Analog Devices Inc. LTC2955IDDB-2#TRPBF

Overview

LTC2955IDDB-2#TRPBF from Analog Devices (formerly Linear Technology) is a micropower pushbutton on/off controller with automatic turn-on capability and active-low enable output, designed to manage system power sequencing in battery-powered embedded systems. It operates across 1.5V–36V supply range, features ±36V robust PB input tolerance, 1.2µA quiescent current, and drives external P-channel MOSFETs via its high-voltage EN output. Used in portable GPS devices for controlled power-up/down triggered by button press or supply presence.

For engineers reviewing the LTC2955IDDB-2#TRPBF datasheet, LTC2955IDDB-2#TRPBF pinout, LTC2955IDDB-2#TRPBF application, or LTC2955IDDB-2#TRPBF equivalent, key selection criteria include its -2 variant's active-low EN polarity, DFN-10 package compatibility, -40°C to +85°C industrial temperature rating, and configurable forced turn-off timing via TMR capacitor.

Technical Context

The LTC2955IDDB-2#TRPBF implements a dual-input power control architecture: debounced pushbutton (PB) and voltage monitor (ON) inputs feed into logic that generates clean enable transitions while enforcing blanking periods (512ms turn-on, 1s lockout) to ensure regulator and µP stability. Its internal LDO powers internal circuitry and provides bias for the 900kΩ pull-up on EN.

Unlike the -1 variant, the -2 version uses EN as an active-low output: pulled low by an N-channel MOSFET during enable assertion, and pulled high to VIN through a 900kΩ resistor during disable - enabling direct gate drive of external P-channel MOSFETs without level-shifting. The DFN-10 package includes SEL and PGD pins for ON-edge mode selection and ON-status indication, unavailable in TSOT-8 variants.

Key Specifications

Pinout & Package

Package: 10-Lead (3mm × 2mm) Plastic DFN with exposed pad (optional GND connection). Pinout validated per Linear Technology LTC2955 Datasheet Rev. FA, Figure "Pin Configuration".

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar pushbutton power control applications.

Compared with LTC2955IDDB-1#TRPBF, the LTC2955IDDB-2#TRPBF provides native P-MOSFET gate drive without external components, while TPS3808G33DBVR offers lower cost and smaller footprint but omits all pushbutton, interrupt, and auto-turn-on functionality essential for user-interactive systems.

Availability

LTC2955IDDB-2#TRPBF is available at Aetrix Electronics and suitable for portable instrumentation, automotive telematics, industrial data loggers, and GPS navigation devices requiring stable component supply across extended temperature ranges and robust ESD immunity.

Supply support for LTC2955IDDB-2#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LTC2955 product line delivers micropower pushbutton controllers with integrated voltage monitoring and interrupt signaling, engineered for reliable power sequencing in battery-constrained and electrically harsh environments.

FAQ

What is the key functional difference between LTC2955IDDB-2#TRPBF and LTC2955IDDB-1#TRPBF?

The LTC2955IDDB-2#TRPBF features an active-low EN output pulled high to VIN via an internal 900kΩ resistor, enabling direct gate drive of external P-channel MOSFETs. In contrast, the LTC2955IDDB-1#TRPBF provides an active-high EN output pulled up by a 2µA current source to ~4.3V, optimized for controlling the SHUTDOWN pin of standard DC/DC converters. This polarity difference dictates the external power-switching topology and eliminates need for level-shifting circuitry in the -2 variant.

How does the TMR pin configure forced turn-off timing in LTC2955IDDB-2#TRPBF?

The TMR pin on LTC2955IDDB-2#TRPBF accepts an external capacitor to ground, setting the additional delay beyond the base 64ms turn-off debounce window. Using CTMR = 0.19 × tTMR (µF/sec), a 0.178µF capacitor yields ~1s total forced turn-off time. If left open, TMR defaults to 64ms; if grounded, forced turn-off is disabled. This allows precise fail-safe shutdown timing when the µP fails to respond to the INT signal.

Can LTC2955IDDB-2#TRPBF automatically turn off the system when the monitored supply drops?

Yes - but only in the DFN-10 package with SEL tied to VIN. When the preceding turn-on was initiated by the ON pin rising edge, a falling edge on ON (indicating supply removal) triggers immediate INT assertion and, if KILL is not asserted, initiates the TMR-based forced turn-off. This behavior is unavailable in TSOT-8 packages and disabled if SEL = GND, making ON-falling-edge response conditional on both hardware configuration and prior event history.

What is the purpose of the PGD pin on LTC2955IDDB-2#TRPBF?

The PGD (Power Good) pin on LTC2955IDDB-2#TRPBF outputs a high signal when the voltage at the ON pin exceeds 0.8V. This allows the system µP to determine whether the current power-on event was triggered by external supply presence (ON pin high) or user button press (PB low), enabling differentiated firmware responses - such as skipping boot diagnostics on supply restoration but requiring full initialization on manual activation.

Does LTC2955IDDB-2#TRPBF require external components for basic pushbutton operation?

No - LTC2955IDDB-2#TRPBF integrates internal pull-up on PB (to ~5.2V LDO), debouncing logic, and EN drive circuitry. Only three external components are mandatory for minimal operation: a 10nF bypass capacitor on VIN, a pull-up resistor on INT (e.g., 10kΩ to system VCC), and optionally a capacitor on TMR for forced turn-off timing. No external resistors are needed for PB, ON, KILL, or EN interfaces in standard configurations.