Analog Devices Inc. LTC1504CS8#TRPBF

Overview

LTC1504CS8#TRPBF from Analog Devices (formerly Linear Technology) is a self-contained, high-efficiency synchronous buck DC/DC regulator IC delivering up to 500mA at adjustable output voltage. It integrates dual on-chip 1.5Ω MOSFETs, operates from 4V–10V input, achieves 92% peak efficiency, and features internal 1% reference accuracy for precision regulation in space-constrained portable systems.

For engineers reviewing the LTC1504CS8#TRPBF datasheet, LTC1504CS8#TRPBF pinout, LTC1504CS8#TRPBF application, or LTC1504CS8#TRPBF equivalent, key selection considerations include its SO-8 package thermal performance, 200kHz fixed switching frequency (synchronizable to 500kHz), adjustable current limit via IMAX pin, soft-start control via external capacitor, and ability to source/sink output current for tight transient regulation.

Technical Context

The LTC1504CS8#TRPBF implements a synchronous buck topology with integrated P-channel high-side and N-channel low-side MOSFETs, enabling bidirectional output current flow for improved load transient response. Its feedback loop uses a transconductance error amplifier (gm_V = 350–1100 µmho) referenced to a trimmed 1.265V internal voltage, with dedicated MIN/MAX comparators providing ±3% fast over/under-voltage override.

A secondary current-limit loop monitors SW-node voltage during Q1 conduction and dynamically pulls down the SS pin via ILIM amplifier to reduce duty cycle; this loop is compensated by the same external soft-start capacitor (typically 0.1µF), eliminating need for separate current-sense resistors while maintaining stability across temperature and load.

Key Specifications

Pinout & Package

Package: 8-lead plastic SO-8 (S8), 150°C max junction temperature, θ_JA = 90°C/W. Requires large copper pour on GND pin (Pin 4) for thermal management.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck regulator applications.

Compared with TPS62231DRVR and MP2307DT-LF-Z, the LTC1504CS8#TRPBF offers unique bidirectional current regulation and integrated current limiting via IMAX-critical for active termination and transient-heavy portable systems-while maintaining proven SO-8 thermal performance at 500mA without requiring layout changes.

Availability

LTC1504CS8#TRPBF is available at Aetrix Electronics and suitable for portable digital systems, active termination circuits, auxiliary voltage supplies, and minimum-part-count switcher designs requiring stable component supply and long-term manufacturability.

Supply support for LTC1504CS8#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 full technical support, documentation, and manufacturing continuity for all Linear-branded power products.

The LTC1504 product line was designed specifically for high-efficiency, low-component-count synchronous buck regulation in space- and thermally-constrained portable and industrial applications - emphasizing integration, thermal robustness, and transient resilience over raw frequency agility.

FAQ

What is the maximum continuous output current supported by the LTC1504CS8#TRPBF?

The LTC1504CS8#TRPBF delivers up to 500mA continuous output current at 3.3V with 5V input under proper thermal conditions (SO-8 package on ≥2 sq-in copper pour). Peak current capability exceeds ±1A, but sustained operation above 500mA requires derating based on ambient temperature and PCB copper area, as specified by θ_JA = 90°C/W.

Does the LTC1504CS8#TRPBF support fixed 3.3V output, or is it adjustable only?

The LTC1504CS8#TRPBF is the adjustable version - it uses the FB pin and an external resistor divider to set output voltage (e.g., 3.3V, 2.5V, 1.8V). For fixed 3.3V operation, use the pin-compatible LTC1504CS8-3.3 variant, which replaces FB with SENSE and includes an internal resistor divider calibrated to 3.30V ±3%.

How does the current limit function work on the LTC1504CS8#TRPBF?

The LTC1504CS8#TRPBF implements current limiting by comparing the voltage drop across its internal high-side P-MOSFET (at SW pin) to a reference set by the IMAX pin. An internal 12µA current sink establishes the IMAX voltage; when sensed switch voltage exceeds this, the ILIM amplifier pulls current from the SS pin, reducing COMP voltage and limiting duty cycle - all without external sense resistors.

Can the LTC1504CS8#TRPBF be synchronized to an external clock?

Yes, the LTC1504CS8#TRPBF supports external synchronization up to 500kHz. Its internal 200kHz oscillator can be overridden by applying a clean square wave to the SHDN pin (with appropriate AC-coupling and biasing), allowing phase alignment with system clocks or noise-sensitive frequency bands - detailed timing requirements are in the Applications Information section.

What is the recommended soft-start capacitor value for the LTC1504CS8#TRPBF?

A 0.1µF ceramic capacitor from SS pin to GND is the standard recommendation for the LTC1504CS8#TRPBF. This value provides ~10ms soft-start ramp time and simultaneously compensates the current-limit loop. Larger values increase ramp time and slow current-limit response; smaller values risk instability during overload recovery - always verify with load-step testing.