Analog Devices Inc. LTC2956CMS-1#PBF

Overview

LTC2956CMS-1#PBF from Analog Devices (formerly Linear Technology) is a micropower wake-up timer IC with pushbutton control and active-high enable output, designed for periodic power cycling of battery-powered systems. It operates from 1.5V to 36V, delivers 0.8µA quiescent current in awake state and 0.3µA in shutdown, and supports configurable wake-up periods from 250ms to 39 days - enabling use in remote sensor nodes performing temperature monitoring or image capture.

For engineers reviewing the LTC2956CMS-1#PBF datasheet, LTC2956CMS-1#PBF pinout, LTC2956CMS-1#PBF application, or LTC2956CMS-1#PBF equivalent, key selection criteria include its MSOP-12 package, -1 variant's low-leakage EN output for direct DC/DC converter control, adjustable ONMAX timing capacitor interface, and ±25kV HBM ESD protection on PB input.

Technical Context

The LTC2956CMS-1#PBF implements a dual-timer architecture: a digitally controlled wake-up period timer (250ms–39 days) set via PERIOD and RANGE resistors, and an analog-digital hybrid maximum awake timer (tONMAX) set by an external capacitor on ONMAX. Its internal 2kHz oscillator feeds a programmable divider (÷1 to ÷2²²) for precise long-interval timing.

It features three status outputs (ONALERT, OFFALERT, PBOUT), debounced pushbutton logic with 32ms typical debounce time, and configurable power-up mode (RUN or SHUTDOWN) determined by the LONG pin voltage divider. The -1 variant provides an active-high EN output with 900kΩ internal pull-up and 0.4V max VOL at 1mA, optimized for driving regulator RUN pins.

Key Specifications

Pinout & Package

Package: 12-Lead Plastic MSOP (3mm × 4.4mm), exposed pad not connected (non-thermal).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar wake-up timer applications.

Compared with LTC2956CMS-2#PBF, the LTC2956CMS-1#PBF offers lower EN output leakage and simpler regulator interface, while TPS3897A33DBVR lacks wake-up functionality entirely - making LTC2956CMS-1#PBF the sole option for battery-efficient periodic task execution.

Availability

LTC2956CMS-1#PBF is available at Aetrix Electronics and suitable for remote environmental sensing, portable medical data logging, and industrial predictive maintenance applications requiring stable component supply across multi-year production cycles.

Supply support for LTC2956CMS-1#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 acquired Linear Technology in 2017 and maintains its precision analog and power management portfolio with rigorous automotive and industrial qualification standards.

The LTC2956 product line delivers ultra-low-power, resistor/capacitor-configurable wake-up timers for battery-critical applications - emphasizing long-term reliability, wide input voltage tolerance, and hardware-based timing autonomy.

FAQ

What is the function of the ONMAX pin on the LTC2956CMS-1#PBF?

The ONMAX pin on the LTC2956CMS-1#PBF accepts an external capacitor to set the maximum allowed awake time (tONMAX) at 13.3ms per nanofarad. When the capacitor is connected to GND, the LTC2956CMS-1#PBF enforces this upper bound on system-on duration - preventing excessive battery drain if firmware hangs. If left floating, tONMAX defaults to 8ms; tying it to GND disables the timer entirely.

How does the LTC2956CMS-1#PBF differ from the LTC2956CMS-2#PBF?

The LTC2956CMS-1#PBF features an active-high EN output optimized for driving DC/DC converter RUN pins, while the LTC2956CMS-2#PBF provides an active-low EN output capable of directly controlling a P-channel MOSFET gate. Both share identical timing, debounce, and alert functions, but their EN polarity and drive characteristics target different power architecture topologies - making them non-interchangeable without board-level redesign.

Can the LTC2956CMS-1#PBF be used with a 1.8V supply?

Yes, the LTC2956CMS-1#PBF operates down to 1.5V, so it functions reliably at 1.8V. All specifications - including 0.8µA quiescent current, 0.9V PB threshold, and 0.4V EN VOL - are guaranteed over the full 1.5V–36V range. No derating or external biasing is required at 1.8V, making it suitable for single-cell LiFePO₄ or alkaline-powered designs.

What is the purpose of the OFFALERT pin on the LTC2956CMS-1#PBF?

The OFFALERT pin on the LTC2956CMS-1#PBF is an open-drain output pulled low for exactly 1 second (tOFF) whenever the device transitions from RUN mode to SHUTDOWN mode. This provides a hardware-level warning that system power will be removed shortly - allowing the MCU to complete flash writes, save registers, or trigger safe state entry before EN goes inactive.

How is the wake-up period configured on the LTC2956CMS-1#PBF?

The wake-up period on the LTC2956CMS-1#PBF is set using two external resistors: one from PERIOD to GND (RPERIOD = 32.4kΩ–324kΩ) and another from RANGE to GND (RRANGE), with a fixed 100kΩ resistor between RANGE and LONG. This resistor network selects both the base timing interval and its decade-scale multiplier - enabling precise adjustment from 250ms to 39 days without firmware or crystal dependencies.