MC68HC05B6
Rev. 4
MOTOROLA
I-3
HIGH SPEED OPERATION
15
I.2
A/D converter characteristics
(1) Performance verified down to 2.5V
VR, but accuracy is tested and guaranteed at
VR = 5V
±
10%.
(2) Source impedances greater than 10k
will adversely affect internal charging time during input sampling.
(3) The external systemerror caused by input leakage current is approximately equal to the product of R
source and input current. Input current to A/D channel will be dependent on external source impedance
(see Figure 8-2).
Table I-3
A/D characteristics for 5V operation
(V
DD
= 5.0 Vdc
±
10%, V
SS
= 0 Vdc, T
A
= –40 to +85
°
C)
Characteristic
Resolution
Number of bits resolved by the A/D
Max deviation fromthe best straight line through
the A/D transfer characteristics
(V
RH
= V
DD
and V
RL
= 0V)
Quantization error
Uncertainty due to converter resolution
Difference between the actual input voltage and
the full-scale equivalent of the binary code
output code for all errors
Conversion range
Analog input voltage range
V
RH
Maximumanalog reference voltage
V
RL
Mnimumanalog reference voltage
V
R(1)
Mnimumdifference between V
RH
and V
RL
Total time to performa single analog to digital
conversion
a. External clock (OSC1, OSC2)
b. Internal RC oscillator
Conversion result never decreases with an
increase in input voltage and has no mssing
codes
Zero input reading
Conversion result when V
IN
= V
RL
Full scale reading
Conversion result when V
IN
= V
RH
Analog input acquisition sampling
a. External clock (OSC1, OSC2)
b. Internal RC oscillator
(2)
Sample/hold
capacitance
Input leakage on A/D pins PD0/AN0–PD7/AN7
VRL, VRH
Parameter
Mn
8
Max
—
Unit
Bit
Non-linearity
—
±
0.5
LSB
—
±
0.5
LSB
Absolute accuracy
—
±
1
LSB
V
RL
V
RL
V
RH
V
V
V
V
V
DD
+ 0.1
V
RH
—
V
SS
– 0.1
3
Conversion time
—
—
32
32
t
CYC
μ
s
Monotonicity
GUARANTEED
00
—
—
FF
Hex
Hex
Sample acquisition
time
—
—
12
12
t
CYC
μ
s
Input capacitance on PD0/AN0–PD7/AN7
—
12
pF
Input leakage
(3)
—
—
1
1
μ
A
μ
A
TPG