Analog Devices Inc. LTC3621HMS8E-5#TRPBF

Overview

LTC3621HMS8E-5#TRPBF from Analog Devices is a 17V, 1A synchronous step-down regulator in thermally enhanced MSOP-8 (MS8E) package with exposed GND pad, fixed 5V output, 2.25MHz switching frequency, ±1% output voltage accuracy, and 3.5µA quiescent current in shutdown-designed for automotive emergency radios and industrial embedded systems requiring high efficiency at light loads.

For engineers reviewing the LTC3621HMS8E-5#TRPBF datasheet, LTC3621HMS8E-5#TRPBF pinout, LTC3621HMS8E-5#TRPBF application, or LTC3621HMS8E-5#TRPBF equivalent, key selection criteria include its H-grade (–40°C to 150°C) junction temperature rating, PGOOD output with ±7.5% window, SGND separation, and MODE/SYNC-configurable operation modes (Burst, pulse-skipping, forced continuous).

Technical Context

The LTC3621HMS8E-5#TRPBF employs constant-frequency peak current mode control with internal compensation and 800µs soft-start. Its 2.25MHz oscillator supports ±40% external synchronization via the MODE/SYNC pin, enabling EMI reduction in noise-sensitive environments.

It integrates PMOS top and NMOS bottom power switches with R_DS(ON) of 0.37Ω and 0.15Ω respectively, delivers full dropout operation down to V_IN = V_OUT, and features overtemperature protection with thermal shutdown at T_J > 150°C.

Key Specifications

Pinout & Package

Package: 8-Lead Plastic MSOP (MS8E) with exposed GND pad (Pin 9), rated for –40°C to 150°C operating junction temperature and θ_JA = 40°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS62130ARGTR and MP2315GJ-Z, the LTC3621HMS8E-5#TRPBF uniquely combines AEC-Q100 H-grade qualification, integrated PGOOD with blanking, separate SGND, and 2.25MHz sync capability - making it the only option qualified for automotive emergency systems requiring both reliability and EMI control.

Availability

LTC3621HMS8E-5#TRPBF is available at Aetrix Electronics and suitable for automotive emergency radios, industrial sensor hubs, and portable handheld scanners requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC3621HMS8E-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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC3621 product line delivers ultralow-I_Q synchronous buck regulators optimized for battery-powered and thermally constrained applications where efficiency at light loads and robustness across wide temperature ranges are critical design requirements.

FAQ

What is the maximum input voltage rating for the LTC3621HMS8E-5#TRPBF?

The LTC3621HMS8E-5#TRPBF has an absolute maximum input voltage rating of 17V. It also includes VIN overvoltage lockout that disables switching when VIN exceeds 19V (rising) and re-enables operation once VIN falls below 18.7V, protecting internal MOSFETs from transients. This makes the LTC3621HMS8E-5#TRPBF suitable for 12V automotive systems with load dump events.

Does the LTC3621HMS8E-5#TRPBF require external feedback resistors to set its output voltage?

No, the LTC3621HMS8E-5#TRPBF is a fixed 5V output variant - the FB pin is internally connected to the regulated output, eliminating the need for external resistors. This simplifies PCB layout, improves long-term output accuracy by removing resistor drift effects, and enhances reliability in high-vibration environments like automotive applications.

How does the PGOOD function work on the LTC3621HMS8E-5#TRPBF?

The PGOOD pin on the LTC3621HMS8E-5#TRPBF is an open-drain output that goes high when V_OUT is within ±7.5% of 5V (i.e., 4.625V–5.375V) and remains high for at least 32 switching cycles after entering regulation. It pulls low immediately upon exiting regulation, with a 32-cycle blanking delay on the falling edge to prevent false triggers during load transients - ensuring robust system power sequencing.

Can the LTC3621HMS8E-5#TRPBF synchronize to an external clock, and what is the capture range?

Yes, the LTC3621HMS8E-5#TRPBF can synchronize its 2.25MHz internal oscillator to an external clock applied to the MODE/SYNC pin. The sync capture range is ±40% of the nominal frequency - i.e., 1.35MHz to 3.15MHz - allowing EMI reduction through frequency dithering or alignment with system clocks in tightly synchronized embedded platforms.

What is the purpose of the SGND pin on the LTC3621HMS8E-5#TRPBF, and how should it be routed?

The SGND pin on the LTC3621HMS8E-5#TRPBF provides a dedicated signal ground return for the FB, MODE/SYNC, and PGOOD pins - isolating sensitive analog reference paths from high-current power ground loops. It must be routed separately from the main GND plane and connected to the analog ground net, then joined to the power GND at a single point near the IC's exposed pad to minimize noise coupling into the feedback network.