Analog Devices Inc. LTC1726EMS8-5#TRPBF

Overview

LTC1726EMS8-5#TRPBF from Analog Devices (formerly Linear Technology) is a triple supply monitor and microprocessor supervisory IC with adjustable reset timeout, watchdog timer, and ±1.5% threshold accuracy over temperature. It monitors 5V, 3.3V, and an adjustable input (e.g., 1.8V), features active-low open-drain RST output guaranteed functional down to VCC3 ≥ 1V or VCC5 ≥ 1V, and draws only 16µA typical supply current - ideal for desktop computers, notebook computers, and portable battery-powered equipment.

For engineers reviewing the LTC1726EMS8-5#TRPBF datasheet, LTC1726EMS8-5#TRPBF pinout, LTC1726EMS8-5#TRPBF application, or LTC1726EMS8-5#TRPBF equivalent, key selection criteria include its triple-supply monitoring capability, capacitor-adjustable reset/watchdog timing (tRT = 3.30 × CRT, tWT = 21.8 × CWT), glitch-immune operation, and MS8 package compatibility with space-constrained embedded power management designs.

Technical Context

The LTC1726EMS8-5#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 power derivation from either VCC5 or VCC3 ensures RST assertion begins at ≥1V on either rail.

Reset assertion occurs when any monitored supply falls below its threshold; deassertion requires all supplies to exceed thresholds plus completion of the externally set tRT delay. The watchdog function resets the system if no WDI transition occurs within tWT, and both tRT and tWT are linearly scalable via external capacitors on RT and WT pins respectively.

Key Specifications

Pinout & Package

Package: 8-Lead Plastic MSOP (MS8), 3.0mm × 3.0mm × 0.86mm, exposed pad optional, RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC1727-5 and LTC1326-2.5, the LTC1726EMS8-5#TRPBF provides the best balance of adjustable monitoring, low quiescent current, and MSOP footprint - making it preferred for cost-sensitive, space-constrained 5V/3.3V systems needing configurable third-rail supervision.

Availability

LTC1726EMS8-5#TRPBF 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 traceable sourcing.

Supply support for LTC1726EMS8-5#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, datasheet archives, and technical documentation for legacy Linear parts including the LTC1726 family.

The LTC1726 belongs to Linear's precision power supervision product line, designed specifically for reliable multi-rail voltage monitoring and watchdog protection in computing, instrumentation, and communications infrastructure.

FAQ

What is the operating temperature range for the LTC1726EMS8-5#TRPBF?

The LTC1726EMS8-5#TRPBF is rated for –40°C to +85°C ambient operation (E-grade). This range is fully specified for all electrical parameters including ±1.5% threshold accuracy, 16µA typical supply current, and reset/watchdog timing performance. The MS8 package has θJA = 200°C/W, requiring appropriate PCB copper area for thermal management at maximum load.

How do I configure the LTC1726EMS8-5#TRPBF to monitor only two supplies?

The LTC1726EMS8-5#TRPBF can be configured to monitor two supplies by tying the unused VCCA pin to either VCC3 or VCC5 - this disables the adjustable input comparator while preserving 5V and 3.3V monitoring. For example, connecting VCCA to VCC3 configures the device as a dual 5V/3.3V supervisor. The RST output remains active-low open-drain and timing remains adjustable via RT and WT capacitors.

What capacitor values are recommended for a 155ms reset timeout and 1s watchdog timeout on the LTC1726EMS8-5#TRPBF?

For a 155ms reset timeout, use CRT = 47nF (tRT = 3.30 × 47,000pF = 155,100µs). For a 1s watchdog timeout, use CWT = 47nF (tWT = 21.8 × 47,000pF = 1,024,600µs ≈ 1.02s). Both capacitors must be low-leakage ceramic types; X7R or C0G dielectrics are recommended to maintain timing accuracy across temperature and voltage.

Does the LTC1726EMS8-5#TRPBF support manual reset functionality?

The LTC1726EMS8-5#TRPBF does not integrate a dedicated manual reset input. However, a push-button reset can be implemented externally by pulling the WDI pin low for >40ns (tWP spec), which clears the watchdog timer and prevents immediate reset - then releasing WDI allows normal watchdog operation to resume. For true hardware reset injection, an external transistor or logic gate driving RST low is required.

Can the LTC1726EMS8-5#TRPBF monitor a 1.2V supply using the VCCA pin?

Yes - the VCCA pin has a nominal 1V threshold with ±1.5% accuracy, making it suitable for monitoring 1.2V supplies when used with an external resistor divider. For example, a 1.2V rail can be scaled to 1.0V at VCCA using R1/R2 = 1:5 (e.g., 10kΩ + 50kΩ), preserving the ±15mV absolute threshold tolerance. The divider must present <66.5kΩ parallel resistance to avoid accuracy degradation per datasheet guidance.