Analog Devices Inc. LTC1326CS8-2.5#TRPBF

Overview

LTC1326CS8-2.5#TRPBF from Analog Devices (formerly Linear Technology) is a micropower triple supply monitor IC designed for systems requiring simultaneous supervision of 2.5V, 3.3V, and an adjustable supply (VCCA). It delivers ±0.75% threshold accuracy, 20µA typical supply current, and guaranteed reset assertion down to VCC25 ≥ 1V or VCC3 ≥ 1V - enabling reliable power-on reset in portable battery-powered equipment and notebook computers.

For engineers reviewing the LTC1326CS8-2.5#TRPBF datasheet, LTC1326CS8-2.5#TRPBF pinout, LTC1326CS8-2.5#TRPBF application, or LTC1326CS8-2.5#TRPBF equivalent, key selection criteria include its dual-mode push-button reset (100µs soft pulse or 200ms hard reset), open-drain RST/SRST outputs with VCC3-referenced weak pull-ups, and glitch-immune triple-supply monitoring architecture with 13µs comparator response time.

Technical Context

The LTC1326CS8-2.5#TRPBF integrates three precision voltage comparators (VRT25 = 2.363V typ, VRT3 = 3.118V typ, VRTA = 1.000V typ) with independent 200ms reset timers and internal power-detect gate drive logic that selects between VCC25 and VCC3 to ensure RST remains valid down to 1V on either rail. Its PBR input features 20ms debounce and dual-mode timing: <2s assertion triggers SRST (100µs pulse), while >2s forces RST low for 200ms post-release.

Reset generation is fully synchronized across all monitored supplies: RST releases only after all thresholds are exceeded for 200ms, and reasserts within 13µs of any supply dropping below its trip point. The device operates over 0°C to 70°C (C-grade), supports OR-tied reset sources via open-drain outputs, and maintains output low-voltage compliance (VOL ≤ 0.4V @ 100µA) even when VCC3 or VCC25 drops to 1.1V.

Key Specifications

Pinout & Package

8-lead plastic SO (Small Outline) package, 0.150-inch body width, RoHS-compliant lead-free finish (#TRPBF).

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 LTC1727-2.5, the LTC1326CS8-2.5#TRPBF offers the lowest quiescent current (20µA vs 35µA/25µA) and tightest threshold accuracy (±0.75% vs ±1.5%), making it ideal for battery-constrained applications where deterministic, low-power reset timing is prioritized over watchdog or per-rail flexibility.

Availability

LTC1326CS8-2.5#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 consistent parametric performance.

Supply support for LTC1326CS8-2.5#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 LTC1326 family.

The LTC1326 series was designed specifically for micropower, high-accuracy triple-supply monitoring in space-constrained portable and computing systems - emphasizing ultra-low quiescent current, guaranteed reset validity at sub-2V supplies, and integrated push-button reset functionality.

FAQ

What is the function of the VCCA pin on the LTC1326CS8-2.5#TRPBF?

The VCCA pin on the LTC1326CS8-2.5#TRPBF is a high-impedance adjustable supply monitor input with a precise 1.000V threshold (±0.75%). It enables supervision of logic rails, DC/DC converter feedback nodes, or other low-voltage domains. When unused, VCCA may be tied directly to VCC3 or VCC25 without affecting operation - the LTC1326CS8-2.5#TRPBF continues to monitor VCC25 and VCC3 independently.

Does the LTC1326CS8-2.5#TRPBF support operation with only two supply rails?

Yes, the LTC1326CS8-2.5#TRPBF supports dual-rail operation. For example, tying VCC25 to VCC3 disables the 2.5V monitor while retaining 3.3V and VCCA supervision. Similarly, leaving VCCA unconnected (or tying it to VCC3) configures the LTC1326CS8-2.5#TRPBF as a dual-supply monitor for VCC25 and VCC3. No external components are required to enable this flexibility.

How does the push-button reset feature work on the LTC1326CS8-2.5#TRPBF?

The LTC1326CS8-2.5#TRPBF implements dual-mode push-button reset: pressing PBR for <2 seconds generates a 100µs soft reset pulse on SRST, while holding PBR >2 seconds asserts RST for 200ms after release. Internal 20ms debounce prevents false triggering from switch bounce. Both modes operate independently of supply status - the LTC1326CS8-2.5#TRPBF guarantees correct reset polarity even during brownout.

What is the minimum supply voltage required for the LTC1326CS8-2.5#TRPBF to assert a valid reset signal?

The LTC1326CS8-2.5#TRPBF guarantees correct RST logic state (low) for VCC25 ≥ 1V or VCC3 ≥ 1V. This means reset assertion remains valid even as either monitored supply collapses toward 1V - a critical capability for detecting brownout conditions before complete power failure. Output low voltage is specified at VOL ≤ 0.4V with 100µA sink current under these conditions.

Can the RST and SRST outputs of the LTC1326CS8-2.5#TRPBF be connected together?

Yes, the RST and SRST outputs of the LTC1326CS8-2.5#TRPBF can be safely OR-tied due to their open-drain architecture and shared VCC3-referenced weak pull-up (6µA). This configuration allows a single reset net to respond to both supply faults (via RST) and user-initiated soft resets (via SRST). External pull-up resistors may be added to achieve faster rise times if required by the target logic family.