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Texas Instruments LM95245CIMM/NOPB
- Part No.:
- LM95245CIMM/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Analog and Digital Output
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM95245CIMM/NOPB.pdf
- Description:
- SENSOR DIGITAL -40C-85C 8VSSOP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM95245CIMM/NOPB from Texas Instruments is an 11-bit SMBus-compatible digital temperature sensor with dual local/remote measurement channels, TruTherm® BJT beta compensation for 45nm Intel processor diodes, ±0.75°C remote accuracy (TA=25–85°C, TD=50–105°C), and programmable T_CRIT/OS thresholds. It delivers precise thermal monitoring in laptop CPU cooling subsystems and server motherboard thermal management.
For engineers reviewing the LM95245CIMM/NOPB datasheet, LM95245CIMM/NOPB pinout, LM95245CIMM/NOPB application, or LM95245CIMM/NOPB equivalent, key selection criteria include remote diode accuracy on sub-90nm processes, SMBus 2.0 timing compliance, digital filter enablement for noise immunity, and VSSOP-8 package compatibility with high-density PCB layouts.
Technical Context
The LM95245CIMM/NOPB implements ΔVBE-based remote sensing with a Sigma-Delta ADC and TruTherm technology to correct for beta variation in Intel 45nm/65nm/90nm process thermal diodes. Its dual-channel architecture independently digitizes local die temperature and external diode junction temperature using 11-bit signed (local) and 13-bit filtered/11-bit unfiltered (remote) formats.
It features a programmable digital filter (enabled by default in Configuration Register 2), shared hysteresis register for OS/TCRIT outputs, and three-level address pin (OS/A0) supporting up to three devices on one SMBus segment. Conversion rate is adjustable from 0.4 Hz to 16 Hz, with standby mode enabling one-shot triggering via SMBus write.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Remote Accuracy | ±0.75°C max (TA=25–85°C, TD=50–105°C, 45nm Intel diode) - enables reliable CPU throttling at critical junction temperatures |
| Local Accuracy | ±2.0°C max (TA=25–100°C) - sufficient for ambient board temperature tracking without self-heating correction |
| Resolution (Remote, Filter On) | 0.03125°C (13-bit unsigned) - supports fine-grained fan speed control and thermal margining |
| Supply Voltage | 3.0 V to 3.6 V - compatible with standard 3.3V system rails and LDO outputs |
| Quiescent Current | 350 µA typ at 1 Hz conversion - enables low-power thermal monitoring in always-on system states |
| SMBus Compatibility | SMBus 2.0 compliant with TIMEOUT support - ensures robust communication in noisy server/laptop environments |
| Operating Temp Range | −40°C to +125°C - supports placement near hot CPU VRMs and under-chassis locations |
Pinout & Package
LM95245CIMM/NOPB is housed in an 8-pin VSSOP package (DGK0008A), optimized for space-constrained thermal sensor placement near processors. Thermal resistance θJA = 210°C/W on 1 oz. copper PCB with no airflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD (Pin 1) | Power supply input | Requires 10 µF + 0.1 µF + 100 pF bypass network; 100 pF must be placed closest to pin to suppress high-frequency noise |
| D+ / D− (Pins 2, 3) | Remote diode analog interface | Differential inputs for Intel thermal diode; forward bias >50 mV corrupts measurement - requires careful PCB routing and ESD protection |
| T_CRIT (Pin 4) | Open-drain critical alert output | Active-low signal asserting when remote/local exceeds programmed TCRIT limit (default +110°C/+85°C); requires external pull-up |
| GND (Pin 5) | Reference ground | Must connect to clean analog ground plane; shared with digital return but isolated from noisy power grounds |
| OS/A0 (Pin 6) | Configurable address/alert pin | Defaults to A0 address select (three SMBus addresses: 18h/29h/4Ch); programmable as open-drain OS output only when pulled high |
| SMBDAT (Pin 7) | SMBus bidirectional data line | Open-drain interface requiring external pull-up; no internal pull-up - timing defined per SMBus 2.0 spec (tHD;DAT, tSU;DAT) |
| SMBCLK (Pin 8) | SMBus clock input | Asynchronous input driving internal state machine; no clock stretching supported - host must manage timing margins |
Key Features
| Feature | Design Value |
|---|---|
| TruTherm® BJT Beta Compensation | Corrects for process-induced beta drift in 45nm/65nm/90nm Intel thermal diodes - eliminates calibration per batch |
| Programmable Remote Digital Filter | Enables 0.03125°C resolution and noise rejection in electrically noisy CPU voltage regulator areas |
| Two Temperature Data Formats | Supports both −128°C to +127.875°C (signed) and 0°C to +255.875°C (unsigned) ranges - avoids rollover in high-temp server applications |
| Shared Hysteresis Register | Single 4-bit register sets hysteresis for all OS/TCRIT comparisons - simplifies thermal trip point tuning across multiple zones |
| Standby Mode with One-Shot Trigger | Reduces current to 300 µA while retaining SMBus responsiveness; allows on-demand conversion without full wake cycle |
Applications
| Laptop CPU Thermal Management | Server Motherboard Hot-Spot Monitoring |
|---|---|
|
Use Scenario: Real-time junction temperature tracking of Intel Core i-series CPUs in ultrabooks with dual-fan cooling. IC Role / Device Role / Timing Role: Remote channel reads CPU die diode; local channel monitors chipset temperature; SMBus updates every 625 ms for dynamic fan PWM control. Use Value: ±0.75°C remote accuracy prevents premature throttling while ensuring safe operation within Intel TJMAX limits. |
Use Scenario: Distributed thermal monitoring across multi-socket Xeon platforms with VRM, memory, and I/O hub hot spots. IC Role / Device Role / Timing Role: Three LM95245CIMM/NOPB units on shared SMBus (via A0 pin addressing) report CPU, VRM, and PCH temperatures to BMC. Use Value: Pin-compatible replacement for LM95235/LM86 enables drop-in upgrade path with improved 45nm diode accuracy. |
| Workstation GPU Thermal Protection | Industrial Embedded Controller Cooling |
|
Use Scenario: GPU die temperature supervision in CAD/CAM workstations where sustained compute loads cause rapid thermal transients. IC Role / Device Role / Timing Role: Remote channel tracks GPU thermal diode; digital filter enabled to reject switching noise from adjacent DC-DC converters. Use Value: 13-bit filtered resolution (0.03125°C) enables precise detection of <1°C thermal ramp rates for predictive fan control. |
Use Scenario: Fanless industrial controller operating in −40°C to +85°C ambient with passive heatsink and thermal shutdown requirements. IC Role / Device Role / Timing Role: Local channel monitors SoC temperature; T_CRIT output directly drives solid-state relay for forced shutdown at +105°C. Use Value: −40°C to +125°C operating range and 300 µA standby current ensure reliability in extended-temperature sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar digital temperature sensor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM95235CIMM/NOPB | Same pinout, identical SMBus interface, but lacks TruTherm® compensation for 45nm diodes; remote accuracy ±1.5°C over wider TD range | Valid for legacy 90nm/130nm processors; not recommended for post-2008 Intel CPUs with sub-65nm thermal diodes | Select LM95235CIMM/NOPB only for cost-sensitive retrofits where 45nm diode accuracy is not required. |
| LM86CIMM/NOPB | Pin-compatible, same VSSOP-8 package, but uses older diode model; no digital filter; remote accuracy ±1.0°C (TA=0–70°C, TD=25–100°C) | Designed for Pentium 4-era platforms; lacks SMBus TIMEOUT support and failsafe reset behavior | Choose LM86CIMM/NOPB only for brownfield designs with existing LM86 firmware and layout - not for new 45nm+ designs. |
Compared with LM95235CIMM/NOPB and LM86CIMM/NOPB, the LM95245CIMM/NOPB provides superior remote accuracy on modern Intel processors, integrated digital filtering for noise-prone VRM regions, and guaranteed SMBus 2.0 TIMEOUT compliance - making it the only option qualified for 45nm thermal diode monitoring in production laptops and servers.
Availability
LM95245CIMM/NOPB is available at Aetrix Electronics and suitable for laptop thermal management, server motherboard monitoring, and workstation GPU cooling requiring stable component supply and long-term lifecycle support.
Supply support for LM95245CIMM/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 over 50 years of innovation in precision sensing and power management ICs.
The LM95245CIMM/NOPB belongs to TI's precision thermal sensor product line, engineered specifically for accurate remote diode monitoring in high-performance computing platforms using Intel 45nm and smaller process nodes.
FAQ
What is the remote temperature accuracy of the LM95245CIMM/NOPB when monitoring a 45nm Intel processor diode?
The LM95245CIMM/NOPB achieves ±0.75°C maximum remote temperature accuracy when measuring a 45nm Intel processor thermal diode under conditions of TA = 25°C to 85°C and TD = 50°C to 105°C. This specification is explicitly guaranteed in the datasheet for that exact process node and temperature range. The LM95245CIMM/NOPB uses TruTherm® BJT beta compensation to achieve this accuracy, which is not available in earlier sensors like the LM86CIMM/NOPB.
Does the LM95245CIMM/NOPB support both signed and unsigned temperature output formats?
Yes, the LM95245CIMM/NOPB supports two simultaneous remote temperature data formats: a 12-bit plus sign (two's complement) format for negative temperatures and a 13-bit unsigned format for values up to +255.875°C. Both are accessible via separate registers, allowing seamless handling of sub-zero cold starts and high-temperature server operation without rollover. The LM95245CIMM/NOPB local channel uses a fixed 10-bit plus sign format with 0.125°C LSB.
How does the digital filter in the LM95245CIMM/NOPB affect resolution and noise performance?
When enabled, the LM95245CIMM/NOPB's programmable digital filter increases remote temperature resolution from 0.125°C (11-bit) to 0.03125°C (13-bit) and suppresses high-frequency noise from nearby switching regulators. The filter is implemented in Configuration Register 2 (FE1/FE0 bits) and is active by default at power-up. Filtered readings are used for all OS/TCRIT comparisons, ensuring thermal alerts reflect true thermal trends rather than transient noise spikes.
Can the OS/A0 pin on the LM95245CIMM/NOPB be used as both an address selector and an over-temperature output?
No - the OS/A0 pin on the LM95245CIMM/NOPB functions exclusively as either an SMBus address input (A0) or an open-drain over-temperature output (OS), but not both simultaneously. It defaults to A0 at power-up and can only be reconfigured as OS when pulled high. When used as OS, only the 4Ch slave address is valid; using A0 for address selection permits three addresses (18h/29h/4Ch). This dual-role limitation is documented in the LM95245CIMM/NOPB functional description.
What is the SMBus timing compliance status of the LM95245CIMM/NOPB?
The LM95245CIMM/NOPB fully meets SMBus 2.0 specifications including TIMEOUT functionality, with guaranteed timing parameters such as tLOW ≥ 4.7 µs, tHIGH ≥ 4.0 µs, and tTIMEOUT = 25–35 ms. It does not support clock stretching and requires strict adherence to SMBus 2.0 setup/hold times (e.g., tSU;DAT ≥ 250 ns). These characteristics are validated across −40°C to +125°C and ensure interoperability with industry-standard BMC and EC controllers.
LM95245CIMM/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:
- -40°C ~ 85°C
- Sensing Temperature - Remote:
- -40°C ~ 85°C
- Output Type:
- SMBus
- Voltage - Supply:
- 3V ~ 3.6V
- Resolution:
- 10 b (Local), 12 b (Remote)
- Features:
- One-Shot, Output Switch, Programmable Resolution, Shutdown Mode, Standby Mode
- Accuracy - Highest (Lowest):
- ±2°C (±6°C)
- Test Condition:
- 25°C ~ 100°C (-40°C ~ 25°C)
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-VSSOP
LM95245CIMM/NOPB FAQ
1.How can I place an order for LM95245CIMM/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM95245CIMM/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 LM95245CIMM/NOPB reliable?
The price and inventory of LM95245CIMM/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM95245CIMM/NOPB is usually 5 days.
3.What payment methods are accepted for LM95245CIMM/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM95245CIMM/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM95245CIMM/NOPB?
LM95245CIMM/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM95245CIMM/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 LM95245CIMM/NOPB?
For technical support, including LM95245CIMM/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM95245CIMM/NOPB requirements.
6.How does Aetrix verify that LM95245CIMM/NOPB is sourced from the original manufacturer or authorized distributors?
All LM95245CIMM/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 LM95245CIMM/NOPB meets industry standards.
7.What is the process for return or replacement of LM95245CIMM/NOPB?
All LM95245CIMM/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM95245CIMM/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 LM95245CIMM/NOPB part is unused and in its original packaging.
Return procedure for LM95245CIMM/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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