Analog Devices Inc. LTC1326CMS8-2.5#PBF

Overview

LTC1326CMS8-2.5#PBF from Analog Devices (formerly Linear Technology) is a micropower precision triple supply monitor IC designed for systems requiring simultaneous supervision of 2.5V, 3.3V, and an adjustable voltage rail. It delivers ±0.75% threshold accuracy, 20µA typical supply current, 200ms internal reset delay, active-low/open-drain RST and SRST outputs, and guaranteed reset assertion down to VCC3 ≥ 1V or VCC25 ≥ 1V - enabling reliable power-on reset in portable battery-powered equipment and notebook computers.

For engineers reviewing the LTC1326CMS8-2.5#PBF datasheet, LTC1326CMS8-2.5#PBF pinout, LTC1326CMS8-2.5#PBF application, or LTC1326CMS8-2.5#PBF equivalent, key selection criteria include its 2.5V/3.3V/ADJ monitoring capability, MSOP-8 package footprint, manual push-button soft/hard reset functionality, glitch-immune comparators, and compatibility with low-voltage logic interfaces requiring open-drain reset signaling.

Technical Context

The LTC1326CMS8-2.5#PBF integrates three precision voltage comparators with 13µs typical response time and 25mV internal hysteresis to suppress transients on VCC25, VCC3, and VCCA inputs. Its power-detect/gate-drive architecture selects the highest available supply (VCC3 or VCC25) to drive the RST output FET, ensuring valid reset state down to 1V on either rail.

Reset generation is governed by a 200ms timer that releases RST only after all monitored supplies exceed their thresholds for the full duration; the PBR input enables dual-mode reset - a 100µs soft pulse (SRST) for DRAM-preserving resets or a full 200ms hard reset (RST) when held >2 seconds - with 20ms internal debounce and 40ns minimum PBR pulse width tolerance.

Key Specifications

Pinout & Package

Package: 8-lead plastic MSOP (MS8), 3.0mm × 3.0mm body, 0.65mm pitch, JEDEC MO-187AC compliant, thermal resistance 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 LTC1726CMS8-2.5 and LTC2903IMS6-2.5, the LTC1326CMS8-2.5 uniquely balances micropower operation (20µA), full triple-supply flexibility (2.5V/3.3V/ADJ), and dual-mode reset (soft/hard) in an industry-standard MSOP-8 package - making it optimal for portable instrumentation and embedded systems requiring both precision and functional completeness.

Availability

LTC1326CMS8-2.5#PBF 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 LTC1326CMS8-2.5#PBF 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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LTC1326CMS8-2.5#PBF belongs to Linear's precision power supervision product line, engineered specifically for reliable multi-rail reset generation in battery-powered, portable, and space-constrained computing systems.

FAQ

What is the primary function of the LTC1326CMS8-2.5#PBF?

The LTC1326CMS8-2.5#PBF is a micropower triple supply monitor IC that simultaneously supervises 2.5V, 3.3V, and an adjustable voltage rail (VCCA). It asserts active-low reset signals (RST and SRST) when any monitored supply falls below its precision threshold (±0.75% accuracy), with built-in 200ms delay and manual push-button reset capability - ensuring robust power-on, brownout, and recovery sequencing in portable electronics.

How does the LTC1326CMS8-2.5#PBF handle power supply transients?

The LTC1326CMS8-2.5#PBF uses comparators with 13µs typical response time and 25mV internal hysteresis to reject short-duration transients on VCC25, VCC3, and VCCA inputs. Its design ensures reset is not falsely triggered by noise spikes; bypassing each VCC input with a 0.1µF capacitor further enhances immunity, as confirmed by transient immunity curves in the datasheet showing reset occurs only above defined overdrive/duration thresholds.

Can the LTC1326CMS8-2.5#PBF be used with only two supply rails?

Yes - the LTC1326CMS8-2.5#PBF supports dual- and single-supply configurations via override techniques. VCC25 can be tied to VCC3 if unused; VCCA may be connected to VCC3 or left floating. The device will monitor only the active rails, maintaining full reset functionality and accuracy for the enabled inputs, as documented in the Applications Information section under "Dual and Single Supply Monitor Operation".

What is the difference between RST (Pin 6) and RST (Pin 5) on the LTC1326CMS8-2.5#PBF?

RST (Pin 6) is an active-low, open-drain output requiring external pull-up; RST (Pin 5) is its active-high, CMOS-buffered complement. When Pin 6 is pulled low, Pin 5 is driven high to VCC3. Pin 5 requires an external pull-down resistor to ensure correct logic high state when Pin 6 is released. This dual-output structure enables direct interfacing with both open-drain and push-pull logic families without level-shifting components.

Does the LTC1326CMS8-2.5#PBF support operation below 2.5V on VCC3?

Yes - the LTC1326CMS8-2.5#PBF guarantees correct RST logic state for VCC3 down to 1V, as explicitly stated in the Absolute Maximum Ratings and Electrical Characteristics tables. This enables use in ultra-low-voltage brownout scenarios where the 3.3V rail collapses partially but remains ≥1V, allowing continued reset assertion while preserving system state integrity during graceful shutdown sequences.