C8051F02X Datasheet, PDF (94/272 Pages) Silicon Laboratories – 8K ISP FLASH MCU Family

C8051F020/1/2/3
The temperature sensor connects to the highest order input of the ADC0 input multiplexer (see Section “5.1. Analog
Multiplexer and PGA” on page 43 for C8051F020/1 devices, or Section “6.1. Analog Multiplexer and PGA” on
page 59 for C8051F022/3 devices). The TEMPE bit within REF0CN enables and disables the temperature sensor.
While disabled, the temperature sensor defaults to a high impedance state and any A/D measurements performed on
the sensor while disabled result in undefined data.
Figure 10.2. REF0CN: Reference Control Register
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
-
-
-
AD0VRS AD1VRS TEMPE BIASE REFBE 00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0 SFR Address:
0xD1
Bits7-5:
Bit4:
Bit3:
Bit2:
Bit1:
Bit0:
UNUSED. Read = 000b; Write = don’t care.
AD0VRS: ADC0 Voltage Reference Select
0: ADC0 voltage reference from VREFA pin.
1: ADC0 voltage reference from DAC0 output.
AD1VRS: ADC1 Voltage Reference Select
0: ADC1 voltage reference from VREFA pin.
1: ADC1 voltage reference from AV+.
TEMPE: Temperature Sensor Enable Bit.
0: Internal Temperature Sensor Off.
1: Internal Temperature Sensor On.
BIASE: ADC/DAC Bias Generator Enable Bit. (Must be ‘1’ if using ADC or DAC).
0: Internal Bias Generator Off.
1: Internal Bias Generator On.
REFBE: Internal Reference Buffer Enable Bit.
0: Internal Reference Buffer Off.
1: Internal Reference Buffer On. Internal voltage reference is driven on the VREF pin.
Table 10.1. Voltage Reference Electrical Characteristics
VDD = 3.0 V, AV+ = 3.0 V, -40°C to +85°C unless otherwise specified
PARAMETER
CONDITIONS
INTERNAL REFERENCE (REFBE = 1)
Output Voltage
25°C ambient
VREF Short-Circuit Current
VREF Temperature Coefficient
Load Regulation
Load = 0 to 200 µA to AGND
VREF Turn-on Time 1
4.7µF tantalum, 0.1µF ceramic bypass
VREF Turn-on Time 2
0.1µF ceramic bypass
VREF Turn-on Time 3
no bypass cap
EXTERNAL REFERENCE (REFBE = 0)
Input Voltage Range
MIN
2.36
1.00
Input Current
TYP MAX UNITS
2.43 2.48
V
30
mA
15
ppm/°C
0.5
ppm/µA
2
ms
20
µs
10
µs
(AV+) - V
0.3
0
1
µA
94
Rev. 1.4