Analog Devices Inc. LTC1474IS8-5#TRPBF

Overview

LTC1474IS8-5#TRPBF from Analog Devices (formerly Linear Technology) is a high-efficiency, low-quiescent-current step-down DC/DC converter with internal P-channel MOSFET, fixed 5V output, and industrial-grade temperature rating (–40°C to +85°C). It delivers up to 300mA load current, achieves >92% peak efficiency at 200mA, operates from 3V to 18V input, and maintains regulation down to 100% duty cycle for ultra-low dropout. It is used in battery-powered portable instruments requiring stable 5V rail generation with micropower shutdown.

For engineers reviewing the LTC1474IS8-5#TRPBF datasheet, LTC1474IS8-5#TRPBF pinout, LTC1474IS8-5#TRPBF application, or LTC1474IS8-5#TRPBF equivalent, key selection criteria include its 6µA shutdown current, programmable current limit (325–400mA), 1.4Ω internal switch R_DS(ON), low-battery detection functional during shutdown, and compatibility with minimal external components (inductor, Schottky diode, two capacitors).

Technical Context

The LTC1474IS8-5#TRPBF employs Burst Mode™ operation to sustain high efficiency across light-to-moderate loads: it alternates short energy bursts (with 4.75µs controlled off-time) and deep-sleep cycles drawing only 9µA typical supply current. Its voltage-mode control loop uses an internal 1.23V reference and feedback comparator with 5mV hysteresis to regulate output within ±2% over line and load.

Peak inductor current is set via internal sense FET and optional external resistor between SENSE and VIN pins; with no external resistor, it defaults to 325–400mA. The low-battery comparator (trip threshold 1.16–1.27V) remains active in shutdown, driving open-drain LBO while monitoring LBI independently of regulator state.

Key Specifications

Pinout & Package

Package: 8-lead MSOP (MS8), 3 mm × 3 mm, exposed pad, RoHS-compliant, rated for industrial temperature range (–40°C to +85°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC1474IS8-5#TRPBF, TPS62231DRYR trades micropower efficiency for tighter ripple control, while MAX17532ATP+ expands input range and current capability at the cost of integrated battery monitoring and minimal BOM simplicity.

Availability

LTC1474IS8-5#TRPBF is available at Aetrix Electronics and suitable for portable medical sensors, industrial data loggers, handheld test equipment, and smart meters requiring stable component supply with guaranteed long-term industrial temperature support.

Supply support for LTC1474IS8-5#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 acquired Linear Technology in 2017 and maintains its legacy high-performance power management portfolio with rigorous qualification and long-term product support.

The LTC1474 series was designed specifically for moderate-current (≤300 mA), battery-critical applications demanding ultralow quiescent current, seamless low-dropout operation, and integrated system monitoring - not general-purpose DC/DC conversion.

FAQ

What is the maximum continuous output current supported by the LTC1474IS8-5#TRPBF?

The LTC1474IS8-5#TRPBF supports up to 300 mA continuous output current under industrial temperature conditions (–40°C to +85°C) with adequate PCB copper area and airflow. This limit is constrained by thermal dissipation from the internal 1.4 Ω P-MOSFET switch and package thermal resistance (θ_JA = 110°C/W for MS8). At 10V input and 5V/300mA output, power dissipation is ~1.5 W - requiring careful thermal layout. Derating is recommended above 70°C ambient.

Does the LTC1474IS8-5#TRPBF require an external current sense resistor to operate?

No, the LTC1474IS8-5#TRPBF does not require an external current sense resistor. With Pins 6 (SENSE) and 7 (VIN) shorted, it defaults to a 325–400 mA peak current limit using its internal 5 Ω sense path. An external resistor (e.g., 1.1 Ω) is optional and used only to reduce peak current for lower-noise operation or smaller inductors - for example, setting I_PEAK ≈ 75 mA. The device functions fully without it.

How does the low-battery detector function during shutdown of the LTC1474IS8-5#TRPBF?

The low-battery detector in the LTC1474IS8-5#TRPBF remains fully operational during shutdown: the internal 1.23 V reference and comparator continue running on the 6 µA shutdown supply current. When the voltage at Pin 3 (LBI) drops below 1.16–1.27 V, Pin 2 (LBO) actively sinks up to 0.7 mA - enabling host microcontrollers to detect battery depletion even while the main regulator is disabled. This feature eliminates need for separate supervisor ICs.

Can the LTC1474IS8-5#TRPBF be used with a 3.3 V input supply?

Yes, the LTC1474IS8-5#TRPBF supports 3 V minimum input voltage and maintains regulation down to 100% duty cycle - meaning it can sustain 5 V output even when VIN = 5.0 V (or slightly below, depending on R_DS(ON) drop). However, at VIN = 3.3 V, the device cannot produce 5 V output due to the step-up requirement; it is strictly a step-down (buck) converter. For 3.3 V output from 3.3 V input, use the LTC1474IS8-3.3#TRPBF variant instead.

What is the purpose of the RUN pin on the LTC1474IS8-5#TRPBF, and what voltage levels control it?

The RUN pin (Pin 8) controls enable/disable of the LTC1474IS8-5#TRPBF. It is logic-compatible: applying ≥0.7 V (or leaving open) places the device in active run mode; pulling ≤0.4 V forces shutdown with 6 µA supply current. A 100 kΩ pull-up resistor to VIN is recommended for default-on behavior. Unlike the LTC1475, the LTC1474IS8-5#TRPBF does not support pushbutton toggle - RUN is level-sensitive only.