L9803 STMicroelectronics, L9803 Datasheet - Page 71

• Manufacturer Part Number: L9803
• Description: Super Smart Power Motor Driver With 8-bit Mcu, Ram, Eeprom, Adc, Wdg, Timers, Pwm And H-bridge Driver
• Manufacturer: STMicroelectronics

L9803
5.5.6
The sensor generates a voltage proportional to the absolute temperature of the die. It works
over the whole temperature range, with a minimum resolution of 1LSB/°K (5mV/°K)
(Figure 36
Note The voltage output of the sensor is only related to the absolute temperature of the
silicon junctions. Junction temperature and ambient temperature must be related taking in
account the power dissipated by the device and the thermal resistance Rth
silicon and the environment around the application board.
Figure 36. Temperature Sensor output
The output of the sensor is not ratiometric with the voltage reference for the ADC conversion
(VCC). When calculating the ADC reading error of this signal the variation of VCC must be
accounted. Additional errors are due to the intrinsic spread of the sensor characteristic.
Precise Temperature Measurement
To allow a more precise measurement of the temperature a trimming procedure can be
adopted (on request).
The temperature is measured in EWS and two values are stored in four EEPROM bytes
(see memory map):
T0L,T0H: temperature of the trimming measurement (in Kelvin).
VT0L,VT0H: output value of the ADC corresponding to T0 (in number of LSBs).
The corrected measurement of the temperature in Kelvin must be accomplished in the
following way:
where VTEMP is the output code in LSB of the ADC corresponding to the measurement.
Example:
If the value stored in EEPROM are:
0C7Ch: 01h ->T0H
0C7Dh: 43h ->T0L
0C7Eh: 01h -> VT0H
0C7Fh: 5Ch -> VT0L
shows the indicative voltage output of the sensor).
2.5
2.2
1.9
1.6
1.3
1.0
223
V
TEMP
TEMP (in °K) = VTEMP * T0 / VT0
273
323
373
Temperature (°K)
423
max
min
473
On-Chip Peripherals
je
between the
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