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Texas Instruments LM81BIMT-3/NOPB — Discrete Semiconductors

LM81BIMT-3/NOPB Texas Instruments Hardware Monitor, ±3°C

MPNLM81BIMT-3/NOPB
End of Life

Texas Instruments LM81BIMT-3/NOPB hardware monitor IC, ±3°C max accuracy, internal and external sensor, 2-wire SMBus output, fan control and alarm, 24-TSSOP package, tube.

$6.92Ref. price · indicative, final on quote
Packaging24-TSSOP (0.173", 4.40mm Width)
RoHSROHS3 Compliant
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

LM81BIMT-3/NOPB specifications
ParameterValue
Output type2-Wire SMBus
Sensor typeInternal and External
MountingSurface Mount
Voltage2.8V ~ 3.8V
Operating temperature-40°C ~ 125°C
PackageTube
Accuracy±3°C(Max)
FunctionHardware Monitor
TopologyADC (Sigma Delta), Comparator, Fan Speed Control, Register Bank
Output fanYes
Output alarmYes
Case24-TSSOP (0.173\", 4.40mm Width)
Sensing temperature-40°C ~ 125°C

Product details

24-TSSOP footprint and board integration

The LM81BIMT-3/NOPB: The tube delivery means the ICs are shipped in antistatic tubes, not tape-and-reel — factor this into pick-and-place feeder setup if your line expects reeled parts.

What ±3°C max accuracy means for your thermal monitoring

For a system that needs to trigger a fan or an alarm at a specific temperature threshold, this tolerance means the actual trip point can be up to 3°C away from the programmed value. If your thermal budget requires tighter control — say, ±1°C at a critical junction — you may need to calibrate the remote diode path or select a higher-grade monitor. For most equipment monitoring (server racks, power supplies, industrial controllers), ±3°C is adequate to prevent thermal runaway without nuisance alarms.

Active production — no end-of-life concern

Texas Instruments lists the LM81BIMT-3/NOPB with a lifecycle stage of 'current' and an official product status of 'Active'. The part is ROHS3 compliant, so it meets the EU RoHS directive without exemption.

Internal architecture: ADC, comparator, fan control, register bank

The LM81BIMT-3/NOPB integrates a sigma-delta ADC, a comparator, fan speed control logic, and a register bank. The sigma-delta ADC converts the analog voltage from the internal temperature sensor and the external diode-connected transistor into a digital value. The comparator checks the converted temperature against programmable limit registers and asserts the ALERT output if a limit is exceeded. The fan speed control block generates a PWM or linear output to drive a cooling fan based on the temperature reading — this closes the loop without host processor intervention. The register bank is accessed over the 2-wire SMBus for configuration and readback.

Supply rail and operating range

This covers most equipment environments except extended military or downhole applications.

Frequently asked questions

What is the LM81BIMT-3/NOPB's temperature accuracy and what does it mean for my system?

This is the total error including the internal sensor and ADC. For thermal monitoring in servers, power supplies, or industrial controllers, this tolerance is sufficient to prevent thermal runaway. If your application requires tighter accuracy (e.g., ±1°C), you may need to calibrate the remote diode path or select a higher-grade monitor.

What compliance documentation does Texas Instruments provide for LM81BIMT-3/NOPB?

Texas Instruments provides a RoHS certificate and material declaration.