tmp88fw45afg TOSHIBA Semiconductor CORPORATION, tmp88fw45afg Datasheet - Page 233

• Manufacturer Part Number: tmp88fw45afg
• Description: 8 Bit Microcontroller Tlcs-870/x Series
• Manufacturer: TOSHIBA Semiconductor CORPORATION

18.6
18.6.1
18.6.2
18.6.3
Figure 18-5 Analog Input Equivalent Circuit and Example of Input Pin Processing
Precautions about AD Converter
outside this range is applied to one of the analog input pins, the converted value on that pin becomes uncertain.
The other analog input pins also are affected by that.
inputs to execute AD conversion, do not execute input/output instructions for all other ports. This is necessary
to prevent the accuracy of AD conversion from degrading. Not only these analog input shared pins, some other
pins may also be affected by noise arising from input/output to and from adjacent pins.
of the analog input source, more easily they are susceptible to noise. Therefore, make sure the output impedance
of the signal source in your design is 5 kΩ or less. Toshiba also recommends attaching a capacitor external to the
chip.
Make sure the analog input pins (AIN0 to AIN15) are used at voltages within VAREF to AVSS. If any voltage
The analog input pins (AIN0 to AIN15) are shared with input/output ports. When using any of the analog
The internal equivalent circuit of the analog input pins is shown in Figure 18-5. The higher the output impedance
Permissible signal
source impedance
5 kΩ (max)
Analog input pin voltage range
Analog input shared pins
Noise Countermeasure
Note) i = 15 to 0
AINi
Internal resistance
Internal capacitance
5 kΩ (typ)
Page 219
C = 12 pF (typ.)
Analog comparator
DA converter
TMP88FW45AFG