Analog Devices Inc. LTC2909CTS8-2.5#TRMPBF

Overview

LTC2909CTS8-2.5#TRMPBF from Analog Devices (formerly 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 open-drain RST output - used in desktop/notebook power sequencing, server core/I/O monitoring, and automotive supply supervision.

For engineers reviewing the LTC2909CTS8-2.5#TRMPBF datasheet, LTC2909CTS8-2.5#TRMPBF pinout, LTC2909CTS8-2.5#TRMPBF application, or LTC2909CTS8-2.5#TRMPBF equivalent, key selection criteria include ADJ1/ADJ2 0.5V nominal threshold tolerance, SEL-pin polarity configuration, internal 200ms reset timeout, buffered 1V reference for negative-supply offset, and TSOT-23-8 package compatibility with space-constrained PCB layouts.

Technical Context

The LTC2909CTS8-2.5#TRMPBF implements two independent 0.5V-threshold comparators with pin-selectable input polarity (via SEL), enabling simultaneous positive-UV/negative-OV or dual-negative-UV detection. Its third fixed UVLO monitors VCC at 2.213V (±1.5%) for 2.5V logic supplies.

Reset assertion uses glitch-filtered comparator outputs feeding a programmable timeout block - selectable as internal 200ms, external capacitor (9ms/nF), or disabled (comparator mode). The buffered 1.000V REF output supports offset-based negative-voltage monitoring without external components.

Key Specifications

Pinout & Package

Package: 8-lead TSOT-23 (3mm × 1.75mm), RoHS-compliant, exposed pad optional for thermal relief.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6816EUT+T and TPS3808G125DBVR, the LTC2909CTS8-2.5#TRMPBF uniquely integrates dual 0.5V-adjustable inputs, SEL-configurable polarity, and a 1V REF in TSOT-23-8 - enabling single-chip monitoring of mixed positive/negative rails without external components, while maintaining ±1.5% accuracy and 200ms timeout.

Availability

LTC2909CTS8-2.5#TRMPBF is available at Aetrix Electronics and suitable for desktop power sequencing, automotive body control modules, and server core/I/O voltage monitoring requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LTC2909CTS8-2.5#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 (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.

The LTC2909 product line delivers precision, low-power supply monitoring ICs for computing, communications, and automotive applications - designed specifically for systems requiring dual-rail supervision, negative-voltage detection, and guaranteed operation down to 0.5V VCC.

FAQ

What is the guaranteed minimum operating voltage for LTC2909CTS8-2.5#TRMPBF to assert a valid RST low?

The LTC2909CTS8-2.5#TRMPBF guarantees RST output voltage low (VOL ≤ 0.15V) with VCC as low as 0.5V and sink current up to 100μA. This ultralow-voltage operation ensures deterministic reset assertion during severe brownout conditions before the host system loses state - a critical capability for automotive and industrial applications where supply collapse is abrupt and uncontrolled.

How does the SEL pin configure input polarity on LTC2909CTS8-2.5#TRMPBF, and what are the three valid states?

The SEL pin on LTC2909CTS8-2.5#TRMPBF sets ADJ1/ADJ2 polarity via three distinct states: tied to VCC enables both inputs for positive-UV/positive-OV monitoring; left open configures ADJ1 for positive-UV and ADJ2 for negative-UV/positive-OV; tied to GND sets both inputs for negative-UV/negative-OV detection. Each state requires no external components and is validated across –40°C to 85°C per datasheet Table 1.

Can LTC2909CTS8-2.5#TRMPBF monitor a negative supply like –5V, and if so, how is it connected?

Yes, LTC2909CTS8-2.5#TRMPBF can monitor –5V using ADJ1 or ADJ2 in negative-polarity mode (SEL = GND or Open). Connect the –5V rail to ADJ1 through a resistor divider referenced to the buffered 1.000V REF output (not GND), per Figure 2 in the datasheet. For –5V UV at –4.425V, the divider ratio yields ~0.5V at ADJ1 when the rail is valid - enabling precise detection without external op-amps or level shifters.

What is the accuracy of the VCC UVLO threshold for LTC2909CTS8-2.5#TRMPBF, and how does it relate to the part number?

The VCC UVLO threshold for LTC2909CTS8-2.5#TRMPBF is 2.213V (nominal), with ±1.5% accuracy over –40°C to 85°C. This value is fixed by the "-2.5" suffix, indicating calibration for 2.5V logic supplies - the threshold is 11.5% below 2.5V (2.5V × 0.885 = 2.213V). Other variants (e.g., -3.3, -5) scale this percentage to their respective nominal voltages.

Does LTC2909CTS8-2.5#TRMPBF require an external timing capacitor for its default 200ms reset timeout?

No, LTC2909CTS8-2.5#TRMPBF does not require an external timing capacitor for its default 200ms reset timeout. Connecting the TMR pin directly to GND activates the internal timeout generator - eliminating BOM cost, layout area, and capacitor tolerance drift. External capacitors are only needed when custom timeout durations (e.g., 10ms or 2s) are required, using the 9ms/nF scaling factor.