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Texas Instruments LM95231CIMM/NOPB
- Part No.:
- LM95231CIMM/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Analog and Digital Output
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM95231CIMM/NOPB.pdf
- Description:
- SENSOR DIGITAL 0C-85C 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,546
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Product details
Overview
LM95231CIMM/NOPB from Texas Instruments is a precision dual remote diode temperature sensor IC with SMBus 2.0 interface and TruTherm™ technology, designed for accurate die-temperature monitoring of Intel Pentium 4 (90nm) processors and discrete MMBT3904 transistors. It measures local die temperature plus two remote thermal diodes with ±0.75°C max remote accuracy, 0.03125°C resolution (digital filtering enabled), and operates from 3.0V–3.6V supply in laptop, server, and workstation thermal management systems.
For engineers reviewing the LM95231CIMM/NOPB datasheet, LM95231CIMM/NOPB pinout, LM95231CIMM/NOPB application, or LM95231CIMM/NOPB equivalent, this page delivers verified technical context, validated pin functions, real-world application mappings, and confirmed alternative parts - all grounded in TI's SNIS139E datasheet and official product documentation.
Technical Context
The LM95231CIMM/NOPB implements a sigma-delta ADC with ΔVBE sensing architecture to measure three thermal zones: its own die (local) and two external diode-connected transistors. Its TruTherm™ circuitry compensates for non-ideality spread in 90nm-process Intel thermal diodes, while analog filtering at D1+/D1− and D2+/D2− inputs reduces sensitivity to PCB trace noise and leakage.
Digital filtering (configurable via register) enables 13-bit signed/unsigned resolution (0.03125°C LSB) for remote readings above 127°C; local sensing uses fixed 9-bit+sign (0.25°C LSB). The device supports programmable conversion rate (1 Hz default), shutdown mode (272 µA), and SMBus 2.0-compliant timing including TIMEOUT reset (25–35 ms low pulse).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Remote Temp Accuracy | ±0.75°C max (Intel 90nm thermal diode, TA=+20°C to +40°C, TD=+45°C to +85°C) |
| Local Temp Accuracy | ±3.0°C max (TA=0°C to +85°C, excludes self-heating effects) |
| Supply Voltage | 3.0 V to 3.6 V - requires 0.1 µF + 100 pF bypassing at VDD pin |
| Supply Current | 402 µA typical (SMBus inactive, 1 Hz conversion); 272 µA in shutdown |
| Resolution (Remote, filtered) | 13-bit unsigned or 12-bit+sign - resolves temperatures >127°C with 0.03125°C LSB |
| SMBus Compatibility | Fully compliant with SMBus 2.0 spec - supports 10 kHz–100 kHz clock, TIMEOUT reset, no clock stretching |
| Operating Temp Range | 0°C to +85°C ambient (LM95231CIMM grade per Electrical Characteristics table) |
Pinout & Package
LM95231CIMM/NOPB is housed in an 8-pin VSSOP package (2.3 mm × 2.0 mm, 0.5 mm pitch), optimized for space-constrained thermal sensing on CPU voltage regulator or motherboard power delivery sections.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| D1+ | Diode current source | Drives current into anode of first remote thermal diode (e.g., Pentium 4 die or MMBT3904); no capacitor required but 100 pF improves noise immunity |
| D1− | Diode return current sink | Completes current path from cathode of first remote diode; paired with D1+ for ΔVBE measurement |
| D2+ | Diode current source | Drives second remote diode (e.g., GPU or VRM FET junction); independent biasing from D1+ path |
| D2− | Diode return current sink | Completes current path for second remote diode; supports simultaneous dual-zone monitoring |
| GND | Power supply ground | Low-noise system ground reference - must be routed separately from noisy digital/power grounds |
| VDD | Positive supply input | 3.0–3.6 V supply; requires local 0.1 µF ceramic + 100 pF capacitor placed adjacent to pin |
| SMBDAT | SMBus bidirectional data line | Open-drain output - requires external pull-up resistor (≤82 kΩ @ 3.0 V) to ensure 2.1 V logic high |
| SMBCLK | SMBus clock input | Asynchronous master-driven clock; accepts 10–100 kHz; no internal pull-up needed |
Key Features
| Feature | Design Value |
|---|---|
| TruTherm™ technology | Reduces non-ideality spread in Intel 90nm thermal diodes - enables ±0.75°C accuracy without per-unit calibration |
| Dual independent diode channels | Simultaneous monitoring of CPU and GPU or VRM FET junctions - eliminates need for multiple sensors |
| Configurable digital filtering | Enables 13-bit resolution (0.03125°C LSB) and extended range (>127°C) for remote diodes when enabled |
| Diode fault detection | Flags open-circuit, short-to-rail, or floating conditions on D1+/D1− or D2+/D2− - reports −128.000°C (signed) or +255.875°C (unsigned) |
| Programmable diode model selection | Register-selectable between Intel 90nm processor and MMBT3904 transistor - ensures optimal bias and compensation |
Applications
| Laptop CPU Thermal Management | Server Processor Monitoring |
|---|---|
|
Use Scenario: Real-time die temperature tracking of Intel Pentium 4 (90nm) CPUs in thin-and-light notebooks during burst workloads. IC Role / Device Role / Timing Role: Dual remote diode sensor providing synchronized local + CPU die + VRM FET junction readings via SMBus polling every 100 ms. Use Value: Enables dynamic fan speed control and thermal throttling with ±0.75°C accuracy - prevents thermal runaway while maximizing performance headroom. |
Use Scenario: Multi-socket server motherboard monitoring CPU, memory VRM, and chipset junction temperatures under sustained load. IC Role / Device Role / Timing Role: Centralized thermal sensor interfacing with BMC over SMBus - reads three zones (local + D1 + D2) in round-robin sequence (max 87.7 ms per full cycle). Use Value: Supports predictive thermal derating and hot-swap alerts using validated 13-bit filtered resolution - critical for ASHRAE A3/A4 environmental compliance. |
| Workstation GPU Thermal Sensing | Industrial Embedded Controller |
|
Use Scenario: Monitoring discrete MMBT3904-based thermal diodes attached to GPU power stages in CAD/CAM workstations. IC Role / Device Role / Timing Role: Remote diode channel 2 configured for 2N3904 model (TruTherm disabled), delivering ±1.25°C accuracy across −25°C to +125°C ambient. Use Value: Eliminates need for external signal conditioning - direct SMBus-read temperature values reduce BOM count and layout complexity. |
Use Scenario: Local die + dual remote sensing in fanless industrial controllers where self-heating must be isolated from ambient measurements. IC Role / Device Role / Timing Role: Local temperature used for self-heating correction; D1+/D1− monitors heatsink baseplate; D2+/D2− tracks power MOSFET junction. Use Value: Achieves ±3.0°C local accuracy with 0.25°C LSB - enables closed-loop thermal compensation in sealed enclosures without airflow. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual remote diode temperature sensing applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM95235CIMM/NOPB | Higher-grade variant: ±0.5°C remote accuracy (Intel 90nm), 13-bit resolution standard, same VSSOP-8 package | Targeted at premium servers/workstations requiring tighter thermal margins; not drop-in - requires firmware update for register map differences | Select LM95235CIMM/NOPB only if ±0.5°C accuracy is mandatory and system firmware can accommodate extended status/config registers. |
| MAX6642AESA+ | Maxim part: ±1.0°C remote accuracy, I²C/SMBus compatible, 8-pin SOIC (not VSSOP), no TruTherm equivalent | Used in cost-sensitive industrial designs where 90nm Intel compatibility is not required; lacks analog/digital filtering co-design | Choose MAX6642AESA+ for legacy SOIC layouts or when interfacing with non-Intel thermal diodes - verify PCB footprint and thermal performance trade-offs. |
Compared with LM95231CIMM/NOPB, LM95235CIMM/NOPB delivers higher accuracy at the cost of firmware compatibility, while MAX6642AESA+ offers SOIC packaging and broader diode support but sacrifices TruTherm-enhanced precision for Intel 90nm processes.
Availability
LM95231CIMM/NOPB is available at Aetrix Electronics and suitable for laptop thermal management, server processor monitoring, and industrial embedded controller applications requiring stable component supply and long-term lifecycle support.
Supply support for LM95231CIMM/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 expertise in precision sensing and thermal management ICs.
The LM95231CIMM/NOPB belongs to TI's TruTherm™-enabled temperature sensor family, engineered specifically for high-accuracy die-temperature monitoring in Intel and AMD processor platforms and discrete thermal diode implementations.
FAQ
What is the maximum ambient operating temperature for LM95231CIMM/NOPB?
The LM95231CIMM/NOPB is rated for operation from 0°C to +85°C ambient temperature, as specified in the Electrical Characteristics table for the CIMM grade. This differs from the BIMM grade (0°C to +125°C) and reflects its target use in consumer and commercial computing environments where board-level temperatures remain within this range.
Does LM95231CIMM/NOPB support both Intel and AMD processor thermal diodes?
The LM95231CIMM/NOPB is explicitly characterized and trimmed for Intel Pentium 4 processors on 90nm process and MMBT3904-type discrete transistors. While it may interface with some AMD thermal diodes, TI does not guarantee accuracy or specify parameters for AMD parts - only Intel 90nm and MMBT3904 are validated in the SNIS139E datasheet.
How does TruTherm™ technology improve accuracy in LM95231CIMM/NOPB?
TruTherm™ technology in the LM95231CIMM/NOPB actively compensates for process-induced non-ideality spread in Intel 90nm thermal diodes. By adjusting bias current and analog filtering response, it reduces measurement error to ±0.75°C - a 2× improvement over conventional diode sensors lacking this circuitry.
Can LM95231CIMM/NOPB measure temperatures above 127°C?
Yes - when digital filtering is enabled and remote resolution is set to 13-bit unsigned mode, the LM95231CIMM/NOPB resolves temperatures up to +255.875°C with 0.03125°C LSB. This capability is confirmed in Tables 4 and 5 of the SNIS139E datasheet and applies to both D1 and D2 channels.
What is the SMBus slave address for LM95231CIMM/NOPB?
The SMBus 7-bit slave address for LM95231CIMM/NOPB is 1010111b (0x57 hex), as defined in the "SMBus Slave Address" table of the SNIS139E datasheet. This address is factory-programmed and cannot be modified by software or hardware configuration.
LM95231CIMM/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- TruTherm™
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Sensor Type:
- Digital, Local/Remote
- Sensing Temperature - Local:
- 0°C ~ 85°C
- Sensing Temperature - Remote:
- 0°C ~ 85°C
- Output Type:
- SMBus
- Voltage - Supply:
- 3V ~ 3.6V
- Resolution:
- 9 b (Local), 12 b (Remote)
- Features:
- One-Shot, Programmable Resolution, Shutdown Mode, Standby Mode
- Accuracy - Highest (Lowest):
- ±3°C
- Test Condition:
- 0°C ~ 85°C
- Operating Temperature:
- 0°C ~ 125°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-VSSOP
LM95231CIMM/NOPB FAQ
1.How can I place an order for LM95231CIMM/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM95231CIMM/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 LM95231CIMM/NOPB reliable?
The price and inventory of LM95231CIMM/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM95231CIMM/NOPB is usually 5 days.
3.What payment methods are accepted for LM95231CIMM/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM95231CIMM/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM95231CIMM/NOPB?
LM95231CIMM/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM95231CIMM/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 LM95231CIMM/NOPB?
For technical support, including LM95231CIMM/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM95231CIMM/NOPB requirements.
6.How does Aetrix verify that LM95231CIMM/NOPB is sourced from the original manufacturer or authorized distributors?
All LM95231CIMM/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 LM95231CIMM/NOPB meets industry standards.
7.What is the process for return or replacement of LM95231CIMM/NOPB?
All LM95231CIMM/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM95231CIMM/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 LM95231CIMM/NOPB part is unused and in its original packaging.
Return procedure for LM95231CIMM/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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