UPD78F9234MC-5A4-A Datasheet, PDF (166/419 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 10 A/D CONVERTER
Table 10-1. Sampling Time and A/D Conversion Time
Reference
Voltage
Range^{Note 1}
Sampling
Time^{Note 2}
AVREF ≥ 4.5 V 12/fXP
AVREF ≥ 4.0 V 24/fXP
AVREF ≥ 2.85 V 96/fXP
48/fXP
48/fXP
24/fXP
Conversion
Time^{Note 3}
36/fXP
72/fXP
144/fXP
96/fXP
72/fXP
48/fXP
fXP = 8 MHz
Sampling
Time^{Note 2}
Conversion
Time^{Note 3}
1.5 μs
4.5 μs
3.0 μs
9.0 μs
12.0 μs
18.0 μs
6.0 μs
12.0 μs
6.0 μs
9.0 μs
3.0 μs
6.0 μs
fXP = 10 MHz
Sampling
Time^{Note 2}
Conversion
Time^{Note 3}
1.2 μs
3.6 μs
2.4 μs
7.2 μs
9.6 μs
14.4 μs
4.8 μs
9.6 μs
4.8 μs
7.2 μs
Setting
Setting
prohibited prohibited
Note 4
Note 4
FR2
0
1
1
1
0
0
FR1
0
0
1
0
1
0
FR0
0
0
0
1
0
1
AVREF ≥ 2.7 V
176/fXP
88/fXP
224/fXP
112/fXP
22.0 μs
11.0 μs
28.0 μs
14.0 μs
(2.4 μs)
17.6 μs
Setting
prohibited
Note 4
(4.8 μs)
22.4 μs
Setting
prohibited
Note 4
1
1
1
0
1
1
(8.8 μs)
(11.2 μs)
Notes 1.
2.
3.
4.
Be sure to set the FR2, FR1, and FR0, in accordance with the reference voltage so that Notes 2 and 3
below are satisfied.
Example When AVREF ≥ 2.7 V, fXP = 8 MHz
• The sampling time is 11.0 μs or more and the A/D conversion time is 14.0 μs or more and 100 μs or
less.
• Set FR2, FR1, and FR0 = 0, 1, 1 or 1, 1, 1.
Set the sampling time as follows.
• AVREF ≥ 4.5 V: 1.0 μs or more
• AVREF ≥ 4.0 V: 2.4 μs or more
• AVREF ≥ 2.85 V: 3.0 μs or more
• AVREF ≥ 2.7 V: 11.0 μs or more
Set the A/D conversion time as follows.
• AVREF ≥ 4.5 V: 3.0 μs or more and less than 100 μs
• AVREF ≥ 4.0 V: 4.8 μs or more and less than 100 μs
• AVREF ≥ 2.85 V: 6.0 μs or more and less than 100 μs
• AVREF ≥ 2.7 V: 14.0 μs or more and less than 100 μs
Setting is prohibited because the values do not satisfy the condition of Notes 2 or 3.
Caution The above sampling time and conversion time do not include the clock frequency error. Select the
sampling time and conversion time such that Notes 2 and 3 above are satisfied, while taking the
clock frequency error into consideration (an error margin maximum of ±5% when using the high-
speed internal oscillator).
Remarks 1. fXP: Oscillation frequency of clock to peripheral hardware
2. The conversion time refers to the total of the sampling time and the time from successively comparing
with the sampling value until the conversion result is output.
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User’s Manual U17446EJ5V0UD