Analog Devices Inc. LTC1726ES8-5#TRPBF

Overview

LTC1726ES8-5#TRPBF from Analog Devices (formerly Linear Technology) is a triple supply monitor and microprocessor supervisory IC with adjustable reset and watchdog timer functions, designed for systems requiring simultaneous monitoring of 5V, 3.3V, and an adjustable voltage rail. It features ±1.5% threshold accuracy over temperature, 16µA typical supply current, and guaranteed RST assertion down to VCC3 ≥ 1V or VCC5 ≥ 1V - enabling reliable power-up sequencing in desktop computers and network servers.

For engineers reviewing the LTC1726ES8-5#TRPBF datasheet, LTC1726ES8-5#TRPBF pinout, LTC1726ES8-5#TRPBF application, or LTC1726ES8-5#TRPBF equivalent, key selection criteria include its adjustable reset timeout (via RT capacitor), independent watchdog timeout (via WT capacitor), open-drain active-low RST output with weak internal pull-up to VCC3, and support for 5V/3.3V/ADJ supply configurations in SO-8 package.

Technical Context

The LTC1726ES8-5#TRPBF integrates three independent voltage comparators (for VCC5, VCC3, and VCCA), a programmable reset timer, and a watchdog timer with edge-triggered WDI input. Its internal bandgap reference enables ±1.5% trip threshold accuracy across –40°C to +85°C, and glitch immunity ensures no false resets during supply transients.

Power is derived dynamically from the highest valid supply among VCC5 and VCC3; VCCA serves as a high-impedance 1V-adjustable threshold input. The part supports override functionality where VCC5 monitoring is disabled when VCC5 ≈ VCC3 ±25mV and <4.15V - allowing flexible reconfiguration between 5V-only and 3.3V-prioritized supervision modes.

Key Specifications

Pinout & Package

Package: 8-Lead Plastic SO (Narrow, 0.150-inch width), RoHS-compliant, operating temperature range –40°C to +85°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC1726ES8-5#TRPBF, LTC1727-5#TRPBF offers per-rail reset control at the expense of pin count and routing complexity, while LTC1326-5#TRPBF trades timing adjustability for superior threshold accuracy and lower unit cost - making each optimal for distinct system-level trade-offs.

Availability

LTC1726ES8-5#TRPBF is available at Aetrix Electronics and suitable for desktop computers, network servers, and intelligent instruments requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LTC1726ES8-5#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 product support, documentation, and manufacturing continuity for legacy Linear parts including the LTC1726 series.

The LTC1726 belongs to Linear's precision power supervision product line, engineered for high-reliability computing and instrumentation systems where deterministic reset behavior, low power, and multi-rail coordination are essential.

FAQ

What is the function of the VCCA pin on the LTC1726ES8-5#TRPBF?

The VCCA pin on the LTC1726ES8-5#TRPBF is a high-impedance adjustable threshold input with a nominal 1V trip point (0.985V–1.015V). It monitors an external voltage rail - such as a DC/DC converter feedback node - and triggers reset if that rail falls below its threshold. When unused, VCCA may be tied to VCC3 or VCC5 without affecting operation.

How does the LTC1726ES8-5#TRPBF determine which supply powers its internal circuitry?

The LTC1726ES8-5#TRPBF dynamically selects its power source from the highest valid voltage among VCC3 and VCC5 pins. If VCC3 > VCC5, VCC3 supplies internal circuitry; if VCC5 > VCC3, VCC5 supplies it. This ensures RST remains asserted until at least one supply reaches 1V, guaranteeing safe initialization under asymmetric power ramp conditions.

Can the watchdog timer on the LTC1726ES8-5#TRPBF be disabled, and how?

Yes, the watchdog timer on the LTC1726ES8-5#TRPBF can be disabled by connecting both the WDI (Pin 5) and WT (Pin 7) pins to GND. With WT grounded, the watchdog function is inactive, and the device operates strictly as a triple-supply monitor with adjustable reset timeout controlled solely by the CRT capacitor on RT (Pin 8).

What is the significance of the "-5" suffix in LTC1726ES8-5#TRPBF?

The "-5" suffix in LTC1726ES8-5#TRPBF denotes the 5V version of the device, specifying its VCC5 input threshold at 4.600V–4.750V (±1.5%) and enabling the VCC5 override function. This variant is configured to monitor 5V, 3.3V, and an adjustable rail - distinguishing it from the LTC1726ES8-2.5#TRPBF, which targets 2.5V/3.3V/ADJ systems.

Does the LTC1726ES8-5#TRPBF require external pull-up resistors on the RST pin?

The LTC1726ES8-5#TRPBF includes a weak internal 6µA pull-up to VCC3 on the RST pin, sufficient for many 3.3V logic interfaces. However, an external pull-up resistor is required when interfacing with 5V logic or when faster rise times are needed - especially in systems with heavy capacitive loading on the reset bus.