SLAS748G March 2011 – January 2024 DAC3482
PRODUCTION DATA
The DAC3482 incorporates a temperature sensor block which monitors the temperature by measuring the voltage across two transistors. The voltage is converted to an 8-bit digital word using a successive-approximation (SAR) analog to digital conversion process. The result is scaled, limited and formatted as a 2s-complement value representing the temperature in degrees Celsius.
The sampling is controlled by the serial interface signals SDENB and SCLK. If the temperature sensor is enabled (tsense_sleep = 0b in register config26) a conversion takes place each time the serial port is written or read. The data is only read and sent out by the digital block when the temperature sensor is read in tempdata(7:0) in config6. The conversion uses the first eight clocks of the serial clock as the capture and conversion clock, the data is valid on the falling eighth SCLK. The data is then clocked out of the chip on the rising edge of the ninth SCLK. No other clocks to the chip are necessary for the temperature sensor operation. As a result the temperature sensor is enabled even when the device is in sleep mode.
For the process described above to operate properly, the serial port read from config6 must be done with an SCLK period of at least 1μs. If this is not satisfied, the temperature sensor accuracy is greatly reduced.