Analog Devices Inc. LTC1728ES5-5#TRMPBF

Overview

LTC1728ES5-5#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 valid for 200ms, supporting reliable power-up sequencing in multi-rail systems such as notebook computers and intelligent instruments.

For engineers reviewing the LTC1728ES5-5#TRMPBF datasheet, LTC1728ES5-5#TRMPBF pinout, LTC1728ES5-5#TRMPBF application, or LTC1728ES5-5#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 compatibility with 5V/3.3V/adjustable supply configurations without individual comparator outputs.

Technical Context

The LTC1728ES5-5#TRMPBF implements a triple-input voltage monitoring architecture with independent comparators for VCC5 (4.675V typ), VCC3 (3.086V typ), and VCCA (1.000V typ), all referenced to an internal bandgap. Its reset logic requires all three inputs to exceed their respective thresholds before initiating a 200ms timer; RST remains low during power-up, brownout, or power-down until all conditions are met and timing completes.

Power is autonomously sourced from whichever supply-VCC5 or VCC3-reaches ≥1V first, ensuring early assertion of RST. The device includes built-in glitch immunity: input transitions must exceed 10% of threshold for ≥50µs to trigger, and the 200ms reset pulse width debounces transient disturbances on monitored rails.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC1326-5 and LTC1985-1.8, the LTC1728ES5-5#TRMPBF offers the optimal balance of 5V/3.3V/adjustable monitoring, industry-standard ±1.5% accuracy, minimal 5-lead SOT-23 footprint, and proven reliability in computing infrastructure-without requiring layout changes or additional support components.

Availability

LTC1728ES5-5#TRMPBF is available at Aetrix Electronics and suitable for desktop computers, notebook computers, and intelligent instruments requiring stable component supply with guaranteed long-term availability and consistent parametric performance.

Supply support for LTC1728ES5-5#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, automotive, communications, and healthcare markets.

The LTC1728 belongs to Analog Devices' precision power monitoring product line, engineered specifically for deterministic, low-power, multi-rail system supervision in space-constrained computing and instrumentation applications.

FAQ

What is the primary function of the LTC1728ES5-5#TRMPBF?

The LTC1728ES5-5#TRMPBF is a micropower triple supply monitor that supervises 5V, 3.3V, and an adjustable input (VCCA), asserting an active-low RESET signal only after all three supplies remain above their precise thresholds for 200ms. It operates from either VCC5 or VCC3, ensuring robust reset behavior during power-up, brownout, and shutdown sequences in the LTC1728ES5-5#TRMPBF-based system.

Does the LTC1728ES5-5#TRMPBF support individual supply status indication?

No, the LTC1728ES5-5#TRMPBF provides only a single shared RESET output. Unlike the LTC1727 series, it does not include individual comparator outputs (COMP3, COMP5, COMPA). This simplifies design for applications requiring only system-wide reset coordination, reducing board area and external component count compared to the LTC1728ES5-5#TRMPBF's feature set.

What are the exact threshold voltages for the LTC1728ES5-5#TRMPBF?

The LTC1728ES5-5#TRMPBF has guaranteed threshold voltages of 4.675V (VCC5, ±1.5%), 3.086V (VCC3, ±1.5%), and 1.000V (VCCA, ±1.5%) over –40°C to +85°C. These values are specified in the Electrical Characteristics table of the official Analog Devices datasheet Rev. E and apply directly to the LTC1728ES5-5#TRMPBF variant.

Can the LTC1728ES5-5#TRMPBF monitor a single 5V supply without false RST assertion during ramp-up?

Yes-the LTC1728ES5-5#TRMPBF includes an internal override function that disables the 5V trip point when VCC5 ≈ VCC3 (within ±25mV) and <4.15V, preventing RST from releasing prematurely between ~3.1V and 4.15V. For critical applications, a simple diode (e.g., MMBD914) can be added between VCC5 and VCC3 to force continuous RST assertion until VCC5 reaches its full 4.675V threshold, as documented for the LTC1728ES5-5#TRMPBF.

What is the minimum operating voltage required for the LTC1728ES5-5#TRMPBF to guarantee correct RST state?

The LTC1728ES5-5#TRMPBF guarantees correct RST logic state for VCC3 ≥ 1V or VCC5 ≥ 1V. This means RST will assert low as soon as either supply reaches 1V during power-up, and remain asserted until all monitored supplies exceed their thresholds and the 200ms timer completes-ensuring fail-safe behavior even under severe brownout conditions affecting the LTC1728ES5-5#TRMPBF.