Analog Devices Inc. LTC1326CMS8#TRPBF

Overview

LTC1326CMS8#TRPBF from Analog Devices (acquired Linear Technology) is a micropower precision triple supply monitor IC designed for systems with multiple voltage rails. It simultaneously monitors 2.5V, 3.3V, and an adjustable supply (VCCA), features ±0.75% threshold accuracy, 20µA typical supply current, 200ms internal reset delay, and dual open-drain reset outputs (RST and SRST). It is used in notebook computers and portable battery-powered equipment requiring reliable power-on and brownout reset generation.

For engineers reviewing the LTC1326CMS8#TRPBF datasheet, LTC1326CMS8#TRPBF pinout, LTC1326CMS8#TRPBF application, or LTC1326CMS8#TRPBF equivalent, key selection criteria include guaranteed RST assertion down to VCC3 ≥ 1V, manual push-button soft/hard reset capability, glitch-immune triple-supply monitoring, and MSOP-8 package compatibility with space-constrained embedded designs.

Technical Context

The LTC1326CMS8#TRPBF implements three independent high-accuracy voltage comparators with 13µs typical response time to suppress transients, and integrates a 200ms reset timer with automatic power-up/power-down sequencing. Its VCC3-powered architecture uses internal gate drive selection between VCC25 and VCC3 to ensure RST remains valid down to 1V on either rail.

It supports flexible configuration via pin-strapping: VCC25 and VCCA inputs can be disabled by tying to VCC3, enabling dual- or single-supply monitoring modes. The PBR input provides debounced manual reset with 20ms internal debounce and configurable soft (100µs) or hard (200ms) reset pulse generation based on button hold duration.

Key Specifications

Pinout & Package

Package: 8-lead plastic MSOP (MS8), 3.0mm × 3.0mm footprint, 0.65mm pitch, θJA = 250°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC1726-2.5 and LTC2903, the LTC1326CMS8#TRPBF delivers optimal balance of micropower operation (20µA), integrated soft/hard reset, and precise 2.5V/3.3V monitoring in an industry-standard MSOP-8 package - making it ideal for portable and battery-sensitive applications where manual reset and DRAM-safe soft reset are critical.

Availability

LTC1326CMS8#TRPBF is available at Aetrix Electronics and suitable for notebook computers, intelligent instruments, and portable battery-powered equipment requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across industrial temperature ranges.

Supply support for LTC1326CMS8#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, formed through the acquisition of Linear Technology in 2017.

The LTC1326 family was developed by Linear Technology as part of its precision power management portfolio, specifically targeting multi-rail embedded systems needing reliable, low-power, and feature-rich supply monitoring with manual reset capability.

FAQ

What is the primary function of the LTC1326CMS8#TRPBF?

The LTC1326CMS8#TRPBF is a micropower triple supply monitor IC that simultaneously supervises 2.5V, 3.3V, and an adjustable supply rail. It generates a 200ms active-low reset signal (RST) when any monitored voltage falls below its precision threshold, and provides a separate 100µs soft reset (SRST) triggered by a short push-button press. Its design ensures deterministic reset behavior during power-up, brownout, and manual intervention scenarios.

Does the LTC1326CMS8#TRPBF support operation with only two supply rails?

Yes, the LTC1326CMS8#TRPBF supports dual- and single-supply configurations. The VCC25 and VCCA inputs can be disabled by tying them to VCC3, allowing the device to function as a dedicated 3.3V monitor. For 2.5V-only monitoring, VCC3 must remain connected but can be configured via external circuitry per the datasheet's override functions - though VCC3 is always required as the IC's power source.

What is the minimum operating voltage for the LTC1326CMS8#TRPBF to assert RST reliably?

The LTC1326CMS8#TRPBF guarantees correct RST logic state (low) for VCC3 ≥ 1V or VCC25 ≥ 1V. This means the device continues to assert reset even as the 3.3V or 2.5V supply collapses toward 1V, providing extended brownout coverage beyond most microcontrollers' operational limits. Below 1V on both rails, reset behavior is not guaranteed.

How does the push-button reset (PBR) function differ between soft and hard reset modes on the LTC1326CMS8#TRPBF?

On the LTC1326CMS8#TRPBF, holding PBR low for less than ≈2 seconds generates a 100µs soft reset pulse on SRST, preserving DRAM refresh cycles. Holding PBR low for more than ≈2 seconds forces the main RST output low for 200ms after release - identical to a power-on reset. Internal 20ms debounce prevents contact bounce from triggering unintended resets.

Can the LTC1326CMS8#TRPBF be used to monitor negative supply voltages?

Yes, the LTC1326CMS8#TRPBF can monitor negative supplies using an external resistor divider and PNP/NPN transistor level-shifting network, as shown in Figure 12 of the datasheet. In this configuration, VCCA senses the scaled positive representation of the negative rail, enabling reset assertion when the negative supply exceeds its trip point (e.g., –5V). The IC itself operates only from positive supplies (VCC3/VCC25).