Analog Devices Inc. LTC2911CDDB-1#TRMPBF

Overview

LTC2911CDDB-1#TRMPBF from Analog Devices (formerly Linear Technology) is a precision triple supply monitor IC with integrated power-fail comparator and latched reset control. It monitors 3.3V (V1), 5V (V2), and an adjustable supply (ADJ) with ±1.5% threshold accuracy over 0°C to 70°C, supports 200ms internal reset timeout, and operates down to 0.5V V_CC. It is used in desktop computers and network servers for reliable power sequencing and early brownout warning.

For engineers reviewing the LTC2911CDDB-1#TRMPBF datasheet, LTC2911CDDB-1#TRMPBF pinout, LTC2911CDDB-1#TRMPBF application, or LTC2911CDDB-1#TRMPBF equivalent, key selection criteria include its fixed 3.3V/5V dual-supply monitoring configuration, DFN-8 (3mm × 2mm) package, PFI-adjustable power-fail threshold, TMR latch capability for margin testing, and guaranteed operation at ultralow 0.5V supply voltage.

Technical Context

The LTC2911CDDB-1#TRMPBF implements three independent voltage comparators: one fixed 3.086V threshold on V1 (3.3V –6.5%), one fixed 4.675V threshold on V2 (5V –6.5%), and one 500mV nominal threshold on ADJ for configurable third-supply monitoring via resistive divider. All comparators feature 1.5% accuracy across temperature and built-in glitch filtering.

Its power-fail function uses the PFI input with 500mV falling-edge / 515mV rising-edge thresholds (3% hysteresis) to drive PFO low for early warning; RST asserts low if any monitored supply falls below its threshold and remains low until all inputs exceed thresholds for ≥200ms (internal timeout). The TMR pin enables latching of RST state or selection between internal 200ms and external capacitor–programmed timeout.

Key Specifications

Pinout & Package

Package: 8-lead (3mm × 2mm) plastic DFN with exposed pad (pin 9, GND). Compact footprint suits space-constrained server and computing applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple-supply monitoring applications.

Compared with MAX6369KA+T and TPS3808G33DBVR, the LTC2911CDDB-1#TRMPBF delivers superior accuracy (±1.5% vs. ±2.5%), integrated power-fail warning with hysteresis, and single-chip triple-monitoring - reducing component count, PCB area, and qualification effort in complex computing and industrial systems.

Availability

LTC2911CDDB-1#TRMPBF is available at Aetrix Electronics and suitable for desktop computers, network servers, and automotive infotainment systems requiring stable component supply, precise multi-rail monitoring, and early power-fail warning capability.

Supply support for LTC2911CDDB-1#TRMPBF 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 LTC2911 family was designed specifically for high-reliability computing and industrial power management, emphasizing precision threshold accuracy, ultralow-voltage operation, and integrated power-fail signaling to simplify system-level power supervision.

FAQ

What is the exact reset threshold voltage for the V1 and V2 pins on the LTC2911CDDB-1#TRMPBF?

The LTC2911CDDB-1#TRMPBF has a guaranteed V1 threshold of 3.086V ±1.5% (3.036V to 3.135V) for 3.3V monitoring and a V2 threshold of 4.675V ±1.5% (4.600V to 4.750V) for 5V monitoring. These values are specified over the full 0°C to 70°C commercial temperature range and reflect the device's fixed -6.5% undervoltage trip points relative to nominal supply rails.

Does the LTC2911CDDB-1#TRMPBF support external reset timeout configuration, or is it fixed at 200ms?

The LTC2911CDDB-1#TRMPBF supports both modes: tying the TMR pin to V1 enables the internal 200ms timeout, while connecting an external capacitor (CTMR) from TMR to GND allows programmable timeout (e.g., 2.2nF yields ~20ms). The datasheet specifies CTMR = tRST × 106.5 pF/ms for design flexibility, and the DFN package supports either configuration without layout change.

How does the power-fail comparator (PFI/PFO) function differ from the main reset comparators in the LTC2911CDDB-1#TRMPBF?

The PFI input on the LTC2911CDDB-1#TRMPBF uses a dedicated comparator with asymmetric thresholds (500mV falling, 515mV rising) and 3% hysteresis to generate early-warning PFO signals, whereas the V1/V2/ADJ comparators use symmetric ±1.5% thresholds for hard reset assertion. This separation allows PFO to trigger well before RST, enabling proactive system response - such as saving state - before supply collapse forces a reset.

Can the LTC2911CDDB-1#TRMPBF operate reliably during power-up when supply voltages are ramping?

Yes. The LTC2911CDDB-1#TRMPBF guarantees valid RST and PFO output states down to 0.5V V_CC, and its proprietary low-voltage drive circuitry ensures clean logic transitions during ramp-up. Its internal V_CC is derived from the higher of V1 or V2, and the 200ms timeout prevents premature release of RST until all monitored rails stabilize - critical for deterministic microprocessor initialization.

What is the purpose of the TMR pin's latch mode, and how is it activated on the LTC2911CDDB-1#TRMPBF?

The TMR pin on the LTC2911CDDB-1#TRMPBF activates latch mode when pulled to GND, freezing the current RST output state (high or low) regardless of subsequent supply conditions. This enables margin testing - e.g., lowering V1 to 3.0V while holding RST asserted - without triggering unintended system reset. Release occurs when TMR is returned to high-impedance or V1, after which RST resumes normal monitoring behavior.