZ-P, the LTC3624IMSE-2#PBF uniquely balances 2.25MHz operation, 2A capability, 3.5µA IQ, and full 2.7V–17V input support - making it optimal for multi-battery chemistries and dynamically reconfigurable power trees where both efficiency and flexibility are mandatory.

Availability

LTC3624IMSE-2#PBF is available at Aetrix Electronics and suitable for battery-powered instrumentation, emergency radios, and industrial sensor nodes requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LTC3624IMSE-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 maintains its precision analog and power management portfolio with rigorous qualification standards and long-term product roadmaps.

The LTC3624IMSE-2#PBF belongs to Linear's monolithic synchronous buck regulator family, designed specifically for space-constrained, battery-sensitive applications demanding ultralow quiescent current without sacrificing transient response or thermal robustness.

FAQ

What is the switching frequency of the LTC3624IMSE-2#PBF and can it be synchronized to an external clock?

The LTC3624IMSE-2#PBF operates at a fixed 2.25MHz switching frequency. Yes, it supports synchronization to an external clock applied to the MODE/SYNC pin across a ±40% range (1.35MHz to 3.15MHz). Sync engagement occurs within 2–3 external clock cycles, and loss of sync is detected within ~2µs. This capability enables EMI reduction in multi-rail systems and eliminates beat frequencies in densely packed PCB layouts.

How does the MODE/SYNC pin configure operating modes on the LTC3624IMSE-2#PBF?

The MODE/SYNC pin on the LTC3624IMSE-2#PBF selects among three distinct operating modes: tie to INTVCC for Burst Mode (3.5µA IQ, 800mA peak clamp), ground for pulse-skipping (lower VOUT ripple, 132mA clamp), or apply 1.0V–2.4V for forced continuous mode (cycle-by-cycle switching down to zero load). In all cases, the pin also serves as the sync input when driven by an external clock signal - no additional configuration pins are required.

What is the minimum on-time limitation of the LTC3624IMSE-2#PBF and how does it affect design at low duty cycles?

The LTC3624IMSE-2#PBF has a typical minimum on-time of 60ns, imposing a practical minimum duty cycle of ~13.5% at 2.25MHz. This limits the lowest achievable output voltage when VIN is high (e.g., 12V input → minimum VOUT ≈ 1.6V). If regulation is lost due to violated minimum on-time, designers must switch to Burst Mode or pulse-skipping operation, or reduce switching frequency via external sync - the LTC3624IMSE-2#PBF cannot operate below this hard timing constraint in forced continuous mode.

Does the LTC3624IMSE-2#PBF support 100% duty-cycle operation and what is its significance in low-VIN applications?

Yes, the LTC3624IMSE-2#PBF supports true 100% duty-cycle operation, allowing VOUT to remain regulated even when VIN drops to within ~100mV of the programmed output voltage. This eliminates the need for a secondary LDO in battery-powered systems where input voltage decays (e.g., Li+ from 4.2V to 2.8V), preserving efficiency and simplifying power architecture - a critical advantage over buck regulators with hard dropout limits.

What thermal considerations apply to the LTC3624IMSE-2#PBF in its 12-lead MSOP package?

The LTC3624IMSE-2#PBF in the 12-lead MSOP package has θJA = 40°C/W and θJC = 10°C/W, with Pin 13 as an exposed thermal pad that must be soldered to a solid PCB ground plane. For reliable 2A operation at +85°C ambient, ≥2 cm² of 2-oz copper connected to the pad is recommended. Junction temperature must stay ≤125°C for I-grade operation; exceeding this degrades lifetime and may trigger overtemperature shutdown at 150°C.