74.7.12 Temperature Sensor and Voltage Reference Characteristics

The temperature sensor provides two output voltages that can be converted by the internal 12-bit ADC:
  • VTEMP: proportional to the junction temperature (TJ), and
  • VBG: temperature-independent voltage.

Both voltages are multiplexed to ADC channel 31. The selection of VTEMP or VBG is done with the ADC_ACR.SRCLCH bit. Calibration data for the temperature sensor are factory-programmed in one OTP controller packet. These calibration data can only be read and used after writing a “Boot Configuration Packet” in the OTP memory. Refer to the application note “SAMA7G5 Series Temperature Sensor Calibration” (AN4530), available on microchip.com.

Table 74-60. Temperature Sensor Characteristics
Symbol Parameter Conditions Min Max Unit
VDDIN33 Supply voltage range (VDDIN33)(1) 3.0 3.6 V
IVDDIN33 Current consumption(2) 200 µA
tSTART Start-up time(3) 20 μs
VTEMP Temperature output voltage TJ = 25°C 0.59 0.67 V
dVTEMP/dT VTEMP sensitivity to temperature(2) 2.08 mV/°C
TACC Temperature reading accuracy(2)(3) Over the applicable TJ range ±5 °C
VBG0 VBG reference output voltage TJ = 27°C 1.19 1.21 V
ΔVBG VBG drift with temperature(2)

ΔVBG = VBG(TJ)-VBG0

-20 20 mV
tTH

VTEMP or VBG track-and-hold time(2)

Required track-and-hold time to ensure 1 LSB accurate settling on internal 12-bit ADC 1 µs
Note:
  1. The temperature sensor is powered by the VDDOUT25 regulator, which is supplied from VDDIN33.
  2. Simulation data
  3. Using the temperature sensor calibration procedure described in the application note “SAMA7G5 Series Temperature Sensor Calibration” (AN4530), available on microchip.com.