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Analog Devices Inc./Maxim Integrated MAX6675ISA
- Part No.:
- MAX6675ISA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Sensor and Detector Interfaces
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX6675ISA.pdf
- Description:
- IC CONV THERMO TO DIGITAL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,664
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Product details
Overview
MAX6675ISA from Maxim Integrated is a cold-junction-compensated K-type thermocouple-to-digital converter IC that performs analog signal conditioning, 12-bit digitization, and ambient temperature compensation. It delivers 0.25°C resolution, supports thermocouple readings up to +1024°C, and operates across -20°C to +85°C. It interfaces via SPI-compatible serial output and includes open thermocouple detection-used in industrial temperature monitoring systems requiring direct thermocouple interfacing with microcontrollers.
For engineers reviewing the MAX6675ISA datasheet, MAX6675ISA pinout, MAX6675ISA application, or MAX6675ISA equivalent, this page provides verified technical context, package mapping, real-world use scenarios, and validated alternative options for thermocouple signal chain design.
Technical Context
The MAX6675ISA integrates a precision low-noise amplifier, cold-junction sensing diode, and 12-bit ADC in a single BiCMOS die. It converts thermoelectric voltage (41 µV/°C for Type-K) into digital temperature data while compensating for ambient temperature drift between -20°C and +85°C.
Its SPI-compatible interface outputs 16-bit frames with D15–D3 containing the 12-bit temperature value (MSB-first), D2 indicating open thermocouple fault, and D1 fixed as device ID. Conversion time is 0.17–0.22 s, and it requires no external calibration components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 0.25°C - enables precise thermal control steps in HVAC and process equipment |
| Max Thermocouple Range | +1024°C - covers full operational range of standard Type-K thermocouples |
| Cold-Junction Range | -20°C to +85°C - matches industrial ambient operating envelope |
| Supply Voltage | 3.0 V to 5.5 V - compatible with common 3.3 V and 5 V logic/microcontroller rails |
| Supply Current | 0.7–1.5 mA - enables low-power operation in battery-backed or energy-constrained systems |
| Serial Clock Frequency | 4.3 MHz - supports fast polling without MCU timing overhead |
| Thermocouple Input Impedance | 60 kΩ - minimizes loading error on high-impedance thermocouple sources |
Pinout & Package
MAX6675ISA is housed in an 8-pin SO (Small Outline) package with gull-wing leads, RoHS-compliant, and rated for vapor-phase reflow at +215°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 GND | Ground reference | Common return path for analog and digital circuitry; must be low-impedance |
| 2 T- | Alumel lead input | Connects to thermocouple's negative leg; externally grounded near GND pin to enable open-circuit detection |
| 3 T+ | Chromel lead input | Connects to thermocouple's positive leg; routed away from noise sources per layout guidelines |
| 4 VCC | Positive supply | 3.0–5.5 V input; requires local 0.1 µF ceramic bypass capacitor to GND |
| 5 SCK | Serial clock input | Accepts MCU-generated clock up to 4.3 MHz; timing-critical for data capture on falling edge |
| 6 CS | Chip select | Active-low enable; forces conversion start when rising, halts conversion when falling |
| 7 SO | Serial data output | Three-state, MSB-first 16-bit frame; D14–D3 = 12-bit temp code; D2 = open-thermocouple flag |
| 8 N.C. | No connection | Not internally bonded; left unconnected on PCB |
Key Features
| Feature | Design Value |
|---|---|
| Direct Type-K thermocouple interface | Eliminates need for external signal conditioning or cold-junction sensor; reduces BOM count by ≥3 components |
| Integrated cold-junction compensation | Uses on-die temperature-sensing diode to correct for board ambient drift - no external RTD or thermistor required |
| SPI-compatible serial output | 16-bit frame format aligns with standard MCU SPI peripherals; no custom firmware drivers needed |
| Open thermocouple detection | D2 flag in output stream enables automatic fault reporting without additional diagnostic circuitry |
| Low self-heating error | BiCMOS process and thermal design limit internal heating impact on measurement accuracy under typical PCB mounting |
Applications
| Industrial Process Monitoring | HVAC System Control |
|---|---|
Use Scenario: Real-time temperature feedback loop in boiler combustion chambers and reactor vessels. IC Role / Device Role / Timing Role: Primary thermocouple digitizer providing calibrated 0.25°C-resolution data to PLC or industrial MCU. Use Value: Enables closed-loop fuel-air ratio control with ±8 LSB thermocouple accuracy over 0°C–700°C range. |
Use Scenario: Zone temperature sensing in commercial rooftop HVAC units with distributed thermostats. IC Role / Device Role / Timing Role: Local analog front-end converting Type-K signals to digital for CAN bus or RS-485 communication modules. Use Value: Reduces system-level calibration burden by embedding cold-junction compensation at the sensor node. |
| Home Appliance Safety | Lab Equipment Calibration |
Use Scenario: Overtemperature cutoff in electric ovens and induction cooktops. IC Role / Device Role / Timing Role: Fault-tolerant temperature monitor feeding safety shutdown logic in microcontroller-based appliance controllers. Use Value: Open thermocouple detection (D2 flag) prevents false "cold" readings during wire break - critical for fail-safe operation. |
Use Scenario: Reference-grade temperature acquisition in benchtop thermal calibration stations. IC Role / Device Role / Timing Role: High-fidelity thermocouple digitizer interfaced to precision DAQ systems via SPI. Use Value: 12-bit resolution and guaranteed ±9 LSB error at 5 V supply support traceable calibration against NIST standards. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar thermocouple-to-digital conversion applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD8495ARZ | Analog output (mV/°C); no integrated ADC or SPI interface; requires external ADC and cold-junction sensor | Better suited for analog signal chains with existing precision ADCs; lacks built-in digital interface | Select AD8495ARZ if system already uses high-resolution SAR ADC and needs analog flexibility; MAX6675ISA preferred for direct MCU integration. |
| MAX31855KASA+ | 14-bit resolution; supports multiple thermocouple types (K/J/N/R/S/T/E/B); higher cost; larger 16-pin SO package | Required where multi-sensor type support or extended accuracy (±2°C) is mandated | Choose MAX31855KASA+ when future-proofing for mixed thermocouple types or needing tighter absolute accuracy; MAX6675ISA offers lower cost and smaller footprint for K-only systems. |
Compared with AD8495ARZ and MAX31855KASA+, the MAX6675ISA provides the most cost-effective, space-efficient solution for dedicated Type-K applications requiring SPI output and minimal external components - balancing resolution, fault detection, and ease of integration without over-engineering.
Availability
MAX6675ISA is available at Aetrix Electronics and suitable for industrial process monitoring, HVAC system control, and home appliance safety applications requiring stable component supply and long-term production continuity.
Supply support for MAX6675ISA 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, medical, and communications applications.
The MAX6675ISA belongs to Maxim's temperature-sensing product line, engineered specifically for simplified, reliable thermocouple interfacing in cost-sensitive embedded systems without sacrificing measurement integrity.
FAQ
What is the maximum thermocouple temperature the MAX6675ISA can measure?
The MAX6675ISA supports thermocouple readings up to +1024°C, corresponding to the full-scale output code (0xFFF). This aligns with the upper limit of standard Type-K thermocouples and is explicitly specified in the datasheet's General Description and Electrical Characteristics sections. The MAX6675ISA achieves this using its internal 12-bit ADC and linearized conversion algorithm.
Does the MAX6675ISA require external cold-junction compensation components?
No, the MAX6675ISA integrates a temperature-sensing diode and compensation circuitry on-die. It autonomously measures ambient temperature at the IC package and applies correction to the thermocouple voltage before digitization. No external RTD, thermistor, or analog circuitry is needed - confirmed in the Detailed Description and Pin Description sections of the datasheet.
How does open thermocouple detection work on the MAX6675ISA?
The MAX6675ISA monitors the T– and T+ inputs and sets bit D2 high in its 16-bit serial output when an open circuit is detected. This requires T– to be externally grounded near the GND pin. The feature is implemented in hardware and does not rely on software polling - detailed in the Applications Information section under "Open Thermocouple".
What is the recommended power supply bypass for the MAX6675ISA?
A 0.1 µF ceramic capacitor must be placed between VCC and GND, located as close as possible to pins 4 and 1. This is specified in the Typical Application Circuit, Pin Description (VCC function), and Applications Information (Noise Considerations) sections to suppress supply noise that would otherwise degrade temperature measurement accuracy.
Is the MAX6675ISA pin-compatible with other Maxim thermocouple converters like the MAX31855?
No, the MAX6675ISA is not pin-compatible with the MAX31855 series. It uses an 8-pin SO package with distinct pin assignments (e.g., N.C. on pin 8, T–/T+ on pins 2/3), whereas MAX31855 variants use 16-pin SO packages with different pinouts and additional features. Direct replacement would require PCB redesign - confirmed by comparing Pin Configuration diagrams and package outlines in both datasheets.
MAX6675ISA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Thermocouple Conditioner
- Input Type:
- Logic
- Output Type:
- Logic
- Current - Supply:
- 1.5 mA
- Operating Temperature:
- -20°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX6675ISA FAQ
1.How can I place an order for MAX6675ISA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6675ISA 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 MAX6675ISA reliable?
The price and inventory of MAX6675ISA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6675ISA is usually 5 days.
3.What payment methods are accepted for MAX6675ISA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6675ISA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6675ISA?
MAX6675ISA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6675ISA 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 MAX6675ISA?
For technical support, including MAX6675ISA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6675ISA requirements.
6.How does Aetrix verify that MAX6675ISA is sourced from the original manufacturer or authorized distributors?
All MAX6675ISA 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 MAX6675ISA meets industry standards.
7.What is the process for return or replacement of MAX6675ISA?
All MAX6675ISA units undergo pre-shipment inspection (PSI). If there is an issue with MAX6675ISA, 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 MAX6675ISA part is unused and in its original packaging.
Return procedure for MAX6675ISA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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