Analog Devices Inc. LTC2909IDDB-3.3#TRPBF

Overview

LTC2909IDDB-3.3#TRPBF from Analog Devices (acquired Linear Technology) is a precision dual-input UV/OV window monitor with fixed 3.3V VCC UVLO, ±1.5% threshold accuracy, 50μA quiescent current, and selectable 200ms internal reset timeout - used for reliable power-up/power-down supervision in core voltage rails of embedded computing and industrial control systems.

For engineers reviewing the LTC2909IDDB-3.3#TRPBF datasheet, LTC2909IDDB-3.3#TRPBF pinout, LTC2909IDDB-3.3#TRPBF application, or LTC2909IDDB-3.3#TRPBF equivalent, key selection criteria include input polarity configuration via SEL pin, glitch-immune dual-comparator architecture, buffered 1V reference for negative-supply offset, 0.5V adjustable threshold tolerance, and DFN-8 package compatibility with space-constrained PCB layouts.

Technical Context

The LTC2909IDDB-3.3#TRPBF integrates two independent 0.5V-threshold comparators with pin-selectable polarity (SEL = VCC/GND/OPEN), enabling simultaneous monitoring of positive UV/OV, negative UV/OV, or mixed-polarity supplies. Its third fixed UVLO channel monitors VCC at 2.921V (−10% of 3.3V) with ±1.5% accuracy over −40°C to +85°C.

Reset assertion is synchronized across all inputs: ⎯R⎯S⎯T pulls low when any monitored supply violates its configured threshold, and remains low for a guaranteed 150–260ms timeout after all inputs return valid. The buffered 1V reference (±15mV accuracy, ±1mA drive) supports resistor-divider-based trip-point setting for negative supplies without external op-amps.

Key Specifications

Pinout & Package

Package: 8-lead 3mm × 2mm plastic DFN (DDB) with exposed thermal pad (Pin 9), rated for −40°C to +85°C operation and 76°C/W junction-to-ambient thermal resistance when pad is connected to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2909CDDB-3.3#TRPBF, the LTC2909IDDB-3.3#TRPBF provides guaranteed operation down to −40°C for harsh environments, while MAX6316US33D3+T offers lower cost and smaller footprint but sacrifices dual-input flexibility and negative-supply support essential for complex power architectures.

Availability

LTC2909IDDB-3.3#TRPBF is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, and automotive body electronics requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LTC2909IDDB-3.3#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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC2909IDDB-3.3#TRPBF belongs to ADI's Linear Technology legacy precision power monitoring product line, engineered specifically for high-accuracy, low-power, multi-rail supervision in space- and energy-constrained embedded systems.

FAQ

What is the guaranteed minimum VCC voltage for reset assertion in LTC2909IDDB-3.3#TRPBF?

The LTC2909IDDB-3.3#TRPBF guarantees ⎯R⎯S⎯T remains asserted low down to VCC = 0.5V, ensuring reliable reset signaling even during severe brownout conditions. This ultralow-voltage operation is validated across the full −40°C to +85°C temperature range and enables safe shutdown sequencing before logic corruption occurs. The part maintains this specification without requiring external support components.

How does the SEL pin configure input polarity for LTC2909IDDB-3.3#TRPBF?

The SEL pin on LTC2909IDDB-3.3#TRPBF selects one of three polarity modes: tied to VCC sets both ADJ1 and ADJ2 for positive-supply UV/OV monitoring; tied to GND configures both for negative-supply UV/OV; left open (high-impedance) enables mixed polarity (ADJ1 positive, ADJ2 negative). Each mode uses the same 0.5V internal threshold but interprets voltage violations differently - e.g., ADJ2 < 0.5V triggers reset in negative mode, while ADJ2 > 0.5V does so in positive mode.

Can LTC2909IDDB-3.3#TRPBF monitor a single supply for both undervoltage and overvoltage conditions?

Yes, LTC2909IDDB-3.3#TRPBF can monitor one supply for UV and OV using three external resistors and the REF pin. For a positive supply like 5V, connect ADJ1 and ADJ2 through separate dividers to set distinct trip points (e.g., 4.425V for UV, 5.575V for OV). For negative supplies like −5V, use REF as the upper reference point. This eliminates the need for two separate supervisors and reduces PCB area and BOM cost.

What is the function of the TMR pin in LTC2909IDDB-3.3#TRPBF, and what are its valid states?

The TMR pin on LTC2909IDDB-3.3#TRPBF controls reset timeout behavior: grounded enables the internal 200ms timeout; connected to VCC disables timeout and places the device in comparator mode (instantaneous reset assertion); connected to a capacitor-to-GND sets programmable timeout (≈9ms/nF). Leakage current is ±2.7μA, and transition currents up to 100μA may occur during state changes - ensure driving circuitry meets these requirements.

Does LTC2909IDDB-3.3#TRPBF require external bypass capacitors, and if so, where?

LTC2909IDDB-3.3#TRPBF requires a minimum 0.1μF ceramic capacitor between VCC and GND, placed as close as possible to the pins to suppress supply noise and ensure stable internal regulation. No bypass capacitor is needed or recommended on the REF pin - its buffered output is designed for direct connection to resistor dividers. The ADJ inputs do not require bypassing, as internal glitch filtering handles transient rejection.