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MC68HC908GR8A_07 Datasheet, PDF (242/260 Pages) Freescale Semiconductor, Inc – Microcontrollers
Electrical Specifications
19.12 ADC Characteristics
Characteristic(1)
Symbol
Min
Max
Unit
Comments
Supply voltage
VDDAD
2.7
(VDD
min)
5.5
(VDD
max)
VDDAD should be tied to
V
the same potential as
VDD via separate
traces.
Input voltages
Resolution
Absolute accuracy
(VREFL = 0 V, VDDAD = VREFH = 5 V ± 10%)
ADC internal clock
VADIN
BAD
AAD
fADIC
0
VDDAD
8
8
−−
±1
0.5
1.048
V
Bits
LSB
MHz
VADIN <= VREFH
Includes quantization
tAIC = 1/fADIC, tested
only at 1 MHz
Conversion range
Power-up time
Conversion time
Sample time(2)
Zero input reading(3)
Full-scale reading(3)
Input capacitance
Input leakage(4)
Port B
RAD
tADPU
tADC
tADS
ZADI
FADI
CADI
—
VREFL
16
16
5
00
FE
—
—
VREFH
17
—
01
FF
(20) 8
±1
V
tAIC cycles
tAIC cycles
tAIC cycles
Hex
Hex
pF
μA
VREFH = VDDAD
VREFL = VSSAD
VIN = VREFL
VIN = VREFH
Not tested
1. VDD = 5.0 Vdc ± 10%, VSS = 0 Vdc, VDDAD = 5.0 Vdc ± 10%, VSSAD = 0 Vdc, VREFH = 5.0 Vdc ± 10%, VREFL = 0
2. Source impedances greater than 10 kΩ adversely affect internal RC charging time during input sampling.
3. Zero-input/full-scale reading requires sufficient decoupling measures for accurate conversions.
4. The external system error caused by input leakage current is approximately equal to the product of R source and input
current.
MC68HC908GR8A • MC68HC908GR4A Data Sheet, Rev. 5
242
Freescale Semiconductor