Analog Devices Inc. LTC2909ITS8-3.3#TRPBF

Overview

LTC2909ITS8-3.3#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 200ms internal reset timeout - designed for core voltage supervision in industrial embedded systems and network infrastructure where reliable power sequencing and brownout detection are critical.

For engineers reviewing the LTC2909ITS8-3.3#TRPBF datasheet, LTC2909ITS8-3.3#TRPBF pinout, LTC2909ITS8-3.3#TRPBF application, or LTC2909ITS8-3.3#TRPBF equivalent, key selection factors include its triple-monitor capability (two adjustable + one fixed VCC), polarity-selectable inputs via SEL pin, buffered 1V reference for negative-supply offset, open-drain RST output with ultralow 0.5V VCC operation guarantee, and TSOT-23-8 package compatibility with space-constrained PCB layouts.

Technical Context

The LTC2909ITS8-3.3#TRPBF implements two independent 0.5V nominal threshold comparators with pin-selectable input polarity (positive UV/–OV or negative –UV/+OV), enabling flexible monitoring of positive, negative, or mixed-rail supplies. Its third fixed-threshold UVLO on VCC is factory-trimmed to 2.921V (±1.5%) for 3.3V logic systems.

Reset assertion is synchronized across all three monitors: RST remains low until VCC exceeds its UVLO threshold, both ADJ inputs are valid per SEL configuration, and the 200ms internal timeout expires. Glitch filtering on ADJ inputs and propagation delay ≤500μs ensure immunity to transient noise without sacrificing threshold precision.

Key Specifications

Pinout & Package

Package: 8-lead TSOT-23 (3mm × 1.75mm), RoHS-compliant, lead-free #TRPBF tape-and-reel.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-input voltage supervisor applications.

Compared with MAX6816EUT+T and TPS3808G33DBVR, the LTC2909ITS8-3.3#TRPBF uniquely delivers triple-monitoring (dual adjustable + fixed VCC), polarity-selectable inputs, and buffered REF in a single TSOT-23-8 package - enabling compact, high-accuracy supervision of complex multi-rail systems without external components.

Availability

LTC2909ITS8-3.3#TRPBF is available at Aetrix Electronics and suitable for industrial PLCs, network servers, automotive infotainment systems, medical imaging devices, and test equipment requiring stable component supply with guaranteed long-term availability.

Supply support for LTC2909ITS8-3.3#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, acquired Linear Technology in 2017 to expand precision power management solutions.

The LTC2909 product line was developed by Linear Technology specifically for high-accuracy, low-power multi-rail voltage supervision in space-constrained embedded systems - emphasizing threshold precision, glitch immunity, and flexible polarity configuration without external components.

FAQ

What is the guaranteed minimum VCC voltage at which LTC2909ITS8-3.3#TRPBF asserts RST?

The LTC2909ITS8-3.3#TRPBF guarantees RST assertion down to VCC = 0.5V, with VOL ≤0.15V at VCC = 3V and 2.5mA sink current. This ultralow-voltage operation ensures reliable reset signaling during deep brownout conditions before the host system loses functional integrity. The device maintains comparator functionality and threshold accuracy throughout this range, validated across –40°C to +85°C.

How does the SEL pin configure input polarity for LTC2909ITS8-3.3#TRPBF, and what are the valid states?

The SEL pin on LTC2909ITS8-3.3#TRPBF accepts three states: connected to VCC (both ADJ1/ADJ2 positive polarity), connected to GND (both negative polarity), or left open (mixed polarity - ADJ1 positive, ADJ2 negative). Each state sets distinct UV/OV detection behavior without external components. Leakage current is limited to ±10μA in open state, and VIH/VIL thresholds are 1.4V/0.4V respectively, ensuring robust noise immunity in industrial environments.

Can LTC2909ITS8-3.3#TRPBF monitor a single supply for both undervoltage and overvoltage conditions?

Yes, LTC2909ITS8-3.3#TRPBF can monitor one supply for UV and OV using three external resistors - RP4, RP5, RP6 for positive supplies or RN4, RN5, RN6 for negative supplies - as shown in Figures 3 and 4 of the datasheet. This configuration uses ADJ1 and ADJ2 simultaneously with shared divider nodes, enabling window monitoring without additional ICs. Accuracy remains ±1.5% for both thresholds across temperature.

What is the function of the REF pin on LTC2909ITS8-3.3#TRPBF, and what load can it drive?

The REF pin on LTC2909ITS8-3.3#TRPBF provides a buffered 1.000V ±15mV reference used to establish offset voltages for negative-supply monitoring (e.g., –5V UV detection). It sources and sinks up to ±1mA while maintaining regulation, and supports capacitive loads up to 1000pF. No bypass capacitor is required or recommended, and REF must be left open if unused to avoid loading errors.

Does LTC2909ITS8-3.3#TRPBF require an external timing capacitor for its 200ms reset timeout?

No, LTC2909ITS8-3.3#TRPBF does not require an external timing capacitor for its default 200ms reset timeout. Connecting the TMR pin directly to GND activates the internal timer, eliminating component count and layout complexity. External capacitors are only needed when programmable timeouts (400μs to 10s) are required - in which case CTMR = 2.2nF yields ~20ms, per the 9ms/nF scaling factor specified in the datasheet.