Universal Thermocouple Amplifier MAX31856 Breakout

SPI thermocouple amplifier breakout supporting B, E, J, K, N, R, S, and T thermocouple types via the MAX31856, with cold-junction compensation and configurable fault/alert outputs. Upgrade over the K-only MAX31855.

Logical pinout · physical placement not verified

Vin
Power input for the breakout. Adafruit Learn says the onboard regulator accepts 3-5VDC and to power it at the microcontroller logic level.
Type · PowerVoltage · 3-5VDC input, same as logic level on Vin
3Vo
3.3V regulator output available from the breakout.
Type · PowerVoltage · 3.3V output, up to 100mA per Adafruit Learn
GND
Common ground for power and logic.
Type · GroundVoltage · 0V
SCK
SPI clock input to the MAX31856 breakout.
Type · SPIVoltage · 3-5V logic safe, use the logic level on Vin
SDO
SPI data out from the MAX31856 to the microcontroller, MISO.
Type · SignalVoltage · 3-5V logic safe, use the logic level on Vin
SDI
SPI data in to the MAX31856 from the microcontroller, MOSI.
Type · SignalVoltage · 3-5V logic safe, use the logic level on Vin
CS
SPI chip select input, driven low to start an SPI transaction.
Type · SPIVoltage · 3-5V logic safe, use the logic level on Vin
FLT
Fault output. Adafruit Learn says it goes low when there is a MAX31856 fault.
Type · Signal
DRDY
Data-ready output for advanced use, goes low after a requested reading is ready.
Type · Signal

Pin	Type	Function	Voltage
Vin	Power	Power input for the breakout. Adafruit Learn says the onboard regulator accepts 3-5VDC and to power it at the microcontroller logic level.	3-5VDC input, same as logic level on Vin
3Vo	Power	3.3V regulator output available from the breakout.	3.3V output, up to 100mA per Adafruit Learn
GND	Ground	Common ground for power and logic.	0V
SCK	SPI	SPI clock input to the MAX31856 breakout.	3-5V logic safe, use the logic level on Vin
SDO	Signal	SPI data out from the MAX31856 to the microcontroller, MISO.	3-5V logic safe, use the logic level on Vin
SDI	Signal	SPI data in to the MAX31856 from the microcontroller, MOSI.	3-5V logic safe, use the logic level on Vin
CS	SPI	SPI chip select input, driven low to start an SPI transaction.	3-5V logic safe, use the logic level on Vin
FLT	Signal	Fault output. Adafruit Learn says it goes low when there is a MAX31856 fault.
DRDY	Signal	Data-ready output for advanced use, goes low after a requested reading is ready.

Logical pinout · physical placement not verified

Pin details

9 connections

Vin
Power input for the breakout. Adafruit Learn says the onboard regulator accepts 3-5VDC and to power it at the microcontroller logic level.
PowerVoltage · 3-5VDC input, same as logic level on Vin
3Vo
3.3V regulator output available from the breakout.
PowerVoltage · 3.3V output, up to 100mA per Adafruit Learn
GND
Common ground for power and logic.
GroundVoltage · 0V
SCK
SPI clock input to the MAX31856 breakout.
SPIVoltage · 3-5V logic safe, use the logic level on Vin
SDO
SPI data out from the MAX31856 to the microcontroller, MISO.
SignalVoltage · 3-5V logic safe, use the logic level on Vin
SDI
SPI data in to the MAX31856 from the microcontroller, MOSI.
SignalVoltage · 3-5V logic safe, use the logic level on Vin
CS
SPI chip select input, driven low to start an SPI transaction.
SPIVoltage · 3-5V logic safe, use the logic level on Vin
FLT
Fault output. Adafruit Learn says it goes low when there is a MAX31856 fault.
Signal
DRDY
Data-ready output for advanced use, goes low after a requested reading is ready.
Signal

Start wiring

I2C · SPI · Single data line · 3.3 – 5 V · Breakout

Verify supply voltage and logic levels before powering up.

Module pins: Vin, 3Vo, GND, SCK, SDO, SDI, CS, FLT. Schematik maps them to your board in the app.

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