
C164CI/SI
C164CL/SL
Data Sheet
55
V2.0, 2001-05
A/D Converter Characteristics
(Operating Conditions apply)
Table 13
A/D Converter Characteristics
Parameter
Symbol
Limit Values
Unit Test
Conditions
min.
max.
Analog reference supply
VAREF SR 4.0
VDD + 0.1 V
1)
1) TUE is tested at V
AREF =5.0 V, VAGND =0 V, VDD = 4.9 V. It is guaranteed by design for all other voltages
within the defined voltage range.
If the analog reference supply voltage exceeds the power supply voltage by up to 0.2 V
(i.e.
VAREF = VDD = +0.2 V) the maximum TUE is increased to ±3 LSB. This range is not 100% tested.
The specified TUE is guaranteed only if the absolute sum of input overload currents on Port 5 pins (see
IOV
specification) does not exceed 10 mA.
During the reset calibration sequence the maximum TUE may be
±4 LSB.
Analog reference ground
VAGNDSR VSS - 0.1 VSS + 0.2 V
–
Analog input voltage range
VAIN SR VAGND
VAREF
V
2)
2) V
AIN may exceed VAGND or VAREF up to the absolute maximum ratings. However, the conversion result in
these cases will be X000H or X3FFH, respectively.
Basic clock frequency
fBC
0.5
6.25
MHz 3)
3) The limit values for f
BC must not be exceeded when selecting the CPU frequency and the ADCTC setting.
Conversion time
tC
CC –
40
tBC +
tS + 2tCPU
–
4)
tCPU = 1 / fCPU
4) This parameter includes the sample time t
S, the time for determining the digital result and the time to load the
result register with the conversion result.
Values for the basic clock
tBC depend on programming and can be taken from Table 14. This parameter depends on the ADC control logic. It is not a real maximum value, but rather a fixum.
Calibration time after reset
tCAL CC –
3328
tBC
–
5)
5) During the reset calibration conversions can be executed (with the current accuracy). The time required for
these conversions is added to the total reset calibration time.
Total unadjusted error
TUE
CC –
Internal resistance of
reference voltage source
RAREF SR –
tBC / 60
- 0.25
k
tBC in [ns]
6)7)
6) During the conversion the ADC’s capacitance must be repeatedly charged or discharged. The internal
resistance of the reference voltage source must allow the capacitance to reach its respective voltage level
within each conversion step. The maximum internal resistance results from the programmed conversion
timing.
7) Not 100% tested, guaranteed by design and characterization.
Internal resistance of analog
source
RASRC SR –
tS / 450
- 0.25
k
tS in [ns]
ADC input capacitance
CAIN CC –
33
pF