Analog Devices Inc. LT1304CS8-3.3#TRPBF

Overview

LT1304CS8-3.3#TRPBF from Analog Devices (formerly Linear Technology) is a micropower step-up DC/DC converter with integrated low-battery detector, designed for 2–4-cell alkaline/NiCd battery systems requiring regulated 3.3V output. It operates from 1.5V to 8V input, delivers up to 300mA load current, features 120µA active quiescent current and 10µA shutdown current with detector active, and uses an internal 1A NPN switch with 370mV saturation voltage at 1A.

For engineers reviewing the LT1304CS8-3.3#TRPBF datasheet, LT1304CS8-3.3#TRPBF pinout, LT1304CS8-3.3#TRPBF application, or LT1304CS8-3.3#TRPBF equivalent, key selection criteria include its fixed 3.3V output accuracy (±3.5%), low-battery detection threshold (1.17V ±65mV hysteresis), 300kHz switching frequency enabling compact magnetics, and SO-8 package compatibility with space-constrained portable instrumentation and medical devices.

Technical Context

The LT1304CS8-3.3#TRPBF implements a hysteretic current-mode boost architecture with independent low-battery comparator A3 that remains powered during shutdown. Its 6µs minimum on-time and 1.5µs fixed off-time define burst-mode operation, while internal 1A peak current limit is programmable via ILIM pin resistor to ground.

Output regulation is achieved by sensing voltage at the SENSE (FB) pin against a 1.24V reference; for the -3.3 variant, this corresponds to a factory-trimmed 3.3V output (3.17–3.43V over temperature). The LBI/LBO pins provide open-collector low-battery signaling with 35–65mV hysteresis, functional down to VIN ≈ 1.4V - below the main regulator's undervoltage lockout.

Key Specifications

Pinout & Package

LT1304CS8-3.3#TRPBF is housed in an 8-lead plastic SO (Small Outline) package, 0.150" wide, with standard SOIC-8 footprint (JEDEC MS-012). Pin 1 is marked by a dot or notch; leads are gull-wing, lead pitch 0.050", body dimensions 0.189" × 0.228".

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1703EASA+ and TPS61200DRCR, the LT1304CS8-3.3#TRPBF offers unique value in legacy alkaline/NiCd systems where guaranteed 1.5V start-up, robust LBO functionality during shutdown, and proven field reliability outweigh newer features like synchronous rectification or ultra-low IQ.

Availability

LT1304CS8-3.3#TRPBF is available at Aetrix Electronics and suitable for portable medical diagnostics, bar code scanners, palmtop computers, and personal data communicators requiring stable component supply across long product lifecycles and industrial temperature ranges.

Supply support for LT1304CS8-3.3#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LT1304 family was developed by Linear Technology specifically for ultra-low-power, battery-operated portable equipment requiring high-efficiency step-up conversion with integrated system supervision - emphasizing long runtime, reliable low-voltage operation, and minimal external component count.

FAQ

What is the minimum input voltage required for LT1304CS8-3.3#TRPBF to start switching?

The LT1304CS8-3.3#TRPBF can begin switching with an input voltage as low as 1.5V, verified across the 0°C to 70°C operating range. This enables reliable startup from deeply discharged 2-cell alkaline or NiCd batteries. Below 1.5V, the internal bandgap reference and comparators may not function, though the low-battery detector (LBO) remains active down to approximately 1.4V.

Does LT1304CS8-3.3#TRPBF require external feedback resistors to set its output voltage?

No, the LT1304CS8-3.3#TRPBF does not require external feedback resistors. It is a fixed-output variant with internal resistor divider trimmed at the factory to deliver 3.3V ±3.5% (3.17V–3.43V). The SENSE/FB pin (Pin 8) connects directly to this internal network and should be left unconnected externally except for optional soft-start capacitor to ILIM.

How does the low-battery detector in LT1304CS8-3.3#TRPBF behave during shutdown mode?

During shutdown (SHDN = LOW), the LT1304CS8-3.3#TRPBF disables its main switching regulator but keeps the LBI/LBO comparator fully operational. The LBO output remains an active open-collector sink capable of driving LEDs or MCU interrupts with up to 500µA current, and the detector functions down to VIN ≈ 1.4V - well below the main regulator's UVLO threshold.

Can LT1304CS8-3.3#TRPBF drive a 300mA load continuously at 3.3V output?

Yes, the LT1304CS8-3.3#TRPBF is rated to deliver up to 300mA at 3.3V output under typical conditions (VIN ≥ 2.5V, TA = 25°C, proper layout and components). Efficiency exceeds 85% at this load with 2-cell input. At lower input voltages (e.g., 1.8V), maximum continuous load decreases due to duty cycle and thermal limits; derating is recommended above 70°C ambient.

What package type and RoHS status does LT1304CS8-3.3#TRPBF use?

The LT1304CS8-3.3#TRPBF is supplied in an 8-lead plastic SO (Small Outline) package, 0.150" wide, with gull-wing leads and JEDEC MS-012 outline. It is RoHS-compliant and lead-free, indicated by the "#TRPBF" suffix per Analog Devices' packaging nomenclature - confirming Pb-free terminations and green molding compound.