Analog Devices Inc. LTC3621EDCB-23.3#TRPBF

Overview

LTC3621EDCB-23.3#TRPBF from Analog Devices is a 2.25MHz, 3.3V fixed-output synchronous step-down regulator delivering up to 1A output current with 3.5µA quiescent current and ±1% output voltage accuracy. It operates from 2.7V to 17V input, supports Burst Mode™, pulse-skipping, and forced continuous operation, and is used in automotive infotainment power rails and portable industrial sensors.

For engineers reviewing the LTC3621EDCB-23.3#TRPBF datasheet, LTC3621EDCB-23.3#TRPBF pinout, LTC3621EDCB-23.3#TRPBF application, or LTC3621EDCB-23.3#TRPBF equivalent, key selection factors include its 2.25MHz switching frequency for compact filter design, 3.3V fixed output with 0.594V–0.606V feedback reference, ultralow IQ in shutdown, and DFN-6 (2mm × 3mm) thermal performance.

Technical Context

The LTC3621EDCB-23.3#TRPBF implements a constant-frequency peak current mode control architecture with internal compensation and 800µs soft-start. Its MODE/SYNC pin enables three operating modes: Burst Mode (≤3.5µA IQ), pulse-skipping (low VOUT ripple), or forced continuous (stable EMI profile).

It features integrated PMOS/NMOS power switches with RDS(ON) of 0.37Ω/0.15Ω at VIN = 5V, overtemperature protection, VIN overvoltage lockout (18V–20V), and undervoltage lockout (2.4V–2.7V). The device supports external clock synchronization within ±40% of 2.25MHz and maintains regulation down to 100% duty cycle.

Key Specifications

Pinout & Package

Package: 6-Lead (2mm × 3mm) Plastic DFN with exposed thermal pad (Pin 7 = GND), rated for –40°C to 125°C junction temperature and θJA = 64°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 MAX17503GCU+T, the LTC3621EDCB-23.3#TRPBF offers the lowest quiescent current (3.5µA) and AEC-Q100 qualification in the smallest footprint (2mm × 3mm), making it optimal for space- and power-constrained automotive and portable applications where 1A output suffices.

Availability

LTC3621EDCB-23.3#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, portable industrial sensors, and emergency radio power supplies requiring stable component supply, long-lifecycle support, and AEC-Q100 compliance.

Supply support for LTC3621EDCB-23.3#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 precision instrumentation, industrial automation, and automotive markets.

The LTC3621 product line delivers ultralow-IQ, high-frequency synchronous buck regulators for battery-powered and automotive systems where efficiency, size, and reliability are critical.

FAQ

What is the guaranteed output voltage accuracy of the LTC3621EDCB-23.3#TRPBF?

The LTC3621EDCB-23.3#TRPBF provides a fixed 3.3V output with guaranteed accuracy of ±1% over temperature and line/load conditions. This is achieved via an internal 0.6V reference with ±1% tolerance (0.594V to 0.606V), ensuring stable 3.3V regulation without external components. The specification applies across the full –40°C to 125°C operating junction temperature range and input voltages from 2.7V to 17V. No external resistors are needed, eliminating drift from component tolerances.

Can the LTC3621EDCB-23.3#TRPBF operate in dropout mode, and how does it behave?

Yes, the LTC3621EDCB-23.3#TRPBF supports full dropout operation with 100% duty cycle capability. When VIN approaches 3.3V, the top PMOS switch remains continuously on while maintaining regulation. In Burst Mode or pulse-skipping, the part transitions in/out of sleep to minimize IQ; in forced continuous mode, it sustains switching. Dropout behavior is validated down to VIN = 3.3V with ≤1% output deviation, and internal circuitry preserves ILIM = 1.6A even at high duty cycles - critical for brownout resilience in automotive and battery systems.

What are the thermal characteristics of the LTC3621EDCB-23.3#TRPBF in its DFN package?

The LTC3621EDCB-23.3#TRPBF in the 6-lead DFN (2mm × 3mm) package has θJA = 64°C/W and θJC = 9.6°C/W, with an absolute maximum junction temperature of 125°C. The exposed thermal pad (Pin 7) must be soldered to a PCB ground plane for effective heat dissipation. Under 1A load at 12V input, typical power loss is ~180mW; with proper copper area (≥250mm² 2oz Cu), junction temperature rise stays below 25°C above ambient - enabling reliable convection-only cooling in sealed enclosures.

How does the MODE/SYNC pin configure operating modes on the LTC3621EDCB-23.3#TRPBF?

The MODE/SYNC pin on the LTC3621EDCB-23.3#TRPBF selects among three distinct modes: tie to INTVCC for Burst Mode (≤3.5µA IQ, 400mA peak clamp); ground for pulse-skipping (lowest VOUT ripple); or apply 1V–VINTVCC–1.2V for forced continuous (EMI-controlled, zero-audio-noise). It also accepts external clocks within ±40% of 2.25MHz for synchronization. All configurations are valid across temperature and load, and mode transitions occur within 2–3 clock cycles - enabling dynamic efficiency/ripple optimization in real-time systems.

Is the LTC3621EDCB-23.3#TRPBF qualified for automotive applications, and what does that entail?

Yes, the LTC3621EDCB-23.3#TRPBF is AEC-Q100 qualified for automotive applications (Grade E, –40°C to 125°C). This includes stress testing for temperature cycling, humidity, mechanical shock, and ESD per AEC standards. The device features VIN overvoltage lockout (18V–20V), undervoltage lockout (2.4V–2.7V), and overtemperature protection - all validated under automotive-grade process controls. It is suitable for infotainment, body electronics, and ADAS subsystems where reliability and extended temperature operation are mandatory.