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Analog Devices Inc./Maxim Integrated MAX6665ASA55+T
- Part No.:
- MAX6665ASA55+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Thermostats - Solid State
- Package:
- 8-SOIC (0.154", 3.90mm Width) Exposed Pad
- Datasheet:
-
MAX6665ASA55+T.pdf
- Description:
- THERMOSTAT 55DEG ACT HI/LO 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,442
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Product details
Overview
MAX6665ASA55+T from Maxim Integrated is a factory-programmed thermal fan controller IC with 55°C activation threshold, ±3°C max trip accuracy, 1°C/4°C/8°C pin-selectable hysteresis, 250mA internal FET driver, and dual overtemperature warning outputs (WARN at +15°C, OT at +30°C above threshold). It drives cooling fans in PC power supplies and server thermal management systems.
For engineers reviewing the MAX6665ASA55+T datasheet, MAX6665ASA55+T pinout, MAX6665ASA55+T application, or MAX6665ASA55+T equivalent, key selection criteria include factory-set 55°C trip point, SO-EP package thermal performance, FANOUT low-side drive capability, WARN/OT open-drain logic compatibility, and supply current under 200µA across -40°C to +125°C.
Technical Context
The MAX6665ASA55+T integrates a precision temperature comparator, 250mA N-channel MOSFET driver, and two independent overtemperature comparators referenced to the same factory-trimmed 55°C threshold. Its HYST pin configures hysteresis via three-state logic (float/GND/VDD), directly setting 1°C/4°C/8°C switching deadband without external components.
FANOUT operates as a low-side switch with <0.6V saturation voltage at 250mA, while WARN and OT are active-low open-drain outputs requiring external pull-ups. The device uses BiCMOS process with 1543 MOS and 119 bipolar transistors, enabling stable operation from 2.7V to 5.5V supply with self-heating compensation up to 7.65°C under full 250mA load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Fan Activation Threshold | Factory-programmed 55°C ±3°C max error - defines precise thermal trip point for cooling initiation |
| FANOUT Drive Capability | 250mA continuous at VFANOUT < 0.6V - supports direct low-side control of 100–250mA DC fans |
| Supply Voltage Range | +2.7V to +5.5V - compatible with 3.3V and 5V system rails without level-shifting |
| Quiescent Current | 65µA typical, ≤200µA max - enables always-on thermal monitoring with minimal system power impact |
| Overtemperature Outputs | WARN active at +15°C, OT active at +30°C above threshold - provides staged thermal response for warning and shutdown |
| Operating Temperature | -40°C to +125°C - qualified for industrial and server environments with full parameter guarantee |
| Hysteresis Options | 1°C (HYST float), 4°C (HYST = GND), 8°C (HYST = VDD) - configurable deadband to prevent fan oscillation |
Pinout & Package
MAX6665ASA55+T is housed in an 8-pin SOIC with exposed paddle (SO-EP), providing enhanced thermal dissipation and low-inductance ground path. 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 | Forces FANOUT on regardless of temperature; enables external microcontroller control |
| 3 HYST | Hysteresis configuration input | Three-state logic selects 1°C (float), 4°C (GND), or 8°C (VDD) hysteresis |
| 4 FANON | Active-high fan status indicator | Push-pull output signals FANOUT state for system monitoring or LED indication |
| 5 OT | Active-low overtemperature output | Open-drain signal at +30°C above threshold; used for hardware thermal shutdown |
| 6 WARN | Active-low warning output | Open-drain signal at +15°C above threshold; triggers early thermal alert before shutdown |
| 7 VDD | Power supply input | 2.7V–5.5V supply; requires local 1µF bypass capacitor to GND for noise immunity |
| 8 FANOUT | Low-side fan driver output | N-channel MOSFET drain; connects to fan cathode; fan anode connects to 4.5V–24V supply |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 250mA fan switch | Eliminates need for external MOSFET, gate driver, and current-sense resistor in fan control circuits |
| Factory-trimmed 55°C threshold | Guarantees accurate thermal trip without calibration or trimming components during production |
| Dual-stage overtemperature signaling | Separate WARN (+15°C) and OT (+30°C) outputs enable graduated system response: alert → throttling → shutdown |
| Pin-selectable hysteresis | Three discrete hysteresis values (1°C/4°C/8°C) set by simple HYST pin connection-no resistors or firmware needed |
| Low 65µA quiescent current | Enables continuous thermal monitoring in battery-backed or energy-sensitive applications without significant power penalty |
Applications
| Server Thermal Management | PC Power Supply Monitoring |
|---|---|
Use Scenario: Real-time fan speed control in 1U/2U rack servers where CPU and VRM heat generation varies dynamically. IC Role / Device Role / Timing Role: Thermal switch that activates cooling fans when die temperature exceeds 55°C, with WARN/OT outputs feeding BMC for predictive thermal mitigation. Use Value: Prevents thermal runaway by triggering staged responses-fan ramp-up at 70°C (WARN), forced shutdown at 85°C (OT)-without software intervention. |
Use Scenario: Overtemperature protection in ATX or SFX power supplies where transformer and MOSFET heating must be actively managed. IC Role / Device Role / Timing Role: Standalone fan controller interfacing directly with 12V/24V cooling fan and PSU supervisor IC via WARN/OT signals. Use Value: Enables fail-safe thermal shutdown independent of main controller, meeting IEC 62368-1 thermal safety requirements for Class II power supplies. |
| Notebook Baseboard Control | Laboratory Instrument Cooling |
Use Scenario: Fan activation in thin-and-light notebooks where space constraints prohibit complex thermal ICs or microcontrollers. IC Role / Device Role / Timing Role: Direct thermal sensor + driver combo mounted near GPU or chipset; FANON feeds EC for logging, FORCEON enables EC-initiated pre-emptive cooling. Use Value: Reduces BOM count by replacing discrete thermistor + comparator + MOSFET solution, cutting layout area by >40%. |
Use Scenario: Temperature-regulated cooling for high-precision oscilloscopes, spectrum analyzers, and bench power supplies. IC Role / Device Role / Timing Role: Localized thermal monitor placed adjacent to power amplifiers or ADC front-ends; OT output disables HV sections upon critical overtemperature. Use Value: Maintains measurement stability by preventing thermal drift in analog signal paths-critical for sub-mV noise floor specifications. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar thermal fan control applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM75BIMM-3/NOPB | ±2°C temp accuracy, no integrated fan driver, I²C interface only, 0.5mA supply current | Requires external MOSFET and MCU firmware for fan control; suited for systems with existing I²C infrastructure | Select when digital temperature telemetry and programmable thresholds are prioritized over simplicity and autonomy |
| MAX6642AESA+ | ±1°C accuracy, dual remote/local sensing, SMBus interface, no internal FET driver | Supports remote diode temperature monitoring but needs external fan driver; targets multi-zone thermal management | Choose when monitoring CPU/GPU junction temperature remotely is required, not just local board temperature |
Compared with LM75BIMM-3/NOPB and MAX6642AESA+, the MAX6665ASA55+T delivers autonomous, self-contained fan control with zero firmware dependency, lower system-level power consumption, and guaranteed 55°C trip point-making it optimal for cost-sensitive, high-reliability thermal safety applications where simplicity and deterministic response are critical.
Availability
MAX6665ASA55+T is available at Aetrix Electronics and suitable for server thermal management, PC power supply monitoring, and laboratory instrument cooling requiring stable component supply, long-term lifecycle support, and guaranteed factory-programmed 55°C trip behavior.
Supply support for MAX6665ASA55+T 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 industrial, computing, and communications applications.
The MAX6665ASA55+T belongs to Maxim's thermal management product line, engineered specifically for autonomous, low-power, single-threshold fan control in space-constrained and reliability-critical systems.
FAQ
What is the exact factory-programmed temperature threshold for MAX6665ASA55+T?
The MAX6665ASA55+T has a factory-programmed fan activation threshold of precisely +55°C, with a maximum tolerance of ±3°C across the full operating temperature range (-40°C to +125°C). This value is laser-trimmed during production and cannot be adjusted externally. The MAX6665ASA55+T datasheet specifies this as the nominal trip point, and all downstream timing and hysteresis calculations (e.g., WARN at +70°C, OT at +85°C) are referenced to this fixed 55°C baseline.
Can MAX6665ASA55+T drive a 24V fan directly?
Yes, the MAX6665ASA55+T can drive fans powered from 4.5V to 24V, but only as a low-side switch: the fan's positive terminal connects to the external 24V rail, and the FANOUT pin connects to the fan's negative terminal. The internal MOSFET handles up to 250mA continuous current with <0.6V saturation voltage, making it compatible with standard 24V, 100–250mA DC cooling fans without additional components.
How does the HYST pin configure hysteresis on MAX6665ASA55+T?
The HYST pin on MAX6665ASA55+T sets hysteresis in three discrete steps: leave unconnected for 1°C, tie to GND for 4°C, or tie to VDD for 8°C. This selection determines the temperature drop required after fan activation before FANOUT turns off. For example, with HYST = VDD, the fan remains on until die temperature falls to 47°C (55°C − 8°C), preventing rapid cycling near the threshold.
What is the function of the FORCEON pin on MAX6665ASA55+T?
The FORCEON pin on MAX6665ASA55+T is an active-low input that overrides the internal thermal control logic: pulling FORCEON low forces FANOUT to turn on regardless of die temperature, while leaving it high (or connecting to VDD) enables normal temperature-based operation. This allows external microcontrollers or system logic to initiate preemptive cooling, such as during high-CPU-load periods before thermal buildup occurs.
Are WARN and OT outputs on MAX6665ASA55+T push-pull or open-drain?
Both WARN and OT outputs on MAX6665ASA55+T are active-low open-drain outputs, requiring external pull-up resistors to a logic-compatible voltage (e.g., 3.3V or 5V). This architecture enables wired-OR connections, voltage-level translation, and direct interfacing with microcontroller interrupt inputs or supervisor ICs without risk of bus contention.
MAX6665ASA55+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Trip Temperature Threshold:
- Hot
- Switching Temperature:
- 55°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
MAX6665ASA55+T FAQ
1.How can I place an order for MAX6665ASA55+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6665ASA55+T 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 MAX6665ASA55+T reliable?
The price and inventory of MAX6665ASA55+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6665ASA55+T is usually 5 days.
3.What payment methods are accepted for MAX6665ASA55+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6665ASA55+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6665ASA55+T?
MAX6665ASA55+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6665ASA55+T 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 MAX6665ASA55+T?
For technical support, including MAX6665ASA55+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6665ASA55+T requirements.
6.How does Aetrix verify that MAX6665ASA55+T is sourced from the original manufacturer or authorized distributors?
All MAX6665ASA55+T 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 MAX6665ASA55+T meets industry standards.
7.What is the process for return or replacement of MAX6665ASA55+T?
All MAX6665ASA55+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6665ASA55+T, 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 MAX6665ASA55+T part is unused and in its original packaging.
Return procedure for MAX6665ASA55+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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