Analog Devices Inc. LTC1326CS8#TRPBF

Overview

LTC1326CS8#TRPBF from Analog Devices (formerly Linear Technology) is a micropower precision triple supply monitor IC designed for systems requiring simultaneous monitoring of 3.3V, 2.5V, and an adjustable supply. 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.

For engineers reviewing the LTC1326CS8#TRPBF datasheet, LTC1326CS8#TRPBF pinout, LTC1326CS8#TRPBF application, or LTC1326CS8#TRPBF equivalent, key selection considerations include its dual-supply override capability (enabling 3.3V-only or 2.5V-only operation), soft-reset pulse width (100µs typ), glitch-immune comparators (13µs response), and compatibility with 8-lead MSOP packaging for space-constrained embedded designs.

Technical Context

The LTC1326CS8#TRPBF integrates three precision voltage comparators with 25mV hysteresis and 13µs typical response time to suppress transients on VCC3, VCC25, 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 even as supplies ramp.

It implements dual-mode push-button reset logic: sub-2-second PBR assertion triggers a 100µs soft reset on SRST (preserving DRAM refresh), while >2-second assertion forces full 200ms hard reset on RST. Both RST and SRST are open-drain with weak internal 6µA pull-ups to VCC3, supporting OR-tied reset buses.

Key Specifications

Pinout & Package

Package: 8-lead plastic MSOP (MS8), 3.0mm × 3.0mm footprint, 0.65mm pitch, 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 LTC2903-2.5, the LTC1326CS8#TRPBF uniquely balances micropower operation (20µA), integrated soft/hard reset modes, and robust 8-lead MSOP packaging - making it optimal for cost-sensitive, battery-powered systems requiring both precision monitoring and user-controllable reset behavior.

Availability

LTC1326CS8#TRPBF is available at Aetrix Electronics and suitable for desktop computers, notebook computers, and portable battery-powered equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LTC1326CS8#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 its precision analog portfolio, including high-reliability power supervision ICs for industrial and computing markets.

The LTC1326 family was designed specifically for multi-rail embedded systems needing accurate, low-power supply monitoring with flexible reset control - targeting applications where reliability, small size, and deterministic timing are critical.

FAQ

What supply voltages does the LTC1326CS8#TRPBF monitor?

The LTC1326CS8#TRPBF monitors three supply rails: VCC3 (3.3V nominal), VCC25 (2.5V nominal), and VCCA (adjustable 1V threshold input). Its internal comparators provide ±0.75% threshold accuracy across all three inputs, with guaranteed reset assertion when any monitored supply drops below its trip point - making the LTC1326CS8#TRPBF ideal for systems with mixed-voltage domains like modern SoCs and FPGAs.

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

The LTC1326CS8#TRPBF implements dual-mode push-button reset: pressing PBR for less than 2 seconds generates a 100µs soft reset pulse on SRST (preserving DRAM refresh), while holding PBR for more than 2 seconds triggers a full 200ms hard reset on RST. The PBR pin features 7µA internal pull-up and 20ms debounce - ensuring reliable operation with mechanical switches. This behavior is intrinsic to the LTC1326CS8#TRPBF's internal timer and logic architecture.

Can the LTC1326CS8#TRPBF be used with only one or two supply rails?

Yes - the LTC1326CS8#TRPBF supports flexible configuration: VCC25 and VCCA inputs can be disabled by tying them to VCC3, allowing use as a single 3.3V monitor or dual 3.3V/adjustable monitor. The LTC1326CS8#TRPBF's override circuitry automatically disables VCC25 when its voltage matches VCC3 within ±25mV, eliminating need for external logic. This adaptability makes the LTC1326CS8#TRPBF suitable for evolving board designs without component changes.

What is the minimum operating voltage for reset assertion on the LTC1326CS8#TRPBF?

The LTC1326CS8#TRPBF guarantees correct RST logic state (low) for VCC3 ≥ 1V or VCC25 ≥ 1V - meaning it remains functional and asserts reset even during deep brownout conditions where supplies dip near 1V. This specification is verified across the commercial temperature range (0°C to 70°C) and is critical for maintaining system integrity in battery-powered applications where voltage sag is common. The LTC1326CS8#TRPBF achieves this via its dual-supply gate-drive architecture.

Does the LTC1326CS8#TRPBF require external components for basic operation?

Yes - the LTC1326CS8#TRPBF requires a minimum 0.1µF ceramic bypass capacitor from VCC3 to GND for stable operation. External pull-up resistors (e.g., 4.7kΩ) on RST and SRST are recommended for faster rise times, though internal 6µA pull-ups to VCC3 provide baseline functionality. No external timing components are needed, as the 200ms reset delay and 100µs soft reset are internally generated - simplifying BOM and layout for the LTC1326CS8#TRPBF.