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Analog Devices Inc./Maxim Integrated MAX6665ASA40+
- Part No.:
- MAX6665ASA40+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Thermostats - Solid State
- Package:
- 8-SOIC (0.154", 3.90mm Width) Exposed Pad
- Datasheet:
-
MAX6665ASA40+.pdf
- Description:
- THERMOSTAT 40DEG ACT HI/LO 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:141
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Product details
Overview
MAX6665ASA40+ from Maxim Integrated is a factory-programmed thermal fan controller with integrated 250mA low-side power switch, +40°C activation threshold (±3°C max error), 1°C/4°C/8°C pin-selectable hysteresis, and dual overtemperature outputs (WARN at +15°C, OT at +30°C above threshold). It drives cooling fans rated up to 24V/250mA in notebook, server, and lab instrument thermal management systems.
For engineers reviewing the MAX6665ASA40+ datasheet, MAX6665ASA40+ pinout, MAX6665ASA40+ application, or MAX6665ASA40+ equivalent, this page delivers verified thermal trip accuracy, FANOUT drive capability, hysteresis configuration logic, WARN/OT timing relationships, and SO-EP package thermal performance data essential for fail-safe fan control design.
Technical Context
The MAX6665ASA40+ implements a die-temperature-sensing comparator with factory-trimmed +40°C trip point and programmable hysteresis via HYST pin voltage level (floating = 1°C, GND = 4°C, VDD = 8°C). Its internal N-channel MOSFET switches the FANOUT pin low to sink up to 250mA, while FANON provides active-high push-pull fan-status feedback.
WARN and OT are open-drain outputs with 2°C hysteresis, activated at fixed offsets (+15°C and +30°C) relative to the FANOUT threshold. FORCEON enables external override of thermal control by forcing FANOUT active regardless of die temperature, supporting system-initiated cooling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Fan Activation Threshold | +40°C ±3°C max error - ensures precise thermal trigger point for cooling initiation in high-reliability systems |
| FANOUT Drive Capability | 250mA continuous sink at VFANOUT < 0.6V - directly drives common 5–24V DC fans without external transistor |
| Supply Voltage Range | +2.7V to +5.5V - compatible with 3.3V and 5V logic rails; fan supply independent (4.5–24V) |
| Quiescent Current | 65µA typical - minimizes standby power impact in always-on thermal monitoring applications |
| Hysteresis Options | 1°C (HYST floating), 4°C (HYST = GND), 8°C (HYST = VDD) - configurable to match system thermal inertia and acoustic requirements |
| WARN/OT Trigger Offsets | +15°C (WARN), +30°C (OT) above threshold - provides staged thermal warning and hard shutdown signals |
| Operating Temperature | −40°C to +125°C - supports deployment near high-power ICs in industrial and computing environments |
Pinout & Package
MAX6665ASA40+ is housed in an 8-pin SOIC with exposed paddle (SO-EP), optimized for thermal dissipation and PCB ground-plane integration. The exposed paddle is internally connected to GND and must be soldered to the PCB ground plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 GND | Ground reference | Common return for internal circuitry and FANOUT current path; connects to exposed paddle |
| 2 FORCEON | Active-low fan override input | Drives FANOUT active regardless of temperature when pulled low; high = normal thermal control |
| 3 HYST | Hysteresis selection input | Floating = 1°C, GND = 4°C, VDD = 8°C - sets turn-off temperature offset to prevent fan oscillation |
| 4 FANON | Active-high fan status output | Push-pull signal indicating FANOUT is actively sinking current (fan ON) |
| 5 OT | Active-low overtemperature output | Open-drain signal asserted when die temp ≥ +70°C; requires external pullup for system shutdown logic |
| 6 WARN | Active-low warning output | Open-drain signal asserted when die temp ≥ +55°C; used for early thermal alert before shutdown |
| 7 VDD | Logic supply input | +2.7V to +5.5V supply; bypass with 1µF capacitor close to pin to suppress ground bounce from fan switching |
| 8 FANOUT | Low-side fan driver output | N-channel MOSFET drain; connects to fan cathode/low side; sinks up to 250mA to GND |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 250mA fan switch | Eliminates need for external MOSFET and gate driver, reducing BOM count and layout area in compact thermal subsystems |
| Factory-programmed +40°C threshold | Guarantees consistent thermal response across production units without calibration or trimming components |
| Dual open-drain overtemperature outputs | Enables hierarchical thermal response: WARN for system throttling, OT for immediate power-down or reset assertion |
| Pin-selectable hysteresis (1°C/4°C/8°C) | Allows matching of thermal recovery behavior to mechanical airflow dynamics and acoustic constraints |
| FORCEON override capability | Supports firmware-controlled fan activation during boot, diagnostics, or transient load conditions independent of temperature |
Applications
| Server CPU Thermal Management | Notebook Fan Control |
|---|---|
|
Use Scenario: Monitoring CPU die temperature in 1U rack servers where airflow is constrained and thermal runaway must be prevented. IC Role / Device Role / Timing Role: Direct die-temperature sensing and low-side fan switching; WARN triggers CPU throttling at +55°C, OT asserts system reset at +70°C. Use Value: Prevents thermal damage during sustained compute loads by enabling staged response with no software dependency. |
Use Scenario: Regulating cooling in ultra-thin notebooks where fan noise must be minimized and thermal inertia is low. IC Role / Device Role / Timing Role: On-chip thermal sensor driving 5V/150mA fan; 1°C hysteresis (HYST floating) prevents audible fan cycling during light workloads. Use Value: Achieves silent operation under idle conditions while ensuring rapid fan activation when GPU/CPU temperature exceeds +40°C. |
| Lab Instrument Overtemperature Protection | PC Power Supply Fan Monitoring |
|
Use Scenario: Safeguarding precision analog circuitry in benchtop oscilloscopes and spectrum analyzers subject to ambient temperature drift. IC Role / Device Role / Timing Role: Localized thermal monitor placed adjacent to power regulators; OT output disables HV supply rails upon reaching +70°C. Use Value: Maintains measurement accuracy by preventing thermal-induced gain/offset drift and avoiding catastrophic failure. |
Use Scenario: Ensuring continuous airflow in ATX PSUs where fan failure could cause MOSFET overheating and secondary component damage. IC Role / Device Role / Timing Role: Fan driver with FORCEON tied to PSU enable signal; FANON confirms fan rotation before main rail startup. Use Value: Enables hardware-level fan health verification and automatic shutdown if fan stalls or disconnects. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar thermal fan controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM75BIMM-3/NOPB | Temperature sensor only (I²C output); no integrated fan driver or WARN/OT outputs | Requires external MCU and MOSFET for fan control; lacks autonomous overtemperature shutdown | Select when system already includes microcontroller-based thermal management and needs only sensor data |
| ADT7470ARQZ | Multi-channel PWM fan controller with SMBus interface; supports variable-speed control, not on/off switching | Designed for complex multi-fan systems with dynamic speed profiles; higher BOM cost and firmware overhead | Select when precise RPM regulation and telemetry reporting are required, not simple thermal-triggered on/off |
Compared with LM75BIMM-3/NOPB and ADT7470ARQZ, the MAX6665ASA40+ delivers autonomous, zero-software fan control with guaranteed +40°C trip point and dual-stage shutdown-ideal for cost-sensitive, safety-critical applications where simplicity and reliability outweigh programmability.
Availability
MAX6665ASA40+ is available at Aetrix Electronics and suitable for notebook thermal management, server cooling subsystems, and laboratory instrument protection requiring stable component supply, long-term lifecycle support, and guaranteed factory-trimmed thresholds.
Supply support for MAX6665ASA40+ 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
Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for demanding industrial, computing, and communications applications.
The MAX6665ASA40+ belongs to Maxim's thermal management product line, engineered for autonomous, fail-safe fan control in space-constrained systems where software-free thermal protection is critical.
FAQ
What is the exact factory-programmed temperature threshold for MAX6665ASA40+?
The MAX6665ASA40+ has a factory-programmed fan activation threshold of +40°C, with a maximum error of ±3°C across the full operating temperature range (−40°C to +125°C). This value is laser-trimmed during production and does not require external calibration. The MAX6665ASA40+ datasheet specifies that trip-point accuracy is ±1°C typical and ±3°C maximum, making it suitable for applications demanding repeatable thermal response without software compensation.
Can MAX6665ASA40+ drive a 24V fan directly?
Yes, the MAX6665ASA40+ can drive fans powered from +4.5V to +24V, with its FANOUT pin rated for continuous 250mA sink current and absolute maximum voltage of +28V. The internal N-channel MOSFET handles the low-side switching, so the fan's positive terminal connects directly to the 24V rail and its negative terminal to FANOUT. No external transistor or level-shifting circuitry is needed, simplifying design for high-voltage cooling systems.
How do I configure hysteresis on MAX6665ASA40+?
Hysteresis on the MAX6665ASA40+ is configured solely via the HYST pin: leave it unconnected for 1°C, tie it to GND for 4°C, or connect it to VDD for 8°C. This selection determines the temperature drop required below the +40°C threshold before FANOUT turns off. Self-heating due to fan current adds ~1.6°C (for 125mA) or ~7.7°C (for 250mA) to effective hysteresis, so physical placement near heat sources must be considered during layout.
What is the function of the FORCEON pin on MAX6665ASA40+?
The FORCEON pin on MAX6665ASA40+ is an active-low input that overrides the internal thermal control logic: pulling FORCEON low forces FANOUT active regardless of die temperature, while leaving it high enables normal +40°C-triggered operation. This allows external microcontrollers or power sequencers to initiate cooling during boot-up, diagnostics, or transient load events-ensuring airflow before thermal stress accumulates.
Are WARN and OT outputs open-drain on MAX6665ASA40+?
Yes, both WARN and OT outputs on MAX6665ASA40+ are active-low open-drain terminals requiring external pullup resistors (typically 4.7kΩ to VDD or system logic rail). WARN activates at +55°C (i.e., +15°C above the +40°C threshold) and OT at +70°C (+30°C above threshold), each with 2°C hysteresis. Their open-drain structure enables wired-OR connection to shared interrupt lines or compatibility with mixed-voltage logic systems.
MAX6665ASA40+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Trip Temperature Threshold:
- Hot
- Switching Temperature:
- 40°C
- Accuracy:
- ±3°C
- Current - Output (Max):
- 250mA
- Output Type:
- Open Drain, Push-Pull
- Output:
- Active High, Active Low
- Output Function:
- FanOn, /FanOut, /OverTemp, /Warn
- Selectable Hysteresis:
- Yes
- Features:
- -
- Voltage - Supply:
- 2.7 V ~ 5.5 V
- Current - Supply:
- 65µA
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-SOIC-EP
MAX6665ASA40+ FAQ
1.How can I place an order for MAX6665ASA40+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6665ASA40+ 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 MAX6665ASA40+ reliable?
The price and inventory of MAX6665ASA40+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6665ASA40+ is usually 5 days.
3.What payment methods are accepted for MAX6665ASA40+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6665ASA40+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6665ASA40+?
MAX6665ASA40+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6665ASA40+ 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 MAX6665ASA40+?
For technical support, including MAX6665ASA40+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6665ASA40+ requirements.
6.How does Aetrix verify that MAX6665ASA40+ is sourced from the original manufacturer or authorized distributors?
All MAX6665ASA40+ 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 MAX6665ASA40+ meets industry standards.
7.What is the process for return or replacement of MAX6665ASA40+?
All MAX6665ASA40+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6665ASA40+, 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 MAX6665ASA40+ part is unused and in its original packaging.
Return procedure for MAX6665ASA40+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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