Analog Devices Inc. LTC2956CUD-1#PBF

Overview

LTC2956CUD-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 battery-powered systems requiring periodic power cycling. It operates from 1.5V to 36V, delivers 0.8µA quiescent current in sleep mode, supports adjustable wake-up periods from 250ms to 39 days via external resistors, and drives DC/DC converter RUN pins directly-used in portable data loggers performing hourly temperature sampling.

For engineers reviewing the LTC2956CUD-1#PBF datasheet, LTC2956CUD-1#PBF pinout, LTC2956CUD-1#PBF application, or LTC2956CUD-1#PBF equivalent, key selection criteria include its 12-lead 3mm × 3mm QFN package, EN output compatibility with low-voltage regulators (e.g., LT3060), ±25kV HBM ESD rating on PB input, and configurable tONMAX timing via ONMAX capacitor.

Technical Context

The LTC2956CUD-1#PBF implements a dual-stage timing architecture: a digital programmable divider (÷1 to ÷2²²) driven by a 1kHz oscillator sets the wake-up period (tPERIOD), while an analog ramp-based tONMAX timer uses the ONMAX pin's capacitor to define maximum awake duration. Configuration resistors at PERIOD, RANGE, and LONG pins are sampled once every 66 seconds during RUN mode to retain settings without continuous bias current.

Its state machine enforces strict timing guards: tAWAKE_MIN (8ms typical) prevents premature SLEEP transitions after EN activation, and tSLEEP_MIN (128ms typical) blocks input responsiveness during system discharge. The PB input features hardware debounce (32ms typical) with debounced output available on PBOUT, and SHUTDOWN entry requires either a long PB press (>tLONG) or sustained SLEEP high-both triggering OFFALERT for controlled system shutdown.

Key Specifications

Pinout & Package

Package: 12-lead 3mm × 3mm plastic QFN (UD package), exposed pad (Pin 13) connected to GND for thermal and electrical performance. RoHS-compliant, lead-free finish (#PBF).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPL5010IPWR and MAX16054ETA+, the LTC2956CUD-1#PBF uniquely combines 1.5V–36V operation, sub-µA sleep current, capacitor-adjustable tONMAX, and dual-alert outputs-enabling autonomous, maintenance-free operation in harsh, battery-constrained environments without µC intervention.

Availability

LTC2956CUD-1#PBF is available at Aetrix Electronics and suitable for remote environmental sensor nodes, portable medical data loggers, industrial intervalometers, and smart asset trackers requiring stable component supply across multi-year production cycles.

Supply support for LTC2956CUD-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 product lines with full datasheet, simulation model, and application support.

The LTC2956 family was designed specifically for ultra-low-power, wide-input-voltage wake-up control in battery-operated instrumentation-emphasizing configurability, ESD robustness, and deterministic hardware-based power sequencing.

FAQ

What is the operating temperature range for the LTC2956CUD-1#PBF?

The LTC2956CUD-1#PBF is rated for 0°C to 70°C ambient operation, as indicated by the "C" grade suffix in its part number. This commercial-grade temperature range suits indoor portable equipment and protected industrial enclosures. Its thermal design-featuring a 3mm × 3mm QFN with exposed GND pad-maintains junction temperatures within safe limits under typical 0.8µA sleep current conditions across this range.

How does the LTC2956CUD-1#PBF differ from the LTC2956CUD-2#PBF?

The LTC2956CUD-1#PBF features an active-high EN output optimized for driving RUN pins of DC/DC regulators like the LT3060, while the LTC2956CUD-2#PBF provides an active-low EN output capable of directly controlling P-channel MOSFET gates. Both share identical timing, debounce, and alert functionality-but EN polarity and internal pull-up structure differ, making them non-interchangeable without circuit modification.

Can the LTC2956CUD-1#PBF be used without a microcontroller?

Yes-the LTC2956CUD-1#PBF supports fully autonomous operation: tie SLEEP low, configure ONMAX with a capacitor for fixed awake time, and set PERIOD/RANGE resistors for desired wake interval. It will power-cycle connected loads (e.g., sensors, RF modules) without any µC involvement, using ONALERT and OFFALERT only if external notification is needed.

What is the purpose of the exposed pad (Pin 13) on the LTC2956CUD-1#PBF QFN package?

The exposed pad (Pin 13) on the LTC2956CUD-1#PBF is electrically connected to GND and serves dual thermal and electrical functions: it lowers thermal resistance (θJA ≈ 68°C/W) to prevent overheating during extended awake states, and provides low-inductance grounding for internal regulators and comparators-improving noise immunity and timing accuracy in sensitive measurement applications.

How is the wake-up period adjusted on the LTC2956CUD-1#PBF?

The wake-up period on the LTC2956CUD-1#PBF is set using two external resistors: a PERIOD resistor from Pin 5 to GND defines the base timing increment (e.g., 100kΩ = 250ms), and a RANGE resistor from Pin 11 to GND-combined with a fixed 100kΩ resistor to Pin 3 (LONG)-selects a binary scaling factor (×1, ×4, ×16, etc.) to extend the range up to 39 days. No programming or firmware is required.