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Texas Instruments LM95235EIMMX
- Part No.:
- LM95235EIMMX
- Manufacturer:
- Texas Instruments
- Category:
- Analog and Digital Output
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM95235EIMMX.pdf
- Description:
- SENSOR DIGITAL -40C-90C 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,568
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Product details
Overview
LM95235EIMMX from Texas Instruments is a precision remote diode temperature sensor IC with SMBus 2.0 interface and TruTherm™ BJT beta compensation technology. It monitors both local die temperature and remote thermal diode junction temperature (e.g., in Intel 65/90 nm processors or MMBT3904 transistors), delivers ±0.75°C remote accuracy over 60°C–100°C, operates from 3.0 V to 3.6 V, and supports programmable digital filtering for noise suppression in high-speed computing systems.
For engineers reviewing the LM95235EIMMX datasheet, LM95235EIMMX pinout, LM95235EIMMX application, or LM95235EIMMX equivalent, this page provides verified technical context, exact pin functions, real-world thermal monitoring use cases, confirmed alternative parts with documented differences, and supply support for industrial and embedded thermal management designs.
Technical Context
The LM95235EIMMX implements ΔVBE-based remote sensing with a sigma-delta ADC and TruTherm technology to correct for BJT beta variation across process nodes - enabling accurate measurement of sub-micron processor diodes. Its dual-channel architecture independently digitizes local (11-bit, ±2.0°C max) and remote (11-bit or 13-bit filtered, ±0.75°C max) temperatures using left-justified 16-bit word format.
SMBus 2.0 compatibility includes timeout recovery, open-drain SMBDAT/SMBCLK with 100 kHz max clock, and three-level address selection via OS/A0 pin. Critical outputs T_CRIT and OS are open-drain, active-low, and configurable with shared hysteresis, programmable thresholds (default 110°C/85°C), and fault detection for diode disconnection or leakage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 3.0 V to 3.6 V - ensures compatibility with 3.3 V system rails and stable operation under typical CPU voltage regulator tolerances. |
| Remote Temp Accuracy | ±0.75°C max (TA = 25°C–85°C, TD = 60°C–100°C) - enables precise thermal throttling control for Intel 65 nm processors without calibration. |
| Local Temp Accuracy | ±2.0°C max (TA = 25°C–100°C) - sufficient for board-level ambient or package temperature monitoring with minimal self-heating impact. |
| Digital Filter Resolution | 0.03125°C (13-bit filtered mode) - improves noise immunity on noisy PCBs while enabling fine-grained fan speed or power state decisions. |
| Conversion Rate Range | 16 Hz to 0.4 Hz - allows dynamic trade-off between update latency (63 ms fastest) and quiescent current (350 µA at 1 Hz). |
| Operating Temperature | −40°C to +90°C (E-grade) - qualified for extended commercial environments including industrial PCs and network equipment. |
| SMBus Compatibility | Fully compliant with SMBus 2.0, including TIMEOUT reset and no clock stretching - ensures interoperability with standard host controllers without firmware modification. |
Pinout & Package
LM95235EIMMX is housed in an 8-pin VSSOP package (DGK0008A), optimized for space-constrained thermal sensor placement near CPUs or GPUs. Thermal resistance θJA = 210°C/W on 1 oz. copper PCB with no airflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VDD | Power supply input | Requires 10 µF || 0.1 µF || 100 pF bypassing; 100 pF must be placed closest to pin to suppress high-frequency noise. |
| 2 D+ | Remote diode positive terminal | Analog input/output; forward-biasing beyond 50 mV corrupts measurement - requires careful PCB routing away from switching nodes. |
| 3 D− | Remote diode negative terminal | Analog input/output; source current up to 225 µA; sensitive to PCB leakage - guard ring recommended for >125°C remote sensing. |
| 4 T_CRIT | Critical temperature alert output | Open-drain, active-low; asserts when either channel exceeds programmed T_CRIT limit; requires external pull-up to VDD or host rail. |
| 5 GND | Ground reference | Must connect to clean analog ground plane; separate from high-current digital ground to avoid measurement offset. |
| 6 OS/A0 | Address select or over-temp output | Three-state input (Low/Mid/High) sets SMBus address (18h/29h/4Ch); configurable as open-drain OS output only when set to High. |
| 7 SMBDAT | SMBus bidirectional data line | Open-drain; requires external pull-up; supports standard SMBus read/write sequences and timeout recovery. |
| 8 SMBCLK | SMBus clock input | Input-only; no clock stretching; accepts 10–100 kHz clocks per SMBus 2.0 spec. |
Key Features
| Feature | Design Value |
|---|---|
| TruTherm™ BJT beta compensation | Enables ±0.75°C remote accuracy on 65/90 nm Intel processors by dynamically correcting for transistor beta drift across temperature and process variation. |
| Programmable digital filter (remote channel) | Configurable 13-bit filtered resolution (0.03125°C) reduces sensitivity to EMI and PCB leakage, improving stability in high-noise server or graphics card environments. |
| Diode model selection bit | Selects internal compensation curve for either MMBT3904 discrete transistor or Intel 65/90 nm processor diodes - eliminates need for external calibration coefficients. |
| Shared hysteresis register | Single 4-bit register applies identical hysteresis to all T_CRIT and OS thresholds - simplifies thermal loop design and avoids oscillation during threshold crossings. |
| Standby mode with one-shot conversion | Reduces quiescent current to 300 µA; host can trigger single local+remote conversion via register write - ideal for battery-backed or low-power wake-on-temp applications. |
Applications
| Laptop CPU Thermal Throttling | Server Blade Fan Control |
|---|---|
|
Use Scenario: Real-time monitoring of Intel Core i7 die temperature during sustained compute loads to prevent thermal runaway. IC Role / Device Role / Timing Role: Remote diode sensor measuring processor junction temperature via integrated thermal diode; local sensor monitors SoC package temperature. Use Value: Enables precise, low-latency (<63 ms) thermal response using factory-calibrated TruTherm compensation - eliminates need for system-level calibration and reduces firmware overhead. |
Use Scenario: Coordinating multi-zone fan speeds across dense 1U server blades based on GPU, CPU, and VRM hotspot temperatures. IC Role / Device Role / Timing Role: SMBus-connected remote sensor feeding temperature data to baseboard management controller (BMC) for closed-loop fan PWM control. Use Value: Three-level address pin allows up to three LM95235EIMMX devices on one SMBus segment - simplifying multi-sensor deployment without address conflicts or additional I²C expanders. |
| Industrial PC System Monitoring | Network Equipment Thermal Safety |
|
Use Scenario: Ensuring reliable operation of fanless industrial PCs in uncontrolled ambient environments (−40°C to +70°C). IC Role / Device Role / Timing Role: Local temperature sensor detecting enclosure ambient rise; remote channel monitors FPGA or PMIC junction temperature via external diode. Use Value: −40°C to +90°C operating range and ±2.0°C local accuracy provide margin for long-term drift and self-heating - supporting 10+ year field deployments without recalibration. |
Use Scenario: Preventing catastrophic failure in carrier-grade switches by triggering graceful shutdown before ASIC junction exceeds 125°C. IC Role / Device Role / Timing Role: Critical temperature monitor asserting T_CRIT pin directly to power sequencer or microcontroller interrupt line upon threshold breach. Use Value: Open-drain T_CRIT and OS outputs drive standard logic-level shutdown circuits; default 110°C T_CRIT threshold aligns with common ASIC thermal limits without register programming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar remote diode temperature sensing applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM95234EIMMX | Single remote channel only; no local temperature sensor; identical SMBus interface and TruTherm engine. | Used where only processor diode monitoring is required - saves cost and board space but lacks local ambient reference. | Select when system design does not require local die temperature feedback and board area is constrained. |
| MAX6642AESA+ | Higher remote accuracy (±0.5°C) over narrower range; no TruTherm compensation; uses different diode model assumptions. | Preferred in legacy x86 platforms with older 130 nm or 180 nm processors where beta drift is less pronounced. | Choose only if interfacing with non-Intel diodes or when tighter accuracy at 25°C–70°C is prioritized over wide-range robustness. |
Compared with LM95235EIMMX, LM95234EIMMX removes local sensing capability but retains full remote functionality and pin compatibility, while MAX6642AESA+ trades TruTherm adaptability for higher nominal accuracy on older process nodes - making LM95235EIMMX the optimal choice for modern sub-65 nm CPU thermal management requiring guaranteed accuracy across full industrial temperature range.
Availability
LM95235EIMMX is available at Aetrix Electronics and suitable for laptop thermal management, server blade cooling, industrial PC monitoring, and network equipment safety systems requiring stable component supply across multi-year production cycles.
Supply support for LM95235EIMMX 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 and embedded processing technologies, with decades of expertise in precision sensing, power management, and interface solutions.
The LM95235EIMMX belongs to TI's high-accuracy thermal sensor product line, designed specifically for real-time, closed-loop thermal management in high-performance computing, servers, and industrial systems where junction temperature fidelity directly impacts reliability and performance.
FAQ
What is the remote temperature accuracy of the LM95235EIMMX when monitoring a 65 nm Intel processor?
The LM95235EIMMX achieves ±0.75°C maximum remote temperature accuracy when measuring a 65 nm Intel processor diode within the temperature range TA = 25°C to 85°C and TD = 60°C to 100°C. This specification is enabled by TruTherm™ BJT beta compensation and is validated per the SNIS142F datasheet. The LM95235EIMMX must be configured with the correct diode model selection bit for Intel 65/90 nm processes to achieve this accuracy.
Does the LM95235EIMMX support both local and remote temperature sensing simultaneously?
Yes, the LM95235EIMMX continuously monitors both local die temperature and remote thermal diode temperature in parallel. It uses independent sigma-delta ADCs and stores results in dedicated registers (Local Temp MSB/LSB and Remote Temp MSB/LSB). Conversion occurs in round-robin fashion with a maximum time of 72 ms per channel, and both values are updated every conversion cycle - enabling synchronized thermal decision-making in the LM95235EIMMX.
Can the LM95235EIMMX operate on a 3.3 V supply rail?
Yes, the LM95235EIMMX is fully specified to operate from 3.0 V to 3.6 V, making it compatible with standard 3.3 V system rails. Its quiescent current is 350 µA typical at 1 Hz conversion rate and 3.3 V supply, and all digital I/O thresholds (VIH/VIL) and SMBus timing parameters remain valid across this range - ensuring robust operation in LM95235EIMMX-based 3.3 V designs.
How does the digital filter in the LM95235EIMMX affect temperature resolution and response time?
When enabled, the LM95235EIMMX digital filter increases remote temperature resolution from 0.125°C (11-bit) to 0.03125°C (13-bit), but introduces step-response delay (e.g., ~150 ms settling for a 20°C step). Filtered readings are used for T_CRIT/OS comparisons, improving noise immunity at the cost of transient tracking speed - a deliberate trade-off validated in Figure 11 of the LM95235EIMMX datasheet for Intel 65/90 nm systems.
Is the LM95235EIMMX pin-compatible with the LM86 or LM89?
Yes, the LM95235EIMMX is explicitly stated as pin-for-pin compatible with the LM86 and LM89 in the official TI datasheet (SNIS142F, section "DESCRIPTION"). All eight pins - including VDD, D+, D−, T_CRIT, GND, OS/A0, SMBDAT, and SMBCLK - match functionally and physically, enabling drop-in replacement in existing LM86/LM89 layouts without PCB revision, provided firmware supports the extended register map and TruTherm features of the LM95235EIMMX.
LM95235EIMMX 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 ~ 90°C
- Sensing Temperature - Remote:
- -40°C ~ 90°C
- Output Type:
- SMBus
- Voltage - Supply:
- 3V ~ 3.6V
- Resolution:
- 10 b (Local), 12 b (Remote)
- Features:
- One-Shot, Output Switch, Programmable Limit, 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
LM95235EIMMX FAQ
1.How can I place an order for LM95235EIMMX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM95235EIMMX 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 LM95235EIMMX reliable?
The price and inventory of LM95235EIMMX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM95235EIMMX is usually 5 days.
3.What payment methods are accepted for LM95235EIMMX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM95235EIMMX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM95235EIMMX?
LM95235EIMMX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM95235EIMMX 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 LM95235EIMMX?
For technical support, including LM95235EIMMX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM95235EIMMX requirements.
6.How does Aetrix verify that LM95235EIMMX is sourced from the original manufacturer or authorized distributors?
All LM95235EIMMX 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 LM95235EIMMX meets industry standards.
7.What is the process for return or replacement of LM95235EIMMX?
All LM95235EIMMX units undergo pre-shipment inspection (PSI). If there is an issue with LM95235EIMMX, 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 LM95235EIMMX part is unused and in its original packaging.
Return procedure for LM95235EIMMX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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