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Analog Devices Inc./Maxim Integrated MAX6668AUA50+T
- Part No.:
- MAX6668AUA50+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Thermostats - Solid State
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX6668AUA50+T.pdf
- Description:
- THERMOSTAT 50DEGC ACT LOW 8UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:1,399
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Product details
Overview
MAX6668AUA50+T from Maxim Integrated is a remote-junction thermal switch with integrated +12V/250mA fan driver, factory-programmed trip threshold of +50°C, ±2.2°C max accuracy over -40°C to +125°C, and fixed 8°C hysteresis - used for autonomous fan control in notebook computers, PC power supplies, and network switches.
For engineers reviewing the MAX6668AUA50+T datasheet, MAX6668AUA50+T pinout, MAX6668AUA50+T application, or MAX6668AUA50+T equivalent, this device delivers drop-in thermal management without software, calibration, or external transistors - ideal for systems requiring reliable, low-quiescent-current (110µA typ) on/off fan activation based on remote diode sensing.
Technical Context
The MAX6668AUA50+T integrates a precision remote-junction temperature sensor, comparator with fixed 8°C hysteresis, and open-drain power MOSFET driver (FANOUT) capable of sinking 250mA at ≤1V saturation. It operates from +3V to +3.6V only and uses DXP/DXN inputs to bias and measure voltage drop across an external diode-connected transistor.
It features FORCEON input for external fan override, PGND as dedicated power ground for the FANOUT switch, and no WARN/OT outputs (exclusive to MAX6670). Thermal shutdown activates at +170°C with 20°C hysteresis, independent of remote-sensing operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Temperature Threshold | +50°C factory-programmed trip point - triggers fan when remote P-N junction exceeds this value. |
| Threshold Accuracy | ±2.2°C max over +40°C to +75°C remote-junction range - ensures predictable activation timing in automotive-grade (-40°C to +125°C) environments. |
| FANOUT Drive Capability | +12V/250mA sink capability - directly powers small cooling fans without external MOSFETs or drivers. |
| Supply Current | 110µA typical quiescent current - enables always-on thermal monitoring with minimal system power impact. |
| Hysteresis | Fixed 8°C - prevents fan oscillation during slow temperature transitions near trip point. |
| Operating Voltage | +3.0V to +3.6V only - requires stable low-voltage rail; not compatible with 5V or wider-range supplies. |
| Thermal Shutdown | +170°C junction protection with 20°C hysteresis - safeguards IC under fault conditions independent of remote sensing. |
Pinout & Package
MAX6668AUA50+T is housed in an 8-pin µMAX package (3.0mm × 3.0mm, 0.5mm pitch), with exposed pad for thermal dissipation. Pin 1 = PGND, Pin 2 = FORCEON, Pin 3 = DXP, Pin 4 = DXN, Pins 5 & 7 = GND, Pin 6 = VDD, Pin 8 = FANOUT.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PGND (Pin 1) | Power Ground | Dedicated return path for FANOUT MOSFET - must be connected separately from signal GND to minimize noise coupling into remote-sensing circuitry. |
| FORCEON (Pin 2) | Fan Override Input | Active-low logic input: pulling low forces FANOUT on regardless of sensed temperature - enables system-level fan control or emergency cooling. |
| DXP (Pin 3) | Current Source Positive | Biases external diode's anode; requires 2200pF capacitor to DXN for noise filtering - floating DXP causes malfunction. |
| DXN (Pin 4) | Current Sink Negative | Connects to cathode of external diode; internally biased - forms Kelvin-sense pair with DXP for accurate VBE measurement. |
| GND (Pins 5, 7) | Signal Ground | Reference for internal circuitry and logic inputs - must be tied to system signal ground, separate from PGND unless low-noise layout permits single-point connection. |
| VDD (Pin 6) | Power Supply | +3.0V to +3.6V supply input - requires local 1µF bypass capacitor to GND placed adjacent to pin. |
| FANOUT (Pin 8) | Fan Drive Output | Open-drain power MOSFET output - sinks up to 250mA to drive fan between +4.5V and +12V; voltage rating limited to +15V absolute max. |
Key Features
| Feature | Design Value |
|---|---|
| +12V/250mA integrated fan driver | Eliminates need for external power MOSFET and gate driver - reduces BOM count and PCB area in space-constrained applications. |
| No calibration required | Factory-trimmed temperature sensor and threshold ensure out-of-box accuracy - avoids production-line trimming steps or firmware compensation. |
| Fixed 8°C hysteresis | Prevents rapid fan cycling during marginal temperature conditions - optimized for thermal inertia of typical cooling systems. |
| +3V to +3.6V single-supply operation | Matches modern low-voltage microcontroller I/O rails - simplifies power domain design versus mixed-voltage solutions. |
| Automotive temperature range | Rated for continuous operation from -40°C to +125°C - suitable for under-hood, industrial, and high-reliability embedded environments. |
Applications
| Desktop PC Power Supply | Notebook Computer Cooling |
|---|---|
|
Use Scenario: Regulates airflow inside ATX PSUs where ambient temperature rises during load transients. IC Role / Device Role / Timing Role: Remote-junction thermal switch that monitors MOSFET heatsink via discrete 2N3904 and activates 12V fan on threshold breach. Use Value: Prevents thermal throttling by enabling fan only when needed - extends PSU lifespan and reduces acoustic noise during light loads. |
Use Scenario: Monitors CPU die temperature using on-die diode in Intel Core i-series processors. IC Role / Device Role / Timing Role: Direct interface to CPU's thermal diode; triggers fan before Tj reaches critical limit (e.g., 100°C). Use Value: Delivers deterministic +50°C trip with ±2.2°C accuracy - avoids premature fan spin-up while ensuring safe thermal margin. |
| Industrial Network Switch | Laboratory Instrument Enclosure |
|
Use Scenario: Manages heat buildup in fan-cooled 24-port Gigabit Ethernet switches operating in uncontrolled ambient environments. IC Role / Device Role / Timing Role: Senses temperature of power-over-Ethernet (PoE) controller IC via remote diode and drives chassis fan. Use Value: Maintains PoE IC junction below 110°C under full load - preserves IEEE 802.3af/at compliance and prevents link drops. |
Use Scenario: Controls cooling for precision analog front-end circuits in benchtop oscilloscopes where thermal drift affects measurement accuracy. IC Role / Device Role / Timing Role: Monitors temperature of op-amp bias network using SST3904 transistor and modulates fan speed via on/off control. Use Value: Limits thermal coefficient-induced offset drift to <1µV/°C - sustains DC accuracy specifications across operating temperature range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar remote-junction thermal switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6670AUB50+T | 10-pin µMAX; adds WARN (+15°C) and OT (+30°C) outputs; pin-selectable hysteresis (4°C/8°C/12°C); same +50°C threshold. | Supports multi-level thermal alerts and configurable hysteresis - required where warning signals or adaptive fan response are needed. | Select MAX6670AUB50+T if system requires overtemperature warnings or hysteresis tuning; MAX6668AUA50+T is preferred for cost-optimized, single-threshold designs. |
| LM71AISD/NOPB | 10-bit digital temperature sensor (I²C output); no integrated fan driver; ±1.5°C accuracy; operates from +2.7V to +5.5V. | Requires external MCU and fan driver circuit - suited for closed-loop PWM fan control, not autonomous on/off switching. | Choose LM71AISD/NOPB only when digital temperature telemetry and programmable control are mandatory; MAX6668AUA50+T provides simpler, lower-power hardware-only solution. |
Compared with MAX6670AUB50+T, MAX6668AUA50+T offers identical thermal sensing performance and fan drive capability in a smaller 8-pin package but lacks dual alarm outputs and hysteresis flexibility; compared with LM71AISD/NOPB, it eliminates firmware dependency and reduces component count by integrating both sensing and actuation.
Availability
MAX6668AUA50+T is available at Aetrix Electronics and suitable for notebook computers, PC power supplies, and industrial network switches requiring stable component supply, long-term lifecycle support, and automotive-grade reliability.
Supply support for MAX6668AUA50+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 demanding industrial, automotive, and computing applications.
The MAX6668/MAX6670 product line was developed specifically for autonomous, software-free thermal management in space-constrained systems - delivering integrated remote-sensing and fan-driving functionality in ultra-small µMAX packages.
FAQ
What is the exact factory-programmed temperature threshold for MAX6668AUA50+T?
The MAX6668AUA50+T has a factory-programmed remote-junction temperature threshold of +50°C. This value is laser-trimmed during production and cannot be adjusted. The threshold applies to the external P-N junction (e.g., 2N3904 base-emitter junction) connected to DXP/DXN pins, with ±2.2°C maximum error across the full -40°C to +125°C operating range. This fixed setting makes MAX6668AUA50+T suitable for applications where consistent, repeatable fan activation at precisely +50°C is required without calibration.
Does MAX6668AUA50+T support 5V operation or require a specific supply voltage?
MAX6668AUA50+T operates exclusively from a +3.0V to +3.6V supply - it does not support 5V operation. The absolute maximum VDD rating is +6V, but functional operation is guaranteed only within the +3V to +3.6V range. Attempting to power MAX6668AUA50+T from 5V may cause improper sensor biasing, inaccurate threshold detection, or permanent damage. A dedicated low-dropout regulator or filtered 3.3V rail is required; the device draws only 110µA typical supply current, making it compatible with low-power system domains.
Can MAX6668AUA50+T drive a 12V fan directly, and what are the current limits?
Yes, MAX6668AUA50+T can drive a +12V fan directly via its FANOUT pin, which is an open-drain power MOSFET rated for 250mA continuous sink current at ≤1V saturation voltage. The absolute maximum FANOUT voltage is +15V, so nominal +12V fans are fully supported. It is not intended for fans exceeding 250mA or requiring >+12V - doing so risks overheating or latch-up. For higher-current fans, an external MOSFET driven by MAX6668AUA50+T's FANOUT signal is recommended.
What is the purpose of the PGND pin on MAX6668AUA50+T, and how should it be connected?
The PGND (Pin 1) on MAX6668AUA50+T is the dedicated power ground return for the FANOUT MOSFET switch - it carries the full 250mA fan current. It must be connected to the fan's ground return path and kept physically separate from signal GND (Pins 5 and 7) to prevent fan-switching noise from coupling into the sensitive remote-temperature sensing circuitry. In PCB layout, PGND should route directly to the fan connector ground and join signal GND at a single point near the device or power supply, minimizing shared impedance paths that could degrade temperature accuracy.
Is MAX6668AUA50+T pin-compatible with MAX6670 variants, and does it include WARN or OT outputs?
No, MAX6668AUA50+T is not pin-compatible with MAX6670 variants - it uses an 8-pin µMAX package versus the MAX6670's 10-pin µMAX. MAX6668AUA50+T does not include WARN or OT outputs; those are exclusive to the MAX6670 family. The MAX6668AUA50+T provides only FANOUT, FORCEON, DXP, DXN, PGND, GND, and VDD. Its hysteresis is fixed at 8°C, whereas MAX6670 offers selectable hysteresis via the HYST pin. These architectural differences mean direct substitution is not possible without board redesign.
MAX6668AUA50+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Trip Temperature Threshold:
- Hot
- Switching Temperature:
- 50°C
- Accuracy:
- ±2.2°C
- Current - Output (Max):
- 250mA
- Output Type:
- Open Drain
- Output:
- Active Low
- Output Function:
- /FanOut
- Selectable Hysteresis:
- No
- Features:
- -
- Voltage - Supply:
- 3 V ~ 3.6 V
- Current - Supply:
- 110µA
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-uMAX/uSOP
MAX6668AUA50+T FAQ
1.How can I place an order for MAX6668AUA50+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6668AUA50+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 MAX6668AUA50+T reliable?
The price and inventory of MAX6668AUA50+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6668AUA50+T is usually 5 days.
3.What payment methods are accepted for MAX6668AUA50+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6668AUA50+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6668AUA50+T?
MAX6668AUA50+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6668AUA50+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 MAX6668AUA50+T?
For technical support, including MAX6668AUA50+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6668AUA50+T requirements.
6.How does Aetrix verify that MAX6668AUA50+T is sourced from the original manufacturer or authorized distributors?
All MAX6668AUA50+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 MAX6668AUA50+T meets industry standards.
7.What is the process for return or replacement of MAX6668AUA50+T?
All MAX6668AUA50+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6668AUA50+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 MAX6668AUA50+T part is unused and in its original packaging.
Return procedure for MAX6668AUA50+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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