Analog Devices Inc. LTC2909CTS8-3.3#TRPBF

Overview

LTC2909CTS8-3.3#TRPBF from Analog Devices (acquired Linear Technology) is a precision triple-input voltage supervisor IC for system power monitoring, featuring two adjustable 0.5V-threshold inputs with pin-selectable polarity (±UV/OV), a fixed 2.921V VCC UVLO threshold (±1.5% accuracy), 200ms internal reset timeout, and open-drain RST output. It operates down to 0.5V VCC and supports negative supply monitoring via buffered 1.000V reference. Used in 3.3V logic systems requiring reliable brownout detection and dual-rail fault coverage.

For engineers reviewing the LTC2909CTS8-3.3#TRPBF datasheet, LTC2909CTS8-3.3#TRPBF pinout, LTC2909CTS8-3.3#TRPBF application, or LTC2909CTS8-3.3#TRPBF equivalent, key selection factors include its ±1.5% threshold accuracy over –40°C to 85°C, 50μA quiescent current, TSOT-23-8 package compatibility, and support for both positive/negative supply monitoring without external polarity components.

Technical Context

The LTC2909CTS8-3.3#TRPBF implements dual comparator-based monitoring with a third independent VCC UVLO channel. Its SEL pin configures ADJ1/ADJ2 input polarity across three states (VCC/Open/GND), enabling flexible UV/OV detection on positive, negative, or mixed rails. The buffered 1.000V reference (±15mV over temperature) offsets negative-monitoring dividers, while the 6.5V shunt regulator allows operation up to 6V directly or higher with series limiting.

Reset assertion is synchronized across all three monitored channels: RST pulls low when any input violates its configured threshold (e.g., ADJ1 < 0.5V in positive mode, ADJ2 > 0.5V in negative mode, or VCC < 2.921V), then holds low for the selected timeout period before releasing. Glitch filtering on comparator outputs suppresses transients ≤100μs at 5% overthreshold, preventing false triggers during load switching or noise events.

Key Specifications

Pinout & Package

Package: 8-lead TSOT-23 (3mm × 1.75mm), RoHS-compliant, lead-free (#PBF), tape-and-reel (#TRPBF). Exposed pad not present in TSOT-23 variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2909ITS8-3.3#TRPBF, the LTC2909CTS8-3.3#TRPBF offers identical electrical performance but narrower temperature rating-sufficient for office equipment and consumer electronics. Versus TPS3808G33DBVR, it delivers triple-input flexibility and negative-rail capability at higher IQ, making it appropriate for complex power architectures where rail diversity outweighs quiescent current concerns.

Availability

LTC2909CTS8-3.3#TRPBF is available at Aetrix Electronics and suitable for desktop computers, network servers, and handheld devices requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LTC2909CTS8-3.3#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, formed through the acquisition of Linear Technology in 2017.

The LTC2909 product line delivers precision, low-power, multi-rail voltage supervision for mission-critical power integrity in computing, communications, and industrial systems-designed to replace discrete supervisor solutions with integrated, calibrated functionality.

FAQ

What is the operating temperature range for the LTC2909CTS8-3.3#TRPBF?

The LTC2909CTS8-3.3#TRPBF is rated for 0°C to 70°C ambient operation. This commercial-grade specification matches typical desktop, notebook, and consumer electronics thermal profiles. For extended-range applications such as automotive or industrial environments, the pin-compatible LTC2909ITS8-3.3#TRPBF (–40°C to 85°C) is recommended. Both variants share identical electrical characteristics and pinout.

How does the SEL pin configure input polarity on the LTC2909CTS8-3.3#TRPBF?

The SEL pin on the LTC2909CTS8-3.3#TRPBF selects one of three polarity modes: tied to VCC configures both ADJ1 and ADJ2 for positive UV/OV monitoring; left open configures ADJ1 for positive and ADJ2 for negative monitoring; tied to GND configures both for negative UV/OV. Each mode enables distinct fault detection-e.g., open SEL allows simultaneous monitoring of a +5V rail for undervoltage and a –5V rail for overvoltage-without external components.

Can the LTC2909CTS8-3.3#TRPBF monitor negative voltages, and how is that implemented?

Yes, the LTC2909CTS8-3.3#TRPBF monitors negative voltages using its buffered 1.000V reference (REF pin) as an offset for external resistor dividers. When SEL is set to GND or OPEN, ADJ inputs operate in negative polarity mode: a negative rail is connected between REF and ADJx, forming a divider that presents 0.5V to the comparator when the rail reaches its trip point (e.g., –4.5V). This eliminates need for external level-shifting circuitry and maintains ±1.5% threshold accuracy across temperature.

What is the purpose of the VCC shunt regulator in the LTC2909CTS8-3.3#TRPBF?

The internal 6.5V shunt regulator on the VCC pin of the LTC2909CTS8-3.3#TRPBF enables direct connection to supplies up to 12V or higher, provided a series current-limiting resistor is used. It clamps VCC to 6.5V ±0.5V, protecting internal circuitry while allowing operation from unregulated sources like automotive batteries or industrial 12V rails. Without the resistor, VCC must remain ≤6V to avoid exceeding the 10mA absolute maximum terminal current.

Does the LTC2909CTS8-3.3#TRPBF require external components for basic 3.3V system monitoring?

No-basic 3.3V system monitoring with the LTC2909CTS8-3.3#TRPBF requires only an external pull-up resistor on the RST pin and a 0.1μF bypass capacitor on VCC. The 200ms internal timeout is activated by tying TMR to GND; the VCC UVLO (2.921V) and SEL = VCC configure both ADJ inputs for positive monitoring. No resistors are needed for ADJ1/ADJ2 if unused-tie ADJ1 to REF and ADJ2 to GND per datasheet guidance.