r5s72060w200fpv Renesas Electronics Corporation., r5s72060w200fpv Datasheet - Page 876

• Manufacturer Part Number: r5s72060w200fpv
• Description: 32-bit Risc Microcomputer Superhtm Risc Engine Family / Sh7200 Series
• Manufacturer: Renesas Electronics Corporation.

Section 17 A/D Converter (ADC)
Table 17.7 Analog Input Pin Ratings
17.7.5
This LSI's analog input is designed such that conversion precision is guaranteed for an input signal
for which the signal source impedance is 5 kΩ or less. This specification is provided to enable the
A/D converter's sample-and-hold circuit input capacitance to be charged within the sampling time;
if the sensor output impedance exceeds 5 kΩ, charging may be insufficient and it may not be
possible to guarantee A/D conversion precision. However, for A/D conversion in single mode with
a large capacitance provided externally for A/D conversion in single mode, the input load will
essentially comprise only the internal input resistance of 3 kΩ, and the signal source impedance is
ignored. However, as a low-pass filter effect is obtained in this case, it may not be possible to
follow an analog signal with a large differential coefficient (e.g., 5 mV/µs or greater) (see
figure 17.10). When converting a high-speed analog signal, a low-impedance buffer should be
inserted.
Rev. 2.00 Dec. 09, 2005 Page 852 of 1152
REJ09B0191-0200
Item
Analog input capacitance
Allowable signal-source impedance
Permissible Signal Source Impedance
AN0 to AN7
Note: Values are reference values.
Figure 17.9 Analog Input Pin Equivalent Circuit
3 kΩ
Min.


20 pF
To A/D converter
Max.
20
5
Unit
pF
kΩ