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Texas Instruments LM94CIMTX
- Part No.:
- LM94CIMTX
- Manufacturer:
- Texas Instruments
- Category:
- Thermal Management
- Package:
- 56-TFSOP (0.240", 6.10mm Width)
- Datasheet:
-
LM94CIMTX.pdf
- Description:
- IC HARDWARE MONITOR 56-TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,937
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Product details
Overview
LM94CIMTX from Texas Instruments is a hardware monitor IC for dual-processor server platforms, integrating an 8-bit ΣΔ ADC, TruTherm™ thermal diode measurement engine, dual PWM fan control outputs, and VRD10.2/11-compliant dynamic VID monitoring across 16 power rails, 4 remote thermal diodes, and 2 LM60 inputs. It operates from +3.0V to +3.6V and delivers 0.0625°C filtered temperature resolution for precision PI-loop fan control in Xeon-class motherboards.
For engineers reviewing the LM94CIMTX datasheet, LM94CIMTX pinout, LM94CIMTX application, or LM94CIMTX equivalent, this page provides verified technical context, SMBus 2.0 interface timing, PI vs. LUT fan control trade-offs, thermal accuracy over 0°C–125°C remote range, and validated alternatives for server thermal management ASIC replacement.
Technical Context
The LM94CIMTX implements a dedicated two-wire SMBus 2.0 interface with tri-level address selection (3 slave addresses), ALERT output supporting interrupt/comparator modes, and XOR-tree test capability. Its analog front-end includes programmable attenuators, external diode signal conditioning, and analog multiplexing for simultaneous monitoring of 16 voltage rails and 4 remote thermal diodes.
It embeds dual independent PI control loops-one per PWM output-each configurable with Tcontrol setpoints and digital temperature filters to suppress acoustical noise. Fan tachometer inputs (4) and GPIOs (8) support PROCHOT and VRD_HOT detection, dual-processor THERMTRIP monitoring, and 7th-VID signal capture for VRD11 compliance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | +3.0V to +3.6V - ensures compatibility with 3.3V standby and main rail domains in server power architectures. |
| Temperature Resolution | 0.0625°C (filtered) - enables fine-grained PI loop tuning for low-noise fan speed transitions in high-density compute environments. |
| Voltage Accuracy | ±2% FS - supports reliable margining and fault detection across 16 monitored rails including ±12V, +5V, +3.3V, Vccp, and memory core voltages. |
| Remote Temp Range | 0°C to +125°C - covers full operational envelope of modern Xeon processors and VRMs under thermal stress. |
| Digital Interface | SMBus 2.0 compliant - guarantees interoperability with Baseboard Management Controllers (BMCs) and host firmware using standard block read/write protocols. |
| Package | 56-pin TSSOP - provides compact footprint for dense motherboard layouts while maintaining thermal performance via 79°C/W θJA (0 m/s airflow). |
| Fan Control Outputs | 2 PWM (open-drain) - drives up to two independent cooling zones with fan boost on tachometer limit error events. |
Pinout & Package
LM94CIMTX is housed in a 56-pin TSSOP package (package code DGG0056A), with exposed pad for thermal dissipation and optimized routing for analog/digital separation. Pin functions are validated per TI SNAS264D Rev FEBRUARY 2024.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GPIO_0/TACH1 – GPIO_3/TACH4 | Fan tachometer input / configurable GPIO | Four dedicated open-drain inputs for RPM feedback; each can be reassigned as general-purpose I/O for system signaling or error monitoring. |
| PWM1 / PWM2 | Fan speed control output | Open-drain PWM outputs supporting 13-step lookup table or PI-loop-based duty cycle generation with fan boost activation on tach error. |
| REMOTE1a+/REMOTE1−, REMOTE2a+/REMOTE2− | Remote thermal diode interface | Dual differential current-source/sink pairs for precision TruTherm measurements of CPU1/CPU2 thermal diodes on sub-micron processes. |
| P1_PROCHOT / P2_PROCHOT | Processor hot signal interface | Bidirectional open-drain lines connected to CPU1/CPU2 PROCHOT pins via level shifter, enabling thermal throttling coordination. |
| SMBDAT / SMBCLK | SMBus 2.0 interface | 5V-tolerant open-drain data/clock lines supporting byte/block transfers and selectable slave address (Address Select pin sets LSBs). |
| VREF | Analog reference output | Stable 2.5V ±1% output used for external ADC referencing or internal A/D calibration, reducing dependency on system supply rails. |
Key Features
| Feature | Design Value |
|---|---|
| TruTherm™ Technology | Enables ±2.5°C remote temperature accuracy at 70°C junction for 90nm/65nm Xeon processors-critical for accurate thermal throttling decisions. |
| Dual PI Fan Control Loops | Each PWM output independently executes proportional-integral control with Tcontrol setpoint, eliminating manual LUT tuning and improving transient response to thermal load changes. |
| Dynamic VID Monitoring | Supports 6/7 VID bits per processor (VRD10.2/11), allowing real-time tracking of CPU voltage scaling states and correlation with thermal behavior. |
| PROCHOT & VRD_HOT Detection | Hardware-level monitoring of dual-processor thermal throttle and voltage regulator hot signals-enables coordinated system-level power management without BMC intervention. |
| Programmable Digital Filters | Configurable temperature smoothing reduces fan speed jitter and acoustic noise during steady-state operation while preserving responsiveness to rapid thermal events. |
Applications
| Server Thermal Management | Workstation Power Integrity |
|---|---|
Use Scenario: Real-time monitoring and autonomous fan control on dual-Xeon server motherboards with 16 voltage rails and dual-socket thermal diodes. IC Role / Device Role / Timing Role: Hardware monitor ASIC performing concurrent voltage, temperature, and VID sampling every 100 ms; generates PWM outputs based on PI-loop calculations. Use Value: Eliminates need for discrete ADCs, comparators, and microcontroller-based thermal logic-reducing BOM count and firmware complexity. | Use Scenario: High-reliability workstation platform requiring precise Vccp tracking, PROCHOT coordination, and multi-rail fault logging during extended computational loads. IC Role / Device Role / Timing Role: Centralized sensor hub interfacing with BMC via SMBus 2.0; reports status registers and triggers ALERT on limit violations. Use Value: Enables deterministic thermal shutdown and voltage margining without host CPU involvement-improving system stability under sustained workloads. |
| Dual-Processor Throttling | VRD11-Compliant Server Platform |
Use Scenario: Coordinated thermal throttling across two Xeon CPUs using shared Tcontrol setpoints and synchronized PROCHOT assertion. IC Role / Device Role / Timing Role: Dual-processor thermal coordinator detecting THERMTRIP signals via GPIO_4/GPIO_5 and asserting PROCHOT to both CPUs simultaneously. Use Value: Prevents asymmetric thermal runaway by enforcing matched throttling behavior-essential for NUMA-aware server designs. | Use Scenario: Next-generation server board implementing VRD11 specification with 7-bit VID support and VRD_HOT signaling for advanced power delivery control. IC Role / Device Role / Timing Role: VRD11 compliance enabler monitoring P1_VID0–P1_VID6 and P2_VID0–P2_VID6, plus VRD1_HOT/VRD2_HOT inputs for regulator health reporting. Use Value: Validates voltage regulator state in real time-supporting dynamic power capping and predictive failure analysis in cloud infrastructure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar hardware monitor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM93CIMTX | Lacks TruTherm™, no VRD11 support, single PI loop, 12 voltage inputs only | Legacy dual-processor servers without dynamic VID or sub-100nm thermal diode requirements | Select when cost sensitivity outweighs need for VRD11 or enhanced thermal accuracy. |
| ADM1027ASTZ | No PI control, fixed 8-step LUT only; supports only 12 voltage inputs and 2 remote diodes; no PROCHOT/VRD_HOT detection | Entry-level server/workstation platforms where autonomous fan control is not required | Choose for simpler thermal management where BMC-driven control suffices and VRD10.2+ features are unnecessary. |
Compared with LM94CIMTX, LM93CIMTX offers reduced feature depth but lower cost for legacy systems, while ADM1027ASTZ trades autonomous PI control and dual-processor thermal coordination for simplified integration-neither matches LM94CIMTX's combined VRD11, TruTherm™, and dual-PI capabilities in modern Xeon platforms.
Availability
LM94CIMTX is available at Aetrix Electronics and suitable for server thermal management, workstation power integrity validation, and dual-processor throttling applications requiring stable component supply and long-term lifecycle support.
Supply support for LM94CIMTX 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 company specializing in analog, embedded processing, and connectivity technologies, with leadership in precision analog and power management ICs.
The LM94CIMTX belongs to TI's TruTherm™ hardware monitor product line, designed specifically for autonomous thermal and power supervision in dual-processor server and high-end workstation platforms.
FAQ
What is the operating temperature range for the LM94CIMTX?
The LM94CIMTX has an operational ambient temperature range of 0°C to +85°C. Its remote thermal diode measurement circuitry maintains ±2.5°C accuracy over 0°C to +125°C for processor junction temperatures-validated for Pentium and Xeon processors on 90nm/65nm processes. This range supports deployment in enterprise server chassis with forced-air cooling and elevated internal ambient conditions. The LM94CIMTX itself must remain within its specified 0°C–85°C ambient envelope to ensure guaranteed performance.
Does the LM94CIMTX support both PI-loop and lookup table fan control simultaneously?
Yes, the LM94CIMTX supports hybrid fan control: each of its two PWM outputs can execute either a 13-step lookup table, a PI control loop, or a combination where the PI loop output modulates the LUT index. This flexibility allows designers to use LUT for coarse speed staging and PI for fine-grained correction-especially valuable in thermally noisy environments. The LM94CIMTX implements separate PI parameters (Kp, Ki, Tcontrol) per zone, and all configurations are stored in nonvolatile configuration registers accessible via SMBus.
How many voltage rails can the LM94CIMTX monitor, and what is the accuracy?
The LM94CIMTX monitors 16 voltage rails with ±2% full-scale accuracy, covering +12V, +5V, +3.3V, +2.5V, +1.969V, +1.5V, +1.312V, +1.236V, +0.984V, −12V, and processor-specific Vccp rails. Each input includes programmable attenuation and leakage current ≤60 nA, ensuring minimal loading on sensitive power domains. The LM94CIMTX uses an 8-bit ΣΔ ADC with total unadjusted error (TUE) bounded at ±2% FS, making it suitable for margining, fault detection, and power sequencing verification in server-class motherboards.
What SMBus functionality does the LM94CIMTX provide?
The LM94CIMTX implements full SMBus 2.0 compliance, including byte and block read/write operations, ALERT output in interrupt or comparator mode, and tri-level Address Select pin enabling one of three slave addresses (0x2C, 0x2D, or 0x2E). It supports standard command codes for reading value/limit/status registers and writing configuration data-including fan control parameters, VID mask settings, and digital filter coefficients. The LM94CIMTX also includes XOR-tree test mode for manufacturing verification, accessible via the ALERT/XtestOut pin.
Can the LM94CIMTX monitor both CPU1 and CPU2 thermal diodes independently?
Yes, the LM94CIMTX independently monitors four remote thermal diodes: two per CPU (REMOTE1a+/REMOTE1− and REMOTE1b+ on AD_IN1; REMOTE2a+/REMOTE2− and REMOTE2b+ on AD_IN2). Its TruTherm™ architecture applies process-specific compensation algorithms to each diode pair, delivering ±2.5°C accuracy at 70°C for both CPUs simultaneously. The LM94CIMTX also supports LM60 analog temperature sensors on AD_IN11 and AD_IN15-allowing mixed-sensor thermal mapping across CPU cores, VRMs, and memory subsystems.
LM94CIMTX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- TruTherm™
- Package/Case:
- 56-TFSOP (0.240", 6.10mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Hardware Monitor
- Sensor Type:
- Internal and External
- Sensing Temperature:
- 0°C ~ 125°C
- Accuracy:
- ±2.5°C(Max)
- Topology:
- ADC (Sigma Delta), Comparator, Fan Control, Multiplexer, Register Bank
- Output Type:
- 2-Wire Serial, I2C/SMBUS
- Output Alarm:
- No
- Output Fan:
- Yes
- Voltage - Supply:
- 3V ~ 3.6V
- Operating Temperature:
- 0°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 56-TSSOP
LM94CIMTX FAQ
1.How can I place an order for LM94CIMTX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM94CIMTX 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 LM94CIMTX reliable?
The price and inventory of LM94CIMTX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM94CIMTX is usually 5 days.
3.What payment methods are accepted for LM94CIMTX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM94CIMTX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM94CIMTX?
LM94CIMTX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM94CIMTX 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 LM94CIMTX?
For technical support, including LM94CIMTX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM94CIMTX requirements.
6.How does Aetrix verify that LM94CIMTX is sourced from the original manufacturer or authorized distributors?
All LM94CIMTX 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 LM94CIMTX meets industry standards.
7.What is the process for return or replacement of LM94CIMTX?
All LM94CIMTX units undergo pre-shipment inspection (PSI). If there is an issue with LM94CIMTX, 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 LM94CIMTX part is unused and in its original packaging.
Return procedure for LM94CIMTX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM94CIMTX Tags
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EMC2101-ACZL-TR
Microchip Technology
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MCP9844T-BE/MNY
Microchip Technology
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EMC2101-R-ACZL-TR
Microchip Technology
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MCP98244T-BE/MNY
Microchip Technology
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TC670ECHTR
Microchip Technology
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SE98ATP,547
NXP Semiconductors
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AMC6821SDBQR
Texas Instruments
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MAX6604AATA+T
Analog Devices Inc./Maxim Integrated
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ADT7475ARQZ-REEL
onsemi
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MAX6643LBBAEE+
Analog Devices Inc./Maxim Integrated
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MAX6684ESA+T
Analog Devices Inc./Maxim Integrated
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MAX6639AEE+
Analog Devices Inc./Maxim Integrated
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