Analog Devices Inc. LTC2951ITS8-1#TRPBF

Overview

LTC2951ITS8-1#TRPBF from Analog Devices (formerly Linear Technology) is a micropower pushbutton ON/OFF controller with open-drain high-true enable output, operating across 2.7V to 26.4V input voltage range and consuming only 6µA typical quiescent current. It provides 128ms fixed turn-on debounce, adjustable KILL timeout for fault-safe power-down, and supports µP handshaking via INT/KILL signals in portable instrumentation and blade server power management.

For engineers reviewing the LTC2951ITS8-1#TRPBF datasheet, LTC2951ITS8-1#TRPBF pinout, LTC2951ITS8-1#TRPBF application, or LTC2951ITS8-1#TRPBF equivalent, key selection criteria include EN polarity (high-true), –40°C to 85°C industrial temperature grade, TSOT-23-8 package compatibility, and configurable KILLT/OFFT timing capacitors for system-level power sequencing control.

Technical Context

The LTC2951ITS8-1#TRPBF implements a dual-stage power sequencing architecture: a 128ms fixed turn-on debounce timer followed by a 512ms KILL blanking window during which the µP must assert KILL high to prevent automatic shutdown. Its KILL comparator features a precise 0.6V threshold with 30mV hysteresis, enabling accurate undervoltage monitoring of VIN or other rails.

Turn-off sequencing combines a 32ms internal debounce (tDB,OFF) extended by external OFFT capacitor, plus a 128ms default KILL turn-off delay (tKILL,OFF DELAY) further adjustable via KILLT capacitor - both timers operate independently and support fail-safe DC/DC converter shutdown when µP fails to respond.

Key Specifications

Pinout & Package

Package: 8-Lead Plastic TSOT-23 (TS8), 2.90mm × 1.60mm footprint, exposed pad optional for thermal relief.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3808G33DBVR and MAX16050ATA+, the LTC2951ITS8-1#TRPBF uniquely integrates pushbutton debounce, µP handshake (INT/KILL), and field-adjustable timing into a single TSOT-23 package - enabling complete, fault-tolerant power sequencing without external logic or firmware overhead.

Availability

LTC2951ITS8-1#TRPBF is available at Aetrix Electronics and suitable for portable instrumentation meters, blade servers, and industrial PDAs requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LTC2951ITS8-1#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 LTC2951 series.

The LTC2951 product line was designed specifically for robust, low-power pushbutton-initiated power sequencing in battery-powered and industrial systems - emphasizing timing precision, high-voltage tolerance, and fail-safe µP coordination.

FAQ

What is the EN output polarity of LTC2951ITS8-1#TRPBF?

The LTC2951ITS8-1#TRPBF features a high-true EN output: EN goes high after a valid pushbutton turn-on event and releases low during power-down. This distinguishes it from the LTC2951-2 variant, which provides low-true EN. The part number suffix "-1" explicitly denotes this polarity, critical for correct interfacing with DC/DC converter shutdown inputs.

Does LTC2951ITS8-1#TRPBF require external pull-up resistors on PB or EN pins?

No external pull-up is required on the PB pin due to its internal 100kΩ pull-up to 1.9V bias. For the EN pin, an external pull-up is only needed if the connected DC/DC converter lacks an internal pull-up on its SHDN pin; otherwise, EN interfaces directly. The LTC2951ITS8-1#TRPBF datasheet confirms both configurations are supported without added components.

How does the KILL blanking timer function during power-on of LTC2951ITS8-1#TRPBF?

After EN asserts high, the LTC2951ITS8-1#TRPBF initiates a 512ms KILL blanking period (tKILL,ON BLANK) during which the KILL input is ignored. This ensures the µP has sufficient time to initialize before being required to drive KILL high. If KILL remains low past 512ms, EN is automatically released - a safety mechanism preventing incomplete power-up states in the LTC2951ITS8-1#TRPBF.

Can LTC2951ITS8-1#TRPBF be used without a microprocessor?

Yes - the LTC2951ITS8-1#TRPBF supports standalone operation. The KILL pin can be tied to a resistor divider monitoring VIN for automatic undervoltage shutdown, or pulled low via RC network for fixed-delay power-off. Figures 5 and 6 in the official datasheet demonstrate these configurations, confirming the LTC2951ITS8-1#TRPBF functions fully without µP intervention.

What is the maximum allowable capacitor value on the KILLT pin of LTC2951ITS8-1#TRPBF?

The LTC2951ITS8-1#TRPBF datasheet specifies no hard upper limit, but practical values range up to 100nF. Using CKILLT = 1500pF yields +11.5ms additional delay; scaling linearly, 100nF provides ~770ms extra timeout. Larger capacitors increase leakage sensitivity and PCB area - the recommended range is 100pF to 10nF for optimal stability and layout efficiency in the LTC2951ITS8-1#TRPBF.