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Texas Instruments LM89-1CIMX/NOPB
- Part No.:
- LM89-1CIMX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Analog and Digital Output
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM89-1CIMX/NOPB.pdf
- Description:
- SENSOR DIGITAL 0C-85C 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,109
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Product details
Overview
LM89-1CIMX/NOPB from Texas Instruments is an 11-bit remote diode and local digital temperature sensor with SMBus 2.0 interface, ±0.75°C remote accuracy at 30°C/80°C, 0.125°C remote resolution, and dual open-drain ALERT/T_CRIT_A outputs for thermal monitoring of MCUs, GPUs, FPGAs, and ASICs in computing systems.
For engineers reviewing the LM89-1CIMX/NOPB datasheet, LM89-1CIMX/NOPB pinout, LM89-1CIMX/NOPB application, or LM89-1CIMX/NOPB equivalent, key selection criteria include remote diode nonideality compensation via offset registers, T_CRIT hysteresis programmability, SMBus TIMEOUT reset capability, and compatibility with thermal diodes on Intel Pentium 4–class dies.
Technical Context
The LM89-1CIMX/NOPB implements a delta-VBE-based sensing architecture with separate 10-bit-plus-sign remote and 8-bit local ADCs. Its SMBus 2.0 interface supports TIMEOUT reset (25–35 ms low pulse), ALERT masking, and ARA protocol compliance for multi-device alert arbitration.
It features programmable conversion rate (31.25 ms base time), dual independent limit comparators (HIGH/LOW/T_CRIT) per channel, and hardware hysteresis applied to both local and remote T_CRIT thresholds via a shared TH register.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Remote Temp Accuracy | ±0.75°C max at TA=30°C, TD=80°C - enables precise die-temperature tracking of high-performance processors |
| Local Temp Accuracy | ±3.0°C max over 25°C–125°C - sufficient for ambient or package-level thermal supervision |
| Remote Resolution | 0.125°C (11-bit) - supports fine-grained thermal throttling decisions |
| Supply Voltage | 3.0 V to 3.6 V - compatible with standard 3.3V system rails and requires 0.1µF + 100pF bypassing |
| SMBus Clock Range | 10 kHz to 100 kHz - ensures interoperability with legacy and modern SMBus controllers |
| T_CRIT Default | 85°C - matches common processor thermal shutdown thresholds for immediate system protection |
| Quiescent Current | 1.7 mA typical at 16 Hz conversion - balances responsiveness and power in always-on monitoring |
Pinout & Package
LM89-1CIMX/NOPB is housed in an 8-pin VSSOP (DGK) package measuring 3.0 mm × 3.0 mm, optimized for space-constrained PCB layouts near high-power ICs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD | Positive supply input | 3.0–3.6 V rail requiring local 0.1 µF + 100 pF decoupling; bulk 10 µF nearby |
| D+ | Diode current source | Drives remote diode anode; mandates 2.2 nF capacitor placed between D+ and D− pins |
| D− | Diode return sink | Completes remote diode current path; sensitive to trace matching and parasitic forward bias |
| T_CRIT_A | Active-low critical alarm | Open-drain output asserting when any temp exceeds T_CRIT; includes programmable hysteresis |
| GND | Power ground reference | Common return for analog and digital sections; must be low-impedance connection |
| ALERT | Active-low general alarm | Open-drain output triggered by HIGH/LOW/T_CRIT violations; supports comparator/interrupt/ARA modes |
| SMBData | SMBus bidirectional data | Open-drain I/O with 5 pF input capacitance; requires external pull-up resistor |
| SMBCLK | SMBus clock input | Input-only clock line with 400 mV hysteresis; defines timing for all SMBus transactions |
Key Features
| Feature | Design Value |
|---|---|
| Remote diode offset calibration | Two 8-bit offset registers (RTOLB/RTOHB) compensate for nonideality factors (e.g., 1.0021) without software intervention |
| Programmable T_CRIT hysteresis | Hysteresis register (TH) sets recovery threshold as T_CRIT − TH, preventing chatter during thermal transients |
| SMBus TIMEOUT reset | Holding SMBData/SMBCLK low >25 ms resets internal state machine, restoring communication after bus lockup |
| Three ALERT operating modes | Configurable as hardware comparator, interrupt flag, or SMBus ARA responder - adapts to host controller architecture |
| Pin/register compatibility | Direct replacement for LM86/LM90/LM99/ADM1032/MAX6657/8 - simplifies migration and second-sourcing |
Applications
| Laptop CPU Thermal Management | Server GPU Monitoring |
|---|---|
Use Scenario: Real-time die temperature tracking of Intel Core i7 or AMD Ryzen mobile CPUs during sustained workloads. IC Role / Device Role / Timing Role: Remote diode sensor interfacing with CPU-integrated thermal diode; reports 0.125°C-resolution readings every 31.25 ms. Use Value: Enables dynamic fan speed control and frequency throttling before thermal throttling occurs, preserving performance and reliability. | Use Scenario: Concurrent monitoring of multiple GPU dies (e.g., NVIDIA A100) in AI training servers using daisy-chained SMBus topology. IC Role / Device Role / Timing Role: Local + remote sensor providing independent alerts via T_CRIT_A (critical shutdown) and ALERT (warning/adjustment). Use Value: Prevents catastrophic overheating by triggering power-down within 31.25 ms of exceeding 85°C, while supporting ARA-based multi-device alert prioritization. |
| Industrial FPGA-Based Vision System | Network Switch ASIC Thermal Protection |
Use Scenario: Monitoring Xilinx Kintex Ultrascale+ FPGA junction temperature in outdoor telecom equipment exposed to wide ambient swings. IC Role / Device Role / Timing Role: Local sensor tracks ambient board temperature; remote diode senses FPGA die via on-die diode; both use same SMBus address (LM89-1C default). Use Value: Offset register tuning compensates for FPGA-specific diode nonideality, achieving ±0.75°C accuracy critical for fanless enclosure design. | Use Scenario: Protecting Broadcom Tomahawk 4 switch ASICs in 100G Ethernet line cards where thermal runaway can cause packet loss or link failure. IC Role / Device Role / Timing Role: Dedicated LM89-1CIMX/NOPB per ASIC, with T_CRIT_A wired to power sequencer to cut VDD within 100 µs of alarm assertion. Use Value: Hardware-level shutdown avoids software delays, meeting sub-millisecond response requirements for carrier-grade reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar remote/local temperature sensing applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM90CIMM/NOPB | Same 8-pin SOIC package; ±0.75°C remote accuracy; but uses different SMBus slave address (1001100 vs 1001101) | Supports dual-sensor configurations on same SMBus without address conflict; lacks LM89-1C's 85°C T_CRIT default | Select when board layout accommodates SOIC and multi-sensor address isolation is required |
| MAX6657ESA+ | Pin-compatible 8-pin SOIC; identical SMBus interface; ±1.0°C remote accuracy (worse than LM89-1C's ±0.75°C) | Higher quiescent current (2.5 mA vs 1.7 mA); no T_CRIT hysteresis register; limited diode nonideality compensation | Select only if MAX6657 is already qualified in existing design and ±1.0°C accuracy suffices |
Compared with LM90CIMM/NOPB and MAX6657ESA+, the LM89-1CIMX/NOPB delivers superior remote accuracy (±0.75°C), integrated T_CRIT hysteresis control, and optimized VSSOP footprint for dense compute modules - making it preferred for new laptop, server, and FPGA designs demanding precision thermal response.
Availability
LM89-1CIMX/NOPB is available at Aetrix Electronics and suitable for laptop CPU thermal management, server GPU monitoring, industrial FPGA-based vision systems, and network switch ASIC thermal protection requiring stable component supply across production lifecycles.
Supply support for LM89-1CIMX/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 power management ICs.
The LM89 product line was designed specifically for high-accuracy, dual-point (local + remote) thermal monitoring in computing platforms - targeting laptops, servers, workstations, and embedded systems where die temperature fidelity directly impacts performance and reliability.
FAQ
What is the SMBus slave address of LM89-1CIMX/NOPB?
The LM89-1CIMX/NOPB has a fixed SMBus slave address of 1001101 (0x4D in hexadecimal). This differs from the base LM89C (1001100, 0x4C) and LM89-1D (1001101, 0x4D but with 105°C T_CRIT default), enabling up to two LM89-1CIMX/NOPB devices on the same bus without address collision. The address is hardwired and not software-configurable.
Does LM89-1CIMX/NOPB support remote diode sensing on modern processors like AMD Ryzen or Intel Core i9?
Yes, LM89-1CIMX/NOPB supports remote diode sensing on AMD Ryzen and Intel Core i9 processors. Its delta-VBE architecture and offset register (RTOLB/RTOHB) allow calibration to nonideality factors as low as 1.0021 - matching specifications of Pentium 4–class and newer thermal diodes. Validation requires verifying diode series resistance (<3.64 Ω) and placement of the mandatory 2.2 nF capacitor between D+ and D−.
How does the T_CRIT_A output behave when the remote temperature exceeds its limit?
When the remote temperature exceeds its programmed T_CRIT limit, the LM89-1CIMX/NOPB asserts T_CRIT_A low immediately after conversion completion (~31.25 ms). It remains asserted until the temperature falls below (T_CRIT − TH), where TH is the value in the hysteresis register. This prevents oscillation during thermal transients and ensures clean shutdown signaling to power controllers or PMICs.
Can LM89-1CIMX/NOPB operate from a 2.5V supply?
No, LM89-1CIMX/NOPB requires a supply voltage between 3.0 V and 3.6 V per its Absolute Maximum Ratings and Recommended Operating Conditions. Operation below 3.0 V risks undefined behavior, including inaccurate conversions, SMBus communication failure, or failure to assert ALERT/T_CRIT_A. A dedicated 3.3V LDO or regulator rail is mandatory.
Is LM89-1CIMX/NOPB RoHS-compliant and lead-free?
Yes, LM89-1CIMX/NOPB is RoHS-compliant and lead-free. The "/NOPB" suffix explicitly denotes "No Lead (Pb)-Free" packaging, conforming to JEDEC J-STD-020 moisture sensitivity level 3 and IPC/JEDEC J-STD-033 handling requirements. Full compliance documentation, including material declarations and test reports, is available through Texas Instruments' Quality & Environmental page.
LM89-1CIMX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm 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:
- 7 b (Local), 10 b (Remote)
- Features:
- One-Shot, Output Switch, Programmable Limit, Shutdown Mode, Standby Mode
- Accuracy - Highest (Lowest):
- ±3°C
- Test Condition:
- 25°C ~ 125°C
- Operating Temperature:
- 0°C ~ 125°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-SOIC
LM89-1CIMX/NOPB FAQ
1.How can I place an order for LM89-1CIMX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM89-1CIMX/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 LM89-1CIMX/NOPB reliable?
The price and inventory of LM89-1CIMX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM89-1CIMX/NOPB is usually 5 days.
3.What payment methods are accepted for LM89-1CIMX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM89-1CIMX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM89-1CIMX/NOPB?
LM89-1CIMX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM89-1CIMX/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 LM89-1CIMX/NOPB?
For technical support, including LM89-1CIMX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM89-1CIMX/NOPB requirements.
6.How does Aetrix verify that LM89-1CIMX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM89-1CIMX/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 LM89-1CIMX/NOPB meets industry standards.
7.What is the process for return or replacement of LM89-1CIMX/NOPB?
All LM89-1CIMX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM89-1CIMX/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 LM89-1CIMX/NOPB part is unused and in its original packaging.
Return procedure for LM89-1CIMX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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