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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Thermal Management

Texas Instruments LM80CIMTX-3/NOPB

Name: LM80CIMTX-3/NOPB
Brand: Texas Instruments
SKU: LM80CIMTX-3/NOPB
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LM80CIMTX-3/NOPB

Manufacturer:: Texas Instruments

Category:: Thermal Management

Package:: 24-TSSOP (0.173", 4.40mm Width)

Datasheet:: LM80CIMTX-3/NOPB.pdf

Description:: IC MPU SYSTEM HDWR MON 24-TSSOP

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Product details

Overview

LM80CIMTX-3/NOPB from Texas Instruments is an ACPI-compatible hardware monitor IC for PC and server thermal/power management, featuring 7 analog voltage inputs (0–2.56 V range), ±1% max voltage monitoring error, ±3°C temperature error over −25°C to +125°C, 8-bit ADC with 10 mV LSB, and dual fan tachometer inputs supporting 1100–8800 RPM measurement. It operates from 2.8 V to 5.75 V and delivers real-time watchdog comparisons via I²C interface.

For engineers reviewing the LM80CIMTX-3/NOPB datasheet, LM80CIMTX-3/NOPB pinout, LM80CIMTX-3/NOPB application, or LM80CIMTX-3/NOPB equivalent, this device serves as a system-level hardware monitor for voltage, temperature, and fan speed in x86-based platforms - requiring attention to I²C address configuration (A0–A2 pins), RST_OUT/OS functional mode selection, chassis intrusion latching behavior, and analog input scaling for ±5 V/±12 V rails.

Technical Context

The LM80CIMTX-3/NOPB integrates a delta-sigma ADC, two independent fan pulse counters with programmable divisors (1–4), and a dedicated temperature sensor with selectable 9-bit (0.5°C) or 12-bit (0.0625°C) resolution. Its internal register map includes WATCHDOG limit storage, interrupt masking, and fan divisor control - all accessible via standard I²C protocol with fixed slave address 0x2C (A2=0, A1=1, A0=0).

It implements dual hardware interrupt outputs: INT (fully maskable, open-drain or open-source) and RST_OUT/OS (dedicated to overtemperature shutdown or master reset, with 10 ms minimum pulse width). The CI (Chassis Intrusion) input supports active-high latching independent of power state, while BTI accepts external temperature sensor interrupts (e.g., LM75) for board-level thermal event aggregation.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage Range	+2.8 V to +5.75 V - supports both 3.3 V and 5 V system rails without level-shifting.
ADC Resolution & LSB	8 bits, 10 mV LSB - enables precise 0–2.56 V analog input measurement with ±1% total unadjusted error.
Temperature Accuracy	±3°C max over −25°C to +125°C - suitable for CPU/GPU thermal margining in industrial PCs.
Fan Input Range	0–V+ logic-compatible inputs - accepts TTL/CMOS tach signals; full-scale count = 255 (stopped fan).
I²C Interface	Standard-mode (100 kHz) compatible - uses SDA/SCL with A0–A2 address pins; default address 0x2C.
Operating Temperature	−25°C to +125°C - qualified for extended-temperature embedded computing environments.
Supply Current	0.2 mA typical operating, 15 µA typical shutdown - enables low-power thermal monitoring during sleep states.

Pinout & Package

TSSOP-24 package (PW suffix), 0.65 mm pitch, thermally enhanced with exposed pad (not electrically connected). Pin 14 (GNDA) must connect to low-noise analog ground plane; Pin 8 (GND) connects to digital ground; separation ≤100 mV required.

Pin/Terminal	Circuit Role	Design Meaning
IN0–IN6 (Pins 15–21)	Analog voltage inputs	Accept 0–2.56 V signals; require external resistor dividers for ±5 V/±12 V rail monitoring.
FAN1/FAN2 (Pins 4–5)	Digital tachometer inputs	Measure fan RPM via pulse period; support programmable divisors (1–4) to extend measurable speed range.
RST_OUT/OS (Pin 13)	Configurable output	Either active-low 5 mA reset pulse (10 ms min) or overtemperature shutdown signal - selected via Fan Divisor register Bits 6–7.
CI (Pin 7)	Chassis intrusion latch	Active-high input with internal open-drain control; retains state across power cycles for tamper detection.
BTI (Pin 6)	Board temperature interrupt	Aggregates O.S. outputs from external LM75/LM56 sensors - enables multi-zone thermal alerting.
INT (Pin 10)	Maskable interrupt output	Open-drain or open-source; asserts when any monitored parameter exceeds WATCHDOG limits.

Key Features

Feature	Design Value
ACPI-compliant hardware monitoring	Direct integration into BIOS/system firmware for OS-directed thermal/power management per ACPI 1.0b spec.
Programmable fan speed divisors	Four selectable divisors (1–4) enable accurate RPM measurement across wide speed ranges (1100–8800 RPM at count=153).
Dual interrupt architecture	Separate INT (maskable, multi-source) and RST_OUT/OS (dedicated thermal/fail-safe) outputs reduce firmware polling overhead.
Chassis intrusion latching	CI pin maintains high state until explicitly reset via Configuration Register Bit 5 - supports physical security logging.
Low-power shutdown mode	Bit 0 of Configuration Register halts monitoring loop, reducing supply current to 15 µA typical - ideal for S3/S4 sleep states.

Applications

Server Thermal Monitoring	Desktop PC Power Management
Use Scenario: Real-time tracking of CPU core voltage, +12 V VRM output, memory rail, and heatsink temperature in 1U rack servers. IC Role / Device Role / Timing Role: Central hardware monitor collecting analog voltages, die temperature, and dual-fan speeds; triggers INT on overvoltage or overtemperature. Use Value: Enables dynamic fan speed control and graceful OS-initiated shutdown before thermal throttling occurs - leveraging 0.5°C temperature resolution and ±1% voltage accuracy.	Use Scenario: Monitoring +3.3 V, +5 V, +12 V, and −12 V supplies alongside CPU and chipset temperatures in ATX motherboards. IC Role / Device Role / Timing Role: ACPI-compliant system health controller interfacing with BIOS to report SMI events and update SMBus registers every ~1.5 s. Use Value: Provides validated watchdog thresholds for each rail and thermal zone - preventing brownouts and thermal damage using factory-programmed limits stored in Value RAM.
Industrial Embedded Controller	Test Equipment Power Sequencing
Use Scenario: Monitoring power integrity and cooling performance in fan-cooled DIN-rail PLCs operating continuously at 70°C ambient. IC Role / Device Role / Timing Role: Standalone hardware supervisor asserting RST_OUT/OS on overtemperature to halt processor execution before junction limit breach. Use Value: Delivers guaranteed −25°C to +125°C operation with 15 µA shutdown current - extending reliability in unventilated enclosures.	Use Scenario: Verifying correct power-up sequence and stable rail settling in automated test fixtures before enabling DUT communication. IC Role / Device Role / Timing Role: Precision voltage monitor validating ±1% tolerance on all supplies prior to releasing reset to microcontroller under test. Use Value: Uses 10 mV LSB ADC and programmable WATCHDOG limits to detect <10 mV deviations - ensuring repeatability in production test environments.

Server Thermal Monitoring

Desktop PC Power Management

Use Scenario: Real-time tracking of CPU core voltage, +12 V VRM output, memory rail, and heatsink temperature in 1U rack servers.

IC Role / Device Role / Timing Role: Central hardware monitor collecting analog voltages, die temperature, and dual-fan speeds; triggers INT on overvoltage or overtemperature.

Use Value: Enables dynamic fan speed control and graceful OS-initiated shutdown before thermal throttling occurs - leveraging 0.5°C temperature resolution and ±1% voltage accuracy.

Use Scenario: Monitoring +3.3 V, +5 V, +12 V, and −12 V supplies alongside CPU and chipset temperatures in ATX motherboards.

IC Role / Device Role / Timing Role: ACPI-compliant system health controller interfacing with BIOS to report SMI events and update SMBus registers every ~1.5 s.

Use Value: Provides validated watchdog thresholds for each rail and thermal zone - preventing brownouts and thermal damage using factory-programmed limits stored in Value RAM.

Industrial Embedded Controller

Test Equipment Power Sequencing

Use Scenario: Monitoring power integrity and cooling performance in fan-cooled DIN-rail PLCs operating continuously at 70°C ambient.

IC Role / Device Role / Timing Role: Standalone hardware supervisor asserting RST_OUT/OS on overtemperature to halt processor execution before junction limit breach.

Use Value: Delivers guaranteed −25°C to +125°C operation with 15 µA shutdown current - extending reliability in unventilated enclosures.

Use Scenario: Verifying correct power-up sequence and stable rail settling in automated test fixtures before enabling DUT communication.

IC Role / Device Role / Timing Role: Precision voltage monitor validating ±1% tolerance on all supplies prior to releasing reset to microcontroller under test.

Use Value: Uses 10 mV LSB ADC and programmable WATCHDOG limits to detect <10 mV deviations - ensuring repeatability in production test environments.

Equivalent & Alternatives

The following parts are listed as comparable options for similar hardware monitoring applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM81CIMTX-3/NOPB	Enhanced version with 10-bit ADC (2.5 mV LSB), improved temp accuracy (±2°C), and extended I²C address range (0x2C–0x2F).	Supports tighter voltage margining and higher-resolution thermal profiling in next-gen server platforms.	Select LM81CIMTX-3/NOPB when ±2°C temp accuracy and finer 2.5 mV LSB resolution are required for advanced thermal management.
ADM1027ARUZ	Analog Devices part with integrated PWM fan control, 12-bit ADC, and SMBus Alert Response Address (ARA) support.	Enables closed-loop fan speed regulation without external MCU intervention - not supported by LM80CIMTX-3/NOPB.	Choose ADM1027ARUZ where automatic PWM-based fan control and ARA compatibility are mandatory for system-level thermal orchestration.

Compared with LM80CIMTX-3/NOPB, LM81CIMTX-3/NOPB offers higher ADC resolution and tighter temperature accuracy for precision monitoring, while ADM1027ARUZ adds autonomous PWM control and SMBus ARA - making it suitable for systems requiring self-regulating cooling without host firmware involvement.

Availability

LM80CIMTX-3/NOPB is available at Aetrix Electronics and suitable for server thermal monitoring, desktop PC power management, industrial embedded controllers, and test equipment power sequencing requiring stable component supply across long-lifecycle deployments.

Supply support for LM80CIMTX-3/NOPB 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies, with decades of heritage in precision data converters and system monitoring solutions.

The LM80CIMTX-3/NOPB belongs to TI's hardware monitor IC product line, designed specifically for ACPI-compliant thermal and power supervision in x86-based computing platforms - emphasizing reliability, low power, and seamless BIOS integration.

FAQ

What is the default I²C address of the LM80CIMTX-3/NOPB and how is it configured?

The LM80CIMTX-3/NOPB defaults to I²C slave address 0x2C (binary 0101100), determined by A2=0, A1=1, A0=0. These address pins (Pins 23–24 and 22) are hardwired to V+ or GND to select one of eight possible addresses (0x28–0x2F). Address configuration must be finalized before system initialization, as the LM80CIMTX-3/NOPB does not support address auto-detection or dynamic reconfiguration during operation.

How does the LM80CIMTX-3/NOPB handle chassis intrusion detection, and what is the role of the CI pin?

The CI (Chassis Intrusion) pin (Pin 7) on the LM80CIMTX-3/NOPB is an active-high, latched input that retains its asserted state even after power cycling. When triggered, it sets a flag in the Interrupt Status Register and can be cleared only by writing Bit 5 of the Configuration Register. This allows the LM80CIMTX-3/NOPB to serve as a tamper-evident security element in servers and industrial enclosures - independent of host processor activity.

Can the LM80CIMTX-3/NOPB monitor negative voltage rails such as −12 V, and if so, how?

Yes, the LM80CIMTX-3/NOPB can monitor negative rails like −12 V using external resistor dividers that translate the negative voltage into the 0–2.56 V input range. For example, a network with R3 and R4 (as specified in TI's SNIS102F datasheet) scales −12 V to +1.9 V at INx pins. Input clamping diodes protect against overvoltage, but external series resistors (~10 kΩ) are recommended when monitoring unpowered rails to limit current to <5 mA per pin.

What is the function of the RST_OUT/OS pin on the LM80CIMTX-3/NOPB, and how is its mode selected?

The RST_OUT/OS pin (Pin 13) on the LM80CIMTX-3/NOPB serves dual functions: active-low master reset (RST_OUT) or overtemperature shutdown (OS). Mode selection is controlled by Bits 6–7 of the Fan Divisor/RST_OUT/OS Register (address 0x05). Setting Bit 6 = 0 configures RST_OUT/OS as reset output (10 ms pulse); setting Bit 6 = 1 enables OS mode, asserting the pin when temperature exceeds programmed limits - both modes require Bit 4 of the Configuration Register to be set.

Does the LM80CIMTX-3/NOPB support 12-bit temperature resolution, and what impact does it have on monitoring cycle time?

Yes, the LM80CIMTX-3/NOPB supports 12-bit temperature resolution via Bit 3 in the OS Configuration/Temperature Resolution Register (0x06), improving resolution to 0.0625°C. However, enabling 12-bit mode increases total monitoring cycle time from ~1.5 seconds (9-bit) to ~2.0 seconds, as the ADC requires additional conversion time. This trade-off must be considered in real-time thermal response requirements - especially in fast-transient environments like CPU boost states.

LM80CIMTX-3/NOPB Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: PowerWise®

Package/Case:: 24-TSSOP (0.173", 4.40mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Not For New Designs

Function:: Hardware Monitor

Sensor Type:: Internal and External

Sensing Temperature:: -25°C ~ 125°C, External Sensor

Accuracy:: ±3°C(Max)

Topology:: ADC, Comparator, Fan Speed Counter, Register Bank

Output Type:: I2C

Output Alarm:: No

Output Fan:: No

Voltage - Supply:: 2.8V ~ 5.75V

Operating Temperature:: -25°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 24-TSSOP

LM80CIMTX-3/NOPB FAQ

1.How can I place an order for LM80CIMTX-3/NOPB through Aetrix?

Please submit a Request for Quotation (RFQ) for LM80CIMTX-3/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LM80CIMTX-3/NOPB reliable?

The price and inventory of LM80CIMTX-3/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM80CIMTX-3/NOPB is usually 5 days.

3.What payment methods are accepted for LM80CIMTX-3/NOPB?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM80CIMTX-3/NOPB transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LM80CIMTX-3/NOPB?

LM80CIMTX-3/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LM80CIMTX-3/NOPB order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LM80CIMTX-3/NOPB?

For technical support, including LM80CIMTX-3/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM80CIMTX-3/NOPB requirements.

6.How does Aetrix verify that LM80CIMTX-3/NOPB is sourced from the original manufacturer or authorized distributors?

All LM80CIMTX-3/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM80CIMTX-3/NOPB meets industry standards.

7.What is the process for return or replacement of LM80CIMTX-3/NOPB?

All LM80CIMTX-3/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM80CIMTX-3/NOPB, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LM80CIMTX-3/NOPB part is unused and in its original packaging.

Return procedure for LM80CIMTX-3/NOPB:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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