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Texas Instruments LM82CIMQAX/NOPB
- Part No.:
- LM82CIMQAX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Analog and Digital Output
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LM82CIMQAX/NOPB.pdf
- Description:
- SENSOR DIGITAL -40C-125C 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:794
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Product details
Overview
LM82CIMQAX/NOPB from Texas Instruments is a dual-sensing digital temperature monitor IC with local die and remote diode junction measurement capability, 7-bit + sign temperature data format (1°C resolution), SMBus/I²C-compatible two-wire interface, and dual open-drain interrupt outputs (INT and T_CRIT_A) for thermal event signaling in embedded computing and industrial control systems.
For engineers reviewing the LM82CIMQAX/NOPB datasheet, LM82CIMQAX/NOPB pinout, LM82CIMQAX/NOPB application, or LM82CIMQAX/NOPB equivalent, this page delivers verified technical context, pin-level design meaning, real-world thermal management use cases, and validated alternative options - all grounded in TI's SNIS113D specification and official package documentation.
Technical Context
The LM82CIMQAX/NOPB integrates a Delta-Sigma ADC to convert both on-chip bandgap voltage (local temperature) and forward voltage drop across an external diode (remote junction) into 8-bit two's complement digital values. It performs sequential conversions - local first, then remote - completing both in ≤600 ms.
Its SMBus 1.1-compliant interface supports timeout recovery (25–40 ms low-time reset), tri-level address selection (ADD0/ADD1), and register-level access to 13 dedicated registers including dual HIGH limit comparators (LHS/RHS), critical threshold (T_CRIT), status flags, and configuration bits for INT/T_CRIT_A masking and polarity inversion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 3.0 V to 3.6 V - defines strict low-voltage operation; requires stable LDO or filtered rail; out-of-range supply disables conversion and resets interface. |
| Local Temp Accuracy | ±3.0°C max (0°C to +85°C) - determines precision of PCB or ambient thermal monitoring without calibration. |
| Remote Diode Accuracy | ±3°C max (+25°C to +100°C); ±4°C max (0°C to +125°C) - sets error budget for CPU/GPU die temperature tracking using discrete or integrated diodes. |
| Conversion Time | ≤600 ms per full cycle (local + remote) - establishes minimum polling interval for real-time thermal response in fan control or shutdown logic. |
| SMBus Clock Frequency | 10 kHz to 100 kHz - constrains host controller timing; compatible with standard microcontroller GPIO-based bit-banging or hardware SMBus peripherals. |
| Interrupt Outputs | Two open-drain outputs (INT, T_CRIT_A) - enable independent alarm routing: INT for per-sensor HIGH thresholds, T_CRIT_A for system-critical over-temperature events. |
| Address Selection | 2 tri-state pins (ADD0, ADD1) - allow up to 9 unique SMBus addresses on one bus, supporting multi-zone thermal monitoring without address conflict. |
Pinout & Package
LM82CIMQAX/NOPB is housed in a 16-pin SSOP (DBQ) package with 0.65 mm pitch and exposed thermal pad. Pin assignments are validated per TI SNIS113D Figure 1 and PIN DESCRIPTIONS table.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 2) | Positive supply input | Must be regulated 3.0–3.6 V; powers internal ADC, logic, and diode bias circuitry; undershoot below 2.3 V triggers power-on reset. |
| GND (Pins 7, 8) | Power return path | Dual ground pins reduce impedance; must connect to low-noise analog/digital ground plane to minimize self-heating error. |
| D+ (Pin 3) | Diode current source | Drives 5–125 µA into remote diode anode; floating when unused; short-to-VCC causes +127°C fault indication. |
| D− (Pin 4) | Diode return sink | Completes remote diode current path; must float if D+ unused; voltage at D− must stay within −0.3 V to (VCC + 0.3 V). |
| ADD0 / ADD1 (Pins 10, 6) | SMBus address select inputs | Tri-level (GND/VCC/floating) configuration sets 7-bit slave address; latched on first SMBus transaction; enables 9-device daisy-chain. |
| SMBData (Pin 12) | Bi-directional serial data line | Open-drain; requires external pull-up (≤30 kΩ); supports SMBus read/write protocols and timeout recovery. |
| SMBCLK (Pin 14) | Serial clock input | Master-generated clock; accepts 10–100 kHz; low-time >40 ms forces interface reset to IDLE state. |
| INT (Pin 11) | Programmable interrupt output | Asserts when local or remote temp exceeds respective T_HIGH; maskable/configurable active-high/low; open-drain. |
| T_CRIT_A (Pin 16) | Critical temperature alarm | Asserts if *any* sensed temperature exceeds T_CRIT; masked per sensor via config register; open-drain with 3 mA sink capability. |
Key Features
| Feature | Design Value |
|---|---|
| Local + remote dual sensing | Enables simultaneous monitoring of system board temperature (via LM82 die) and processor die temperature (via CPU-integrated diode), eliminating need for separate sensors. |
| Two independent interrupt outputs | Allows hierarchical thermal response: INT for warning-level throttling (e.g., fan ramp-up), T_CRIT_A for immediate shutdown or reset initiation. |
| Tri-level address selection | Supports up to 9 LM82CIMQAX/NOPB devices on one SMBus without external multiplexers - ideal for multi-board or multi-CPU server thermal management. |
| Diode fault detection | Automatically identifies open-circuit (D+ floating → +127°C + OPEN flag) or short-circuit (D+ to GND → 0°C) conditions before each conversion, preventing false alarms. |
| SMBus timeout recovery | Resets serial interface if SMBData/SMBCLK held low ≥25 ms - prevents bus lockup during host reset or firmware crash without requiring hardware reset. |
Applications
| Server CPU Thermal Monitoring | Industrial PLC Temperature Supervision |
|---|---|
|
Use Scenario: Real-time die temperature tracking of Intel Pentium II–class CPUs or ASICs with integrated thermal diodes in rack-mounted servers. IC Role / Device Role / Timing Role: LM82CIMQAX/NOPB acts as remote diode interface and local ambient sensor, performing sequential local/remote conversions every ~600 ms to feed thermal control firmware. Use Value: Enables accurate, low-overhead CPU throttling and fan speed control without adding discrete analog circuitry or calibration overhead. |
Use Scenario: Continuous thermal supervision of programmable logic controller (PLC) backplane and I/O module junctions in factory automation cabinets. IC Role / Device Role / Timing Role: LM82CIMQAX/NOPB monitors local PCB temperature and remote diode-equipped power transistors, triggering INT on overtemp and T_CRIT_A on critical failure. Use Value: Provides deterministic, register-accessible thermal alerts with SMBus logging - replacing mechanical thermostats and reducing field failure rates. |
| Network Switch Fan Control | Medical Imaging Power Supply Monitoring |
|
Use Scenario: Closed-loop fan speed regulation in enterprise Ethernet switches based on ASIC and PHY die temperatures. IC Role / Device Role / Timing Role: LM82CIMQAX/NOPB reads remote diodes on switch fabric and SerDes ICs, updating T_HIGH registers dynamically via SMBus writes to adapt to load changes. Use Value: Delivers responsive, noise-optimized cooling while maintaining <±3°C accuracy across operating temperature range (−40°C to +125°C). |
Use Scenario: Safety-critical overtemperature protection for high-voltage DC-DC converters in MRI and CT scanner power supplies. IC Role / Device Role / Timing Role: LM82CIMQAX/NOPB senses local heatsink temperature and remote diode on IGBT gate driver, asserting T_CRIT_A to initiate controlled shutdown if either exceeds 105°C. Use Value: Meets IEC 60601-1 thermal safety requirements with dual-redundant sensing and fail-safe open-drain alarm signaling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-sensing digital temperature monitoring applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM84CIMQX/NOPB | Pin-for-pin and register-compatible; adds extended remote diode accuracy (±2°C over +25°C to +100°C) and improved SMBus timing margins. | Better suited for high-precision CPU thermal management where tighter remote sensing tolerance is required. | Select LM84CIMQX/NOPB when upgrading from LM82CIMQAX/NOPB for enhanced remote diode accuracy without layout change. |
| MAX6657ESA+ | Single-supply 3.0–5.5 V operation; local-only sensing; no remote diode interface; different register map and SMBus address scheme. | Limited to ambient/PCB temperature monitoring; lacks remote junction capability needed for processor die sensing. | Choose MAX6657ESA+ only for cost-sensitive, local-only applications where remote diode functionality is unnecessary. |
Compared with LM82CIMQAX/NOPB, LM84CIMQX/NOPB offers measurable improvement in remote diode accuracy without sacrificing compatibility, while MAX6657ESA+ trades remote sensing capability for wider supply range and lower unit cost - making it a functional but not drop-in alternative.
Availability
LM82CIMQAX/NOPB is available at Aetrix Electronics and suitable for server thermal management, industrial PLC supervision, network switch fan control, and medical power supply monitoring requiring stable component supply across long-life production cycles.
Supply support for LM82CIMQAX/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 sensing and industrial-grade IC design.
The LM82CIMQAX/NOPB belongs to TI's thermal sensing portfolio, engineered specifically for dual-point (local + remote) temperature monitoring in computing, communications, and industrial equipment where SMBus integration and deterministic interrupt behavior are essential.
FAQ
What is the operating temperature range of the LM82CIMQAX/NOPB?
The LM82CIMQAX/NOPB operates across −40°C to +125°C, with specified local temperature accuracy of ±3.0°C (0°C to +85°C) and remote diode accuracy of ±3°C (+25°C to +100°C). Its extended range supports deployment in harsh environments such as industrial control cabinets and telecom base stations where ambient extremes occur.
Does the LM82CIMQAX/NOPB require external components for basic operation?
Yes - LM82CIMQAX/NOPB requires external pull-up resistors on SMBData and SMBCLK (typically 4.7 kΩ), plus optional pull-ups on INT and T_CRIT_A outputs. No external passive components are needed for temperature sensing itself, as the internal diode bias current source and Delta-Sigma ADC are fully integrated.
How does the LM82CIMQAX/NOPB detect remote diode faults?
The LM82CIMQAX/NOPB performs automatic diode fault detection before each remote conversion: an open-circuit diode (D+ floating) returns +127°C and sets the OPEN bit in the Status Register; a shorted D+ (to GND or D−) yields 0°C without setting OPEN. This enables robust system-level diagnostics without host software intervention.
Can multiple LM82CIMQAX/NOPB devices share the same SMBus?
Yes - LM82CIMQAX/NOPB supports up to 9 devices on one SMBus via tri-level ADD0/ADD1 pins (GND/VCC/floating), generating unique 7-bit slave addresses. Address latching occurs on the first SMBus transaction, ensuring stable multi-device operation without runtime reconfiguration.
What happens to the LM82CIMQAX/NOPB during an SMBus communication timeout?
If SMBData or SMBCLK remains low for ≥25 ms, the LM82CIMQAX/NOPB resets its serial interface to the IDLE state (both lines high), clearing pending transactions. This built-in timeout recovery prevents bus lockup during host resets or firmware hangs - a key reliability feature confirmed in TI's SNIS113D specification.
LM82CIMQAX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Sensor Type:
- Digital, Local/Remote
- Sensing Temperature - Local:
- -40°C ~ 125°C
- Sensing Temperature - Remote:
- -40°C ~ 125°C
- Output Type:
- I2C/SMBus
- Voltage - Supply:
- 3V ~ 3.6V
- Resolution:
- 7 b
- Features:
- Output Switch, Programmable Limit
- Accuracy - Highest (Lowest):
- ±3°C (±4°C)
- Test Condition:
- 0°C ~ 85°C (-40°C ~ 125°C)
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 16-SSOP
LM82CIMQAX/NOPB FAQ
1.How can I place an order for LM82CIMQAX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM82CIMQAX/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 LM82CIMQAX/NOPB reliable?
The price and inventory of LM82CIMQAX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM82CIMQAX/NOPB is usually 5 days.
3.What payment methods are accepted for LM82CIMQAX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM82CIMQAX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM82CIMQAX/NOPB?
LM82CIMQAX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM82CIMQAX/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 LM82CIMQAX/NOPB?
For technical support, including LM82CIMQAX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM82CIMQAX/NOPB requirements.
6.How does Aetrix verify that LM82CIMQAX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM82CIMQAX/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 LM82CIMQAX/NOPB meets industry standards.
7.What is the process for return or replacement of LM82CIMQAX/NOPB?
All LM82CIMQAX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM82CIMQAX/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 LM82CIMQAX/NOPB part is unused and in its original packaging.
Return procedure for LM82CIMQAX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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