Analog Devices Inc. LTC1728HS5-5#TRMPBF

Overview

LTC1728HS5-5#TRMPBF from Analog Devices is a micropower precision triple supply monitor in 5-lead SOT-23 package, designed to simultaneously monitor 5V, 3.3V, and an adjustable input (VCCA) with ±1.5% threshold accuracy over temperature. It provides a single active-low open-drain RESET output asserted until all three supplies remain within specification for 200ms, supporting reliable power-up sequencing in embedded computing systems.

For engineers reviewing the LTC1728HS5-5#TRMPBF datasheet, LTC1728HS5-5#TRMPBF pinout, LTC1728HS5-5#TRMPBF application, or LTC1728HS5-5#TRMPBF equivalent, key selection criteria include guaranteed RST operation down to VCC3 ≥ 1V or VCC5 ≥ 1V, 10µA typical supply current, glitch-immune undervoltage detection, and high-temperature operation up to +125°C.

Technical Context

The LTC1728HS5-5#TRMPBF implements a comparator-based triple-monitor architecture with internal bandgap reference and 200ms reset delay timer. All three inputs-VCC5 (5V), VCC3 (3.3V), and VCCA (adjustable)-are independently compared against precise thresholds (VRT5 = 4.675V typ, VRT3 = 3.086V typ, VRTA = 1.000V typ), with RST deasserted only after all pass and sustain compliance.

Power is autonomously drawn from whichever supply (VCC5 or VCC3) reaches ≥1V first, ensuring early reset assertion during brownout. The device lacks individual comparator outputs (unlike LTC1727), delivering only the combined RST signal-simplifying layout while maintaining tight timing control and power-good behavior for microprocessor supervision.

Key Specifications

Pinout & Package

Package: 5-Lead Plastic TSOT-23 (S5), 1.90mm × 1.50mm footprint, 0.95mm height, lead-free finish, tape-and-reel (TRMPBF = 500-unit reel).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple-supply monitoring applications.

Compared with LTC1728ES5-5#TRPBF, the LTC1728HS5-5#TRMPBF delivers extended temperature operation critical for harsh environments, while LTC1326-5#PBF adds watchdog and reset-button functions at the cost of increased board area and complexity-making LTC1728HS5-5#TRMPBF the preferred choice for compact, high-temp, pure-supervision applications.

Availability

LTC1728HS5-5#TRMPBF is available at Aetrix Electronics and suitable for desktop computers, notebook computers, and network servers requiring stable component supply with guaranteed long-term availability and extended temperature performance.

Supply support for LTC1728HS5-5#TRMPBF 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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, communications, automotive, and consumer markets.

The LTC1728 belongs to Analog Devices' precision power supervision product line, engineered specifically for reliable multi-rail monitoring in space- and power-constrained embedded systems with demanding thermal profiles.

FAQ

What is the operating temperature range of the LTC1728HS5-5#TRMPBF?

The LTC1728HS5-5#TRMPBF is specified for operation from –40°C to +125°C, making it suitable for extended-temperature industrial, automotive under-hood, and high-density server applications where ambient heat exceeds standard commercial grade limits. This H-grade rating is confirmed in the Absolute Maximum Ratings table and Order Information section of the official datasheet.

Does the LTC1728HS5-5#TRMPBF provide individual supply status outputs?

No, the LTC1728HS5-5#TRMPBF provides only a single active-low open-drain RST output. Unlike the LTC1727 family, it does not include individual comparator outputs (e.g., COMP3, COMP5, COMPA). Its design focuses on consolidated reset generation rather than per-rail status indication-simplifying interface and reducing pin count in the 5-lead SOT-23 package.

How does the LTC1728HS5-5#TRMPBF handle power sequencing during startup?

The LTC1728HS5-5#TRMPBF automatically selects its power source from the highest valid supply (VCC5 or VCC3), asserting RST low as soon as either reaches ≥1V. RST remains low until all three monitored supplies-VCC5, VCC3, and VCCA-exceed their respective thresholds and stay valid for 200ms, ensuring deterministic, glitch-immune power-up sequencing without external timing components.

Can the LTC1728HS5-5#TRMPBF monitor a 1.8V supply instead of 5V?

No-the LTC1728HS5-5#TRMPBF variant is specifically configured for 5V/3.3V/adjustable monitoring. For 1.8V systems, Analog Devices offers the LTC1728HS5-1.8#TRMPBF or LTC1728HS5-3.3#TRMPBF, each with factory-trimmed thresholds optimized for those rail combinations. Using the -5 variant for 1.8V monitoring would result in incorrect trip points and unreliable reset behavior.

What is the minimum supply voltage required to guarantee correct RST logic state in the LTC1728HS5-5#TRMPBF?

The LTC1728HS5-5#TRMPBF guarantees correct RST logic state (low or high) for VCC3 ≥ 1V or VCC5 ≥ 1V, as stated in the Features and Absolute Maximum Ratings sections. This ensures early reset assertion during brownout and reliable operation even as supplies sag near their lower limits-critical for fail-safe system shutdown.