Analog Devices Inc. LTC2909IDDB-2.5#TRMPBF

Overview

LTC2909IDDB-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 8-lead DFN (3mm × 2mm) package. It monitors positive or negative supplies via pin-selectable input polarity and delivers open-drain reset output for power sequencing in embedded computing systems.

For engineers reviewing the LTC2909IDDB-2.5#TRMPBF datasheet, LTC2909IDDB-2.5#TRMPBF pinout, LTC2909IDDB-2.5#TRMPBF application, or LTC2909IDDB-2.5#TRMPBF equivalent, key selection criteria include guaranteed 0.5V ADJ threshold accuracy over –40°C to +85°C, internal 200ms reset timeout, buffered 1V reference for negative-supply offset, 6.5V shunt regulator capability, and SEL/TMR pin configuration flexibility for UV/OV monitoring of mixed-polarity rails.

Technical Context

The LTC2909IDDB-2.5#TRMPBF implements two independent 0.5V-threshold comparators with polarity selectable via three-state SEL pin (VCC/GND/open), enabling simultaneous monitoring of positive UV, positive OV, negative UV, or negative OV conditions on ADJ1 and ADJ2. Its third comparator monitors VCC against a fixed 2.213V UVLO threshold (±1.5%) for 2.5V logic supply validation.

Reset assertion is synchronized across all inputs: ⎯R⎯S⎯T pulls low when any monitored voltage violates its configured condition (e.g., ADJ1 < 0.5V in positive mode or > 0.5V in negative mode), and remains low for a timeout period set by TMR pin state-internally 200ms (TMR = GND), externally programmable (TMR = capacitor to GND), or disabled (TMR = VCC, comparator mode).

Key Specifications

Pinout & Package

Package: 8-lead DFN (3mm × 2mm), exposed pad (Pin 9), RoHS-compliant, moisture-sensitive level 1.

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 LTC2909IDDB-2.5#TRMPBF offers guaranteed operation down to –40°C for harsh environments; compared with TPS3808G33DBVR, it provides full dual-rail configurability, polarity selection, and 1V reference - making it uniquely suited for complex multi-supply systems requiring mixed-polarity fault detection.

Availability

LTC2909IDDB-2.5#TRMPBF is available at Aetrix Electronics and suitable for desktop motherboard power sequencing, notebook core voltage supervision, automotive infotainment supply monitoring, industrial PLC I/O protection, and embedded computing reset management requiring stable component supply across extended temperature ranges.

Supply support for LTC2909IDDB-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, formed through the acquisition of Linear Technology in 2017.

The LTC2909 product line delivers precision, low-power supply monitoring ICs designed for reliable power-up, power-down, and brownout detection in space-constrained, thermally demanding applications across computing, automotive, and industrial markets.

FAQ

What is the operating temperature range for the LTC2909IDDB-2.5#TRMPBF?

The LTC2909IDDB-2.5#TRMPBF is rated for industrial temperature operation from –40°C to +85°C. This specification is guaranteed across all electrical parameters including ADJ input threshold accuracy (±1.5%), VCC UVLO threshold (2.213V ±1.5%), and quiescent current (50μA typical). The DFN package's exposed pad enhances thermal dissipation to maintain reliability within this range.

How does the SEL pin configure input polarity on the LTC2909IDDB-2.5#TRMPBF?

The SEL pin on the LTC2909IDDB-2.5#TRMPBF selects one of three polarity configurations: tied to VCC enables positive polarity on both ADJ1 and ADJ2 (for +UV/+OV detection); tied to GND enables negative polarity on both (for –UV/–OV); left open enables positive on ADJ1 and negative on ADJ2 (for mixed-rail monitoring). Each configuration is validated in the datasheet's Table 1 and requires no external components.

Can the LTC2909IDDB-2.5#TRMPBF monitor a negative supply voltage?

Yes, the LTC2909IDDB-2.5#TRMPBF can monitor negative supplies by configuring the corresponding ADJ input for negative polarity (via SEL pin) and connecting it to a resistor divider between the negative rail and the buffered REF pin (1.000V). For example, monitoring –5V UV uses ADJ1 with SEL = GND and a divider referenced to REF, ensuring the ADJ1 voltage falls below 0.5V when the –5V rail drops too close to ground.

What is the function of the TMR pin on the LTC2909IDDB-2.5#TRMPBF?

The TMR pin on the LTC2909IDDB-2.5#TRMPBF controls reset timeout behavior: grounding TMR enables the internal 200ms timeout; connecting a capacitor to GND sets an external timeout (≈9ms/nF); tying TMR to VCC disables timeout and places the device in comparator mode, where outputs respond immediately without delay. All modes are electrically validated and consume <2μA at TMR.

Does the LTC2909IDDB-2.5#TRMPBF require external components for basic operation?

For basic operation, the LTC2909IDDB-2.5#TRMPBF requires only a 0.1μF bypass capacitor on VCC and an external pull-up resistor on ⎯R⎯S⎯T. No external components are needed for polarity selection (SEL), timeout (TMR = GND), or reference use (REF left open if unused). Resistor dividers on ADJ1/ADJ2 are required only when monitoring custom supply voltages beyond the native 0.5V threshold.