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Texas Instruments LM64CILQ-F
- Part No.:
- LM64CILQ-F
- Manufacturer:
- Texas Instruments
- Category:
- Thermal Management
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LM64CILQ-F.pdf
- Description:
- IC TEMP SENSOR REMOTE 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,685
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Product details
Overview
LM64CILQ-F from Texas Instruments is a remote diode temperature sensor IC with integrated PWM fan control, 5 GPIOs, and SMBus 2.0 interface. It delivers ±1.0°C remote diode accuracy (30°C–50°C ambient, 120°C–140°C diode), 0.125°C resolution, and open-drain ALERT/T_Crit outputs for thermal management in CPU/GPU subsystems.
For engineers reviewing the LM64CILQ-F datasheet, LM64CILQ-F pinout, LM64CILQ-F application, or LM64CILQ-F equivalent, key selection criteria include remote diode accuracy over extended junction range, programmable 8-step PWM lookup table for acoustic noise reduction, tachometer input for closed-loop RPM monitoring, and SMBus TIMEOUT support for robust bus recovery.
Technical Context
The LM64CILQ-F implements a ΔVBE-based remote sensing architecture with a 10-bit plus sign ΔΣ ADC, factory-trimmed for MMBT3904 diode-connected transistors (TACTUAL = TLM64 + 16°C). Its digital comparators monitor local/remote temperatures against user-programmable high/low/T_Crit setpoints, driving open-drain ALERT and T_Crit outputs independently.
It integrates an SMBus 2.0-compliant two-wire interface with TIMEOUT detection (25–35 ms low-time reset), supports 10–100 kHz clock frequency, and provides 5 configurable GPIOs plus 5 default-input GPD pins-all with 10 kΩ typical pull-up requirements. The PWM output operates as an open-drain driver with 6 mA sink capability and ±10% frequency accuracy.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Remote Diode Accuracy | ±1.0°C max (30°C–50°C ambient, 120°C–140°C diode); enables precise thermal throttling at critical GPU/CPU junction temps |
| Temperature Resolution | 0.125°C (11-bit remote, 8-bit local); supports fine-grained thermal response curves in fan control LUTs |
| PWM Output | Open-drain, 6 mA sink, ±10% frequency accuracy; directly drives external MOSFET/fan driver without level-shifting |
| SMBus Interface | SMBus 2.0 compliant with TIMEOUT reset (25–35 ms); prevents bus lockup during communication faults |
| Supply Range | 3.0 V to 3.6 V DC; compatible with standard 3.3 V system rails and bypassed via 0.1 µF + 100 pF + 10 µF capacitors |
| Tachometer Input | Digital input with 90 kHz counter clock; measures fan RPM from open-collector tach signal with ±10% accuracy |
| Operating Temp Range | 0°C to +85°C ambient; validated for sustained operation in server motherboard and VRM thermal zones |
Pinout & Package
LM64CILQ-F is housed in a 24-pin WQFN package (4 mm × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are validated per TI SNAS207B Rev. January 2024.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 18, 19 | GPIO1–GPIO5 | Open-drain digital I/O; configurable as inputs or outputs with 10 kΩ pull-up-used for status signaling or auxiliary control |
| 4 | PWM | Open-drain fan speed control output; power-on default low; sinks up to 6 mA to drive external switching transistor |
| 5 | VDD | 3.0–3.6 V power supply input; requires local 0.1 µF + 100 pF ceramic + 10 µF bulk capacitance |
| 6, 7 | D+, D− | Remote diode analog inputs; require 2.2 nF capacitor across pins for noise filtering and stable ΔVBE measurement |
| 8 | T_Crit | Open-drain critical temperature alert; pulled low when remote temp exceeds programmable T_Crit setpoint (no latch) |
| 12 | A0 | SMBus address select (0x18 or 0x4E); enables dual-device addressing on same bus without external logic |
| 13 | GND | Analog/digital ground reference; shared return for all signals and power-must be low-impedance plane |
| 14 | ALERT | Open-drain multi-condition alert; asserts low on local/remote high/low/T_Crit violations; maskable via register |
| 15 | TACH | Digital tachometer input; accepts open-collector fan pulses; internal 3 kΩ pull-up to VDD |
| 16, 17 | SMBDAT, SMBCLK | Bidirectional SMBus data/clock; 1.5 kΩ pull-up to VDD; support TIMEOUT, repeated start, and ARA protocols |
| 20–24 | GPD1–GPD5 | General-purpose default inputs; must be hard-wired high/low; used for static configuration (e.g., SMBus address strapping) |
Key Features
| Feature | Design Value |
|---|---|
| Programmable 8-step PWM lookup table | Enables non-linear fan speed vs. temperature mapping to reduce acoustic noise at mid-range loads without sacrificing cooling at peak |
| Factory-trimmed remote diode sensing | Calibrated for MMBT3904 diodes with fixed +16°C offset; eliminates need for per-unit calibration in graphics processor thermal monitoring |
| Three independent alert outputs | Separate open-drain ALERT (multi-condition), T_Crit (critical-only), and software-maskable status registers allow flexible fault prioritization |
| Integrated tachometer input | Directly measures fan RPM from standard 2-pulse-per-revolution tach signal-no external counter IC required |
| SMBus TIMEOUT recovery | Automatic state-machine reset after 25–35 ms bus low time; ensures reliable bus recovery after master hang or cable disconnect |
Applications
| Computer Processor Thermal Management | Graphics Processor Thermal Management |
|---|---|
|
Use Scenario: Real-time junction temperature monitoring and dynamic fan speed adjustment for x86 CPUs under variable workloads. IC Role / Device Role / Timing Role: Remote diode sensor and PWM controller; samples local/remote temps every 31.25 ms and updates fan duty cycle within one conversion cycle. Use Value: Maintains CPU die temperature ≤85°C under full load while minimizing acoustic noise via 8-step LUT-based quieting. |
Use Scenario: Thermal protection of discrete GPUs in gaming laptops and AI inference accelerators. IC Role / Device Role / Timing Role: Measures GPU diode junction (via onboard MMBT3904) and drives PWM-cooled heatsink; triggers T_Crit shutdown at 105°C. Use Value: Achieves ±1.0°C accuracy at 120–140°C diode range-critical for preventing thermal runaway in high-power GPUs. |
| Voltage Regulator Module (VRM) Monitoring | Industrial Power Supply Thermal Control |
|
Use Scenario: Monitoring MOSFET and inductor temperature in multiphase VRMs powering CPUs/FPGAs. IC Role / Device Role / Timing Role: Local temperature sensor + remote diode interface; uses GPIOs to signal VRM fault conditions to PMBus host. Use Value: Enables coordinated thermal derating across VRM phases using single SMBus address (A0-strapped) and shared ALERT line. |
Use Scenario: Fan-cooled AC/DC and DC/DC power supplies in telecom and industrial equipment. IC Role / Device Role / Timing Role: Dual-sensor thermal manager-local sense for PCB ambient, remote diode for heatsink baseplate. Use Value: Supports wide operating range (0°C–85°C ambient) and delivers stable 1.1 mA supply current-ideal for convection-limited enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar remote diode temperature sensing and fan control applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM99CIMM/NOPB | ±1.5°C remote accuracy (0°C–100°C diode), no integrated PWM output, 12-bit resolution, 16-pin QFN | Lacks direct fan drive-requires external PWM generator; better resolution but lower high-temp accuracy than LM64CILQ-F | Select when higher resolution outweighs need for integrated PWM and critical 120–140°C diode accuracy |
| ADM1032ARMZ-REEL | ±2.0°C remote accuracy (0°C–125°C diode), SMBus 1.1 only, no tach input, 8-pin MSOP | No tachometer monitoring or 8-step LUT-fan control is basic on/off or external PWM; smaller footprint but less feature-rich | Select for space-constrained legacy systems where tach feedback and acoustic optimization are not required |
Compared with LM99CIMM/NOPB and ADM1032ARMZ-REEL, LM64CILQ-F uniquely combines ±1.0°C high-temperature remote accuracy, integrated PWM with programmable LUT, and tachometer input-making it optimal for thermally aggressive CPU/GPU cooling where precision, noise control, and closed-loop verification are essential.
Availability
LM64CILQ-F is available at Aetrix Electronics and suitable for computer processor thermal management, graphics processor thermal management, and voltage regulator module applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM64CILQ-F 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 and embedded processing technologies, with leadership in precision analog, power management, and interface solutions.
The LM64CILQ-F belongs to TI's thermal management sensor product line, designed specifically for high-accuracy remote diode monitoring and intelligent fan control in computing and power electronics systems.
FAQ
What is the remote diode temperature accuracy specification for LM64CILQ-F over its full operating range?
The LM64CILQ-F achieves ±1.0°C maximum remote diode temperature accuracy when ambient temperature is 30°C to 50°C and diode junction temperature is 120°C to 140°C. Over the broader range of 0°C to 85°C ambient and 25°C to 140°C diode, accuracy degrades to ±3.0°C max. This high-precision window is factory-trimmed for MMBT3904 diodes with a fixed +16°C offset (TACTUAL = TLM64 + 16°C), making LM64CILQ-F especially suited for GPU thermal monitoring where junction accuracy above 120°C is critical.
How does the 8-step PWM lookup table in LM64CILQ-F improve acoustic performance compared to linear fan control?
The 8-step PWM lookup table in LM64CILQ-F allows non-linear mapping of temperature to fan duty cycle-enabling slower, quieter fan speeds at moderate temperatures while ramping aggressively near thermal limits. Unlike linear control, this reduces mid-load acoustic noise without compromising peak cooling. Each step is independently programmable via SMBus registers, and the table is applied in real time during each 31.25 ms conversion cycle. This feature makes LM64CILQ-F ideal for noise-sensitive applications like thin-client PCs and embedded vision systems where LM64CILQ-F replaces multiple discrete components.
Can LM64CILQ-F measure fan RPM, and what is the accuracy and interface requirement?
Yes, LM64CILQ-F includes a dedicated tachometer input (pin 15, TACH) that measures fan RPM from standard open-collector tach signals. It provides ±10% accuracy across a full-scale count of 65535 with a 90 kHz internal counter clock and 1 Hz update rate. The TACH pin has an internal 3 kΩ pull-up to VDD, eliminating external biasing. This integrated tachometer function enables closed-loop fan control validation-ensuring actual airflow matches the PWM command-and is a key differentiator versus alternatives like LM99CIMM/NOPB which lack this capability in LM64CILQ-F.
What SMBus features does LM64CILQ-F support, and how does TIMEOUT recovery work?
LM64CILQ-F fully supports SMBus 2.0, including TIMEOUT detection, repeated start, and Alert Response Address (ARA) protocol. TIMEOUT recovery activates when SMBDAT or SMBCLK remains low for 25–35 ms-automatically resetting the internal state machine and releasing both lines to high-impedance. This prevents bus lockup during master failure or cable disconnection. Unlike SMBus 1.1 devices, LM64CILQ-F's TIMEOUT behavior is hardware-enforced and requires no firmware intervention, enhancing system robustness in mission-critical thermal management applications where LM64CILQ-F serves as the primary thermal watchdog.
What are the power supply requirements and current consumption characteristics of LM64CILQ-F?
LM64CILQ-F operates from a 3.0 V to 3.6 V DC supply (typical 3.3 V ±0.3 V), drawing 1.1 mA typical supply current at 16 Hz conversion rate with SMBus inactive. In STANDBY mode, current drops to 320 µA. Decoupling requires a 0.1 µF ceramic capacitor in parallel with a 100 pF ceramic capacitor, plus a 10 µF bulk capacitor near the VDD pin. These low-power traits make LM64CILQ-F suitable for always-on thermal monitoring in battery-backed systems and energy-efficient servers where LM64CILQ-F contributes minimal overhead to overall platform power budget.
LM64CILQ-F Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Fan Control, Temp Monitor
- Sensor Type:
- Internal and External
- Sensing Temperature:
- 0°C ~ 85°C, 25°C ~ 140°C
- Accuracy:
- ±1°C Local(Max), ±3°C Remote(Max)
- Topology:
- ADC (Sigma Delta), Comparator, Fan Speed Control, Register Bank
- Output Type:
- 2-Wire SMBus
- Output Alarm:
- Yes
- Output Fan:
- Yes
- Voltage - Supply:
- 3V ~ 3.6V
- Operating Temperature:
- 0°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-WQFN (4x5)
LM64CILQ-F FAQ
1.How can I place an order for LM64CILQ-F through Aetrix?
Please submit a Request for Quotation (RFQ) for LM64CILQ-F 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 LM64CILQ-F reliable?
The price and inventory of LM64CILQ-F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM64CILQ-F is usually 5 days.
3.What payment methods are accepted for LM64CILQ-F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM64CILQ-F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM64CILQ-F?
LM64CILQ-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM64CILQ-F 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 LM64CILQ-F?
For technical support, including LM64CILQ-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM64CILQ-F requirements.
6.How does Aetrix verify that LM64CILQ-F is sourced from the original manufacturer or authorized distributors?
All LM64CILQ-F 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 LM64CILQ-F meets industry standards.
7.What is the process for return or replacement of LM64CILQ-F?
All LM64CILQ-F units undergo pre-shipment inspection (PSI). If there is an issue with LM64CILQ-F, 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 LM64CILQ-F part is unused and in its original packaging.
Return procedure for LM64CILQ-F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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