Analog Devices Inc. LTC2909CDDB-2.5#TRMPBF

Overview

LTC2909CDDB-2.5#TRMPBF from Analog Devices (acquired Linear Technology) is a precision dual adjustable-input undervoltage/overvoltage monitor with fixed 2.5V VCC UVLO, ±1.5% threshold accuracy, 50μA quiescent current, and 200ms internal reset timeout - used in desktop/notebook power sequencing and core I/O supply monitoring.

For engineers reviewing the LTC2909CDDB-2.5#TRMPBF datasheet, LTC2909CDDB-2.5#TRMPBF pinout, LTC2909CDDB-2.5#TRMPBF application, or LTC2909CDDB-2.5#TRMPBF equivalent, key selection criteria include input polarity configurability via SEL pin, buffered 1V reference for negative-supply offset, guaranteed 0.5V ADJ threshold tolerance over temperature, and ultralow 0.5V VCC operation for brownout detection.

Technical Context

The LTC2909CDDB-2.5#TRMPBF implements dual independent comparators with 0.5V nominal trip thresholds, each configurable for positive-polarity UV/(–)OV or negative-polarity (–)UV/+OV monitoring via three-state SEL pin logic. Its VCC UVLO is fixed at 2.213V (11.5% below 2.5V) with ±1.5% accuracy across 0°C to 70°C.

Reset assertion uses glitch-filtered comparator outputs feeding a programmable timeout block - selectable as internal 200ms, external capacitor-timed (9ms/nF), or disabled (comparator mode). The open-drain ⎯R⎯S⎯T output guarantees logic-low down to VCC = 0.5V with VOL ≤ 0.15V at 2500μA sink current.

Key Specifications

Pinout & Package

Package: 8-lead 3mm × 2mm DFN (DDB), exposed pad (Pin 9) optional ground connection for thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2909CDDB-2.5#TRMPBF, the -3.3 variant maintains full feature parity but shifts UVLO to 3.3V systems, while TPS3808G33DBVR sacrifices polarity flexibility and negative-rail support for lower unit cost and smaller footprint - making it viable only in simplified positive-only monitoring scenarios.

Availability

LTC2909CDDB-2.5#TRMPBF is available at Aetrix Electronics and suitable for desktop motherboard power sequencing, notebook core voltage validation, and network server I/O supply watchdog applications requiring stable component supply and long-term industrial lifecycle support.

Supply support for LTC2909CDDB-2.5#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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC2909 product line delivers precision, low-power supply monitoring ICs optimized for multi-rail computing and embedded systems - designed to replace discrete supervisory circuits with integrated UV/OV detection, polarity flexibility, and robust glitch immunity.

FAQ

What is the guaranteed minimum operating VCC for LTC2909CDDB-2.5#TRMPBF?

The LTC2909CDDB-2.5#TRMPBF guarantees functional reset assertion down to VCC = 0.5V, with ⎯R⎯S⎯T output voltage low (VOL) ≤ 0.15V at 2500μA sink current. This ultralow-voltage operation ensures deterministic brownout response in systems with unregulated or weakly regulated supplies. The specification is validated across the full 0°C to 70°C operating temperature range and applies to the LTC2909CDDB-2.5#TRMPBF part specifically.

How does the SEL pin configure input polarity on LTC2909CDDB-2.5#TRMPBF?

On the LTC2909CDDB-2.5#TRMPBF, the SEL pin selects ADJ1/ADJ2 polarity via three states: SEL = VCC sets both inputs to positive polarity (UV detection for positive rails), SEL = GND sets both to negative polarity (UV detection for negative rails), and SEL = open enables mixed polarity (ADJ1 positive, ADJ2 negative). This configuration requires no external components and is validated per Table 1 in the official datasheet for the LTC2909CDDB-2.5#TRMPBF.

Can LTC2909CDDB-2.5#TRMPBF monitor a single supply for both UV and OV conditions?

Yes, the LTC2909CDDB-2.5#TRMPBF can monitor one supply for both UV and OV using three external resistors (RP4/RP5/RP6 for positive rails or RN4/RN5/RN6 for negative rails), as shown in Figures 3 and 4 of the datasheet. This configuration leverages ADJ1 and ADJ2 with shared resistor network to detect upper and lower thresholds simultaneously - a capability confirmed for the LTC2909CDDB-2.5#TRMPBF in Application Information section.

What is the accuracy of the buffered REF output on LTC2909CDDB-2.5#TRMPBF?

The buffered REF output on LTC2909CDDB-2.5#TRMPBF is specified as 1.000V ±15mV (±1.5%) over the full 0°C to 70°C temperature range, with ±1mA sourcing/sinking capability. It requires no bypass capacitor and drives capacitive loads up to 1000pF without stability issues - a design value explicitly documented for the LTC2909CDDB-2.5#TRMPBF in Electrical Characteristics Table.

Does LTC2909CDDB-2.5#TRMPBF support external capacitor-based reset timeout?

Yes, the LTC2909CDDB-2.5#TRMPBF supports external capacitor-based timeout by connecting CTMR from TMR (Pin 7) to GND, yielding tRST = 9ms/nF (e.g., 2.2nF → 20ms). This mode is fully characterized and validated for the LTC2909CDDB-2.5#TRMPBF, with timing accuracy dependent on ceramic capacitor leakage and layout parasitics - distinct from its default 200ms internal timeout (TMR = GND).