Analog Devices Inc. LTC1474IS8-3.3#PBF

Overview

LTC1474IS8-3.3#PBF from Analog Devices (formerly Linear Technology) is a high-efficiency, low-quiescent-current step-down DC/DC converter with internal P-channel MOSFET switch, fixed 3.3V output, and 8-lead SOIC package. It delivers up to 250mA output current, achieves >92% efficiency at 200mA with VIN = 10V, operates from 3V to 18V input, and draws only 10µA no-load supply current - ideal for battery-powered portable instruments and wireless modems.

For engineers reviewing the LTC1474IS8-3.3#PBF datasheet, LTC1474IS8-3.3#PBF pinout, LTC1474IS8-3.3#PBF application, or LTC1474IS8-3.3#PBF equivalent, key selection criteria include its 3.3V fixed output accuracy (±2%), 1.4Ω typical switch R_DS(ON), programmable current limit (325–400mA), active-low shutdown (6µA IQ), and low-battery detector functional during shutdown.

Technical Context

The LTC1474IS8-3.3#PBF uses Burst Mode™ operation to maintain regulation while minimizing quiescent current: it alternates short energy bursts (switch on, inductor ramp-up, 100mV current-sense trip) with extended sleep cycles where only voltage comparator, reference, and low-battery comparator remain active. Its internal 1.23V reference compares against a fixed resistive divider to regulate VOUT = 3.3V ±2%.

Shutdown is logic-controlled via RUN pin (ground = shutdown, open/high = run); the low-battery comparator (LBI/LBO pins) remains fully operational in shutdown, with 1.23V threshold and 5mV hysteresis. The device supports 100% duty cycle for ultra-low dropout and includes short-circuit protection via peak-current limiting.

Key Specifications

Pinout & Package

Package: 8-lead plastic SOIC (SO-8), 150°C/W θ_JA, RoHS-compliant #PBF finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC1474IS8-3.3#PBF, LTC3621EMS8E-3.3#PBF offers superior light-load efficiency but removes integrated battery monitoring, while TPS62231DRYR trades Burst Mode flexibility for predictable switching frequency and higher ripple performance - neither replicates the combined low-IQ, low-battery-aware, shutdown-active functionality of the LTC1474IS8-3.3#PBF.

Availability

LTC1474IS8-3.3#PBF is available at Aetrix Electronics and suitable for cellular telephony, portable instrumentation, battery chargers, and intrinsic safety applications requiring stable component supply, industrial temperature grading, and long-term lifecycle continuity.

Supply support for LTC1474IS8-3.3#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, industrial automation, and communications markets.

The LTC1474 series was designed specifically for battery-powered systems demanding ultralow quiescent current, wide input range, and integrated power management features - targeting portable medical devices, handheld test equipment, and remote sensors.

FAQ

What is the guaranteed output voltage tolerance for LTC1474IS8-3.3#PBF over temperature and load?

The LTC1474IS8-3.3#PBF guarantees a 3.3V output within ±2% (3.234V to 3.366V) over full industrial temperature range (–40°C to +85°C) and load current from 0mA to 250mA, as specified in the Electrical Characteristics table under V_OUT parameter with "G" designation.

Does LTC1474IS8-3.3#PBF support 100% duty cycle operation, and what is the minimum input voltage to sustain 3.3V output?

Yes, LTC1474IS8-3.3#PBF supports 100% duty cycle operation, enabling dropout as low as V_OUT – V_GS(th). With typical P-MOSFET characteristics, it sustains regulated 3.3V output down to approximately 3.4V input - verified in Typical Performance Characteristics (Figure G01) and explicitly stated in the FEATURES section.

How does the low-battery detector in LTC1474IS8-3.3#PBF behave during shutdown mode?

The low-battery detector in LTC1474IS8-3.3#PBF remains fully active during shutdown: LBI continues to compare input voltage against the internal 1.23V reference, and LBO sinks current when LBI falls below threshold. This behavior is confirmed in the DESCRIPTION, FEATURES, and OPERATIONS sections, and enables wake-on-low-battery functionality without exiting shutdown.

What is the maximum continuous output current supported by LTC1474IS8-3.3#PBF, and how is current limiting implemented?

LTC1474IS8-3.3#PBF supports up to 250mA continuous output current in typical applications. Current limiting is implemented via internal peak-current control: the SENSE pin monitors voltage across an internal 0.25Ω resistor (plus optional external R_SENSE), tripping at 100mV to enforce a 325–400mA switch current limit - providing inherent short-circuit protection and predictable inductor sizing.

Can LTC1474IS8-3.3#PBF be used with a 3.0V input supply, and what is its minimum operating input voltage?

Yes, LTC1474IS8-3.3#PBF is rated for 3V minimum input voltage per Absolute Maximum Ratings and Electrical Characteristics tables. At 3.0V input, it delivers 3.3V output in 100% duty cycle mode - confirmed by the "Very Low Dropout Operation: 100% Duty Cycle" feature and Figure G01 showing >70% efficiency at VIN = 3V, I_LOAD = 1mA.