
MC68HC05B6
Rev. 4.1
Freescale
I-3
HIGH SPEED OPERATION
15
I.2
A/D converter characteristics
Table I-3 A/D characteristics for 5V operation
(VDD = 5.0 Vdc ± 10%, VSS = 0 Vdc, TA = –40 to +85°C)
Characteristic
Parameter
Min
Max
Unit
Resolution
Number of bits resolved by the A/D
8
—
Bit
Non-linearity
Max deviation from the best straight line through
the A/D transfer characteristics
(VRH = VDD and VRL = 0V)
—
± 0.5
LSB
Quantization error Uncertainty due to converter resolution
—
± 0.5
LSB
Absolute accuracy
Difference between the actual input voltage and
the full-scale equivalent of the binary code
output code for all errors
—
± 1LSB
Conversion range Analog input voltage range
VRL
VRH
V
VRH
Maximum analog reference voltage
VRL
VDD + 0.1
V
VRL
Minimum analog reference voltage
VSS – 0.1
VRH
V
VR(1)
(1) Performance verified down to 2.5V VR, but accuracy is tested and guaranteed at VR = 5V±10%.
Minimum difference between VRH and VRL
3—
V
Conversion time
Total time to perform a single analog to digital
conversion
a. External clock (OSC1, OSC2)
b. Internal RC oscillator
—
32
tCYC
s
Monotonicity
Conversion result never decreases with an
increase in input voltage and has no missing
codes
GUARANTEED
Zero input reading Conversion result when VIN = VRL
00
—
Hex
Full scale reading
Conversion result when VIN = VRH
—FF
Hex
Sample acquisition
time
Analog input acquisition sampling
a. External clock (OSC1, OSC2)
b. Internal RC oscillator(2)
(2) Source impedances greater than 10k will adversely affect internal charging time during input sampling.
—
12
tCYC
s
Sample/hold
capacitance
Input capacitance on PD0/AN0–PD7/AN7
—
12
pF
Input leakage(3)
(3) The external system error 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
Input leakage on A/D pins PD0/AN0–PD7/AN7
VRL, VRH
—
1
A