Datasheet

Analog-to-Digital Converter Characteristics
MC68HC908QY/QT Family Data Sheet, Rev. 6
Freescale Semiconductor 161
16.14 Analog-to-Digital Converter Characteristics
Characteristic Symbol Min Max Unit Comments
Supply voltage
V
DDAD
2.7
(V
DD
min)
5.5
(V
DD
max)
V—
Input voltages
V
ADIN
V
SS
V
DD
V—
Resolution
(1 LSB)
RES 10.5 21.5 mV —
Absolute accuracy
(Total unadjusted error)
E
TUE
— ± 1.5 LSB Includes quantization
ADC internal clock
f
ADIC
0.5 1.048 MHz
t
ADIC
= 1/f
ADIC
,
tested only at 1 MHz
Conversion range
V
AIN
V
SS
V
DD
V—
Power-up time
t
ADPU
16 —
t
ADIC
cycles t
ADIC
= 1/f
ADIC
Conversion time
t
ADC
16 17
t
ADIC
cycles t
ADIC
= 1/f
ADIC
Sample time
(1)
1. Source impedances greater than 10 kΩ adversely affect internal RC charging time during input sampling.
t
ADS
5—
t
ADIC
cycles t
ADIC
= 1/f
ADIC
Zero input reading
(2)
2. Zero-input/full-scale reading requires sufficient decoupling measures for accurate conversions.
Z
ADI
00 01 Hex
V
IN
= V
SS
Full-scale reading
(3)
F
ADI
FE FF Hex
V
IN
= V
DD
Input capacitance
C
ADI
— 8 pF Not tested
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.
I
IL
—± 1 μA—
ADC supply current
V
DD
= 3 V
V
DD
= 5 V
I
ADAD
Typical = 0.45
Typical = 0.65
mA
mA
Enabled
Enabled