Analog Devices Inc. LTC3541EDD-2#TRPBF

Overview

LTC3541EDD-2#TRPBF from Analog Devices (formerly Linear Technology) is a dual-output power management IC integrating a 500mA synchronous buck converter and a 300mA very low dropout (VLDO) linear regulator in a single 10-lead DFN package. It delivers fixed 1.875V buck and 1.5V VLDO outputs from a 2.7V–5.5V input, enabling compact, high-efficiency power for portable logic and analog rails. Its auto-startup sequencing powers the buck output before enabling the VLDO, supporting Li-ion battery-powered digital cameras and cellular phones.

For engineers reviewing the LTC3541EDD-2#TRPBF datasheet, LTC3541EDD-2#TRPBF pinout, LTC3541EDD-2#TRPBF application, or LTC3541EDD-2#TRPBF equivalent, key selection criteria include its dual-rail capability with independent enable control, 2.25MHz constant-frequency operation, <3µA shutdown current, 20mV typical VLDO dropout at 50mA, and thermal/short-circuit protection across both regulators.

Technical Context

The LTC3541EDD-2#TRPBF implements a current-mode, constant-frequency (1.8–2.7MHz) synchronous buck architecture with internal P- and N-channel MOSFETs (R_DS(ON) = 0.25Ω / 0.35Ω), enabling up to 500mA output with 90% typical efficiency. Its VLDO regulator uses an N-channel pass device with 1.6V–5.5V LVIN range and 20–50mV dropout at 50mA load, optimized for low-noise analog supply generation.

Control logic interprets ENBUCK, ENVLDO, and MODE pins per a defined truth table to configure three operational modes: buck-only, VLDO-only (linear mode), or dual-output with auto-sequencing. The device supports both Burst Mode® (for light-load efficiency) and pulse-skip (for low-noise constant-frequency operation), with independent quiescent current specs per mode (e.g., 55µA buck-only Burst sleep, 85µA dual-output Burst sleep).

Key Specifications

Pinout & Package

10-lead (3mm × 3mm) plastic DFN package with exposed thermal pad (Pin 11, GND). Pin 4 (NC) must remain unconnected and un-biased.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output power management applications.

Compared with TPS62125DSGR and MAX8646ETE+, the LTC3541EDD-2#TRPBF uniquely combines fixed 1.875V/1.5V dual outputs, auto-sequencing, and VLDO-specific low-noise/low-dropout performance in one DFN package-enabling smaller footprint and lower system-level complexity for portable dual-rail applications.

Availability

LTC3541EDD-2#TRPBF is available at Aetrix Electronics and suitable for digital cameras, cellular phones, and DSL modems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LTC3541EDD-2#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 acquired Linear Technology in 2017 and maintains its high-performance analog and power management portfolio. Linear Technology was renowned for precision DC/DC converters and low-noise regulators.

The LTC3541EDD-2#TRPBF belongs to Linear's VLDO™ regulator family, designed specifically for portable systems needing compact, efficient dual-rail power with minimal external components and robust protection.

FAQ

What is the minimum input voltage required for the LTC3541EDD-2#TRPBF to regulate both outputs?

The LTC3541EDD-2#TRPBF requires VIN ≥ 2.7V to operate the buck regulator and LVIN ≥ 1.6V for the VLDO. However, for full dual-output regulation with auto-sequencing, the datasheet specifies VIN ≥ LVOUT + 1.4V = 2.9V minimum. Below 2.9V, only the VLDO may regulate if powered independently from a separate LVIN source.

Can the LTC3541EDD-2#TRPBF generate output voltages other than 1.875V and 1.5V?

No-the LTC3541EDD-2#TRPBF has factory-trimmed internal feedback networks that fix VOUT at 1.875V and LVOUT at 1.5V. These values are not adjustable via external resistors. For programmable outputs, consider the pin-compatible LTC3541-1 (1.2V/1.5V) or LTC3541-3 (1.875V/1.2V) variants.

How does the LTC3541EDD-2#TRPBF handle thermal overload conditions?

The LTC3541EDD-2#TRPBF includes overtemperature protection that disables the VLDO or linear regulator when junction temperature reaches ~160°C. Both regulators are reset upon fault clearance. This protection is distinct from the 125°C absolute maximum junction rating-operation above 125°C degrades reliability even if protection hasn't triggered.

Is the exposed pad (Pin 11) of the LTC3541EDD-2#TRPBF electrically connected to GND?

Yes-the exposed pad (Pin 11) is internally connected to GND and must be soldered to a PCB thermal pad tied to the system ground plane. This connection is mandatory for both electrical functionality (reference integrity) and thermal performance (θ_JA = 43°C/W assumes proper pad soldering).

What is the difference between VLDO mode and linear regulator mode in the LTC3541EDD-2#TRPBF?

In VLDO mode (ENBUCK = high, ENVLDO = high), the N-channel pass transistor is supplied from LVIN and delivers up to 300mA at 1.5V. In linear regulator mode (ENBUCK = low, ENVLDO = high), the same transistor is supplied from VIN and delivers up to 30mA at 1.5V-optimized for pre-buck startup or low-current analog bias where LVIN is unavailable.