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Analog Devices Inc./Maxim Integrated MAX6670AUB40+T
- Part No.:
- MAX6670AUB40+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Thermostats - Solid State
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX6670AUB40+T.pdf
- Description:
- THERMOSTAT 40DEGC ACT LOW 10UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:4,189
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Product details
Overview
MAX6670AUB40+T from Maxim Integrated is a remote-junction thermal switch with integrated +12V/250mA fan driver, factory-programmed +40°C activation threshold, open-drain WARN and OT alarm outputs, and pin-selectable 4°C/8°C/12°C hysteresis. It directly controls cooling fans in automotive-grade systems (-40°C to +125°C) using an external diode-connected transistor for remote temperature sensing.
For engineers reviewing the MAX6670AUB40+T datasheet, MAX6670AUB40+T pinout, MAX6670AUB40+T application, or MAX6670AUB40+T equivalent, key selection criteria include its 110µA typical supply current, ±2.2°C max remote-junction temperature accuracy over +40°C to +75°C, +15°C WARN offset, +30°C OT shutdown offset, and 10-pin µMAX package compatibility with high-noise industrial thermal management layouts.
Technical Context
The MAX6670AUB40+T implements a dedicated analog temperature comparator with internal current source/sink for remote P-N junction sensing (e.g., 2N3904), coupled to an open-drain power MOSFET FANOUT driver capable of sinking 250mA at ≤1V saturation. Its dual alarm outputs-WARN (active-low at +15°C above trip) and OT (active-low at +30°C above trip)-provide tiered thermal response without software intervention.
Hysteresis is controlled via the HYST pin: GND = 4°C, floating = 8°C, VDD = 12°C. The FORCEON input overrides thermal control by forcing FANOUT active regardless of sensed temperature, enabling external system-level fan coordination. All logic inputs tolerate 0.2×VDD low and 0.8×VDD high thresholds across the full -40°C to +125°C operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Fan Activation Threshold | +40°C factory-programmed trip point for remote P-N junction sensing |
| FANOUT Drive Capability | +12V/250mA open-drain power MOSFET output with ≤1V VOL at full load |
| WARN Output Offset | +15°C above fan trip threshold - provides early warning before critical thermal shutdown |
| OT Output Offset | +30°C above fan trip threshold - triggers system-level thermal shutdown |
| Supply Current | 110µA typical at +3.3V - enables always-on thermal monitoring in low-power systems |
| Temperature Accuracy | ±2.2°C max error over +40°C to +75°C remote-junction range - ensures reliable trip consistency |
| Operating Voltage | +3V to +3.6V VDD - compatible with 3.3V logic rails and automotive LDOs |
| Hysteresis Options | Pin-selectable 4°C (HYST=GND), 8°C (HYST=FLOAT), or 12°C (HYST=VDD) |
Pinout & Package
MAX6670AUB40+T is housed in a 10-pin µMAX package (3.0mm × 3.0mm × 0.8mm, 0.5mm pitch), optimized for space-constrained PCB layouts near heat sources. PGND serves as dedicated power ground for the FANOUT MOSFET; DXP/DXN form a differential remote-sensing interface requiring 2200pF noise-filtering capacitor.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 PGND | Power Ground | Dedicated return path for FANOUT MOSFET current - must be routed separately from signal GND to avoid ground bounce |
| 2 FORCEON | Fan-Control Input | Active-low override: drives FANOUT ON regardless of temperature when pulled low |
| 3 DXP | Current Source Positive | Connects to anode of remote diode; requires 2200pF cap to DXN for EMI immunity |
| 4 DXN | Current Sink Negative | Connects to cathode of remote diode; internally biased to ~0.7V below DXP |
| 5 GND | Signal Ground | Reference for internal circuitry and logic inputs - separate from PGND |
| 6 VDD | Positive Supply | +3V to +3.6V input; bypass with 1µF ceramic cap placed adjacent to pin |
| 7 FANOUT | Fan-Drive Output | Open-drain power MOSFET output sinking up to 250mA - connects directly to fan cathode |
| 8 WARN | Warning Output | Active-low open-drain signal asserted when remote temp exceeds +40°C by +15°C |
| 9 HYST | Hysteresis Control | Three-level logic input selecting 4°C (GND), 8°C (float), or 12°C (VDD) hysteresis |
| 10 OT | Overtemperature Output | Active-low open-drain signal asserted when remote temp exceeds +40°C by +30°C |
Key Features
| Feature | Design Value |
|---|---|
| Integrated +12V/250mA Fan Driver | Eliminates need for external MOSFET and gate driver - reduces BOM count and layout area |
| Pin-Selectable Hysteresis | Enables precise tuning of thermal on/off cycling behavior to match system cooling dynamics and acoustic requirements |
| Dual Alarm Outputs (WARN/OT) | Provides two independent thermal severity levels - allows staged system response (e.g., log event → throttle → shutdown) |
| No Calibration Required | Factory-trimmed temperature sensor delivers ±2.2°C accuracy without end-of-line calibration steps |
| Automotive Temperature Range | Guaranteed operation from -40°C to +125°C ambient - suitable for under-hood and industrial control environments |
| Remote Diode Interface | Supports standard 2N3904/CMPT3904 transistors as sensing elements - avoids costly dedicated thermal diodes |
Applications
| Server Power Supplies | Automotive ECUs |
|---|---|
|
Use Scenario: Thermal management of 80 PLUS Platinum AC-DC power supplies in rack-mounted servers. IC Role / Device Role / Timing Role: Remote-junction thermal switch triggering +12V cooling fan when MOSFET heatsink exceeds +40°C. Use Value: Prevents thermal runaway during sustained 92% efficiency operation while maintaining <110µA quiescent current draw. |
Use Scenario: Overtemperature protection for engine control unit (ECU) microcontrollers in under-hood applications. IC Role / Device Role / Timing Role: Monitors die temperature of MCU via on-die diode and asserts OT signal to initiate safe shutdown at +70°C. Use Value: Enables fail-safe response within 4ms of exceeding +70°C (i.e., +40°C +30°C OT offset), meeting ISO 26262 ASIL-B timing constraints. |
| Industrial Network Switches | Laboratory Instrumentation |
|
Use Scenario: Fan speed control in fanless-designed managed switches deployed in unventilated cabinets. IC Role / Device Role / Timing Role: Drives 250mA blower fan only when remote diode on PHY IC reaches +40°C, with WARN alert at +55°C. Use Value: Reduces acoustic noise by 12dB(A) versus continuous fan operation while ensuring junction temperatures stay below +85°C. |
Use Scenario: Thermal safety interlock in benchtop oscilloscopes with high-speed ADCs generating localized hotspots. IC Role / Device Role / Timing Role: Senses temperature of ADC die using discrete 2N3904 and disables analog front-end when OT activates at +70°C. Use Value: Guarantees measurement integrity by preventing parametric drift caused by >+70°C silicon temperatures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar remote thermal switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6668AUA40+T | 8-pin µMAX, fixed 8°C hysteresis, no WARN/OT outputs | Lacks dual alarm signaling; suitable only for basic on/off fan control without warning hierarchy | Select when cost-sensitive designs require minimal functionality and board space permits 8-pin footprint |
| LM57BISD-40/NOPB | Adjustable threshold (−40°C to +125°C), 6-pin WSON, no integrated fan driver | Requires external MOSFET and level-shifting; supports wider temperature range but adds complexity | Select when system needs programmable trip points or operates beyond +75°C remote-junction range |
Compared with MAX6668AUA40+T, the MAX6670AUB40+T adds WARN/OT alarms and hysteresis flexibility at the cost of two extra pins; compared with LM57BISD-40/NOPB, it integrates the fan driver and eliminates external components but fixes the threshold at +40°C.
Availability
MAX6670AUB40+T is available at Aetrix Electronics and suitable for server power supplies, automotive ECUs, industrial network switches, and laboratory instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6670AUB40+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) is a U.S.-based semiconductor company specializing in precision analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.
The MAX6670AUB40+T belongs to Maxim's remote temperature switch product line, designed specifically for autonomous, software-free thermal management in space- and power-constrained systems where reliability across extreme temperatures is mandatory.
FAQ
What is the exact remote temperature sensing accuracy of the MAX6670AUB40+T over its specified operating range?
The MAX6670AUB40+T guarantees ±2.2°C maximum temperature threshold error for remote-junction measurements between +40°C and +75°C, tested across the full automotive temperature range (-40°C to +125°C ambient) at VDD = +3.3V. This accuracy is factory-trimmed and does not require field calibration. Typical error is ±1°C under the same conditions. The MAX6670AUB40+T achieves this using a matched BiCMOS current-source architecture that compensates for base-emitter voltage drift in standard diode-connected transistors like the 2N3904.
Can the MAX6670AUB40+T drive a 12V fan directly, and what are the voltage limits on the FANOUT pin?
Yes, the MAX6670AUB40+T drives +12V fans directly via its FANOUT pin, which is rated for up to +15V absolute maximum voltage and sinks 250mA with ≤1V saturation voltage at full load. The device's internal power MOSFET is designed for nominal +12V fan operation, and the PGND pin provides a dedicated low-inductance return path for fan current. Exceeding +15V on FANOUT risks permanent damage, and connecting fans rated above +12V nominal violates the device's specified operating conditions per the datasheet Absolute Maximum Ratings table.
How does the HYST pin configuration affect thermal control behavior in the MAX6670AUB40+T?
The HYST pin on the MAX6670AUB40+T selects hysteresis values of 4°C (HYST = GND), 8°C (HYST = floating), or 12°C (HYST = VDD). This determines the temperature delta between fan turn-on (+40°C) and turn-off (+40°C − hysteresis), preventing rapid cycling near the trip point. For example, with HYST = VDD, the fan turns off at +28°C after turning on at +40°C. The hysteresis is implemented in the internal comparator and affects only the FANOUT output - WARN and OT thresholds remain fixed at +55°C and +70°C respectively, independent of HYST state.
What is the function of the FORCEON input on the MAX6670AUB40+T, and how is it used in system design?
The FORCEON input on the MAX6670AUB40+T is an active-low control signal that forces the FANOUT driver ON regardless of remote temperature, overriding the internal thermal comparator. When FORCEON is pulled low (≤0.2×VDD), the fan activates immediately - useful for system-initiated cooling during high-CPU-load states or diagnostic modes. In normal operation, FORCEON is held high (≥0.8×VDD) to enable autonomous thermal control. The input draws only 1µA bias current, minimizing impact on host controller GPIO drive requirements.
Does the MAX6670AUB40+T require external components for stable operation, and if so, which ones are mandatory?
Yes, the MAX6670AUB40+T requires three mandatory external components: a 1µF ceramic bypass capacitor between VDD and GND (placed adjacent to the pin), a 2200pF capacitor between DXP and DXN for remote-sensing noise filtering, and a diode-connected transistor (e.g., 2N3904) connected between DXP (anode) and DXN (cathode). The datasheet explicitly warns against omitting the DXP–DXN capacitor in noisy environments, as its absence can introduce >+30°C measurement error due to EMI coupling on the sensing lines.
MAX6670AUB40+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Trip Temperature Threshold:
- Hot
- Switching Temperature:
- 40°C
- Accuracy:
- ±2.2°C
- Current - Output (Max):
- 250mA
- Output Type:
- Open Drain
- Output:
- Active Low
- Output Function:
- /FanOut, /OverTemp, /Warn
- Selectable Hysteresis:
- Yes
- 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:
- 10-uMAX/uSOP
MAX6670AUB40+T FAQ
1.How can I place an order for MAX6670AUB40+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6670AUB40+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 MAX6670AUB40+T reliable?
The price and inventory of MAX6670AUB40+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6670AUB40+T is usually 5 days.
3.What payment methods are accepted for MAX6670AUB40+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6670AUB40+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6670AUB40+T?
MAX6670AUB40+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6670AUB40+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 MAX6670AUB40+T?
For technical support, including MAX6670AUB40+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6670AUB40+T requirements.
6.How does Aetrix verify that MAX6670AUB40+T is sourced from the original manufacturer or authorized distributors?
All MAX6670AUB40+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 MAX6670AUB40+T meets industry standards.
7.What is the process for return or replacement of MAX6670AUB40+T?
All MAX6670AUB40+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6670AUB40+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 MAX6670AUB40+T part is unused and in its original packaging.
Return procedure for MAX6670AUB40+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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