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Analog Devices Inc./Maxim Integrated MAX6686AU40H
- Part No.:
- MAX6686AU40H
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Thermostats - Solid State
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX6686AU40H.pdf
- Description:
- DUAL TEMPERATURE SWITCH
- Quantity:
- Payment:
- Shipping:
Inventory:2,829
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Product details
Overview
MAX6686AU40H from Maxim Integrated is a dual-output remote-junction temperature switch using an external diode-connected transistor for precision CPU die temperature monitoring. It features factory-programmed +125°C upper trip threshold, pin-selectable +40°C to +80°C lower threshold (in 5°C steps), ±1.5°C accuracy, open-drain active-low THIGH and TLOW outputs, and operates from 3.0V to 5.5V with 200µA average supply current.
For engineers reviewing the MAX6686AU40H datasheet, MAX6686AU40H pinout, MAX6686AU40H application, or MAX6686AU40H equivalent, this device serves as a dedicated thermal protection solution in high-reliability computing and FPGA systems where independent high- and low-temperature alarms with hysteresis are required.
Technical Context
The MAX6686AU40H integrates a BiCMOS remote-junction sensor front-end with oversampling and noise filtering to reject interference from switching regulators and digital noise sources. Its DXP/DXN differential inputs require a 2200pF ceramic capacitor for stable threshold accuracy, and S1/S2 logic levels must be set before VDD power-up to lock the lower trip point.
Both THIGH and TLOW outputs are open-drain and active-low, enabling wired-OR alarm aggregation. The device implements 5°C hysteresis on both thresholds to prevent output chatter near trip points, and its internal remote-diode current source delivers 8–12µA at low level and 80–120µA at high level for optimal PNP sensing junction biasing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Upper Trip Threshold | +125°C factory preset - triggers THIGH assertion for critical overtemperature shutdown |
| Lower Trip Range | +40°C to +80°C in 5°C increments - selected via S1/S2 pins for configurable warning-level detection |
| Temperature Accuracy | ±1.5°C over -40°C to +125°C ambient - ensures reliable thermal margin control without calibration |
| Supply Voltage Range | 3.0V to 5.5V - compatible with standard 3.3V and 5V system rails without level-shifting |
| Average Supply Current | 200µA at +25°C - enables low-power thermal monitoring in always-on subsystems |
| Hysteresis | 5°C typical - prevents oscillation during slow thermal transients near threshold boundaries |
| Output Type | Open-drain, active-low THIGH and TLOW - supports flexible pull-up to any voltage ≤5.5V and alarm bus sharing |
Pinout & Package
MAX6686AU40H is housed in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), RoHS-compliant with lead-free option available. The package features exposed pad for thermal enhancement and is specified for operation from -40°C to +125°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD (Pin 1) | Power supply input | 3.0V–5.5V main supply; requires 0.1µF bypass capacitor to GND for noise immunity |
| GND (Pin 2) | Ground reference | Common return path; DXN must connect to this pin with shortest possible trace |
| DXP (Pin 3) | Remote diode anode interface | Sources 8–120µA current into external PNP base-emitter junction; pairs with DXN |
| DXN (Pin 4) | Remote diode cathode interface | Sinks matching current from external PNP; requires 2200pF capacitor to DXP for noise filtering |
| THIGH (Pin 5) | Upper-temperature alarm output | Open-drain, active-low - asserts when remote junction exceeds +125°C; needs external pull-up |
| TLOW (Pin 6) | Lower-temperature alarm output | Open-drain, active-low - asserts when remote junction exceeds programmed lower threshold |
| S1 (Pin 7) | Lower threshold select input | Logic input (GND/VDD/floating) - sets lower trip point with S2 per Table 1; must be stable before power-up |
| S2 (Pin 8) | Lower threshold select input | Logic input (GND/VDD/floating) - used with S1 to select +40°C to +80°C range in 5°C steps |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent temperature alarms | Simultaneous +125°C critical shutdown (THIGH) and user-configurable warning (TLOW) enable layered thermal management |
| Pin-programmable lower threshold | S1/S2 pins select exact +40°C, +45°C, ..., +80°C trip points - eliminates firmware dependency for hardware-based alerts |
| Remote junction sensing architecture | Uses external PNP transistor (e.g., 2N3904) as sensing element - measures actual IC die temperature, not board ambient |
| Integrated noise rejection | Oversampling + 2200pF DXP/DXN filter capacitor suppresses EMI from nearby switching regulators and high-speed traces |
| Low quiescent power | 200µA average supply current allows continuous monitoring in battery-backed or energy-constrained subsystems |
Applications
| CPU Thermal Protection | FPGA Junction Monitoring |
|---|---|
|
Use Scenario: Real-time monitoring of microprocessor die temperature during high-load operation. IC Role / Device Role / Timing Role: Remote-junction temperature switch providing hardware-level overtemperature shutdown signal to CPU reset controller. Use Value: Prevents thermal runaway by asserting THIGH at precisely +125°C, independent of system software responsiveness. |
Use Scenario: Detecting unsafe junction temperatures in high-density FPGA packages during configuration and compute-intensive tasks. IC Role / Device Role / Timing Role: Dual-threshold alarm generator triggering fan speed ramp-up (TLOW) and hard reset (THIGH) based on measured die temperature. Use Value: Enables staged thermal response: +65°C warning (TLOW) initiates cooling; +125°C (THIGH) forces immediate safe shutdown. |
| Multichip Module (MCM) Thermal Control | Industrial Embedded Controller Protection |
|
Use Scenario: Monitoring thermal coupling between stacked ASICs or memory dies in compact MCM assemblies. IC Role / Device Role / Timing Role: Remote-sensing switch interfacing with discrete PNP transistors placed adjacent to each die for localized temperature feedback. Use Value: Achieves ±1.5°C accuracy across -40°C to +125°C, ensuring consistent trip behavior despite inter-die thermal gradients. |
Use Scenario: Protecting programmable logic controllers (PLCs) operating in unventilated enclosures with wide ambient swings. IC Role / Device Role / Timing Role: Standalone hardware thermal supervisor that remains functional even if host MCU fails or hangs. Use Value: Open-drain outputs allow direct connection to existing watchdog or power-control circuits without level translation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output remote-junction temperature switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6685AU40H | TLOW is CMOS push-pull, active-high; same upper/lower thresholds and accuracy | Requires active-high logic interface for lower-alarm signaling; incompatible with wired-OR alarm buses | Select MAX6685AU40H only when system design mandates active-high TLOW and no shared alarm lines |
| LM95235CIMMX/NOPB | Serial SMBus output (not dual digital outputs); ±1.0°C accuracy; includes diode fault detection | Provides full temperature readback and diagnostics, but lacks hardware-triggered dual alarms | Choose LM95235CIMMX/NOPB when digital temperature telemetry and fault logging are prioritized over autonomous hardware shutdown |
Compared with MAX6685AU40H and LM95235CIMMX/NOPB, the MAX6686AU40H uniquely delivers two independent, open-drain, active-low hardware alarms - enabling fail-safe thermal response without processor involvement or communication overhead.
Availability
MAX6686AU40H is available at Aetrix Electronics and suitable for CPU thermal protection, FPGA junction monitoring, multichip module thermal control, and industrial embedded controller protection requiring stable component supply across extended temperature ranges.
Supply support for MAX6686AU40H 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 and mixed-signal ICs for demanding industrial, computing, and communications applications.
The MAX6685/MAX6686 product line delivers hardware-based thermal supervision for semiconductor die temperature monitoring, targeting systems where deterministic, low-latency overtemperature response is critical.
FAQ
What is the exact upper temperature trip threshold for MAX6686AU40H?
The MAX6686AU40H has a factory-programmed upper trip threshold of +125°C. This value is fixed and non-adjustable. THIGH asserts low when the remote-sensing junction temperature exceeds +125°C, with 5°C hysteresis ensuring clean deassertion at +120°C. This specification is guaranteed across the full -40°C to +125°C ambient operating range.
How do I configure the lower temperature trip point on MAX6686AU40H?
The lower trip point of MAX6686AU40H is set using S1 and S2 pins, which must be connected to GND, VDD, or left floating *before* applying power to VDD. For the +40°C to +80°C range, combinations include S1=GND/S2=GND (+40°C), S1=GND/S2=FLOAT (+45°C), up to S1=VDD/S2=VDD (+80°C). Configuration after power-up is ignored.
Can MAX6686AU40H monitor temperature without a microcontroller?
Yes, MAX6686AU40H operates autonomously without firmware. It uses an external diode-connected PNP transistor (e.g., 2N3904) as the sensing element and generates two independent hardware alarm signals - THIGH and TLOW - that directly drive reset controllers, fan drivers, or shutdown logic. No serial interface or host intervention is required.
What external components are mandatory for reliable operation of MAX6686AU40H?
Three external components are mandatory: (1) a 0.1µF ceramic capacitor from VDD to GND for power-supply decoupling; (2) a 2200pF ceramic capacitor across DXP and DXN to filter noise and ensure ±1.5°C accuracy; and (3) pull-up resistors (typically 10kΩ) on THIGH and TLOW to the desired logic rail (≤5.5V). DXN must also connect to GND with the shortest possible trace.
Is MAX6686AU40H compatible with discrete diodes as the temperature sensor?
No, MAX6686AU40H requires a diode-connected transistor - specifically a PNP with grounded collector (e.g., 2N3904 base-to-collector shorted) - not a standard PN junction diode. Discrete diodes exhibit inconsistent VBE characteristics and fail to meet the ±1.5°C accuracy specification. The device's current source and sensing architecture are optimized for transistor-based remote junctions.
MAX6686AU40H Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Trip Temperature Threshold:
- Cold, Hot
- Switching Temperature:
- 40°C
- Accuracy:
- ±1.5°C
- Current - Output (Max):
- 20mA
- Output Type:
- Open Drain
- Output:
- Active Low
- Output Function:
- /OverTemp
- Selectable Hysteresis:
- No
- Features:
- Selectable Trip Point
- Voltage - Supply:
- 3 V ~ 5.5 V
- Current - Supply:
- 200µA
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-µMAX
MAX6686AU40H FAQ
1.How can I place an order for MAX6686AU40H through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6686AU40H 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 MAX6686AU40H reliable?
The price and inventory of MAX6686AU40H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6686AU40H is usually 5 days.
3.What payment methods are accepted for MAX6686AU40H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6686AU40H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6686AU40H?
MAX6686AU40H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6686AU40H 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 MAX6686AU40H?
For technical support, including MAX6686AU40H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6686AU40H requirements.
6.How does Aetrix verify that MAX6686AU40H is sourced from the original manufacturer or authorized distributors?
All MAX6686AU40H 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 MAX6686AU40H meets industry standards.
7.What is the process for return or replacement of MAX6686AU40H?
All MAX6686AU40H units undergo pre-shipment inspection (PSI). If there is an issue with MAX6686AU40H, 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 MAX6686AU40H part is unused and in its original packaging.
Return procedure for MAX6686AU40H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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